This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for A Study of Insulin Efsitora Alfa (LY3209590) Compared to Glargine in Adult Participants With Type 2 Diabetes Who Are Starting Basal Insulin for the First Time (QWINT-1) (NCT05662332), a randomized phase 3 study. The primary outcome is Change From Baseline in Hemoglobin A1c (HbA1c) [Noninferiority Analysis].
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT05662332 |
| Phase | Phase 3 |
| Condition | Type 2 Diabetes, T2D |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 795 |
| Arms in the primary outcome | 2 |
| Lead sponsor | Eli Lilly and Company |
| Results posted | Yes |
2. Clinical Question
Population
Adults with type 2 diabetes who were starting basal insulin therapy for the first time. The primary analysis population included randomized participants who received at least one dose and had an HbA1c measurement at baseline or Week 52, with participants discontinuing treatment because of inadvertent enrollment excluded. Measurements were included regardless of study-treatment use or rescue medication.
Intervention
Insulin efsitora alfa, administered subcutaneously once weekly for 52 weeks. The registry describes fixed-dose titration steps of 100 U, 150 U, 250 U, and 400 U.
Comparator
Insulin glargine, administered subcutaneously once daily for 52 weeks, with titration by standard sliding-scale dose adjustments.
Primary question
How did HbA1c change from baseline to Week 52 in the two treatment groups, and did the registry's noninferiority analysis support a conclusion about the comparison? The posted group estimates were -1.19 for efsitora and -1.16 for glargine. The registry reports an ANCOVA-based difference of -0.03 with a 95% confidence interval from -0.18 to 0.12. The noninferiority margin and its interpretation are not reported in the registry record, so the interval alone cannot be used to determine whether the prespecified noninferiority criterion was met.
3. Trial Design
QWINT-1 (NCT05662332) is described as a Phase 3, randomized, parallel-design, open-label controlled study. It compared insulin efsitora alfa with insulin glargine in adults with type 2 diabetes who had not previously started basal insulin therapy. The registry lists enrollment as 795. The study status is completed; the recorded start date is 2023-01-14 and primary completion date is 2024-07-19.
Participants assigned to efsitora received subcutaneous treatment once weekly for 52 weeks. The registry describes a fixed-dose escalation using 100 U, 150 U, 250 U, and 400 U. Participants assigned to glargine received subcutaneous treatment once daily for 52 weeks, with dose titration by standard sliding-scale adjustments. The open-label design means masking is listed as none; treatment allocation was randomized, but the registry does not describe blinding of participants or study personnel.
The primary endpoint was change in HbA1c from baseline to Week 52, analyzed for noninferiority. The registry also lists a superiority analysis of HbA1c change and secondary outcomes covering fasting glucose, basal insulin dose, hypoglycemia, nocturnal hypoglycemia, and body weight. The record lists 14 outcome measures and 9 analyses, while 13 secondary outcomes are posted. The registry does not report the original sample-size justification, the planned noninferiority margin, or interim-analysis arrangements. Those omissions limit interpretation of how the study's design choices were intended to support its primary inference.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | Insulin Efsitora Alfa | Insulin Glargine |
|---|---|---|
| STARTED | 397 | 398 |
| Received at Least One Dose of the Study Drug | 397 | 398 |
| COMPLETED | 362 | 361 |
| NOT COMPLETED | 35 | 37 |
Reasons for not completing this period:
| Reason | Insulin Efsitora Alfa | Insulin Glargine |
|---|---|---|
| Death | 3 | 3 |
| Lost to Follow-up | 3 | 8 |
| Physician Decision | 1 | 2 |
| Protocol Deviation | 2 | 1 |
| Withdrawal by Subject | 14 | 14 |
| Assigned Treatment by Mistake | 5 | 7 |
| Non-compliance with study drug | 4 | 1 |
| Due to Bariatric surgery | 1 | 0 |
| Subject Moving out of State | 0 | 1 |
| Subject Missed the Schedule | 1 | 0 |
| The Patient Moved to Another City | 1 | 0 |
Analysis population for the primary outcome, as defined in the registry: All randomized participants who received at least one dose of the study drug and had HbA1c measurement at baseline or Week 52, excluding participants discontinuing the study treatment due to inadvertent enrollment. All measurements were included regardless of the use of study treatment or rescue medication.
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
Population: All randomized participants who received at least one dose of the study drug.
| Characteristic | Unit | Efsitora | Glargine | Total |
|---|---|---|---|---|
| Participants analysed | 397 | 398 | 795 | |
| Age, Continuous | years | 56.40 (SD 10.02) | 56.20 (SD 9.67) | 56.30 (SD 9.84) |
| Sex: Female, Male: Female | Participants | 194 | 203 | 397 |
| Sex: Female, Male: Male | Participants | 203 | 195 | 398 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 338 | 336 | 674 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 59 | 61 | 120 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 1 | 1 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 106 | 107 | 213 |
| Race (NIH/OMB): Asian | Participants | 3 | 6 | 9 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 1 | 1 | 2 |
| Race (NIH/OMB): Black or African American | Participants | 13 | 10 | 23 |
| Race (NIH/OMB): White | Participants | 270 | 272 | 542 |
| Race (NIH/OMB): More than one race | Participants | 3 | 1 | 4 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 1 | 1 | 2 |
| Region of Enrollment: Argentina | participants | 170 | 171 | 341 |
| Region of Enrollment: Mexico | participants | 129 | 129 | 258 |
| Region of Enrollment: United States | participants | 98 | 98 | 196 |
| HemoglobinA1c (HbA1c) | Percentage of HbA1c | 8.20 (SD 0.91) | 8.28 (SD 1.06) | 8.24 (SD 0.99) |
6. Primary Endpoint
The registry lists the primary outcome as Change From Baseline in Hemoglobin A1c (HbA1c) [Noninferiority Analysis], measured over Baseline, Week 52.
| Element | Registry entry |
|---|---|
| Result type | Least Squares Mean |
| Measure of spread | Standard Error |
| Unit | Percentage of HbA1c |
| Endpoint classification | Continuous Endpoint |
Hemoglobin A1c (HbA1c) is the glycated fraction of hemoglobin A. The registry describes it as a measure used to identify average plasma glucose concentration over the last 2-3 months. The primary endpoint was change in HbA1c from baseline to Week 52, expressed as a percentage of HbA1c. A change score compares the end-of-period measurement with the baseline measurement, while the group-level least-squares means are adjusted estimates from the specified model rather than simple raw averages.
HbA1c is used in this trial as a measure of longer-term glycemic status, complementing a single glucose measurement. The endpoint's time frame allows comparison of the groups' estimated changes during the treatment period. The registry labels the primary analysis as noninferiority, which asks whether the treatment-group contrast is compatible with a prespecified bound for an unacceptable difference. That bound, or noninferiority margin, is not reported in the registry record. Without it, the reported confidence interval can be described, but it cannot independently establish whether the noninferiority criterion was satisfied.
The analysis population and missing-data approach also affect what the estimate represents. The record specifies participants who received at least one dose and had an HbA1c measurement at baseline or Week 52, subject to an exclusion for inadvertent enrollment discontinuation. Week 52 missing values were imputed using a return-to-baseline multiple-imputation approach. This means the reported estimate combines observed information with values generated under the stated imputation method rather than being based only on complete Week 52 measurements.
7. Results Posted in the Registry
- Glargine: mean -1.16 versus -1.19 on control; difference 0.03 (95% CI -0.12 to 0.18), standardized effect d = 0.03; z-test p = 0.697.
Mean difference: Glargine
95% CI: -0.12 to 0.18
Recalculated from the posted summary statistics
8. Secondary Efficacy Endpoints
The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.
| Secondary outcome | Type | Effect measure | Estimate (95% CI) | Planning size, 80% power |
|---|---|---|---|---|
| Change From Baseline in HbA1c [Superiority] | Continuous Endpoint | Mean difference | 0.03 (-0.12 to 0.18) | 18,556 per arm |
| Change From Baseline in Fasting Glucose | Continuous Endpoint | Mean difference | -4.16 (-9.90 to 1.58) | 1,361 per arm |
| Basal Insulin Dose at Week 52 | Continuous Endpoint | Mean difference | 43.70 (25.00 to 62.40) | 120 per arm |
Change From Baseline in HbA1c [Superiority]
- Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
- Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
- Result:
- Glargine: mean -1.16 versus -1.19 on control; difference 0.03 (95% CI -0.12 to 0.18), standardized effect d = 0.03; z-test p = 0.697.
- Interpretation:
- The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Glargine and the control. The interval gives the range of effects that remain compatible with the data.
Change From Baseline in Fasting Glucose
- Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
- Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
- Result:
- Glargine: mean -50.92 versus -46.76 on control; difference -4.16 (95% CI -9.90 to 1.58), standardized effect d = -0.11; z-test p = 0.155.
- Interpretation:
- The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Glargine and the control. The interval gives the range of effects that remain compatible with the data.
Basal Insulin Dose at Week 52
- Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
- Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
- Result:
- Glargine: mean 332.80 versus 289.10 on control; difference 43.70 (95% CI 25.00 to 62.40), standardized effect d = 0.36; z-test p = <0.001.
- Interpretation:
- The 95% confidence interval excludes no difference, so the mean is statistically higher for Glargine than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.
The secondary outcomes broaden the account beyond HbA1c, covering fasting glucose, basal insulin dose, hypoglycemia and nocturnal hypoglycemia measures, and body weight. The posted pattern is not a single uniform treatment-group contrast across these different kinds of outcomes. The model estimates for fasting glucose are relatively close, while basal insulin dose at Week 52 has a more separated reported comparison. Event-rate and incidence outcomes address hypoglycemia in different ways, and body weight addresses a separate measure.
These outcomes provide context for the primary HbA1c finding but do not alter what the primary endpoint measures. A treatment-use outcome such as insulin dose is not interchangeable with a glycemic endpoint; nor are event counts and the proportion of participants with an event equivalent quantities. Each has its own estimand, analysis population, and uncertainty. They should be interpreted according to their definitions and posted analyses rather than combined into one overall claim.
Unadjusted secondary results carry less inferential weight when many outcomes are examined because the chance of at least one apparently noteworthy result can increase across multiple comparisons. Adjustment methods, a testing hierarchy, and the extent to which secondary outcomes were confirmatory are not reported in the registry record. The listed secondary outcomes therefore help describe the range of measured results, but isolated p-values should not be treated as definitive evidence. The relationship to the primary result is descriptive: secondary findings can complement the primary comparison, but they cannot supply the missing noninferiority margin or resolve the primary endpoint's decision criterion.
Secondary outcomes registered for this trial, for reference (only those above were recalculated):
- Change From Baseline in HbA1c [Superiority]
- Change From Baseline in Fasting Glucose
- Basal Insulin Dose at Week 52
- Rate Per Year of Hypoglycemia Events
- Percentage of Participants With Hypoglycemia Events (Incidence)
- Rate Per Year of Nocturnal Hypoglycemia Events
- Percentage of Participants With Nocturnal Hypoglycemia Events (Incidence)
- Change From Baseline in Body Weight
9. Statistical Interpretation
At Week 52, the posted least-squares mean HbA1c change was -1.19 in the efsitora group and -1.16 in the glargine group. These are estimated within-group changes from baseline. The registry's ANCOVA result gives a between-group LS mean change difference of -0.03, with a 95% confidence interval from -0.18 to 0.12. The interval includes zero, so the posted estimates do not show a clear separation between the groups in either direction for this contrast. The registry labels this result as a noninferiority analysis, but the noninferiority margin is not reported; therefore, the interval cannot by itself establish the noninferiority conclusion.
The separate superiority analysis of HbA1c change reports p = 0.684. This result does not provide evidence of superiority under that analysis. It should not be treated as proof that the treatments are identical: a nonsignificant superiority test may reflect compatible estimates across a range of differences, as the confidence interval illustrates. The registry's noninferiority question is distinct from its superiority question, and interpretation of the former depends on the unreported margin.
The recalculated unadjusted contrast is 0.03, with a 95% confidence interval from -0.121 to 0.181 and p = 0.697. It is close to the sponsor-reported estimate in size, though the sign differs because the contrasts are oriented in opposite directions. The sponsor's ANCOVA result is the appropriate result to prioritize: it uses the stated adjusted model, while the recalculation is based on posted group summaries and is unadjusted. These analyses should not be conflated.
Secondary outcomes add context but do not replace the primary endpoint. The posted fasting-glucose estimates indicate decreases in both groups; the registry's reported between-group estimate has a confidence interval spanning zero. The Week 52 basal insulin dose comparison is more clearly separated in the posted model result, but dose is a treatment-use measure rather than the primary HbA1c outcome. Other secondary outcomes concern hypoglycemia and body weight. Their role in interpretation depends on outcome-specific estimates, analysis methods, and multiplicity handling, which is not reported for the family of secondary analyses.
Overall, the posted primary result is a small estimated between-group contrast with a confidence interval that includes zero. The data as reported do not establish a meaningful direction or magnitude of difference in HbA1c change without reference to a noninferiority margin and the full prespecified analysis plan. They also do not support conclusions about outcomes, populations, or durations beyond those recorded for this trial.
10. Statistical Methods Explained
The primary analysis uses an analysis of covariance (ANCOVA) model to estimate adjusted mean changes and their between-group contrast. ANCOVA relates the outcome to treatment assignment while accounting for specified covariates. The registry lists baseline HbA1c, country, GLP-1 receptor agonist use at randomization, and treatment as model variables, with Type III sums of squares. Adjustment can improve precision and account for measured differences represented by those terms; it does not remove uncertainty or correct for factors not included in the model.
The reported outcome is a least-squares (LS) mean change. An LS mean is a model-based adjusted mean, not necessarily the arithmetic average of the observed changes. The group estimates of -1.19 and -1.16 are accompanied in the posted outcome by standard errors of 0.055 and 0.054. A standard error describes the estimated uncertainty of a mean; it is not the spread of individual participant outcomes. The registry does not give standard deviations for these group estimates in the primary outcome listing.
The sponsor's posted primary comparison is an ANCOVA LS mean change difference of -0.03, with a 95% confidence interval from -0.18 to 0.12. A confidence interval describes a range of estimates compatible with the data and the model at the stated confidence level. It is not a probability statement that the true effect lies inside the particular realized interval. Its clinical or noninferiority interpretation requires a threshold specified in advance. The noninferiority margin is not reported in the registry record, so the confidence interval cannot be compared with that margin.
The registry states that missing Week 52 data were imputed using a return-to-baseline multiple-imputation approach. Multiple imputation creates plausible values for missing outcomes under a modeling assumption, analyzes completed datasets, and combines the resulting estimates to reflect imputation uncertainty. A return-to-baseline approach uses an assumption that the missing outcome returns toward baseline rather than following the observed treatment-period trajectory. The exact imputation model details and sensitivity analyses are not reported in the registry record. Results therefore depend, in part, on assumptions about missing outcomes.
The primary analysis population is defined in the record as randomized participants who received at least one dose and had an HbA1c measurement at baseline or Week 52. Participants discontinuing study treatment due to inadvertent enrollment were excluded. Measurements were included regardless of continued study-treatment use or rescue medication. This is not simply an all-randomized population, because receiving a dose and having an eligible measurement are specified conditions. The number of participants contributing to the primary outcome is listed by group in the outcome results.
What does the recalculation represent?
The recalculated comparison uses the posted group means and standard errors to form a simple unadjusted contrast and approximate interval. The listed estimate is 0.03, the 95% confidence interval is -0.121 to 0.181, and the unadjusted p-value is 0.697. The pooled standard deviation is marked as approximate. This calculation does not reproduce the sponsor's ANCOVA: it does not adjust for baseline HbA1c, country, GLP-1 receptor agonist use, or the other specified model structure. It is a check based on summary statistics, not an alternative primary analysis. The sponsor's analysis takes precedence if a discrepancy is present; the record does not flag a discrepancy for this result.
How should the p-values be read?
A p-value measures how incompatible the observed data are with a specified null hypothesis under the statistical model and its assumptions. It is not the probability that the null hypothesis is true, and it does not measure clinical importance. The primary noninferiority analysis has no p-value reported in the registry record. The posted secondary HbA1c superiority analysis reports p = 0.684; the recalculated unadjusted p-value is 0.697. These values answer a superiority question, not the noninferiority question. No conclusion about superiority or noninferiority should be based on a p-value alone.
For other secondary continuous outcomes, the registry also posts LS means and standard errors and reports model-based comparisons. The specific method differs for basal insulin dose, which is listed as a mixed models analysis. Model choice matters because estimates and uncertainty depend on the outcome structure, covariates, and assumptions. The registry does not provide enough detail to reconstruct all models or independently verify their assumptions.
Why does over-dispersion matter generally?
General statistical explanation: for count outcomes such as event rates, over-dispersion means observed variability is greater than a model's assumed variability. Ignoring it can make uncertainty estimates too small and results appear more precise than warranted. This trial's hypoglycemia outcomes include event-rate measures, but the statistical models and over-dispersion handling for those outcomes are not reported in the registry record. The general issue is relevant when interpreting rate analyses, but it cannot be used to infer which method the trial used.
The record labels the primary endpoint noninferiority and also lists a secondary HbA1c superiority analysis. Those objectives require different inferential criteria. Noninferiority depends on a margin and usually focuses on whether the confidence interval excludes an unacceptable loss; superiority evaluates evidence for a difference in a specified direction or any difference, according to its test. The registry does not report the noninferiority margin or the detailed testing hierarchy. This limits assessment of how the primary and secondary hypotheses were formally connected.
11. Confidence Intervals and Precision
The sponsor-reported primary estimate is an LS mean change difference of -0.03, with a 95% confidence interval from -0.18 to 0.12. The interval includes zero and spans estimates in both directions. Thus, the posted data are compatible with a small advantage in either direction under the model, as well as with little separation. The confidence interval communicates uncertainty around the estimated contrast; it does not prove equivalence or that the groups have identical effects.
The recalculated unadjusted contrast is 0.03, with a 95% confidence interval from -0.121 to 0.181. The sign reversal reflects the contrast direction: the recalculation expresses glargine relative to efsitora, while the sponsor-reported comparison is oriented oppositely. The intervals are similar in span, but they arise from different analyses. The sponsor's adjusted ANCOVA result is the reported primary analysis and should guide interpretation.
Precision depends on more than the number of participants. The standard errors, covariate adjustment, missing-data handling, and assumptions of the model all contribute to uncertainty. The confidence interval does not incorporate every possible source of uncertainty, such as departures from the model or unreported sensitivity analyses. The registry does not report the noninferiority margin, so the interval's relation to the threshold for that decision cannot be assessed.
For the superiority analysis of HbA1c change, the reported p-value is 0.684, and the recalculated unadjusted p-value is 0.697. Neither p-value supplies a measure of the size or precision of the effect by itself; the estimate and interval are more informative for those purposes. The primary confidence interval is the key posted uncertainty summary for the noninferiority comparison, but its decision meaning remains incomplete without the margin.
12. Planning a Similar Trial: Sample Size
This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.
| Effect to detect | Participants per arm, 80% power | Participants per arm, 90% power |
|---|---|---|
| 100% of the observed effect | 18,556 | 24,841 |
| 75% of the observed effect | 32,988 | 44,161 |
| 50% of the observed effect | 74,222 | 99,362 |
The sample-size figures are planning illustrations based on the observed effect, not the trial's original design justification. For the continuous outcomes in this record, the figures are participants per arm, not total events. The stated planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is set to the stated fraction of the observed effect. The original design assumptions are not reported in the registry record.
The 80% power column gives the planned participants per arm under those assumptions for an 80% chance of detecting the specified effect if it were the true effect. The 90% power column gives the corresponding per-arm planning figure for a 90% chance. These are conventional planning targets, not guarantees about what a future study will find. For example, planning for 100% of the observed HbA1c effect gives 18,556 participants per arm for 80% power and 24,841 participants per arm for 90% power. Planning for 75% of the observed effect gives 32,988 participants per arm for 80% power and 44,161 participants per arm for 90% power; planning for 50% gives 74,222 and 99,362, respectively.
Smaller target effects require more participants because they are harder to distinguish from random variation. These figures are not observed power and do not determine whether the completed trial was adequately designed. They are illustrations calculated from the observed effect under stated simplified assumptions. The registry does not report the original noninferiority margin or the assumptions used to choose the trial's enrollment target.
13. How the Sample Size Is Derived
Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z1−α/2 = 1.960) and the desired power (z1−β = 0.842 for 80% and 1.282 for 90%).
Formula
n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.
Worked calculation for this trial
- Observed difference Δ = 0.030; pooled standard deviation σ = 1.031.
- n = 2 × (1.96 + 0.842)2 × 1.0312 / 0.0302 = 18,555.4, rounded up to 18,556 participants per arm for 80% power.
The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).
R code
alpha <- 0.05
z_a <- qnorm(1 - alpha / 2) # two-sided
delta <- 0.03 # observed difference in means
sigma <- 1.03142590280998 # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))
# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")
# Simulation: exact two-sample t-test using simulated means and variances
set.seed(5662332)
n <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n)) # difference in sample means
s2 <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1)) # pooled sample variance
tstat <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))
Output from running the code
100% of observed effect: n per arm = 18,556 (80% power), 24,841 (90% power)
75% of observed effect: n per arm = 32,988 (80% power), 44,161 (90% power)
50% of observed effect: n per arm = 74,222 (80% power), 99,362 (90% power)
power.t.test: 18556.4
Simulated power at n = 18,556 per arm: 0.803 (20000 replicates)
The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.
14. Analyses Reported by the Sponsor
| Method | Estimate | 95% CI | P-value |
|---|---|---|---|
| ANCOVA | LS Mean Change difference -0.03 | -0.18 to 0.12 | not reported |
The sponsor's primary analysis is an ANCOVA estimate of the LS mean change difference: -0.03, with a 95% confidence interval from -0.18 to 0.12. The recalculation from posted summary statistics gives an unadjusted contrast of 0.03, with a 95% confidence interval from -0.121 to 0.181 and p = 0.697. The sign differs because the contrast is expressed in the opposite direction; both estimates are close to zero.
The recalculation is not a reproduction of the sponsor's analysis. It uses summary means and standard errors and does not adjust for the covariates specified in the ANCOVA model. The sponsor's result is the principal result to interpret because it is the registry's reported model-based primary analysis. The record does not flag a discrepancy for this endpoint. The primary noninferiority p-value is not reported in the registry record, and the noninferiority margin is also not reported, so neither can be inferred from the recalculation or from the superiority p-value.
15. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary noninferiority analysis and a secondary superiority analysis of HbA1c change, as well as multiple other secondary outcomes. A testing hierarchy specifies which hypotheses are tested first and how the interpretation of later tests depends on earlier results. Multiplicity adjustment controls the risk of false-positive conclusions when several hypotheses are considered. The hierarchy and multiplicity procedures for the analyses are not reported in the registry record. The secondary p-values should therefore be read as posted, outcome-specific results rather than assumed to have family-wise error control.
The primary result's noninferiority margin is not reported. The margin is central to the noninferiority question because it defines the largest difference considered acceptable under the trial's criterion. The registry's confidence interval can be described, but without that threshold and the planned decision rule, the formal noninferiority conclusion cannot be independently evaluated from the registry record.
For the primary endpoint, Week 52 missing data were imputed with a return-to-baseline multiple-imputation approach. The analysis population included randomized participants who received at least one dose and had an HbA1c measurement at baseline or Week 52, excluding participants who discontinued treatment because of inadvertent enrollment. Measurements were included regardless of study-treatment use or rescue medication. The full imputation specification, sensitivity analyses under alternative missing-data assumptions, and missing-data methods for all secondary endpoints are not reported in the registry record.
The record does not report the trial's original sample-size justification, interim analyses, or a complete statistical analysis plan. In particular, it does not identify the assumptions used to select enrollment or the treatment of all planned comparisons. These gaps do not invalidate the posted estimates, but they limit evaluation of how closely the displayed analyses follow the full prespecified plan and how robust conclusions are to alternative assumptions.
16. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Efsitora | 26 | 397 | 6.5% |
| Glargine | 21 | 398 | 5.3% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Efsitora | 3 of 397 |
| Glargine | 3 of 398 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Efsitora | 104 of 397 |
| Glargine | 121 of 398 |
Most frequent serious adverse event terms
| Event term | Organ system | Efsitora | Glargine |
|---|---|---|---|
| Acute myocardial infarction | Cardiac disorders | 2 of 397 | 2 of 398 |
| Myocardial ischaemia | Cardiac disorders | 2 of 397 | 1 of 398 |
| Cardiac failure congestive | Cardiac disorders | 2 of 397 | 0 of 398 |
| Cholecystitis acute | Hepatobiliary disorders | 0 of 397 | 2 of 398 |
| Pneumonia | Infections and infestations | 1 of 397 | 1 of 398 |
| Lower limb fracture | Injury, poisoning and procedural complications | 2 of 397 | 0 of 398 |
| Hypoglycaemia | Metabolism and nutrition disorders | 1 of 397 | 1 of 398 |
| Ischaemic stroke | Nervous system disorders | 2 of 397 | 0 of 398 |
| Thrombocytopenia | Blood and lymphatic system disorders | 1 of 397 | 0 of 398 |
| Acute coronary syndrome | Cardiac disorders | 1 of 397 | 0 of 398 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Efsitora | Glargine |
|---|---|---|---|
| Influenza | Infections and infestations | 29 of 397 | 23 of 398 |
| Drug titration error | Injury, poisoning and procedural complications | 13 of 397 | 39 of 398 |
| Urinary tract infection | Infections and infestations | 18 of 397 | 25 of 398 |
| Headache | Nervous system disorders | 20 of 397 | 20 of 398 |
| Hypertension | Vascular disorders | 21 of 397 | 16 of 398 |
| Covid-19 | Infections and infestations | 21 of 397 | 9 of 398 |
Serious events with the highest arm-level rate: abnormal uterine bleeding (0.5%), adnexa uteri mass (0.5%), prostatectomy (0.5%), acute myocardial infarction (0.5%), cardiac failure congestive (0.5%).
The registry reports serious adverse events for 26 participants in the efsitora group, with 397 at risk, and 21 participants in the glargine group, with 398 at risk. It also reports other adverse events for 104 participants in the efsitora group and 121 in the glargine group, using the same respective at-risk counts. Deaths are listed as 3 in each group. These counts describe the posted record; they do not establish whether an event was caused by treatment.
The serious-event terms listed at 0.5% each are abnormal uterine bleeding, adnexa uteri mass, prostatectomy, acute myocardial infarction, cardiac failure congestive, and myocardial ischaemia. These are listed terms, not a complete account of every event or an estimate of comparative risk for each condition. The registry does not report the event definitions, severity breakdowns, causality assessments, or a statistical comparison for these safety counts. The figures should therefore be read descriptively, with attention to the at-risk denominators and the limitations of the posted detail, rather than as proof that one regimen is safer.
17. What the Result Does, and Does Not, Mean
The central posted finding is a small estimated difference in HbA1c change at Week 52: the group estimates are -1.19 for efsitora and -1.16 for glargine, and the sponsor-reported adjusted contrast is -0.03. Its 95% confidence interval, from -0.18 to 0.12, includes zero. This describes an uncertain contrast under the reported ANCOVA model. It does not show that the groups are identical, and it does not establish that any difference is clinically important or unimportant.
The registry labels the primary analysis noninferiority, but the margin needed to interpret that test is not reported. The interval therefore cannot be compared with the acceptance threshold, and the formal noninferiority conclusion cannot be independently assessed from the registry record. The secondary superiority analysis reports p = 0.684, which does not provide evidence of superiority under that test. That result is not proof of equivalence and does not substitute for the noninferiority criterion.
The findings apply to the recorded study population, regimens, outcome definitions, and follow-up period. Efsitora was administered weekly with fixed-dose titration for 52 weeks; glargine was administered daily with sliding-scale adjustments for the same period. The results do not establish what would occur with different dosing strategies, longer follow-up, other populations, or outcomes not reported in the registry.
Secondary outcomes and adverse-event counts add descriptive context, but their interpretation is limited by the absence of reported multiplicity procedures, detailed analysis methods for some measures, and complete safety definitions. No single secondary result should be used to replace the primary endpoint or to support a broad overall claim. The record supports a careful description of estimated changes and uncertainty, not medical advice or a general conclusion about treatment choice.
18. Why This Trial Matters Statistically
This trial illustrates why the statistical question must match the endpoint and the design objective. A noninferiority analysis is not the same as a superiority test: the first depends on a prespecified acceptable margin, while the second evaluates evidence for a difference. The posted HbA1c estimate is close to zero and its confidence interval includes zero, but without the noninferiority margin the primary decision cannot be reconstructed from the registry record.
It also shows the value of distinguishing adjusted model results from simple recalculations. The sponsor's ANCOVA incorporates baseline HbA1c, country, GLP-1 receptor agonist use at randomization, and treatment. The unadjusted recalculation is a useful summary-statistic check, but it does not answer precisely the same model-based question. Reporting both requires clarity about direction, adjustment, and the role of each estimate.
Finally, the record highlights how missing-data assumptions and multiple outcomes shape interpretation. The primary endpoint used return-to-baseline multiple imputation, and the study reported a range of secondary outcomes. Transparency about the imputation model, noninferiority margin, multiplicity plan, and sample-size justification would help readers assess the strength and scope of the conclusions. These are statistical reporting issues, not merely technical details: they determine how confidently estimates can answer the intended clinical question.
19. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
Several trial-specific details needed for a complete statistical assessment are not reported in the registry record. The noninferiority margin and the full decision rule for the primary hypothesis are absent. The original sample-size justification is not reported, so the relationship between enrollment and the intended noninferiority precision cannot be evaluated from the record. Interim-analysis plans and the full analysis plan are also not reported.
The primary analysis uses an imputed Week 52 outcome, but the full imputation model, assumptions beyond the return-to-baseline description, and sensitivity analyses are not reported. Because missing-data assumptions can affect an estimated change, the robustness of the primary result to alternative assumptions cannot be assessed. Methods for missing values across secondary outcomes are likewise not fully described.
The trial was open-label, with no masking listed. The registry does not describe whether any outcome assessment or other study procedures were protected from knowledge of treatment assignment. This does not establish that measurement bias occurred, but it is relevant context when considering outcomes that could be influenced by study conduct or participant reporting.
The registry lists multiple secondary outcomes, but multiplicity handling and the confirmatory status of each analysis are not reported. Safety information is presented as counts and selected event terms; definitions, causality assessments, and statistical comparisons are not reported. Finally, the registry record's summary cannot replace a complete protocol or statistical analysis plan. These limitations concern what can be established from the record, not proof that the trial lacked additional prespecified procedures.
20. Related Tutorials
21. Related Statistical Calculators
22. Sources
- ClinicalTrials.gov: A Study of Insulin Efsitora Alfa (LY3209590) Compared to Glargine in Adult Participants With Type 2 Diabetes Who Are Starting Basal Insulin for the First Time (QWINT-1) — NCT05662332.
- Registry record last updated 2025-08-06; status last verified 2025-07.
- Results first posted 2025-08-06.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
23. Record Summary
QWINT-1 (NCT05662332) is a completed Phase 3, randomized, parallel, open-label comparison of weekly insulin efsitora alfa and daily insulin glargine in insulin-naïve adults with type 2 diabetes. Both regimens were followed for 52 weeks. The primary outcome was change in HbA1c from baseline to Week 52.
The sponsor-reported ANCOVA estimate for the primary noninferiority analysis was -0.03, with a 95% confidence interval from -0.18 to 0.12. The registry also reports a secondary HbA1c superiority p-value of 0.684. The noninferiority margin, original sample-size justification, multiplicity procedures, and full missing-data sensitivity analyses are not reported in the registry record. The posted results describe a near-zero adjusted contrast with uncertainty in both directions, but the noninferiority decision cannot be evaluated without the margin.