Comparison of Glargine to Degludec Insulin Transition With or Without a Bridging Glargine Dose: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Comparison of Glargine to Degludec Insulin Transition With or Without a Bridging Glargine Dose (NCT04623086), a randomized phase 4 study. The primary outcome is Mean Change in Percent Time in Range.

2. Clinical Question

This is a question about a short-term difference in a continuous glucose-monitoring measure between two transition strategies. It is not a comparison of long-term glucose control or a measure of whether one strategy is suitable for a particular person. The registry identifies the study as a pilot, randomized comparison. It does not report additional information about the intended clinical threshold for a meaningful difference, or whether participants were followed for outcomes beyond the stated measurement period. Those details are not reported in the registry record.

3. Trial Design

The registry describes a completed, randomized, parallel-group phase 4 pilot study sponsored by the University of Washington. Its title concerns transitioning from insulin glargine to insulin degludec with or without a bridging glargine dose. The registry records overall enrollment of 59 participants. The two groups listed for the primary outcome are insulin glargine and insulin degludec, with 19 participants, and insulin degludec and placebo, with 18 participants. These are the group sizes attached to the posted primary outcome; the registry does not explain the relationship between those outcome counts and total enrollment.

Allocation is recorded as randomized, masking as quadruple, and the model as parallel. The registry does not describe who was masked, how the random sequence was generated, how allocation was concealed, or how the masking was maintained. The intervention descriptions specify daily subcutaneous insulin degludec in both groups, with glargine in the bridging group and saline placebo in the comparator group. They do not provide further detail on dose selection or on how the transition was carried out beyond the descriptions recorded.

The primary outcome is a mean change in percent time in range, measured over the 48 hours before and the 48 hours after the first degludec dose. The stated glucose range is 70-180 mg/dL, inclusive, and the monitor named in the outcome description is the Dexcom G6. The registry also lists secondary measures of glucose variability, nocturnal time in range, time above range, time below range, and correction boluses. The registry's own original design assumptions, including its sample-size justification and planned statistical methods, are not reported in the registry record. Participant flow, withdrawal information, and the analysis population definitions are also not reported in the registry record.

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.

Before assignment: 12 participants did not meet study inclusion/exclusion criteria and were screen failures. 47 participants started study procedures but only 37 were randomized.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Change in percent time spent in target glycemic range (TIR, glucose 70-180 mg/dL, both values included) in the 48 hours before and the 48 hours after the 1st dose of IDeg, as noted on study continuous glucose monitor (dexcom G6)

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: We included all participants who had completed the treatment period in the final analysis. This included wearing the study continuous glucose monitor from time of randomization to study completion and implementing the transition from baseline insulin regimen to degludec (3 doses at least) according to protocol. We did not include subjects who either were "Unassigned" or "Screen Failures" as we could not obtain all the baseline characteristics in these two groups of participants.

6. Primary Endpoint

The registry lists the primary outcome as Mean Change in Percent Time in Range, measured over 48 hours prior to 48 hours after 1st dose of degludec insulin.

The primary endpoint is mean change in percent time spent in the target glucose range, defined as 70-180 mg/dL with both boundaries included. It compares the 48 hours before the first degludec dose with the 48 hours after that dose, using readings from a Dexcom G6 continuous glucose monitor. The measure is expressed as a percentage of time in the measured period. A positive change represents an increase in time in range across the before-and-after periods; a negative change represents a decrease. This describes the direction of the measure, not a judgment about whether the size of a change matters clinically.

Time in range is used as a continuous summary of glucose readings across a specified monitoring period. Unlike a single reading, it reflects the share of monitored time within the defined range. Comparing each group's mean change can describe whether the average short-term change differed between the transition strategies. The group averages do not show the full pattern of individual participants' glucose readings or changes.

The registry reports the endpoint as a mean with standard deviation. The stated comparison period is short and begins around the first degludec dose. It therefore addresses short-term glucose-monitoring changes during the transition, not longer-term glycemic outcomes, clinical events, or quality of life. The registry does not report a threshold for a clinically important difference or additional details about how missing monitor readings were handled.

7. Results Posted in the Registry

• Insulin Glargine and Insulin Degludec: mean 2.00 versus -6.10 on control; difference 8.10 (95% CI -2.38 to 18.58), standardized effect d = 0.50; z-test p = 0.130.

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.

Coefficient of Variation (CV) of Percent-time-in-range

• 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 deviations.
• Result:
  • Insulin Glargine and Insulin Degludec: mean 3.00 versus -1.10 on control; difference 4.10 (95% CI -0.90 to 9.10), standardized effect d = 0.53; z-test p = 0.108.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Insulin Glargine and Insulin Degludec and the control. The interval gives the range of effects that remain compatible with the data.

Nocturnal Percent Time in Range of 70-180 mg/dL Nocturnal Time in Range (N-TIR)

• 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 deviations.
• Result:
  • Insulin Glargine and Insulin Degludec: mean 5.10 versus -7.00 on control; difference 12.10 (95% CI -10.07 to 34.27), standardized effect d = 0.35; z-test p = 0.285.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Insulin Glargine and Insulin Degludec and the control. The interval gives the range of effects that remain compatible with the data.

Percent Time Above 180 mg/dL (TAR-1)

• 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 deviations.
• Result:
  • Insulin Glargine and Insulin Degludec: mean 5.40 versus 6.50 on control; difference -1.10 (95% CI -10.09 to 7.89), standardized effect d = -0.08; z-test p = 0.810.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Insulin Glargine and Insulin Degludec and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes cover variability in time in range, nocturnal time in range, time above range, time below range, and correction boluses. The posted results therefore examine several related aspects of glucose monitoring rather than a single independent confirmatory question. The available summary comparisons show a mixture of directions and degrees of uncertainty; they do not form a consistent pattern that independently settles the primary question. The registry lists seven secondary outcomes, but the posted results described in the record do not include group estimates for every listed measure.

These measures provide context for the primary time-in-range result. For example, variability and time outside the target range can describe features not captured by the primary average alone. However, secondary measures are not interchangeable with the primary endpoint, and a result on one does not establish a difference on another. Nor should findings from several related outcomes be counted as multiple independent confirmations: the measures may reflect overlapping aspects of the same glucose-monitoring period.

Unadjusted secondary p-values carry less weight when many outcomes are examined. In general, testing multiple hypotheses without an adjustment or a prespecified hierarchy raises the chance of obtaining at least one apparently noteworthy result even if no corresponding effect exists. The registry does not report a multiplicity adjustment, a hierarchy of secondary outcomes, or whether these analyses were designated as confirmatory or exploratory. Their results are therefore best interpreted as exploratory evidence that may help shape future questions, rather than definitive tests on their own.

The time-above-range analysis deserves particular caution because the sponsor-reported result does not agree with the comparison implied by the posted group summaries. The registry record does not explain the difference, so that result cannot be confidently integrated into an overall pattern. Overall, the secondary outcomes add descriptive breadth but do not remove the uncertainty around the primary estimate or demonstrate a coherent, confirmed effect across measures.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Coefficient of Variation (CV) of Percent-time-in-range
• Nocturnal Percent Time in Range of 70-180 mg/dL Nocturnal Time in Range (N-TIR)
• Percent Time Above 180 mg/dL (TAR-1)
• Time Above Range-2 (TAR-2)
• Time Below Range-1 (TBR-1)
• Time Below Range-2 (TBR-2)
• Correction Boluses

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous: each participant's change in percent time in range is summarized numerically, and the posted group results are means with standard deviations. A mean describes the average value within a group. A standard deviation describes how dispersed individual values are around that group mean; it is not the uncertainty interval for the mean and does not describe the full distribution.

What does the difference in means represent?

The comparison is the mean in the bridging-dose group minus the mean in the degludec-and-placebo group. For the primary outcome, the posted mean difference is 8.1. The positive sign indicates that the mean change was higher in the bridging group. Because the outcome is a change in percent time in range, this is a difference in average changes, not a difference in final time in range after the transition. It also does not imply that every participant changed in the same direction.

The registry reports a two-sided t-test for the mean difference. In general, a t-test evaluates how compatible the observed difference is with a null model of no difference, while accounting for sampling variability under the test's assumptions. A two-sided test considers deviations in either direction. The registry record does not report all details needed to assess the exact implementation, including whether the analysis used an equal-variance or unequal-variance form of the test, any covariate adjustment, or how missing observations were handled.

How should the p-value be understood?

In general, a p-value is the probability, under a specified null model and its assumptions, of obtaining a result at least as incompatible with that model as the observed result. It is not the probability that the null hypothesis is true, and it is not the probability that the finding is due to chance. It does not measure the size or clinical importance of an effect. The sponsor-reported primary p-value is 0.14; an unadjusted recalculation from the posted summary statistics gives 0.13. These values indicate that the observed data do not provide strong evidence against the null model under the test used, but they do not establish absence of a difference.

The recalculations are unadjusted comparisons derived from the posted group means, standard deviations, and group sizes. They are not a substitute for an individual-participant-data analysis or the sponsor's complete analysis. In general, a recalculation from summary statistics cannot account for methods or data handling that are not described in the registry record. For this primary outcome, the reported and recalculated estimates agree, while their p-values are close.

Why does the confidence interval matter?

A confidence interval gives a range of effect estimates compatible with the observed data under the interval's method and assumptions. In repeated use of a method, intervals at a stated confidence level have a specified coverage property; an individual interval is not a probability statement about the true effect. The primary 95% interval, -2.378 to 18.58, includes zero, the value corresponding to no mean difference. It also spans differences in both directions and a range of positive values. Its breadth is an important part of interpretation: the estimate is not precise enough to pin down a narrow range of plausible effects.

In general, the width of an interval depends on the amount of information in the data and the variability of the outcome, as well as the method used. A small pilot comparison with notable outcome variability will generally yield less precise estimates than a larger study with comparable variability. This is a general statistical explanation, not a statement about the trial's intended sample-size rationale; that rationale is not reported in the registry record.

What does over-dispersion mean for a continuous outcome?

For continuous data, a broad spread of participant-level changes can make the estimated group difference uncertain. The primary group standard deviations are 14.7 and 17.6, while the observed mean difference is 8.1. These values do not establish a particular distributional shape. In general, when individual observations vary widely relative to a group difference, the data may support a broad range of effects even if the point estimate is not zero. This is one reason to interpret the interval alongside the means and p-value.

Over-dispersion is often discussed for count outcomes, where variability exceeds what a simple model assumes. That specific count-data issue is not the primary endpoint here, which is continuous. More generally, an analysis model that does not reflect the outcome's variability or distribution can produce unreliable uncertainty estimates. The registry does not report diagnostic checks or alternative model analyses, so their use cannot be assessed.

What is not documented about the analysis?

The registry reports the primary endpoint, group summaries, and a t-test result. It does not report whether the analysis followed intention-to-treat principles, whether participants were excluded from an analysis, how missing monitor data were treated, or whether the outcome was adjusted for baseline values. It also does not report prespecified covariates, a hierarchy for secondary outcomes, an adjustment for multiple testing, or a sensitivity analysis. These details matter because they clarify which participants and data contribute to an estimate and how much weight to give a collection of results. Their absence from the registry record limits methodological appraisal; it does not establish that the procedures were not used.

11. Confidence Intervals and Precision

The primary recalculated mean difference is 8.1, with a 95% confidence interval from -2.378 to 18.58. The interval is broad and includes zero, so the posted summary data are compatible with no difference as well as with differences in either direction. Its upper end allows a considerably larger positive difference than the point estimate, while the lower end allows a small negative difference. The result is therefore not a precise estimate of the size or direction of the underlying mean difference.

In general, a confidence interval communicates uncertainty around an estimate more directly than a p-value alone. It does not mean there is a 95% probability that the true effect lies within this particular interval. Rather, the stated confidence level describes the long-run behavior of the interval-producing method under its assumptions. Interpretation also depends on whether those assumptions, including the analysis population and handling of missing observations, are appropriate; those details are not reported in the registry record.

The group standard deviations are 14.7 for the bridging group and 17.6 for the degludec-and-placebo group. They indicate variability in observed participant changes, not uncertainty about the treatment difference by themselves. The interval reflects uncertainty in the comparison, which depends on both group variability and the amount of information in the groups. The registry does not report a clinically important difference threshold, so the interval cannot be categorized against a registry-defined threshold for meaningful benefit or harm.

The sponsor reports the same primary mean difference, 8.1, and a p-value of 0.14; the unadjusted summary-statistic recalculation gives p = 0.13. The close p-values do not remove the imprecision evident in the interval. Taken together, the estimate should be read as suggestive of a possible positive difference in mean change, but not as a precise or conclusive estimate.

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.

The planning figures are illustrative, not a report of the study's original design calculations. For these continuous outcomes, the figures are participants per arm. 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 at the stated fraction of the observed effect. The registry's own original sample-size assumptions and justification are not reported in the registry record.

The 80% power column means the planned number of participants per arm under those assumptions to give an 80% chance of rejecting the null model if the specified effect were the true effect. The 90% power column uses the same general interpretation but targets a 90% chance under that specified effect and those assumptions. These are prospective planning concepts, not guarantees about a future study's results. The figures are not observed power.

The rows describe planning for the full observed effect, 75% of the observed effect, and 50% of the observed effect. A smaller effect is harder to distinguish from random variation, so the planning calculation requires more participants per arm. The displayed figures can therefore help show how sample-size requirements change when the target effect is more modest. They should not be treated as a recommended trial size without considering the clinical question, outcome variability, analysis plan, and feasibility.

These illustrations are based on the observed effect in this pilot, which is itself uncertain. If the observed effect is unusually large or small because of sampling variation, planning directly from it may not represent a reliable target. The illustrations also do not incorporate any adjustment for multiple secondary outcomes, missing data, or other design features. The registry does not report whether the original study's enrollment target was based on these assumptions.

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 z_1−α/2 = 1.960) and the desired power (z_1−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

1. Observed difference Δ = 8.100; pooled standard deviation σ = 16.174.
2. n = 2 × (1.96 + 0.842)² × 16.174² / 8.100² = 62.6, rounded up to 63 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 <- 8.1                      # observed difference in means
sigma <- 16.1736469957415                     # 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(4623086)
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 = 63 (80% power), 84 (90% power)
 75% of observed effect: n per arm = 112 (80% power), 149 (90% power)
 50% of observed effect: n per arm = 251 (80% power), 336 (90% power)
power.t.test: 63.6 
Simulated power at n = 63 per arm: 0.798 (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

For the primary outcome, the sponsor reports a mean difference of 8.1 and a two-sided p-value of 0.14. The unadjusted recalculation from the posted group summaries also gives a mean difference of 8.1, with p = 0.13. The small difference between the p-values may reflect details of the analysis or rounding; the registry record does not report enough information to identify its source. The posted primary confidence interval is based on the recalculation, not an interval reported by the sponsor.

The sponsor-reported analyses for the coefficient of variation and nocturnal time in range are also close to the unadjusted recalculations: the mean differences match, and the reported p-values are 0.11 and 0.29, compared with recalculated values of 0.108 and 0.285. For time above 180 mg/dL, however, the posted group means imply a difference of -1.1, while the sponsor reports -11.9 with p = 0.015. These results do not align, and the registry record does not explain the discrepancy. No conclusion about its cause can be drawn from the posted summaries.

The recalculations are simple, unadjusted calculations from summary statistics; they do not replace the sponsor's analysis or disclose what additional methods the sponsor may have used. Where the registry's own analysis and a recalculation differ, interpretation should distinguish clearly between them rather than treating the recalculation as a correction. The registry does not provide enough detail to reconcile the time-above-range result.

15. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary outcome and several secondary outcomes. It does not report whether the primary outcome was selected in advance as the single confirmatory endpoint, whether secondary analyses followed a prespecified order, or whether any adjustment was made for testing multiple outcomes. These details are important because the chance of at least one small p-value increases as more hypotheses are tested without adjustment. In general, a multiplicity strategy can control that risk, but it may also change the interpretation and precision of individual comparisons. No such strategy is described in the registry record, so the secondary p-values should be treated cautiously.

Missing-data handling is also not reported in the registry record. The primary outcome depends on continuous glucose-monitor recordings across the stated periods, but the registry does not say what completeness threshold was required, how partial recordings were handled, or whether any values were imputed. It does not describe missingness by group or explain whether missingness was considered in the analysis. These omissions matter because an analysis based only on participants with sufficiently complete recordings can differ from one that includes all randomized participants using an appropriate method. The record does not provide enough information to assess that possibility.

The analysis population is not defined. The registry does not report whether the primary analysis included all randomized participants, only participants who received the assigned transition, or another population. It also does not report whether participants were excluded after randomization or how protocol deviations were addressed. Randomization supports a fair comparison when the analysis and follow-up preserve the randomized groups, but the record does not provide the detail needed to evaluate these aspects.

The registry does not report a full statistical analysis plan, sensitivity analyses, subgroup analyses, or procedures for handling multiple comparisons. These absences limit assessment of whether analyses were prespecified and how robust the results may be to alternative reasonable choices. They should be understood as limitations in the registry record, not proof that the study team did not undertake these procedures.

16. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

For the insulin glargine and insulin degludec group, the registry records 0 serious adverse events among 19 participants at risk and 0 other adverse events among 19 at risk. For the insulin degludec and placebo group, it records 0 serious adverse events among 18 participants at risk and 0 other adverse events among 18 at risk. The entire-study-period entry records 0 serious adverse events and 0 other adverse events among 59 participants at risk. The registry also records 0 deaths in each listed group and for the entire study period.

These are the event counts recorded in the registry; they do not show that the risk of an adverse event is zero. A small study may be unable to identify uncommon events, and zero recorded events does not establish that two strategies have equal safety. The registry does not provide event terms, severity classifications beyond the serious/non-serious grouping, exposure-adjusted rates, or additional details about safety monitoring. The safety figures therefore describe what was recorded during the reported study period, not a comprehensive estimate of comparative safety.

17. What the Result Does, and Does Not, Mean

The primary result estimates a short-term difference in mean change in time in range between a bridging glargine strategy and direct conversion to degludec with placebo. The observed mean difference is 8.1 percentage points in favor of the bridging group, while the sponsor-reported two-sided p-value is 0.14. The unadjusted recalculation yields a 95% confidence interval from -2.378 to 18.58. That interval includes no difference and estimates in either direction, so the data do not pin down a clear effect size.

The result does not establish that the bridging strategy improves glucose control, nor does it establish that the strategies are equivalent or that there is no difference. A nonsignificant test is not proof of no effect. Demonstrating equivalence or noninferiority requires a design with an appropriate prespecified margin and analysis; such a margin is not reported in the registry record. The point estimate is only one estimate among a range of values compatible with the data.

The endpoint is limited to changes in monitored time in range during the 48 hours before and after the first degludec dose. It does not establish longer-term effects, effects on outcomes not measured in the registry, or how the transition should be managed for an individual. No medical recommendation follows from this statistical comparison.

The study is described as a pilot, and the primary outcome group sizes are 19 and 18. The registry does not report the original sample-size rationale or a threshold for a clinically important difference. Those limitations, together with the outcome's variability and the broad interval, mean the estimate is uncertain. The secondary measures may offer additional descriptive context, but their multiplicity and the unexplained mismatch in one sponsor-reported comparison further limit confirmatory interpretation.

18. Why This Trial Matters Statistically

This trial raises a practical statistical question: how should short-term monitoring data be interpreted when comparing two transition strategies in a randomized pilot? Its primary endpoint is a mean change in time in range, a continuous measure that retains information about magnitude rather than reducing each participant's readings to a simple event count. The comparison therefore illustrates the value of examining both the group means and the variability around them.

The primary estimate also shows why a p-value should not stand alone. The reported p-value does not provide the range of differences compatible with the data, while the confidence interval makes the uncertainty and the possibility of effects in either direction explicit. A point estimate can appear potentially meaningful yet remain too imprecise to support a firm conclusion. This distinction is especially important in pilot studies, where limited information and variable outcomes can leave wide uncertainty.

The registry also offers a useful example of the difference between sponsor-reported analyses and simple calculations from posted group summaries. For most of the comparisons discussed, the two are close, but the time-above-range result does not align. Recognizing such differences is important: summary-statistic recalculation can help readers examine results, but it cannot reveal undocumented analysis choices or resolve mismatches without further information.

Finally, the several related secondary outcomes illustrate why a collection of unadjusted findings needs careful interpretation. Statistical significance across multiple outcomes is not a substitute for a prespecified analysis strategy, and absence of a small p-value does not establish equivalence. The study is informative as a record of a randomized pilot and the uncertainty around its short-term estimates; it does not settle the comparative 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.

The registry record leaves important details about eligibility criteria, participant characteristics, allocation procedures, masking roles, and intervention implementation unreported. Although it records randomization, quadruple masking, and a parallel design, it does not describe how those procedures were carried out. This limits the ability to judge the risk of selection or measurement bias from the record alone.

The primary endpoint concerns a short monitoring window around the first degludec dose. The registry does not report longer-term follow-up for this outcome, a clinically important difference threshold, or the original sample-size justification. The primary analysis groups are small and the group standard deviations are substantial, while the confidence interval is broad. These features limit precision and make the point estimate sensitive to sampling variation.

The record does not define the analysis population, describe participant flow, or report how incomplete continuous-glucose-monitor recordings were handled. It also does not state whether the analysis was adjusted for baseline values or other covariates. Without these details, readers cannot fully assess whether the posted comparison reflects all randomized participants or how missing readings may affect the result.

Multiplicity procedures are not reported despite the several secondary outcomes. In addition, the sponsor-reported time-above-range analysis differs materially from the contrast implied by the posted group summaries, and the record does not explain why. The available summaries also do not provide estimates for every listed secondary measure. Finally, zero recorded adverse events in the listed groups should not be interpreted as evidence that uncommon risks are absent. Each limitation concerns what can be assessed from the registry record; none establishes that an unreported procedure was not performed.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Comparison of Glargine to Degludec Insulin Transition With or Without a Bridging Glargine Dose — NCT04623086.
• Registry record last updated 2024-02-28; status last verified 2024-02.
• Results first posted 2024-02-28.
• 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.

23. Record Summary

The registry describes a completed randomized, quadruple-masked, parallel-group phase 4 pilot study sponsored by the University of Washington. It records enrollment of 59 participants with type 1 diabetes. The comparison is insulin glargine with the first insulin degludec dose versus insulin degludec with placebo.

The primary outcome is mean change in percent time in the 70-180 mg/dL range during the 48 hours before and after the first degludec dose. The posted group means are 2.0 and -6.1, with a mean difference of 8.1. The sponsor reports p = 0.14; an unadjusted recalculation gives p = 0.13 and a 95% confidence interval from -2.378 to 18.58.

The estimate is uncertain and does not establish a difference or equivalence. Several secondary outcomes are listed, but multiplicity methods and key analysis details are not reported in the registry record. The sponsor-reported time-above-range comparison does not align with the posted group summaries.