Surgery or Lifestyle With Intensive Medical Management in the Treatment of Type 2 Diabetes: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Surgery or Lifestyle With Intensive Medical Management in the Treatment of Type 2 Diabetes (NCT01073020), a randomized na study. The primary outcome is Fasting Plasma Glucose <126 mg/dL and HbA1c < 6.5% at Three Years of Follow-up..

2. Clinical Question

The trial addresses a treatment-comparison question in a population for whom the registry background describes uncertainty about the best approach. The rationale notes that bariatric procedures may affect metabolic control and that medical management of type 2 diabetes has also advanced. The study therefore compares surgical approaches with an intensive program rather than with no treatment or routine care.

The comparisons should be read separately. The LAGB result concerns LAGB versus its associated intensive medical and weight management group. The RYGB result concerns RYGB versus its associated medical-management group. The posted results do not establish a direct randomized comparison between LAGB and RYGB, and they do not establish that one surgical approach is superior to the other.

The primary question concerns the proportion meeting a defined glycemic target at a specified follow-up, not average change in glucose or HbA1c. The registry also lists glycemic control as measured by HbA1c, body mass index, and cardiovascular risk among secondary outcomes. Further definitions and results for those outcomes are not reported in the registry record.

3. Trial Design

This was a randomized, open-label, parallel-group trial listed as completed. The registry record gives total enrollment as 88 and identifies Joslin Diabetes Center as the sponsor. The trial is listed with phase NA. The start is recorded as 2010-01 and primary completion as 2014-12.

The record describes two parallel comparisons: LAGB versus intensive medical diabetes and weight management, and RYGB versus intensive medical diabetes and weight management. The intervention list names adjustable gastric band surgery and RYGB surgery, along with separate intensive-management groups associated with each surgical comparison. The record does not describe a single pooled medical-control group for the reported primary comparisons.

Participants were randomized, but masking was listed as none. The results therefore come from an open-label design. Details of the randomization procedure, allocation concealment, stratification, and any steps to reduce bias in outcome assessment are not reported in the registry record.

The primary endpoint was assessed at three years of follow-up. The posted arm counts for that endpoint are 16 for LAGB, 17 for its associated medical-management group, 19 for RYGB, and 19 for its associated medical-management group. These endpoint analysis counts do not account for the full enrollment listed in the record. The registry describes some reasons participants were not analyzed, but a complete account of missing outcome data and the analysis population is not reported in the registry record.

The arm descriptions include some procedural details: LAGB was described as using the pars flaccida technique, and the RYGB description mentions a Roux limb and pancreaticobiliary limb. The available descriptions are truncated, so further protocol details are not reported in the registry record. The original sample-size justification, planned statistical model, and prespecified analysis strategy are also not reported.

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: After initial contact, patients will undergo the following: 1) Telephone screening (review inclusion and exclusion criteria, description of interventions), 2) Attend clinical trial orientation session (detailed description of interventions, protocol, procedures, surgical clearance, nutritional evaluation, risks, benefits), 3) Medical and surgical screening visit (sign informed consent, screening lab tests, history and physical, psychological evaluation for bariatric surgery, exercise clearance).

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Patients not analyzed include: 7 of 23 in LAGB (4 withdrew consent before intervention,1 determined to not be a surgical candidate before intervention, and 2 withdrew consent between 1 and 3 years); 5 of 22 in IMWM (LAGB Grp) (4 withdrew consent, 1 death); 3 of 22 in the RYGB group (1 withdrew consent; 1 breast cancer diagnosis and 1 psychiatric illness pre-intervention); 2 of 21 IMWM (RYGB Grp) withdrew consent before intervention.

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: Participants first selected whether they preferred gastric band or RYGB. After consent, they were randomized to either surgery or intensive medical diabetes and weight management. This resulted in 2 independent substudies, one of which compared band to its corresponding intensive medical diabetes and weight management group, and one of which compared RYGB to its corresponding intensive medical diabetes and weight management group..

6. Primary Endpoint

The registry lists the primary outcome as Fasting Plasma Glucose <126 mg/dL and HbA1c < 6.5% at Three Years of Follow-up., measured over 3 years.

The primary endpoint is the percentage of patients attaining glycemic control at three years of follow-up. The registry defines attainment as both fasting plasma glucose <126 mg/dL and HbA1c < 6.5%. In other words, a participant had to meet both thresholds to count as attaining the endpoint. The outcome is binary at the participant level: each person either met the definition or did not.

This kind of endpoint is used to express how common a specified target state was in each group at a stated follow-up time. It differs from an average glucose value or average HbA1c because it reports the fraction meeting a threshold rather than the distribution of measurements. A threshold-based endpoint can be clinically interpretable, but it also depends on the exact cutoffs and the time point chosen. Those definitions are part of the registry outcome description.

The registry lists HbA1c, body mass index, and cardiovascular risk among secondary outcomes, but further results for those measures are not reported in the registry record. The primary results therefore address only the stated combined glucose and HbA1c target. They do not by themselves describe the full course of glycemic measurements, the amount of change for participants who did not meet the target, or other clinical outcomes.

7. Results Posted in the Registry

• Intensive Medical Diabetes & Weight Management (LAGB Grp): 5.9% (1/17) versus 12.5% (2/16) on control; risk difference -6.6 percentage points (95% CI -26.3 to 13.1), risk ratio 0.47 (0.05–4.70); unadjusted two-proportion z-test p = 0.509.
• RYGB: 42.1% (8/19) versus 12.5% (2/16) on control; risk difference 29.6 percentage points (95% CI 2.1 to 57.1), risk ratio 3.37 (0.83–13.65); unadjusted two-proportion z-test p = 0.053.
• Intensive Medical Diabetes & Weight Management (RYGB Grp): 0.0% (0/19) versus 12.5% (2/16) on control; risk difference -12.5 percentage points (95% CI -28.7 to 3.7); unadjusted two-proportion z-test p = 0.112.

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is a binary proportion: the percentage of participants meeting the registry's combined fasting plasma glucose and HbA1c definition. For this endpoint, each comparison can be expressed as a difference between the observed proportions in the surgical and medical-management groups. A risk difference is an absolute contrast: zero would mean the observed proportions were equal, a positive value means the first group in the stated contrast had a higher observed proportion, and a negative value means it had a lower observed proportion. The interpretation depends on which arm is placed first.

The unadjusted recalculation for the LAGB comparison uses 2 events among 16 participants in the LAGB group and 1 among 17 in its associated medical-management group. Its risk difference is -0.066 when expressed as medical management compared with LAGB. The confidence interval is -0.263 to 0.131, and the unadjusted p-value is 0.509. Because the interval includes zero, the posted data are compatible with a range of contrasts that includes no difference as well as differences in either direction.

For RYGB, the recalculation uses 8 events among 19 participants in the surgical group and 2 among 16 in the comparator used for that recalculation. It gives a risk difference of 0.296, a confidence interval from 0.021 to 0.571, and p = 0.053. The posted arm results also include 0 events among 19 participants in the RYGB-associated medical-management group; the registry's sponsor analysis compares that group with RYGB and reports p = 0.005. The record's reported test and the simple recalculation do not yield matching p-values, and the discrepancy is flagged. The sponsor's own analysis takes precedence.

A confidence interval describes a range of effect estimates compatible with the data and the method used to calculate the interval. It communicates uncertainty about the effect size, rather than the probability that the true effect lies within a particular realized interval. A wide interval indicates that the data allow a broad range of effects. A p-value addresses how unusual the observed data would be under a specified null hypothesis and test assumptions; it is not a measure of effect size, clinical importance, or the probability that the null hypothesis is true.

The registry reports the sponsor's own analyses as Chi-squared tests of proportions. The record gives the analysis values and p-values but does not report confidence intervals for those analyses, details of the test implementation, or any adjustment for covariates. The simple recalculations are unadjusted checks from the posted summary counts. They do not reproduce or replace an analysis that might use participant-level data, an alternate analysis population, or a different handling of missing outcomes. The registry record does not explain whether any such features account for the discrepancy.

The results are presented as separate comparisons, which is important because the medical-management arms are labeled for their associated surgical groups. Pooling the medical groups or treating the trial as a single three-arm comparison would require a stated analysis rationale that is not reported in the registry record. Nor should a contrast between a medical-management arm and the LAGB arm be read as a randomized comparison of the two surgical procedures.

The registry lists four outcome measures, three secondary outcomes, and eight analyses. It does not report how the primary and secondary analyses were ordered or whether multiplicity was addressed. When multiple outcomes or comparisons are tested, the chance of at least one nominally notable result can increase unless the testing strategy accounts for the multiplicity. This is a general statistical consideration, not evidence that a particular adjustment was or was not used in the trial.

Missing data matter because the primary outcome is defined at follow-up and not every enrolled participant appears in the endpoint analysis counts. The registry gives partial reasons for participants not analyzed in the LAGB and associated medical group descriptions. It does not provide a complete flow of participants for every arm, a full missing-data strategy, or a sensitivity analysis. Without those details, the posted proportions cannot establish how the outcome would look under alternative assumptions about participants with missing follow-up.

The analysis population is also not fully described. The record does not state whether the primary analysis followed an intention-to-treat principle, a per-protocol approach, or another rule. The endpoint group counts should therefore be understood as the posted analyzed denominators, not as proof of a particular analysis population. Likewise, randomization is stated, but details needed to evaluate allocation and implementation are not reported.

Finally, statistical significance and practical importance are distinct. A test result does not show whether an observed difference is meaningful to patients or clinicians, and a non-significant result does not show that the groups are equivalent. Establishing equivalence or noninferiority requires prespecified margins and appropriate analyses, which are not reported in the registry record. The statistical interpretation should remain tied to the observed endpoint proportions, their uncertainty, the sponsor-reported analyses, and the limitations of the available record.

10. Confidence Intervals and Precision

The recalculated LAGB risk difference is -0.066, with a confidence interval from -0.263 to 0.131. This interval spans zero and includes values in both directions. The result therefore does not identify a precise direction or size of contrast from the posted counts. The unadjusted p-value is 0.509.

For the recalculated RYGB contrast, the risk difference is 0.296 and the confidence interval runs from 0.021 to 0.571. The interval is broad, so the effect size remains uncertain even though the interval does not include zero. The corresponding recalculated p-value is 0.053. The sponsor-reported RYGB result instead gives p = 0.005, and the registry record flags a discrepancy; the sponsor's analysis takes precedence.

A confidence interval is a measure of precision as well as direction. A narrow interval would indicate that the data constrain the estimated contrast more tightly; a wide interval leaves more plausible values. The intervals for these recalculations allow a substantial range of possible differences. The small endpoint groups contribute to the limited precision, and the record does not report adjusted confidence intervals from the sponsor's analyses.

The registry lists risk ratios and odds ratios for some recalculated comparisons, but relative measures can be difficult to interpret when event counts are sparse, including when a group has no observed events. The absolute proportions and risk differences keep the comparison tied to the observed endpoint frequencies. None of these measures removes uncertainty or resolves the discrepancy between the recalculation and sponsor analysis.

Precision should not be confused with whether a result crosses a conventional significance threshold. An estimate may be imprecise even when a test yields a small p-value, and a non-significant p-value does not establish that the groups are alike. The posted results support cautious description of the analyzed participants, not a precise estimate of a general treatment effect.

11. 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 sample-size figures are planning illustrations derived from the observed effect, not the trial's original design justification. For these binary outcomes, the entries are participants per arm, rather than total events. The stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The planning effect is the stated fraction of the observed effect.

For the LAGB comparison, the planning figures are 298 participants per arm for 80% power and 399 participants per arm for 90% power when planning for 100% of the observed effect. For 75% of the observed effect, the corresponding figures are 574 and 767 participants per arm. For 50% of the observed effect, they are 1,386 and 1,854 participants per arm.

For the RYGB comparison, the figures are 35 and 46 participants per arm for 80% and 90% power when planning for 100% of the observed effect. For 75% of the observed effect, they are 57 and 75 participants per arm. For 50% of the observed effect, they are 114 and 151 participants per arm.

The 80% power column means the planned sample size is calculated to give an 80% chance of detecting the assumed effect under the stated assumptions, if that effect is present and the model assumptions hold. The 90% column uses a higher target chance of detection. In both cases, smaller assumed effects require more participants, because smaller differences are harder to distinguish from random variation. These figures are not observed power; they are planning illustrations based on the posted effect estimates. The trial's own original sample-size assumptions are not reported in the registry record.

12. 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, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.125; treatment proportion p₁ = 0.059; average p̄ = 0.092.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.4086 = 0.8008.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.4059 = 0.3416.
4. n = (0.8008 + 0.3416)² / (-0.0662)² = 298.0, rounded up to 298 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
p0 <- 0.125                          # control proportion
p1 <- 0.0588235294117647                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^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 (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(1073020)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 298 (80% power), 399 (90% power)
 75% of observed effect: n per arm = 574 (80% power), 767 (90% power)
 50% of observed effect: n per arm = 1,386 (80% power), 1,854 (90% power)
power.prop.test: 298 
Simulated power at n = 298 per arm: 0.810 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-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.

13. Analyses Reported by the Sponsor

The registry's own analyses report a Chi-squared test for each principal surgical-versus-medical comparison. For LAGB versus its associated medical-management group, the record reports a proportion value of 0.08 and p = 0.60. For RYGB versus its associated medical-management group, it reports a proportion value of 0.42 and p = 0.005. The registry does not provide confidence intervals for these analyses in the posted results.

The unadjusted recalculations use the posted event counts and produce p = 0.509 for the LAGB contrast and p = 0.053 for the RYGB contrast. The RYGB recalculation therefore differs from the sponsor-reported p-value. The record flags a discrepancy, and the sponsor's own analysis takes precedence. The record does not explain why the results differ, so no cause should be inferred.

Recalculation is a check on the posted summary counts, not a replacement for the sponsor's analysis. It may not capture the sponsor's analysis population or any method choices not described in the registry. Conversely, the posted record does not include enough detail to fully reproduce the sponsor's tests. The two sets of results should be identified distinctly rather than blended into a single estimate.

14. Multiplicity, Missing Data and Analysis Populations

The record lists four outcome measures, including the primary endpoint and three secondary outcomes, and eight analyses. It does not report a multiplicity adjustment, a hierarchy of hypotheses, or a strategy for interpreting results across outcomes and comparisons. When multiple statistical tests are conducted, the chance of at least one apparently notable finding can increase. Whether that concern was addressed in the trial's analysis is not reported in the registry record.

The primary endpoint description notes participants who were not analyzed and gives some reasons in the LAGB and associated medical-management groups. It reports 7 of 23 in LAGB as not analyzed, with reasons including withdrawal of consent, not being a surgical candidate before intervention, and withdrawal between one and three years. It reports 5 of 22 in the LAGB-associated medical group as not analyzed, with reasons including withdrawal of consent and death. The description of participants not analyzed in the RYGB group is incomplete in the registry record; a complete account for all arms is not reported.

The posted endpoint denominators are 16, 17, 19, and 19. The record does not state the full participant flow for every arm or explain how missing follow-up was handled in the analysis. It does not report imputation, sensitivity analyses, or assumptions about outcomes for participants without endpoint data. Missingness can affect a proportion if participants without data differ from those analyzed; this is a general statistical concern, not a conclusion about the reason for missing outcomes in this trial.

The registry also does not report whether the primary analysis used all randomized participants, only participants with available endpoint data, or another defined population. An intention-to-treat analysis population, a per-protocol population, and a complete-case analysis can answer different questions. Without the stated analysis population and complete handling rules, the posted arm proportions should be read as results for the reported denominators.

15. 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 5% reporting threshold.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: bariatric surgery revisions and complications (44.4%), renal (15.8%), presyncope (10.5%), orthopedic procedures (10.5%), supraventricular arrhythmia (10.5%).

The registry reports serious adverse events among 9 of 18 participants at risk in the LAGB surgery group, 6 of 22 in the LAGB-associated intensive medical and weight management group, 11 of 19 in the RYGB surgery group, and 5 of 19 in the RYGB-associated medical-management group. These are registry counts of participants affected and participants at risk; they should not be confused with the primary endpoint denominators.

The record reports zero other adverse events in each listed group. Deaths are recorded as zero in the LAGB surgery group, one in the LAGB-associated medical group, zero in the RYGB surgery group, and zero in the RYGB-associated medical group. The registry does not provide further details about the death in the available record.

The listed serious-event terms include bariatric surgery revisions and complications at 44.4%, renal at 15.8%, and presyncope, orthopedic procedures, supraventricular arrhythmia, and psychiatric hospitalizations at 10.5% each. The denominator and counting rules for these term percentages are not reported in the registry record. The counts are descriptive; they do not by themselves establish comparative safety, causation, or the severity and timing of individual events.

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

The posted results describe how often participants in the analyzed groups met the registry's combined glycemic-control definition at three years. The observed percentages were 13% for LAGB, 5% for its associated medical-management group, 42% for RYGB, and 0.0% for its associated medical-management group. The registry's own analyses report p = 0.60 for the LAGB comparison and p = 0.005 for the RYGB comparison.

Those results do not establish that one operation is preferable to the other. The record presents separate comparisons with separate associated medical-management groups, not a direct randomized comparison between LAGB and RYGB. Nor do the reported proportions show what happened to every enrolled participant, because endpoint analysis counts are smaller than total enrollment and the missing-data account is incomplete.

The results also do not establish that the observed proportions would be the same in other populations or at other follow-up times. The registry outcome is specific to a joint glucose and HbA1c threshold at three years. It does not report the distribution of continuous glucose measures, changes over time, or complete results for the listed secondary outcomes. The record does not report the original statistical plan or the reasons for the discrepancy between the sponsor's RYGB test and the simple unadjusted recalculation.

A statistically notable result is not, by itself, evidence about the size of benefit that matters to patients, nor is a non-notable result proof of equivalence. The confidence intervals from the recalculations reflect substantial uncertainty, and the sponsor-reported and recalculated RYGB p-values differ. Interpretation should therefore distinguish the observed endpoint frequencies, the sponsor's own tests, and the limited precision and reporting detail.

These are findings from a completed randomized trial, but the registry information alone does not support a treatment recommendation. It provides a record of the stated design, endpoint, results, and selected safety counts; it does not provide a complete clinical or statistical report.

17. Why This Trial Matters Statistically

This trial is statistically notable because its primary endpoint is a binary target that condenses two laboratory thresholds into a participant-level outcome. That makes the reported percentages easy to describe, while making the result dependent on the chosen thresholds and follow-up time. The same trial could show a different pattern if it reported continuous measurements or a different endpoint definition, but such results are not reported in the registry record.

The parallel comparisons also make clear why comparator structure matters. LAGB and RYGB are each paired with a separately labeled intensive medical-management group. Treating these as one shared control or reading the results as a direct surgery-versus-surgery test would change the question. A statistical contrast is meaningful only when the groups and estimand match the design and analysis.

The record also illustrates the difference between a sponsor-reported test and a calculation from summary counts. The RYGB p-values differ, and the registry flags the discrepancy. Reproducibility requires enough information about the population, outcome handling, and analysis method to understand such differences; those details are not fully reported. In this case, the sponsor's own analysis takes precedence, while the recalculation offers a clearly labeled unadjusted comparison.

Finally, small endpoint groups and incomplete missing-data information constrain the conclusions. Confidence intervals communicate the range of uncertainty more directly than a significance label alone, and the planning illustrations show how much larger studies might need to be under specified assumptions. Those illustrations are not evidence of the study's original design or its observed power. Together, these features make the record a useful example of interpreting proportions, comparator-specific analyses, uncertainty, and reporting gaps without overstating what the data establish.

18. 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.
• Participant counts were reconstructed from posted percentages and arm sizes, so small rounding differences are possible.

The registry record provides limited detail about eligibility, participant characteristics, allocation procedures, and implementation of randomization. It identifies an open-label design but does not report whether outcome assessment was blinded. The arm descriptions are truncated, so the procedural details available do not constitute a complete protocol description.

The primary endpoint results are reported for analyzed denominators that are smaller than the total enrollment. Reasons for participants not analyzed are only partly described, and a complete account for all groups is not reported. The analysis population, missing-data method, and sensitivity analyses are not reported in the registry record. These omissions limit assessment of how attrition might affect the endpoint proportions.

The registry reports sponsor analyses but does not provide confidence intervals for those tests or enough detail to reproduce them fully. The simple unadjusted recalculation for RYGB gives a different p-value from the sponsor's reported result, and the source of that discrepancy is not reported. The sponsor's own analysis takes precedence, but the record does not permit a detailed reconciliation.

The original sample-size justification and planned statistical analysis are not reported. The record also does not describe any multiplicity strategy despite listing multiple outcomes and analyses. Results for the secondary outcomes are not included in the available record. The safety information is limited to selected counts and event terms; the denominator and counting rules for the listed term percentages are not reported.

These reporting limitations mean the results should be interpreted as registry-record findings for the stated endpoint and analyzed groups, rather than as a complete account of all trial outcomes or analytic decisions.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Surgery or Lifestyle With Intensive Medical Management in the Treatment of Type 2 Diabetes — NCT01073020.
• Registry record last updated 2021-06-28; status last verified 2021-05.
• Results first posted 2021-05-06.
• 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.

22. Record Summary

NCT01073020, titled “Surgery or Lifestyle With Intensive Medical Management in the Treatment of Type 2 Diabetes,” is listed as a completed randomized, open-label, parallel trial sponsored by Joslin Diabetes Center. Enrollment was 88. The record lists a start of 2010-01 and primary completion of 2014-12.

The study compared LAGB and RYGB separately with intensive medical diabetes and weight management. The primary endpoint was attainment of fasting plasma glucose <126 mg/dL and HbA1c < 6.5% at three years. The registry reports sponsor-analysis p-values of 0.60 for the LAGB comparison and 0.005 for the RYGB comparison. A discrepancy is flagged between the sponsor's RYGB analysis and a simple unadjusted recalculation; the sponsor's analysis takes precedence.

The record lists HbA1c, body mass index, and cardiovascular risk as secondary outcomes, but further results are not reported in the registry record. The original sample-size justification, complete missing-data strategy, and full statistical analysis plan are also not reported.