Observational Study of Nevirapine Extended Release in Human Immunodeficiency Virus (HIV) Patients in Daily Clinical Practice: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Observational Study of Nevirapine Extended Release in Human Immunodeficiency Virus (HIV) Patients in Daily Clinical Practice (NCT01524900), a registered phase not stated study. The primary outcome is Number of Patients Reporting Non-serious Adverse Events, Serious Adverse Events, and Non-serious and Serious Adverse Events Leading to Treatment Discontinuation.

2. Clinical Question

The broader study aim also included efficacy and treatment adherence. Listed secondary outcomes include virologic response at Week 24 using a viral-load threshold of <50 copies/mL, change in CD4+ cell count, change in Morisky Medication Adherence Scale score, and whether once-daily nevirapine was reported as more convenient than a twice-daily formulation. Numerical results for these outcomes are not reported in the registry record.

3. Trial Design

The registry describes NCT01524900 as an open-label, prospective, non-interventional, uncontrolled post-marketing surveillance study. It concerns nevirapine extended release in HIV-1-infected patients receiving routine clinical care. The record lists an enrollment of 398 and a completed status. The recorded study start is 2012-03, and primary completion is 2014-05.

Treatment was not assigned by the study. Patients were documented if pharmacotherapy with nevirapine extended release was initiated, and the decision to start it was independent of study participation. The treating physician’s judgment and the individual patient’s need informed treatment initiation. This design can describe what was recorded among treated patients, but it does not create a randomized treatment comparison.

The intended observation plan described in the registry summary was five visits over a twenty-four week period. The primary endpoint, however, gives a timeframe of up to 72 weeks. How that endpoint timeframe relates to the planned visit schedule is not reported in the registry record. The record’s stated study aim covered safety, efficacy, and adherence in routine practice.

The adverse-event results divide patients into treatment-naïve patients, patients switching from nevirapine immediate release, pretreated patients grouped by baseline viral-load status, and patients whose baseline viral load was not documented. These categories provide context for the posted counts, but they are not randomized arms or a like-for-like control comparison. The registry does not report further details about how these groups were formed or how patients were followed within them.

The record lists seven outcome measures and zero analyses. Statistical methods for the primary endpoint, a formal sample-size justification, an analysis plan, and any interim analyses are not reported in the registry record. The enrollment figure therefore should not be read as evidence of a particular power calculation or planned treatment contrast.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Patients from TS.

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: Patients from the Treated Set (TS): This patient set includes all HIV-1 infected patients who were dispensed Viramune® and were documented to have taken at least one dose of Viramune®and of a antiretroviral combination partner.

6. Primary Endpoint

The registry lists the primary outcome as Number of Patients Reporting Non-serious Adverse Events, Serious Adverse Events, and Non-serious and Serious Adverse Events Leading to Treatment Discontinuation, measured over up to 72 weeks.

The primary endpoint counts patients reporting non-serious adverse events and serious adverse events, as well as patients with either type of event leading to treatment discontinuation. Its stated timeframe is up to 72 weeks. The endpoint is intended to characterize safety during routine clinical use of a regimen that includes nevirapine extended release.

Counting patients with events can provide a direct descriptive account of how many people in the recorded population experienced an event. Separating serious from non-serious events distinguishes categories of reported severity, while identifying events leading to discontinuation adds information about whether treatment was stopped in connection with an event. These counts do not, by themselves, determine whether treatment caused an event. In an uncontrolled observational study, events may also reflect patients’ underlying health, other medicines, or circumstances not captured in the registry results.

The registry’s endpoint description identifies several event categories, but the analysis method, event-collection rules, and handling of repeated events are not reported in the registry record. In particular, the posted adverse-event group counts should be read as reported participant counts, not as adjusted estimates or comparative effects. The record does not provide a comparator group, confidence intervals, or a statistical test for the primary endpoint.

The endpoint timeframe of up to 72 weeks differs from the twenty-four week observation period described in the study summary. The registry does not explain how the endpoint follow-up was reconciled with that schedule. This matters when interpreting the duration over which events could be captured.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

General statistical context. Descriptive counts report how many participants in a recorded group had an event. They are useful for summarizing the observed data, but a count alone does not show the probability of an event in a broader population. A rate or proportion requires a clearly defined denominator and consistent event and follow-up definitions. Even when a denominator is reported, the interpretation depends on whether participants were followed for comparable periods and whether events were captured consistently.

In this record, the adverse-event results present at-risk and affected counts for the listed patient categories. The registry does not report confidence intervals or a statistical model for these results. The figures should therefore be read as descriptive counts, not adjusted estimates. The group categories also differ in treatment history and baseline viral-load documentation. Because treatment was not randomized and there is no control group, comparisons between categories could reflect differences in their patients, clinical circumstances, or follow-up rather than differences attributable to nevirapine extended release.

General statistical context: uncertainty. A confidence interval is a range constructed by a statistical procedure to express uncertainty around an estimate. Its interpretation depends on the chosen method and assumptions, including how observations were sampled and how outcomes were measured. A narrow interval generally indicates greater precision under those assumptions; a wide interval indicates less precision. No confidence interval is reported for the primary endpoint in the registry record, so its precision cannot be assessed from interval estimates.

A p-value, when used, describes how compatible the observed data are with a specified null model under the test’s assumptions. It does not measure the probability that a treatment works, and it does not establish causation. The registry record does not report p-values or a statistical test for the results. No p-value should be inferred from counts alone.

General statistical context: over-dispersion. For count outcomes, some statistical models assume that variability follows a particular distribution. Over-dispersion means the data vary more than that model expects. If it is present and not accounted for, uncertainty estimates from the model may be too small. Whether this issue applies depends on the outcome and model. The registry does not report a count model or an assessment of over-dispersion, so there is no basis to say whether it was relevant to the sponsor’s analysis.

General statistical context: observational designs. In a randomized study, allocation can help balance measured and unmeasured characteristics between treatment groups on average. In an uncontrolled observational study, treatment selection is part of clinical care rather than a randomized assignment. Patients receiving treatment may differ in health status, prior treatment, or other factors that also influence outcomes. Statistical adjustment can sometimes address measured differences, but it cannot guarantee removal of unmeasured confounding. The registry does not report an adjusted analysis here, and its patient categories should not be treated as experimental treatment arms.

General statistical context: missing information. Missing outcome data can affect interpretation if the availability of measurements is related to patients’ health or outcomes. Analysts commonly describe how much information is missing, assess patterns of missingness, and specify how missing observations are handled. These choices can affect estimates and uncertainty. The registry record does not report missing-data procedures, the number of participants with outcome data, or sensitivity analyses. The category for patients with baseline viral load not documented is a reported patient group; it does not, by itself, explain missingness in other variables or outcomes.

Planning and power. A sample-size calculation is a planning exercise based on assumptions about the outcome, the effect of interest, variability, significance level, and allocation. It is not an observed result and cannot show that a study detected an effect. The record does not report its own sample-size justification or a statistical analysis plan. No numerical planning estimate or power result is reported in the registry record. Any sample-size illustration should be understood as hypothetical planning rather than observed power.

Multiplicity. When a study assesses multiple outcomes or makes multiple statistical comparisons, the chance of at least one false-positive finding can increase if each result is tested separately without accounting for the collection of tests. Methods for handling this issue depend on which outcomes and comparisons were planned and on the study’s inferential goals. The registry lists seven outcome measures, but zero analyses are reported. A multiplicity strategy is not reported in the registry record, and the available information does not establish which outcomes, if any, were treated as confirmatory.

Overall, the registered results permit a descriptive reading of the recorded adverse-event counts and serious-event terms. They do not provide the inferential machinery needed to estimate treatment effects, compare regimens, or quantify precision. Those distinctions are central when interpreting routine-practice surveillance data.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists seven outcome measures, including the primary safety endpoint and secondary measures addressing virologic response, CD4+ cell count, adherence score, and reported convenience. It records zero analyses. Numerical results for the listed secondary outcomes, statistical tests, confidence intervals, and a prespecified multiplicity strategy are not reported in the registry record.

Multiplicity matters when several outcomes or comparisons are tested. If each is assessed independently using a conventional significance threshold, the chance of at least one apparently positive result can increase across the collection of tests. Statistical approaches can control or otherwise address that issue, but their suitability depends on which outcomes were planned, their priority, and the intended interpretation. The record does not identify a testing hierarchy or adjustment method, so no multiplicity-adjusted conclusions can be drawn.

Missing-data handling and analysis populations are also not reported in the registry record. The record does not describe the number of participants contributing data to each outcome, how incomplete follow-up was handled, or whether any sensitivity analyses were conducted. Without this information, readers cannot determine whether the reported adverse-event counts represent complete follow-up for all participants in the listed categories.

In general, missingness can affect interpretation when participants with unavailable measurements differ systematically from those with recorded outcomes. An analysis population definition clarifies who contributes to each estimate; a missing-data strategy explains how absent observations are treated. Neither should be inferred from the enrollment figure alone. The existence of a category with baseline viral load not documented does not establish how missing outcome values were handled. These reporting gaps limit assessment of both precision and potential bias.

11. Safety Results

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

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: coronary artery disorder (0.4%), diarrhoea (0.4%), gastroenteritis (0.4%).

The serious adverse-event results give the number of affected patients alongside the number at risk in each listed category. The registry reports 2 serious adverse events among patients switching from nevirapine immediate release and 0 in each of the other four categories: treatment-naïve patients, pretreated patients with baseline viral load ≤ 50 Copies/ML, pretreated patients with baseline viral load > 50 Copies/ML, and patients with baseline viral load not documented. These are the posted counts, not a comparison against an untreated group.

The registry also reports 0 non-serious adverse events in each category. A zero count means no affected participants were recorded in that category’s posted results; it does not establish that the event cannot occur. The record does not report confidence intervals, event-collection details, or a formal analysis of these counts. Death counts are not reported in the registry record.

Coronary artery disorder, diarrhoea, and gastroenteritis are each listed among the top serious terms at 0.4%. The record does not explain the denominator or term-coding details for these percentages. They should be read as the listed percentages, not as evidence of causation or as a basis for comparing patient groups. Because the study is uncontrolled, the reported events cannot be attributed to treatment on the basis of these figures alone.

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

The results have a limited but useful descriptive meaning: the registry records safety-event counts among patients receiving nevirapine extended release in routine clinical practice, across several patient categories. In the listed safety results, serious events were recorded for 2 patients in the nevirapine immediate-release switching group and for 0 patients in each of the other listed groups. Non-serious adverse-event counts were 0 in all five groups. The registry lists three serious-event terms at 0.4% each.

These figures do not show whether the treatment caused an event. The study was non-interventional and uncontrolled, and treatment decisions were made independently of study participation. There is no randomized comparator, and the patient categories are not a like-for-like control comparison. Differences in clinical history or other unreported factors could affect both treatment choices and event reporting.

The record also does not provide numerical results for its listed efficacy and adherence outcomes. It therefore does not establish a comparative effect on virologic response, CD4+ cell count, adherence, or convenience. The study aim includes these areas, but aims are not results. The record’s zero analyses and absence of reported inferential results mean that estimates of effect and their precision cannot be evaluated.

In general, a descriptive result tells readers what was recorded in the observed study population. A comparative effect asks how outcomes differ under alternative treatment strategies, which requires a suitable comparison and assumptions that support causal interpretation. This record supports the former kind of reading, not the latter. It also does not establish how complete event capture was over the endpoint timeframe of up to 72 weeks.

The findings should not be extended beyond the recorded groups or treated as a guarantee of safety. They are not a substitute for a controlled comparison, and they do not quantify uncertainty around the counts. The intended observation schedule of five visits over twenty-four weeks and the primary endpoint timeframe of up to 72 weeks are both stated in the registry; how they relate is not reported.

13. Why This Trial Matters Statistically

Routine-practice observational studies address a different statistical question from randomized trials. They can record outcomes among patients treated in ordinary care, where treatment choices reflect clinical judgment and individual circumstances. That context can make descriptive safety reporting relevant, while also limiting the causal conclusions that can be drawn from the results.

This study’s structure makes that distinction especially important. It is described as prospective and non-interventional, with no control group. Its patient categories reflect treatment history and baseline viral-load documentation, rather than randomized allocation. The reported adverse-event counts therefore illustrate the kind of information a surveillance record can contain, but they cannot establish how the same patients would have fared under another regimen.

The record also illustrates why outcome definitions and follow-up periods matter. The primary endpoint counts patients reporting events, including events leading to treatment discontinuation, and gives a timeframe of up to 72 weeks. The study summary describes five planned visits over twenty-four weeks. Because the relationship between these timeframes is not explained, readers should be cautious about assuming uniform event observation over the endpoint period.

Statistically, the record is also a reminder to distinguish study aims from reported analyses. Safety, efficacy, and adherence were study aims, and several secondary outcomes are named. Yet the record lists zero analyses and does not provide numerical results for those secondary outcomes. Without estimates, uncertainty measures, and an analysis plan, the scope for inferential conclusions is limited.

These features do not make descriptive results meaningless. They define what the results can answer: what events were recorded in the listed groups, rather than whether treatment changes risk compared with an alternative. Keeping that distinction clear helps prevent overinterpretation of observational safety data.

14. 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 main limitation is the uncontrolled, non-interventional design. Treatment was initiated independently of the study, and there is no randomized or other control group in the registry record. The results therefore cannot isolate a treatment effect from differences in patient characteristics, clinical decisions, or other influences on outcomes.

The record lists adverse-event counts for patient categories but does not report confidence intervals, adjusted analyses, or a statistical test. It also does not describe event-collection procedures, event adjudication, or how repeated events were treated. These omissions constrain interpretation of the completeness and precision of the safety results.

The registry describes five visits over a twenty-four week observational period, while the primary endpoint timeframe is up to 72 weeks. The record does not explain how those timeframes fit together or whether follow-up was consistent across participants. It also does not report participant flow, outcome-specific analysis populations, or missing-data procedures. Enrollment of 398 alone does not establish how many participants contributed data to each endpoint.

Although the study aimed to examine efficacy and adherence, numerical results for the listed secondary outcomes are not reported in the registry record. The record lists seven outcome measures and zero analyses; a statistical analysis plan, sample-size justification, multiplicity approach, and interim analyses are not reported. This prevents assessment of planned contrasts, outcome prioritization, and the precision intended for the study.

The meaning of the serious-event term percentages and the denominator used for them are not explained in the record. Death counts are not reported. These gaps, together with the lack of a control comparison, mean that the posted results are best treated as limited descriptive surveillance information rather than a basis for comparative or causal conclusions.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Observational Study of Nevirapine Extended Release in Human Immunodeficiency Virus (HIV) Patients in Daily Clinical Practice — NCT01524900.
• Registry record last updated 2015-06-02; status last verified 2015-06.
• Results first posted 2015-06-02.
• 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.

18. Record Summary

NCT01524900 is a completed, open-label, prospective, non-interventional, uncontrolled post-marketing surveillance study of nevirapine extended release with other antiretroviral drugs in HIV-1-infected patients in routine clinical practice. The registry lists enrollment of 398, a start of 2012-03, and primary completion in 2014-05. Treatment initiation was independent of the study and based on patient need and the treating physician’s judgment.

The primary endpoint counts patients reporting non-serious and serious adverse events, including events leading to treatment discontinuation, over a timeframe of up to 72 weeks. The registry summary describes five planned visits over twenty-four weeks. Posted safety results include serious-event counts by patient category, while numerical results for the listed secondary efficacy and adherence outcomes are not reported in the registry record.

The record lists seven outcome measures and zero analyses. A control comparison, inferential estimates, and key details about analysis populations, missing data, and statistical methods are not reported. The adverse-event counts are therefore descriptive and do not establish causation or comparative treatment effects.