Treatment Regimen in Menstrual Cycle Regularization and Persistence in Routine Clinical Practice in Russia, Ukraine, Kazakhstan and Uzbekistan: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Treatment Regimen in Menstrual Cycle Regularization and Persistence in Routine Clinical Practice in Russia, Ukraine, Kazakhstan and Uzbekistan (NCT01711216), a registered phase not stated study. The primary outcome is Number of Patients Received Dydrogesterone Therapy Cycles (by Cycle Number).

2. Clinical Question

3. Trial Design

This was a post-marketing, prospective, multicenter, observational program of dydrogesterone use for irregular menstrual cycles in routine clinical practice. The registry lists Russia, Ukraine, Kazakhstan and Uzbekistan in the study title. Adult women received dydrogesterone as prescribed by the treating physician. The record describes no randomized assignment and no concurrent control group, so treatment decisions remained part of clinical practice rather than a controlled comparison described by the study.

The registry lists an enrollment of 999 and a status of completed. The recorded start was 2012-08, and the primary completion date was 2014-08. These dates describe the study record; they do not establish how long any individual participant was followed. The primary outcome timeframe is stated as up to 6 months.

The stated rationale was that post-marketing data on cycle regularization and on persistence after treatment cessation were limited. The program aimed to observe possible implications of treatment length and response pattern. That aim should be distinguished from the primary outcome as listed: the number of patients receiving therapy cycles by cycle number. The registry lists 18 outcome measures, including several measures of cycle duration, bleeding duration, menstrual pain, anxiety and treatment satisfaction. Numeric results for those outcomes are not reported in the registry record.

Because treatment was given in routine practice, differences in patient characteristics, prescribing choices, follow-up and reporting may shape the observed data. The registry does not report enough detail to determine how those factors were handled analytically. In particular, the record does not describe a protocol-defined treatment schedule, randomization, or a control comparison. Findings from an observational program can characterize what was recorded in the participating clinical settings, but they cannot by themselves isolate a treatment effect from other explanations.

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: A total of 1000 patients were screened. 1 Patient failed screening and 999 were enrolled into the program.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Follow-up analysis set 915 patients. Follow-up Analysis Set (subset of FAS): Patients in the FAS for whom the last reported menstrual cycle during the treatment period was regular. Data for 55 patients was missing. Therefore, 860 patients were analyzed.

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: Full Analysis Set (FAS): All eligible patients who received at least 1 dose of program drug and at most 6 treatment cycles

6. Primary Endpoint

The registry lists the primary outcome as Number of Patients Received Dydrogesterone Therapy Cycles (by Cycle Number), measured over up to 6 months.

The primary outcome is titled “Number of Patients Received Dydrogesterone Therapy Cycles (by Cycle Number).” Its unit is participants, its parameter is a number, and its stated timeframe is up to 6 months. In practical terms, it is intended to describe how many patients received treatment cycles at different cycle numbers. This can characterize treatment continuation within the period covered by the outcome, which is relevant to the program’s stated interest in treatment length.

The endpoint is not a direct measure of cycle regularization: the title concerns treatment-cycle counts, while regular-cycle status is used in the described follow-up analysis-set definition. Nor does the endpoint, as described, establish persistence after treatment cessation. Those questions require outcome definitions and observations that distinguish treatment exposure from menstrual outcomes after treatment ends.

The record says that the follow-up analysis set included 915 patients for whom the last reported menstrual cycle during treatment was regular. Data for 55 patients were missing, and 860 patients were analyzed. The registry does not report the actual number of patients in each therapy-cycle category, so the endpoint’s numerical findings and their precision are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical interpretation starts with the study design. This was prospective and observational, with treatment given according to the treating physician’s standard clinical practice. In general, prospective observation means that information is collected as events unfold rather than reconstructed only after the fact. It does not make treatment assignment random. Because the registry describes no control group, differences in outcomes cannot be attributed to treatment by comparing randomized groups.

What the primary outcome counts

The primary outcome is a count of participants categorized by the number of dydrogesterone therapy cycles received, over a timeframe of up to 6 months. A count can describe how many people fall into each treatment-cycle category. The registry record does not give those category counts, so the distribution cannot be interpreted numerically. The title should not be mistaken for a continuous measure of menstrual-cycle duration or for a direct estimate of persistence after treatment has stopped.

In general, counts are often reported with uncertainty estimates when the aim is to quantify how precisely the observed frequencies represent a broader population. A confidence interval describes a range of values compatible with the observed data under the statistical model used. It does not remove bias from participant selection or measurement. No confidence interval for this primary outcome is reported in the registry record, so its statistical precision cannot be assessed from the posted results.

Why the analysis population matters

The outcome description identifies a follow-up analysis set of 915 patients, defined as a subset of the FAS for whom the last reported menstrual cycle during treatment was regular. Data for 55 patients were missing, and 860 were analyzed. In general, an analysis population determines which participants contribute to a result and therefore what question that result answers. A population selected according to an observed outcome can differ from the full enrolled group. The record does not report the rationale for this definition, how the missing information arose, or whether other populations were analyzed.

Missing data can affect interpretation when participants with unavailable outcomes differ from those with recorded outcomes. General approaches include analyzing available observations, making assumptions about missing outcomes, or conducting sensitivity analyses under alternative assumptions. These approaches can lead to different conclusions, so clear reporting is important. For this study, the record states the number missing and the number analyzed but does not report the missing-data method or sensitivity analyses. No assumptions about the unrecorded cycles can be made from the available information.

Reading planning calculations

In general, a sample-size calculation estimates how many participants would be needed under specified assumptions to detect a chosen effect with a chosen level of statistical power. The planning illustrations associated with the results use a two-sided significance level of 0.05, equal allocation between two arms and a normal approximation; the effect to detect is expressed as a stated fraction of the observed effect. For non-time-to-event outcomes, such illustrations are expressed as participants per arm for 80% power or 90% power. Time-to-event illustrations instead refer to a total number of events.

Those assumptions are planning illustrations, not a description of the study’s original design. The trial is observational and has no described randomized two-arm comparison, so equal allocation between arms does not characterize the program’s actual treatment assignment. Such calculations are not observed power and do not demonstrate that the study was adequately sized for its endpoint. The registry record does not report a sample-size justification for the observational program, and no such rationale should be inferred from a planning illustration based on an observed effect.

Multiplicity and model assumptions

Multiplicity arises when several outcomes or comparisons are examined: the chance of at least one apparently notable result can increase as the number of statistical tests grows. The registry lists 18 outcome measures. In general, researchers may address multiplicity by defining a primary outcome in advance, using an adjustment, or treating secondary analyses as exploratory. The registry record does not report a multiplicity adjustment, a hierarchy of tests, or enough detail to determine how the outcomes were interpreted together.

Statistical models also rely on assumptions about the data. For counts, one general concern is over-dispersion: the observed variability may exceed what a simple count model expects. When that occurs, standard errors from an unsuitable model may be too small, making uncertainty appear lower than it is. The registry record does not report a model for the primary outcome or diagnostics for its assumptions. This is a general consideration, not a claim that over-dispersion occurred in this study.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 18 outcome measures, covering treatment-cycle counts, regular cycles, cycle and bleeding duration, menstrual pain, anxiety and satisfaction. Examining multiple outcomes can make chance findings more likely in general, especially when each is tested separately. Statistical practice may address this through a prespecified hierarchy or multiplicity adjustment, or by clearly treating secondary analyses as exploratory. Neither an adjustment nor a testing hierarchy is reported in the registry record. Without that information and without the numeric results, the combined evidence across outcomes cannot be evaluated.

For the primary outcome, the registry describes a follow-up analysis set of 915 patients, defined by a regular last reported menstrual cycle during treatment. It states that data for 55 patients were missing and that 860 patients were analyzed. The record does not explain why those data were missing, how missingness was handled beyond reporting the analyzed number, or whether sensitivity analyses were performed. In general, missingness can bias an estimate if the availability of an observation is related to the outcome or to participant characteristics. Whether that concern applies cannot be determined from the registry record.

The registry does not report whether results were also analyzed in the full enrolled population or under alternative analysis-population definitions. The primary outcome’s conditional analysis-set definition should therefore be kept in view: it does not describe an analysis of all enrolled participants. The available information is insufficient to assess how the population definition and missing observations affect the reported endpoint, whose numerical result is itself not reported in the registry record.

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 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: abortion missed (0.1%), ectopic pregnancy (0.1%).

The safety figures list 986 patients at risk for both serious and other adverse events. The record reports 2 patients with serious adverse events and 14 with other adverse events. It also lists “Abortion missed” and “Ectopic pregnancy” as the top serious adverse-event terms, each at 0.1%. These are descriptive figures recorded during the study; they are not a comparison against an untreated group or another treatment.

In general, an adverse event occurring during a study does not, by itself, show that the study treatment caused it. Causal interpretation depends on factors such as timing, clinical assessment, background risk and comparison data. The registry record does not provide a controlled safety comparison or enough detail to make a causal assessment. The listed percentages and counts should therefore be read as reported event information, not as evidence that an event was or was not caused by dydrogesterone.

The record does not report additional detail needed to interpret event timing, duration, outcomes or participant-level exposure. Nor does it provide enough information to assess whether all events were captured in the same way across sites. The reported safety counts are useful as a description of what was recorded, but they do not establish comparative risk or explain the clinical circumstances of individual events.

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

The posted record describes a prospective observational program of dydrogesterone use for irregular menstrual cycles in routine practice. It identifies a primary outcome focused on the number of patients receiving therapy cycles by cycle number and states that the outcome timeframe was up to 6 months. It also describes a follow-up analysis set and reports that data for 55 patients were missing, with 860 patients analyzed.

The registry record does not report the primary outcome values or numerical results for the listed secondary outcomes. Consequently, the available information cannot show how treatment-cycle counts were distributed, how often regular cycles were reported, or the size of any changes in cycle duration, bleeding, pain or anxiety. The record’s stated interest in persistence after treatment cessation does not substitute for reported post-treatment outcome data. The listed endpoint concerns therapy cycles, and its numerical result is not reported.

The safety information is descriptive: 2 serious adverse events and 14 other adverse events were reported among 986 at risk, and two serious terms are listed at 0.1% each. Without a randomized comparator or other controlled comparison, these figures do not estimate whether treatment changed event risk. They also do not establish that an event was caused by treatment.

In general, observational findings can help describe clinical practice and generate questions for further study. They are vulnerable to differences between patients, treatment decisions and follow-up that are not controlled by randomization. In this record, missing outcome data, the conditional analysis-set definition, and the absence of reported outcome values further limit interpretation. The record does not support a conclusion about treatment efficacy, comparative effectiveness, or causal safety. It documents the study’s purpose, design and some safety counts, while leaving the principal outcome findings unreported.

13. Why This Trial Matters Statistically

This record illustrates why study design and result availability both matter when interpreting clinical statistics. A prospective observational program can describe treatment use in routine practice, including how many therapy cycles patients receive if those counts are reported. It is not equivalent to a randomized trial: treatment decisions were made according to the treating physician’s standard clinical practice, and no concurrent control group is described. Any observed pattern would therefore need to be interpreted as an association within the recorded care setting, not automatically as a treatment effect.

The primary outcome is especially relevant to the program’s stated interest in treatment length. Its focus on therapy cycles by cycle number could describe continuation during the stated timeframe of up to 6 months. However, the registry record does not report the cycle-category results, so that descriptive question cannot be answered from the posted information. The broader interest in persistence after cessation also requires keeping treatment exposure distinct from outcomes observed after treatment has ended.

Analysis-population details are another important statistical feature. The record defines a follow-up analysis set by regularity of the last reported menstrual cycle during treatment, then notes missing data for 55 patients and analysis of 860. These details affect who contributes to the endpoint and should be considered before interpreting any result. The registry record does not report the missing-data method or sensitivity analyses.

Finally, the record lists 18 outcome measures but does not report numeric results for them. Multiple outcomes raise general questions about how findings were prioritized and whether multiplicity was considered; those methods are not reported. The record is therefore informative about the observational design and intended questions, but the absence of outcome values sharply limits statistical conclusions.

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.

Several limitations are specific to the information reported for this program. First, the registry describes no randomized allocation or concurrent comparator. Treatment was prescribed according to the treating physician’s standard clinical practice, so patient and clinician choices may be related to outcomes. The record does not provide a basis for separating a treatment effect from differences in care or participant characteristics.

Second, the primary outcome values are not reported in the registry record. Although the endpoint is described as the number of patients receiving therapy cycles by cycle number, the actual category counts and any uncertainty estimates are unavailable. The secondary outcomes are listed, but their numeric results are also not reported. The stated interest in persistence after treatment cessation cannot be evaluated without corresponding reported post-treatment results.

Third, the analysis population is restricted to a follow-up set defined by a regular last reported menstrual cycle during treatment. The record reports data missing for 55 patients and analysis of 860, but does not explain the missingness, the method used to handle it, or whether sensitivity analyses were conducted. The effect of this population definition and missing information cannot be assessed.

Fourth, the record lists 18 outcome measures but does not report a testing hierarchy or multiplicity method. It also does not report the statistical model or assumptions used for the primary outcome. Finally, the safety counts lack a controlled comparison and do not establish causation. These limitations constrain interpretation of treatment patterns, outcomes and safety from the posted record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Treatment Regimen in Menstrual Cycle Regularization and Persistence in Routine Clinical Practice in Russia, Ukraine, Kazakhstan and Uzbekistan — NCT01711216.
• Registry record last updated 2015-12-22; status last verified 2015-11.
• Results first posted 2015-10-30.
• 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

The registry describes a completed, prospective, multicenter, observational post-marketing program of dydrogesterone for irregular menstrual cycles in routine clinical practice in Russia, Ukraine, Kazakhstan and Uzbekistan. The listed enrollment is 999. The recorded study start was 2012-08, and the primary completion date was 2014-08.

The primary outcome concerns the number of patients receiving therapy cycles by cycle number, with a timeframe of up to 6 months. Its follow-up analysis set is described as 915 patients; data for 55 were missing, and 860 were analyzed. The registry lists 18 outcome measures, but numerical results for the primary and secondary outcomes are not reported in the registry record.

For safety, the record lists 2 patients with serious adverse events and 14 with other adverse events among 986 at risk. “Abortion missed” and “Ectopic pregnancy” are listed as serious terms at 0.1% each. The observational design and lack of a described control group limit causal interpretation of these figures.