Metformin for Rising PSA Remote Trial: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Metformin for Rising PSA Remote Trial (NCT02376166), a na na study. The primary outcome is Number of Participants That Completed All Telemedicine Visits.

2. Clinical Question

M-RePoRT was framed as a pilot of bringing clinical-trial participation closer to patients through telemedicine. Its rationale was that travel and geographic barriers may make trial participation difficult, and that remote visits could reduce that burden. The principal question was therefore about the feasibility of the remote-visit approach, rather than a controlled test of metformin’s effect on prostate cancer or PSA.

The registry also lists secondary outcomes concerning stable PSA levels at 6 months, medication adherence measured by electronic monitoring, and patient satisfaction measured by survey questions. These outcomes could describe disease-marker patterns and participants’ experience, but the registry record does not report their results. The study’s single-group structure also means that any observed changes would not, by themselves, distinguish a treatment effect from the course of disease or other influences.

3. Trial Design

M-RePoRT is recorded as a completed, single-group study with enrollment of 15 participants. Its listed condition is prostate cancer, and the trial summary describes the target population as men with biochemically recurrent disease after definitive local therapy. The registry lists the phase and allocation as NA and masking as none. Because there is no randomized comparator, the design is not a like-for-like comparison of metformin with another treatment or with no treatment.

The intervention is metformin. The arm description states 850 mg PO once daily for 4 weeks. The primary outcome concerns completion of telemedicine visits over 6 months. The trial summary describes a single on-site visit for enrollment and remote visits during the remainder of the study. The registry record does not report further detail about the visit schedule or the medication regimen beyond the arm description.

The study was intended as a pilot addressing trial access and participation burden. That objective is distinct from establishing comparative efficacy: a single-group feasibility study can describe whether participants completed planned visits, but without a control group it cannot isolate the effect of remote care or metformin. The record lists 22 outcome measures and zero analyses. It records the study as completed, with a start of 2014-07 and primary completion of 2016-12; those dates do not establish how many participants completed follow-up.

The sponsor is listed as Matthew Galsky. The registry record does not report a formal sample-size justification, an interim-analysis plan, or a detailed statistical analysis plan. The absence of those details means the design should be interpreted from the stated pilot objective and endpoint definition, without assuming additional prespecified procedures.

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:

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.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants That Completed All Telemedicine Visits, measured over 6 months.

The primary endpoint is the number of participants who completed all telemedicine visits. It is assessed over 6 months and represents a feasibility outcome: whether participants could remain engaged with the remote-visit approach for the planned period. The endpoint does not directly measure tumor response, PSA change, or a clinical benefit from metformin.

The registry defines feasibility as completion of all telemedicine visits by > 2/3 of enrolled patients, unless treatment was discontinued early for toxicity or disease progression. This threshold gives the pilot a stated criterion for judging whether the remote follow-up approach reached its intended level of completion. The exception matters because a participant who stops treatment early for a stated clinical reason may not be classified the same way as someone who simply fails to complete visits.

The endpoint is relevant to the trial’s access-focused rationale. If participants can complete remote visits, that would describe the practicality of this model among those enrolled. It would not show that remote visits improve accrual compared with conventional trial care, because no such comparator is included. Nor would visit completion alone establish that the approach is acceptable to all eligible patients or generalizable beyond this small enrolled group.

The registry record gives the endpoint definition but does not report its result. It therefore does not establish how many participants completed all visits or whether the stated feasibility criterion was met.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a single-group design tell us?

A single-group study follows participants receiving the same intervention without assigning a separate control group. Its outcomes can describe what happened among those enrolled, including whether visits were completed or what measurements were recorded over time. It cannot directly estimate a contrast between metformin and another treatment, because no comparison group is present. Differences between a participant’s measurements at different times are not automatically treatment effects: they may also reflect disease progression, natural fluctuation, measurement variability, or other care.

Random allocation and masking are listed as NA and none, respectively. The record therefore does not describe a randomized, masked comparison. This is consistent with the pilot’s feasibility focus, but it limits causal interpretation. Findings from a small, selected group may also differ from participation in a larger or more diverse population. Generalizability depends on who was eligible, who enrolled, and how follow-up was conducted; detailed information on those matters is not reported in the registry record.

How should a completion threshold be read?

The primary outcome is a count: the number of participants completing all telemedicine visits. The stated success criterion is completion by > 2/3 of enrolled patients, except when treatment ended early for toxicity or disease progression. This is a decision rule for the feasibility question. It does not itself quantify uncertainty, and it is not the same as reporting the observed completion count. To interpret the endpoint, readers would need the result and a clear account of how early discontinuations were handled. The primary result and that accounting are not reported in the registry record.

For a binary outcome such as completion or non-completion, the count can also be expressed as a proportion, with a confidence interval describing uncertainty around that proportion. With limited enrollment, an estimate may be imprecise; a confidence interval helps show that uncertainty rather than implying that the observed proportion is exact. No primary completion estimate or interval is reported in the registry record, so its precision cannot be assessed.

What does the statistical plan establish?

The registry lists 22 outcome measures and zero analyses. It does not report a detailed statistical analysis plan, sample-size justification, interim analyses, or analysis populations. Those omissions do not show that a procedure was or was not used outside the registry entry; they mean those details are not reported in the registry record. Interpretation should not assume a particular model, adjustment, missing-data strategy, or prespecified subgroup analysis.

The record includes a general description of planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It also distinguishes total events for time-to-event illustrations from participants per arm for other outcomes. Those assumptions describe planning calculations, not the design of this single-group trial. A two-arm calculation does not create a control group in the trial, and an illustration based on an effect does not establish that the effect was observed in this study. Planning sample sizes are not observed power, and the record does not report a trial-specific sample-size justification.

Why do outcome definitions and analysis results differ?

An outcome definition specifies what investigators intended to measure, including its unit and timeframe. An analysis result adds the observed data and a statistical summary. Here, the primary endpoint is defined as a participant count over 6 months, but the registry record does not report the resulting count or an analysis. Likewise, the listed secondary outcomes identify measures of PSA stability, adherence, and satisfaction without reporting their findings. Knowing an endpoint was registered is not enough to infer its result.

For clinical measurements, statistical precision is distinct from clinical importance. A point estimate describes the observed data, while a confidence interval conveys uncertainty around that estimate under the statistical method. A p-value, if reported, assesses compatibility of data with a specified null model; it is not a measure of the size or importance of an effect. Neither an estimate nor a p-value for the primary endpoint is reported in the registry record, so these properties cannot be evaluated.

Why can over-dispersion matter?

General statistical explanation: for count outcomes, some models assume that variability follows a particular distribution. Over-dispersion means the observed counts vary more than that model expects. If over-dispersion is ignored, estimated uncertainty can be too small and statistical tests can be misleading. The primary endpoint is a count of participants completing visits, but the registry record does not report a fitted count model or an over-dispersion assessment. No such analysis should be inferred from the endpoint description alone.

Ultimately, the strongest statistical reading is bounded by what is recorded: the endpoint, its feasibility threshold, study structure, enrollment, and selected safety summaries are stated, while the primary and secondary analyses are not. That leaves the pilot’s intended question clear but its reported outcome evidence incomplete.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Metformin")
n      <- c(15)
events <- c(12)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Metformin  15  12  80.0  51.9  95.7  54.8  93.0  54.4  92.7

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 22 outcome measures, including the primary visit-completion endpoint and secondary measures of PSA stability, adherence, and patient satisfaction. When a study examines multiple outcomes, the chance of at least one apparently unusual result can increase if each is assessed separately without accounting for multiplicity. Statistical approaches can address this, but the record does not report a multiplicity strategy or identify which outcome analyses, if any, were prespecified as confirmatory. No adjustment should be assumed.

The record lists zero analyses. Results for the primary endpoint and the listed secondary outcomes are not reported in the registry record. It is therefore not possible to assess missing outcome data, compare the number analyzed with the number enrolled, or determine how incomplete follow-up was handled. The primary definition allows an exception for treatment discontinued early because of toxicity or disease progression, but the record does not report how many participants met that circumstance or how those cases entered the analysis.

Analysis populations are also not reported in the registry record. It is unclear from the entry whether any reported analyses would have included everyone enrolled, only participants with available outcome data, or another defined group. For a feasibility study, transparent accounting of visit completion and reasons for non-completion is important because missing follow-up may itself relate to the feasibility question.

The absence of these details is a limit on interpretation, not evidence that a particular analysis or missing-data method was used. The registry entry does not report an interim-analysis plan, a missing-data strategy, or a detailed statistical analysis plan.

12. 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.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: dehydration (6.7%).

The registry safety entry lists 15 participants at risk for serious adverse events, with 1 participant affected, and 15 at risk for other adverse events, with 15 affected. It lists no deaths. Dehydration is the top serious adverse event term, reported as 6.7%. These figures describe events recorded in the metformin group; they do not compare risk with an untreated or alternative-treatment group.

The serious-event count and the top-term percentage answer different descriptive questions. The count indicates how many participants were recorded as having a serious adverse event, while the term identifies dehydration among the serious-event listings. The registry record does not provide enough detail to determine whether the event occurred in the participant counted with a serious event, the event’s timing or duration, or the investigators’ assessment of relationship to treatment. No causal attribution should be inferred from the listing alone.

Because this is a single-group pilot with 15 participants, the safety entries are limited observations from the enrolled group. They do not establish how often such events would occur in a broader population or whether the intervention changed risk relative to another option. The registry record does not report further detail about event severity, management, or follow-up in this summary.

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

The registry record establishes that M-RePoRT was a completed pilot with enrollment of 15 participants and a feasibility-oriented primary endpoint: completion of all telemedicine visits over 6 months. It also states the criterion the investigators intended to use, completion by > 2/3 of enrolled patients subject to an exception for early discontinuation due to toxicity or disease progression. These details clarify the question, but they do not establish the answer.

The primary completion result is not reported in the registry record. Consequently, it is not possible to say from the posted results whether the remote-visit approach met its criterion, how many participants completed visits, or how precisely completion was estimated. Secondary outcomes are listed but their results are also not reported. The record therefore does not support conclusions about PSA stability, adherence, or patient satisfaction.

The single-group design is central to what the study can mean. The record describes metformin and remote follow-up in one group, without a control group. Even if changes in PSA or other measurements had been reported, the design would not separate the effects of metformin from the underlying course of disease, measurement variation, or other influences. It also cannot establish that telemedicine improved enrollment or access compared with another trial-delivery model.

The posted safety counts provide a limited description of events in the enrolled group, including 1 participant with a serious adverse event, dehydration listed at 6.7% among the top serious terms, and no deaths. These observations are not comparative risk estimates and do not establish causation.

Thus, the record is informative about the pilot’s rationale, population, intervention description, feasibility endpoint, and selected safety summaries. It does not report enough outcome analysis to establish whether the feasibility target was achieved or what the study found about PSA, adherence, or satisfaction. These limits concern the registry record and should not be converted into a claim that the study itself produced no additional analyses or findings elsewhere.

14. Why This Trial Matters Statistically

This trial raises a statistical question that is different from the usual treatment-comparison question: can a remote trial design support continued participation? The primary endpoint focuses on completion of telemedicine visits, linking the study’s measurement directly to its access and feasibility rationale. In clinical research, a delivery model may be promising in principle yet difficult to implement; measuring completion makes participation itself an outcome to examine.

The distinction between feasibility and efficacy matters. A pilot can describe whether its planned procedures appear workable among enrolled participants, while a controlled trial is needed to compare outcomes across assigned approaches. M-RePoRT has a single group and no randomized comparator, so its design is aligned with describing participation rather than estimating a comparative treatment effect. Its primary result, however, is not reported in the registry record, leaving the stated feasibility question unanswered in the posted results.

The trial also illustrates why endpoint definitions, thresholds, and results must be read separately. A prespecified completion criterion explains how feasibility was to be judged, but only the observed data can show whether the criterion was met. Reporting the count, reasons for missed visits, and uncertainty would allow readers to judge both implementation and precision. Those primary outcome details are not reported in the registry record.

Finally, the study’s listed secondary measures show that remote participation can be assessed alongside clinical measurements, adherence, and patient experience. Their inclusion does not guarantee that the registry provides interpretable results for each. Distinguishing registered questions from reported analyses is essential: it prevents a study’s rationale or planned outcomes from being mistaken for demonstrated findings.

15. 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.

Enrollment was 15, and the study has no control group. Findings from a small single-group pilot, even if fully reported, would be limited for estimating comparative effects and may not generalize to patients who were not enrolled. The registry record does not report participant characteristics beyond the intended population, so the representativeness of the enrolled group cannot be assessed from this entry.

The primary endpoint measures completion of telemedicine visits, not a clinical outcome. That is appropriate to the stated feasibility focus, but it cannot answer whether metformin altered PSA or disease course. Although the record lists PSA stability, adherence, and satisfaction outcomes, their results are not reported in the registry record. The primary completion result is also absent, so the pilot’s central feasibility finding cannot be assessed.

The medication description states 850 mg PO once daily for 4 weeks, while the primary endpoint timeframe is 6 months. The registry record does not report further detail about treatment exposure or the relationship between the medication schedule and the full follow-up period. The brief study summary is incomplete, so additional protocol details should not be inferred.

The record does not report a detailed statistical analysis plan, sample-size justification, analysis populations, missing-data strategy, or multiplicity approach. It therefore does not support evaluation of how outcomes were analyzed, how incomplete follow-up was handled, or how uncertainty was quantified. Safety summaries are also limited: detailed event narratives, timing, and treatment attribution are not reported in the registry record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Metformin for Rising PSA Remote Trial — NCT02376166.
• Registry record last updated 2017-12-22; status last verified 2017-11.
• Results first posted 2017-12-22.
• 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.

19. Record Summary

M-RePoRT is a completed, single-group pilot for men with biochemically recurrent prostate cancer. It records enrollment of 15 participants, no masking, and metformin as the intervention; the arm description states 850 mg PO once daily for 4 weeks.

The primary endpoint is completion of all telemedicine visits over 6 months, with feasibility defined as completion by > 2/3 of enrolled patients, subject to the stated exception for early discontinuation due to toxicity or disease progression. The record lists 22 outcome measures and zero analyses. The primary and secondary outcome results are not reported in the registry record.

The safety listing records 1 participant with a serious adverse event among 15 at risk, dehydration at 6.7% as the top serious term, and no deaths. Because there is no comparator and the outcomes are not reported, the record describes the trial’s purpose and structure but does not establish whether the feasibility criterion was met or whether metformin changed PSA outcomes.