This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Demonstrating the Clinical and Economic Benefit of 5 Alpha Reductase Inhibitor Adherence in Benign Prostatic Hyperplasia (NCT01334723), a registered phase not stated study. The primary outcome is Number of Participants With Risk of Acute Urinary Retention and Surgery Based on an MPR Threshold of 70%.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01334723 |
| Phase | Phase not stated |
| Condition | Prostatic Hyperplasia |
| Allocation | Not Stated |
| Design model | Not Stated |
| Masking | Not Stated |
| Enrollment | 35032 |
| Arms in the primary outcome | n/a |
| Lead sponsor | GlaxoSmithKline |
| Results posted | Yes |
2. Clinical Question
Population
Participants in the IHCIS database with a claims diagnosis of benign prostate hyperplasia or enlarged prostate were eligible under the registry description. Participants also needed at least 60 days of 5-ARI therapy during the enrollment period. The remaining eligibility detail is not reported in the registry record.
Intervention
The exposure of interest was adherence to 5-alpha-reductase inhibitor therapy, measured using the medication possession ratio (MPR). The record defines MPR as days on therapy divided by total follow-up days, and uses MPR = 70% as the adherence threshold for the primary analysis.
Comparator
The registry lists participants adherent with 5-ARI therapy and participants non-adherent to therapy. These are exposure groups in a retrospective database study, not groups described as randomly assigned. The record does not state how treatment adherence was assigned or whether other differences between groups were adjusted for.
Primary question
Was MPR-based adherence associated with claims-defined acute urinary retention or prostate surgery during the stated follow-up period? The registry describes analyses of the association but does not report event counts, comparative estimates, confidence intervals, or p-values for these outcomes. The strength and precision of any association therefore cannot be assessed from the registry record.
3. Trial Design
This is a retrospective study using the Integrated Health Care Information Solutions database, described as covering 2000-2006. The registry gives an enrollment of 35032 and labels the study completed. The listed start and primary completion dates are both 2010-04. The study was sponsored by GlaxoSmithKline.
The registry describes two exposure categories: adherence to 5-alpha-reductase inhibitor therapy and non-adherence. It does not describe random allocation; the record explicitly notes that allocation is not stated and that the arms are not a like-for-like control comparison. The exposure groups should therefore be understood as observational categories based on therapy adherence, rather than assigned treatment groups.
The primary outcome concerns acute urinary retention (AUR) and prostate surgery. Separate outcome cohorts are identified for AUR and surgery. The registry defines AUR using claims codes and surgery using procedure codes, and describes MPR as the adherence measure. The primary analysis applies an MPR threshold of 70%. Listed secondary outcomes include mean length of 5-ARI therapy, BPH-related costs across several MPR thresholds, and costs for every 30 days of therapy.
The record does not report the full eligibility criteria, the method used to identify or classify adherence beyond the MPR description, the handling of confounding, or the statistical analysis plan. It also does not report the number of participants included in each outcome cohort. The enrollment figure should not be treated as the analysis size for either endpoint.
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: Patients were not recruited for nor enrolled in this study. This study is a retrospective observational study. Data from medical records or insurance claims databases are anonymized and used to develop a patient cohort. All diagnoses and treatments are recorded in the course of routine medical practice.
Overall Study
| Stage | Acute Urinary Retention Outcomes Cohort | Prostate Surgery Outcomes Cohort |
|---|---|---|
| STARTED | 17293 | 17739 |
| COMPLETED | 17293 | 17739 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: Enrolled Population: participants in the IHCIS database with a diagnosis of benign prostate hyperplasia or enlarged prostate as indicated by ICD-9-CM code on claims (222.2x or 600.xx). Participants were included if they had at least 60 days of 5-ARI therapy during the enrollment period, 6 months of continuous enrollment, and no prior surgery.
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.
| Characteristic | Unit | Acute Urinary Retention Outcomes Cohort | Prostate Surgery Outcomes Cohort | Total |
|---|---|---|---|---|
| Participants analysed | 17293 | 17739 | 35032 | |
| Age, Customized: Age >= 50 | participants | 17293 | 17739 | 35032 |
| Age, Customized: Age < 50 | participants | 0 | 0 | 0 |
| Sex: Female, Male: Female | Participants | 0 | 0 | 0 |
| Sex: Female, Male: Male | Participants | 17293 | 17739 | 35032 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants With Risk of Acute Urinary Retention and Surgery Based on an MPR Threshold of 70%, measured over The 5 and a half year period from January 1, 2000 to June 30, 2006.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is titled “Number of Participants With Risk of Acute Urinary Retention and Surgery Based on an MPR Threshold of 70%.” It concerns the association between 5-ARI adherence and two outcomes: acute urinary retention and prostate surgery. The registry describes the endpoint unit as participants and the parameter as a number. The stated timeframe is the 5 and a half year period from January 1, 2000 to June 30, 2006.
For AUR, the record specifies a claims-based definition using ICD-9-CM codes 599.6x, 788.20, or 788.29. Surgery is defined using CPT procedure codes, but the specific codes are not reported in the registry record. MPR is defined as the number of days that 5-ARI therapy was taken divided by the total number of follow-up days. For the primary analysis, MPR = 70% is the threshold used to distinguish the adherence categories.
These outcomes are used to examine whether adherence categories were associated with clinically consequential events recorded in claims. A participant count alone does not show how common an event was within a group or how groups compare; interpretation also depends on the relevant group denominators and comparative estimate. Those endpoint results are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry describes a retrospective analysis of the relationship between 5-ARI adherence and the likelihood of AUR or prostate surgery. It gives the exposure definition and claims-based outcome definitions, but does not provide the observed counts or comparative results for either outcome. As a result, the record does not establish the direction, magnitude, or statistical precision of an association.
The primary analysis uses MPR = 70% as its adherence threshold. MPR is a measure based on medication availability over follow-up, not direct confirmation that medication was taken. The registry’s definition describes days of therapy relative to follow-up days. The record does not report details about how days of therapy or follow-up were derived, or how periods with incomplete claims information were handled. Such details matter because the exposure classification depends on those measurements.
The listed enrollment is 35032, but the record does not report how many participants contributed to the AUR analysis or the surgery analysis. The outcome cohorts are identified separately, so the enrollment figure should not be read as the denominator for either endpoint. Without the group-specific denominators and event counts, absolute event frequencies cannot be interpreted from the registry record.
No comparative effect estimate, confidence interval, or p-value is reported for the primary endpoint. A confidence interval, in general, describes the range of effect estimates compatible with the data and analysis under its assumptions. Without an estimate and interval, readers cannot judge either the estimated association or its precision. The registry also does not report whether the analyses adjusted for other participant characteristics or differences in follow-up.
The observational design is important to interpretation. Adherence status was not described as randomly assigned, and the registry states that the arms are not a like-for-like control comparison. Differences between adherence groups could reflect factors other than adherence. Whether such factors were measured and addressed is not reported in the registry record. Consequently, even if a difference were reported elsewhere, the registry information alone would not show that adherence caused it.
The registry lists secondary outcomes on therapy duration and BPH-related costs, including comparisons at MPR thresholds of 70%, 75%, and 80%, and costs for every 30 days of therapy. Their numerical results are not reported in the registry record. The record identifies 8 outcome measures and 6 analyses, but does not explain how those analyses relate to each outcome or how multiplicity was handled.
9. Statistical Methods Explained
The registry’s methods description centers on an observational exposure measure, a claims-based outcome definition, and a comparison between adherence categories. The available description is sufficient to explain the intended questions, but not to reproduce the analyses or evaluate their numerical results. Key details about the analytic methods and findings are not reported in the registry record.
How is adherence represented?
MPR is defined as days that 5-ARI therapy was taken divided by total follow-up days. The primary analysis uses MPR = 70% as its threshold. This converts a continuous measure into adherence categories for the stated comparison. Categorization can make groups easier to describe, but it also discards information about variation within each category. Participants near the threshold may be classified differently despite having similar MPR values. These are general features of threshold-based analyses; the registry does not report whether any alternative exposure definitions were tested.
The record does not give further operational detail about calculating MPR, including the underlying claims rules, the handling of overlapping prescriptions, or the definition of follow-up for this calculation. It also does not report whether adherence was treated as fixed or allowed to vary over time. These details can affect how participants are classified and how exposure relates temporally to an outcome.
How are the outcomes defined?
AUR is identified using the specified ICD-9-CM codes 599.6x, 788.20, or 788.29. Surgery is identified using CPT procedure codes, but the specific codes are not listed. Claims codes are administrative records rather than direct descriptions of clinical adjudication. In general, a claims-based definition relies on the accuracy and completeness of coding. The registry does not report validation of either outcome definition, nor does it state whether an event had to meet additional requirements to be counted.
The primary endpoint title refers to the number of participants with risk of AUR and surgery. The description says the analysis evaluates the association between compliance and risk of either outcome. However, the record does not provide event counts, group denominators, risk estimates, or a detailed specification of the effect measure. It is therefore not possible to determine from the registry record whether the reported analysis used a particular comparative measure or how follow-up time was incorporated into the estimate.
What does the record say about statistical testing?
The registry does not report the statistical model, covariates, variance estimator, missing-data method, or inferential procedure used for the primary analysis. It does not state whether estimates were adjusted, how uncertainty was calculated, or whether assumptions were checked. Those methods should not be inferred from the fact that the study compares groups or from the endpoint label.
In general, over-dispersion matters when the variability in an outcome is greater than a model assumes. If a model underestimates variability, its uncertainty estimates may be too narrow. This general point does not establish that over-dispersion was present or relevant in this study. The outcome model and any assessment of dispersion are not reported in the registry record.
The registry lists sample-size assumptions for planning illustrations: a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation, with the effect to detect set as a stated fraction of the observed effect. For time-to-event tables, the assumptions describe total events using Schoenfeld; other illustrations are described as participants per arm. These are planning illustrations based on an observed effect, not the study’s own design justification and not observed power. The registry does not report a design-stage sample-size justification. The observed effect and the fractions used for the illustrations are not reported in the registry record.
Because the registry gives no outcome estimates, the planning assumptions cannot be used to reconstruct the results or establish whether an analysis had adequate precision. Sample-size illustrations are conditional on assumptions about the effect to detect, allocation, and analysis. They do not substitute for reporting the observed effect and its uncertainty.
10. Multiplicity, Missing Data and Analysis Populations
The registry identifies 8 outcome measures and 6 analyses. It lists the primary outcome concerning AUR and surgery, as well as secondary outcomes for mean length of 5-ARI therapy, BPH-related costs at MPR thresholds of 70%, 75%, and 80%, and BPH-related costs for every 30 days of therapy. The record does not specify which analyses correspond to each outcome measure, whether additional comparisons were conducted, or which outcomes were designated as primary for statistical testing beyond the primary endpoint description.
Multiplicity arises when researchers assess several outcomes, comparisons, or analyses. In general, the chance of obtaining at least one apparently unusual result can increase as the number of tests increases, depending on their relationships and the testing approach. The registry record does not report whether any multiplicity adjustment or other strategy for interpreting multiple analyses was used. It also does not report a prespecified hierarchy for interpreting the listed outcomes.
Handling of missing data is not reported in the registry record. The record does not describe missing claims, incomplete follow-up, gaps in pharmacy data, exclusions due to unavailable variables, or methods for addressing missing observations. The full population description is incomplete: it states that eligible participants had at least 60 days of 5-ARI therapy and then begins a further criterion referring to 6 months, but the remainder is not reported in the registry record.
The record does not provide participant counts for the analysis populations or explain whether all eligible participants were included in each outcome analysis. Enrollment of 35032 is reported, but it cannot be assumed to be the denominator for the AUR or surgery analysis. The definitions of the analysis populations, exclusions after cohort identification, and flow of participants through the analyses are not reported.
11. What the Result Does, and Does Not, Mean
The registry record establishes that the study was designed to examine an association between 5-ARI adherence and AUR or prostate surgery in a claims database. It specifies MPR as the adherence measure, gives a threshold of 70% for the primary analysis, and describes claims-based outcome definitions. It also identifies additional therapy-duration and cost outcomes.
It does not report the comparative results needed to judge whether the adherence categories differed in AUR or surgery outcomes. Event counts, denominators, effect estimates, confidence intervals, and p-values are not reported in the registry record. Therefore, the record does not show the direction or size of any association, nor how precisely it was estimated. The absence of these results in the registry record is not evidence that the groups had equal outcomes.
Even a reported association would not, by itself, establish that adherence caused a change in outcomes. This is a retrospective study with exposure categories based on therapy adherence, and the record does not describe random assignment. It also does not report whether possible differences between groups were measured or adjusted for. General statistical interpretation of observational comparisons must account for the possibility that observed differences reflect factors other than the exposure being studied.
The enrollment figure of 35032 should not be read as the number analyzed for either endpoint. The registry identifies separate outcome cohorts but does not state their sizes. Likewise, the listed planning assumptions do not establish the precision or power of the observed analyses. Sample-size illustrations are planning exercises, not observed power, and the registry’s observed effect values are not reported.
Accordingly, the record is informative about the study question and its intended measures, but it is insufficient for judging the magnitude, uncertainty, or causal meaning of the findings. Numerical outcome results and fuller analytic details are not reported in the registry record.
12. Why This Trial Matters Statistically
This study raises a useful statistical question about how an exposure defined from longitudinal claims data relates to later clinical events and health-care costs. Its design also highlights a distinction that is central to clinical research: observing different outcomes among adherence categories is not equivalent to assigning a treatment and comparing randomized groups. The registry explicitly notes that allocation is not stated and that the arms are not a like-for-like control comparison.
The MPR threshold makes the exposure operational and connects the primary analysis to a stated adherence definition. At the same time, a threshold-based comparison depends on how medication days and follow-up are measured, and it can conceal variation within the resulting categories. Clear reporting of the exposure construction and sensitivity analyses would help readers understand how dependent conclusions are on the chosen threshold; such details are not reported in the registry record.
The outcome definitions also illustrate the trade-off in using administrative claims. Claims permit analysis of recorded diagnoses and procedures over a specified period, while interpretation depends on coding rules and data completeness. The registry gives codes for AUR but not the CPT codes for surgery, and it does not report validation of the claims definitions.
Most importantly, statistical interpretation requires estimates and uncertainty, not just a research question and an enrollment figure. Without group-specific event counts, denominators, comparative estimates, or confidence intervals, readers cannot assess effect size or precision. The record therefore demonstrates why outcome reporting and transparent methods are essential to evaluating an observational study, while not providing enough results to draw conclusions about the association under study.
13. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The registry record leaves important design and analysis details unspecified. It does not report the full eligibility criteria: the population description ends after a reference to 6 months of, without completing the criterion. The exact construction of the analysis cohorts and the number of participants included in the AUR and surgery analyses are also not reported.
The record identifies AUR with ICD-9-CM codes 599.6x, 788.20, or 788.29, but does not report validation of this claims-based definition. Surgery is identified using CPT procedure codes, although the codes themselves are not reported in the registry record. It does not describe how claims gaps, outcome timing, or repeated events were handled.
Although MPR is defined and the primary threshold is stated, further details on the derivation of therapy days and follow-up days are not reported. The record does not say whether adherence was updated over time or how exposure classification was aligned with outcome follow-up. It also does not describe whether other factors were adjusted for, or how confounding was assessed.
Finally, the registry does not report primary outcome counts, group denominators, effect estimates, confidence intervals, or p-values. Missing-data procedures, the statistical model, and multiplicity handling are not reported. These omissions prevent an independent assessment of the results’ magnitude, precision, and robustness from the registry record.
14. Related Tutorials
15. Related Statistical Calculators
16. Sources
- ClinicalTrials.gov: Demonstrating the Clinical and Economic Benefit of 5 Alpha Reductase Inhibitor Adherence in Benign Prostatic Hyperplasia — NCT01334723.
- Registry record last updated 2017-05-30; status last verified 2017-05.
- Results first posted 2011-11-28.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
17. Record Summary
NCT01334723 is a completed retrospective study sponsored by GlaxoSmithKline. It uses the IHCIS database, described as covering 2000-2006, to examine associations between 5-ARI adherence and AUR or prostate surgery among participants with benign prostatic hyperplasia or enlarged prostate. The registry reports enrollment of 35032 and lists 2010-04 as both the start and primary completion date.
The primary analysis uses MPR = 70% as the adherence threshold. AUR is identified using specified ICD-9-CM codes, while surgery is defined using CPT procedure codes. Secondary outcomes concern therapy duration and BPH-related costs. The registry does not report the comparative outcome results, analytic cohort sizes, or sufficient statistical details to assess the estimates’ precision or causal interpretation.