Depo Provera Self-Administration Study: Putting a Patient-Centered Practice to the Test at Planned Parenthood: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Depo Provera Self-Administration Study: Putting a Patient-Centered Practice to the Test at Planned Parenthood (NCT02509767), a randomized phase 4 study. The primary outcome is Number of Participants With Depot Medroxyprogesterone Acetate (DMPA sc) Continuation at One Year by Self-report in Both the Self- and Clinic Administration Arms.

2. Clinical Question

The trial addresses a question about how the contraceptive injection is administered, rather than a comparison between different medications. Its primary endpoint is continuation by self-report at one year. That endpoint captures whether participants reported continuing DMPA sc; it is not a direct measure of injection technique, a clinical examination, or a record of every scheduled dose.

The registry describes the investigators’ hypothesis that continuation would be higher among self-injection users. The posted outcome counts show more participants with reported continuation in the self-administration arm than in the clinic-administration arm, and the unadjusted risk-difference estimate is positive. The estimate and its confidence interval describe the size and uncertainty of that observed between-arm contrast. They do not establish that the same contrast would occur in other settings or populations.

3. Trial Design

The registry record describes a completed, randomized, parallel-group, phase 4 trial with no masking. The sponsor is Planned Parenthood Federation of America. The study start is recorded as 2015-08 and primary completion as 2017-04. The brief summary describes recruitment at two Planned Parenthood affiliates and follow-up for one year. The trial compared self-administration of subcutaneous depot medroxyprogesterone acetate (DMPA sc) with clinic administration, described as usual or standard care.

The registry lists enrollment as 401. The brief summary says that a total of 400 female patients ages 15-44 requesting DMPA would be randomized. These are different record statements: the former is the recorded enrollment, while the latter describes the planned total in the summary. The outcome results use arm-specific denominators of 157 for self-administration and 159 for clinic administration. Those denominators apply to the posted primary outcome results and should not be treated as a complete accounting of all enrolled participants or as evidence about why results are unavailable for others.

In the self-administration arm, the description says participants would be taught by a nurse or other qualified personnel using instructions based on the packaging insert; the description is truncated after that point in the registry record. In the clinic arm, a qualified person administered the injection and participants received standard care. The record describes an unmasked trial, so participants and personnel were not masked to the assigned administration approach.

The primary outcome was self-reported DMPA sc continuation at one year, measured by self-administered questionnaire. The registry also lists satisfaction, satisfaction with home use, and costs among the secondary outcomes. A detailed account of allocation procedures, concealment, adherence procedures, and the original sample-size justification is not reported in the registry record. The recorded status is completed, but that status alone does not supply further information about conduct or analysis.

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

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: One subject who was randomized to the self-administration arm enrolled and immediately withdrew from the study. Therefore the total number enrolled was 401, but the total number analyzed was 400.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Depot Medroxyprogesterone Acetate (DMPA sc) Continuation at One Year by Self-report in Both the Self- and Clinic Administration Arms, measured over 12 months from enrollment.

The primary endpoint counts participants who reported continuing DMPA sc at one year. The registry defines the assessment as self-report by self-administered questionnaire, with the timeframe given as 12 months from enrollment. The posted counts are 108 of 157 in the self-administration arm and 85 of 159 in the clinic-administration arm.

Continuation is relevant to the trial’s stated question because the investigators proposed that self-administration might be associated with greater continuation than standard clinic administration. A binary endpoint makes the comparison a contrast in the proportion of participants meeting the recorded continuation outcome. The registry’s count-based outcome therefore describes how many participants in each arm reported continuation, while the risk difference expresses the between-arm contrast in proportions.

Self-report is the measurement method specified for this endpoint. The registry record does not report a validation method, a definition of continuation beyond the description in the outcome title, or a separate measure based on clinic records. It also does not explain how missing questionnaire responses were handled. These details matter when interpreting what the endpoint represents: the posted result concerns reported continuation, not necessarily independently verified medication use throughout follow-up.

The endpoint is not a measure of satisfaction, cost, safety, or correct injection technique. Those are separate issues in the registry’s listed outcomes. The primary comparison should therefore be read narrowly as a comparison of self-reported DMPA sc continuation at one year between the randomized administration approaches.

7. Results Posted in the Registry

• Self-Administration: 68.8% (108/157) versus 53.5% (85/159) on control; risk difference 15.3 percentage points (95% CI 4.7 to 25.9), risk ratio 1.29 (1.08–1.54); unadjusted two-proportion z-test p = 0.005.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Number of Participants Who Were Satisfied With Depot Medroxyprogesterone Acetate (DMPA sc) at One Year by Self-Report in Both the Self- and Clinic Administration Arms

• Endpoint type: Binary: the number of participants with the event, compared as proportions.
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Self-Administration: 87.3% (137/157) versus 92.5% (147/159) on control; risk difference -5.2 percentage points (95% CI -11.8 to 1.4), risk ratio 0.94 (0.88–1.02); unadjusted two-proportion z-test p = 0.126.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Self-Administration and the control. The interval gives the range of effects that remain compatible with the data.

The registry identifies satisfaction with DMPA sc, satisfaction with home use in the self-administration arm, and costs associated with contraceptive care as secondary outcomes. A posted comparison is available for satisfaction with DMPA sc at one year in both arms. The results for satisfaction with home use and costs are not reported in the registry record. The overall secondary evidence is therefore incomplete: it can add limited context to the primary continuation finding, but it cannot provide a full account of the listed secondary questions.

The posted satisfaction comparison does not establish a clear between-arm difference. That result should not be treated as a contradiction of the primary continuation comparison, because satisfaction and continuation are different outcomes and capture different aspects of participants’ experience. A participant’s report of continuation does not determine satisfaction, and satisfaction does not establish continued use. The outcomes may be related, but the registry record does not report an analysis of that relationship.

Secondary outcomes generally carry less weight than the primary outcome when they are exploratory, when a plan for their analysis is not reported, or when several outcomes are examined. Testing multiple hypotheses increases the chance that at least one result may appear notable by chance unless the analysis accounts for multiplicity. The registry record does not report whether an adjustment or hierarchy was prespecified, and the results for several listed secondary outcomes are unavailable. The secondary findings should therefore be treated as supportive or exploratory rather than as equivalent evidence to the primary endpoint.

Because the registry does not report numerical results for every listed secondary outcome, it is not possible to judge their direction, magnitude, or precision. The posted results support a cautious reading: the primary endpoint addresses continuation, while the available secondary satisfaction result offers a separate and less conclusive perspective. The unreported home-use and cost outcomes cannot be used to strengthen or weaken the primary comparison.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Number of Participants Who Were Satisfied With Depot Medroxyprogesterone Acetate (DMPA sc) at One Year by Self-Report in Both the Self- and Clinic Administration Arms
• Number of Participants Who Were Satisfied With Home Use of Depot Medroxyprogesterone Acetate (DMPA sc) at One Year by Self-Report in the Self-Administration Arm
• Costs Associated With Contraceptive Care

9. Statistical Interpretation

10. Statistical Methods Explained

The principal effect measure is the risk difference. For a binary outcome, each arm’s risk is the proportion of participants with the event—in this trial, self-reported continuation. The risk difference subtracts the comparator-arm proportion from the intervention-arm proportion. A positive value means the event proportion is higher in the intervention arm; a negative value means it is lower. Here the posted estimate is 0.153 for self-administration relative to clinic administration. This is an absolute contrast in proportions, not a ratio.

What does the confidence interval express?

A confidence interval describes the uncertainty around an estimated effect under the assumptions of the statistical method used. The primary risk-difference interval extends from 0.047 to 0.259. Because the interval lies above zero, the values supported by this interval indicate a positive unadjusted contrast. The interval does not mean that there is a 95% probability that the true effect lies inside these particular limits. Nor does it account automatically for issues not represented by the statistical model, including outcome measurement error, missing data, or limitations in generalizability.

What does the p-value add?

The unadjusted p-value for the primary comparison is 0.005. A p-value describes how incompatible the observed data are with a null hypothesis of no difference, under the assumptions of the test. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of an effect. The risk-difference estimate and its interval provide information about magnitude and precision; the p-value is a related but different summary of evidence against the null model.

The registry marks the trial as randomized, which supports a comparison based on assigned groups in principle. In a randomized trial, assignment is intended to reduce systematic differences in baseline characteristics between groups. Randomization does not guarantee identical groups, and it does not resolve problems arising after assignment, such as incomplete follow-up or outcomes measured differently. The registry record does not report the method used to generate the allocation sequence or whether allocation was concealed before assignment, so those aspects cannot be evaluated from the record.

The trial is described as having no masking. In general, masking can reduce the chance that knowledge of assignment affects participant behavior, care, assessment, or reporting. Here, the primary outcome was self-reported, so awareness of whether injections were self-administered or given in clinic is relevant to how responses might be influenced. That possibility is not proof of biased reporting; the registry record does not report an assessment of such bias.

The primary outcome is binary and posted as counts of participants with continuation. The analysis compares proportions, with the risk difference as the stated metric. The record also lists risk-ratio and odds-ratio summaries, but the risk difference directly communicates the absolute contrast in the outcome proportions. Ratios can be useful for different questions, but their interpretation is distinct; the choice of measure should match the clinical and research question.

The primary p-value and effect interval are unadjusted. An unadjusted comparison does not account for covariates or for testing multiple outcomes unless those adjustments are explicitly included. The registry record lists four outcome measures and has no reported analyses count, while the posted results include the primary comparison and a reported secondary comparison. The statistical analysis plan, any covariate adjustment, and any prespecified handling of multiple comparisons are not reported in the registry record. The unadjusted results should therefore be interpreted as posted summaries rather than assumed to represent a fully specified adjusted analysis.

The posted primary results identify the outcome denominators separately by arm. The registry does not report how participants without a recorded primary outcome were treated, whether the analysis was by intention to treat, or whether another analysis population was used. These omissions limit assessment of potential bias from missing data or departures from assignment. Counts with an outcome and the corresponding denominators are essential context; they do not independently reveal why other participants may not appear in the outcome analysis.

In general, over-dispersion matters when outcome variability is greater than a statistical model assumes. A model that understates variability can produce intervals that are too narrow and p-values that are too small. The primary outcome is presented as a binary count comparison, not as a count model with a dispersion parameter, and no over-dispersion analysis is reported in the registry record. That general issue should not be mistaken for a documented feature of this trial’s primary analysis.

There is no discrepancy flag for the posted recalculated comparison. Such recalculations are simple unadjusted summaries from the posted counts and are not substitutes for a sponsor’s prespecified analysis. When a discrepancy is flagged, the sponsor’s own analysis takes precedence. No sponsor-reported analysis is listed in the registry record for this comparison, so the unadjusted result is best understood as a summary of the posted data and not as a complete account of all analyses that may have been conducted.

11. Confidence Intervals and Precision

The primary risk-difference estimate is 0.153, and its 95% confidence interval ranges from 0.047 to 0.259. The interval does not include zero, and both limits are positive. This means the posted unadjusted comparison is compatible with a positive difference in reported continuation, while the width of the interval shows that the exact size of that difference remains uncertain.

Precision is not the same as correctness. A narrow interval would indicate less sampling uncertainty under the analysis assumptions, but it would not rule out bias from self-report, incomplete outcome data, or other design and conduct limitations. Likewise, an interval that excludes zero does not by itself establish clinical importance. The registry record does not define a threshold for a clinically meaningful difference, so the importance of the estimated magnitude cannot be judged against a prespecified benchmark from this record.

The arm-specific outcome counts and denominators help put the risk difference in context. The point estimate is an absolute contrast between the posted proportions, whereas the confidence interval describes uncertainty around that contrast. The p-value of 0.005 is consistent with the interval’s exclusion of zero, but it does not replace the interval as a guide to the range of effect sizes compatible with the data.

Precision also depends on which participants contributed outcome data and on the assumptions used in analysis. The registry record does not report missing-data handling, the original analysis plan, or whether the posted comparison was adjusted for any covariates. The interval should therefore be read as precision for the reported unadjusted comparison, not as a complete measure of uncertainty from every source.

For the listed secondary satisfaction comparison, the interval crosses zero. That pattern indicates that the posted estimate does not pin down the direction of the contrast as precisely as the primary estimate does. The registry record does not report numerical results for all other listed secondary outcomes, so their precision cannot be assessed from the posted outcome information.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are illustrative calculations based on fractions of the observed effect, not the trial’s original design assumptions. The record specifies a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is set at the stated fraction of the observed effect. The original trial’s sample-size justification and assumptions are not reported in the registry record.

The planning figures are participants per arm for the binary outcomes in this trial; they are not total event counts. The record’s note distinguishes these from time-to-event planning, where figures would represent total events, but the primary outcome is a participant count. The 80% power column describes the per-arm planning size associated with an 80% chance of detecting the assumed effect under the calculation’s assumptions if that effect were present. The 90% power column uses a higher target chance of detection and consequently requires a larger planned sample for a given assumed effect.

For the primary continuation comparison, the listed per-arm figures rise as the assumed effect is reduced from 100% of the observed effect to 75% and then 50%. This illustrates a general planning principle: smaller effects are harder to distinguish from random variation and therefore require more participants to achieve the same target power, all else held constant. The same general pattern applies when comparing the 80% and 90% power targets: aiming for greater power requires more participants under the stated assumptions.

These calculations use the observed effect as their starting point, so they are not an independent justification for the trial’s design and should not be treated as a forecast of results in a future study. They are planning illustrations only, not observed power. Observed power is not a useful substitute for interpreting the estimate and its confidence interval; the posted results are better understood through the effect estimate, its precision, and the study’s limitations.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.535; treatment proportion p₁ = 0.688; average p̄ = 0.611.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.6894 = 1.3512.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.6808 = 0.5730.
4. n = (1.3512 + 0.5730)² / (0.1533)² = 157.5, rounded up to 158 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
p0 <- 0.534591194968553                          # control proportion
p1 <- 0.687898089171974                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(2509767)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 158 (80% power), 211 (90% power)
 75% of observed effect: n per arm = 286 (80% power), 382 (90% power)
 50% of observed effect: n per arm = 653 (80% power), 874 (90% power)
power.prop.test: 157.5 
Simulated power at n = 158 per arm: 0.803 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when a study examines more than one outcome, comparison, subgroup, or analysis. In general, as the number of statistical tests increases, so does the chance of obtaining at least one apparently unusual result even when no true effect exists. Researchers can address this through prespecified outcome hierarchies, adjusted significance thresholds, or other methods. The registry lists a primary outcome and secondary outcomes, but a multiplicity strategy is not reported in the registry record. The unadjusted secondary results should therefore be interpreted cautiously.

The record lists four outcome measures and reports no analyses count. It does not explain whether the primary comparison was prespecified in a statistical analysis plan, whether any analyses were conducted but not posted, or whether secondary outcomes were analyzed according to a preplanned hierarchy. This absence does not demonstrate that no plan existed; it means the plan is not reported in the registry record. The registry also does not report a prespecified clinical threshold for interpreting the magnitude of the primary risk difference.

Missing outcome data are another concern for interpretation. The posted primary comparison has arm-specific denominators, but the record does not explain the relationship between those denominators and all randomized participants, why some participants may lack a recorded outcome, or how missing responses were handled. It does not report whether missing outcomes were excluded, imputed, or addressed in sensitivity analyses. Without that information, the risk of bias related to incomplete follow-up cannot be assessed from the registry results alone.

The registry does not report whether the analysis followed intention to treat, whether participants were analyzed according to assignment regardless of what they did, or whether another analysis population was used. It also does not describe adherence, protocol deviations, or exclusions after randomization. Those details affect how closely the reported estimates preserve the advantages of random assignment. No specific statistical adjustment or missing-data method should be inferred in their absence.

The primary endpoint was self-reported, and the trial was unmasked. In general, participant awareness of assignment can influence reported outcomes, though the registry record does not establish that this occurred. The record does not report validation against clinical records or another independent measurement source. These limitations add uncertainty beyond the sampling uncertainty represented by the confidence interval.

15. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 1% reporting threshold.

The registry reports serious adverse events for participants at risk in each arm. In the self-administration arm, 0 serious adverse events were reported among 201 at risk; in the clinic-administration arm, 0 were reported among 200 at risk. The registry also reports 0 other adverse events in each arm, with 201 and 200 participants at risk, respectively. Deaths are reported as 0 in both arms.

These figures describe the adverse-event counts posted in the registry record. They do not establish that no adverse events occurred outside the record’s reporting definitions or follow-up, and they do not show that the approaches have identical safety profiles. The registry lists no serious adverse-event terms, and it does not provide further detail about event definitions, ascertainment, timing, severity categories beyond the serious/other distinction, or the relationship between safety follow-up and the primary outcome follow-up.

The at-risk counts used for safety reporting differ from the denominators in the primary continuation results. Those are separate reporting populations and should not be conflated. The safety figures should be read as the reported counts in the safety record, not as a substitute for the continuation analysis or as proof of absence of risk.

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

The posted primary result shows a positive unadjusted risk difference for self-reported DMPA sc continuation at one year, comparing self-administration with clinic administration. The estimate is 0.153, with a 95% confidence interval from 0.047 to 0.259 and an unadjusted p-value of 0.005. In the analyzed outcome data, reported continuation was more common in the self-administration arm. The interval indicates uncertainty about the size of the contrast even though it lies above zero.

This result does not, by itself, prove that self-administration caused the difference. Randomization supports causal interpretation in principle, but the registry does not report important procedural and analytic details, including allocation concealment, missing-data handling, and the analysis population. The study was unmasked, and the primary outcome was self-reported. Those features matter when assessing how closely the observed contrast represents a causal effect of assignment.

The finding is specific to reported continuation at one year in the study context described in the registry. It is not a direct measure of all aspects of use, satisfaction, injection technique, costs, or safety. The record does not report results for every listed secondary outcome, so claims about those outcomes cannot be drawn from the primary result. The posted safety counts also do not establish equivalence or absence of risk.

The result should not be generalized automatically to people outside the study population or to settings unlike the two Planned Parenthood affiliates described in the brief summary. The registry record does not report a prespecified threshold for a meaningful difference, so statistical evidence of a positive contrast should not be treated as proof that the magnitude meets any particular clinical or practical standard.

In short, the posted results support a positive unadjusted association between assignment to self-administration and self-reported continuation in this trial’s analyzed outcome data. The confidence interval provides a range for the estimated contrast under the analysis assumptions, while the incomplete reporting of methods and secondary outcomes limits broader conclusions.

17. Why This Trial Matters Statistically

This trial illustrates how the statistical question depends on the outcome definition. The primary endpoint is not simply whether a participant received an injection at a clinic visit; it is self-reported continuation at one year. That distinction shapes both the interpretation of the effect estimate and the questions raised about measurement, missing responses, and participant awareness of assignment.

The risk difference is useful because it expresses the primary contrast on an absolute scale. It makes the comparison about the difference between the arms’ proportions reporting continuation, rather than relying only on a relative measure. The confidence interval then shows the range of values compatible with the unadjusted result under the method used. Considering the estimate, interval, and p-value together gives a fuller account than treating a threshold-based significance label as the whole result.

The trial also shows why statistical evidence and reporting completeness are distinct. Randomization is an important design feature, yet interpretation still depends on how randomization was implemented, who contributed outcome data, how missingness was handled, and whether analyses followed a prespecified plan. The registry record does not report several of these details. A positive result can coexist with uncertainty about these aspects of conduct and analysis.

Finally, the registry lists several secondary questions in addition to continuation. Separating the primary endpoint from secondary outcomes helps prevent satisfaction, home use, costs, and safety from being treated as interchangeable evidence. The unreported secondary results and the absence of a reported multiplicity plan further illustrate why a primary finding should be interpreted on its own terms and why exploratory results warrant restraint.

18. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The trial’s primary outcome is self-reported by questionnaire, and the record does not report validation against clinic records or another independent source. Because the trial was unmasked, participants knew whether they were assigned to self-administration or clinic administration. The registry does not show whether awareness affected reporting, but it limits assessment of potential measurement or reporting bias.

The registry record does not report how the allocation sequence was generated or whether assignment was concealed. It also does not describe the analysis population, adherence, post-randomization exclusions, or handling of missing outcome data. The primary outcome denominators are not accompanied by a complete explanation of who lacked a recorded outcome or why. These omissions make it difficult to assess attrition and whether the reported comparison fully reflects randomized assignment.

The study context is described as two Planned Parenthood affiliates serving diverse patient populations, and the brief summary identifies female patients ages 15-44 requesting DMPA. The record does not report enough detail about participant characteristics or site-specific results to judge how well the findings apply to other populations and care settings. The recorded enrollment is 401, while the brief summary describes a planned total of 400; the registry does not explain the difference.

The registry lists satisfaction with home use and costs as secondary outcomes but does not report their numerical results. It also does not report a multiplicity plan or the original sample-size justification. These gaps limit a full assessment of the study’s broader aims and the role of secondary analyses. The available primary result should therefore be interpreted as a posted unadjusted comparison, not as a complete report of every planned analysis or outcome.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Depo Provera Self-Administration Study: Putting a Patient-Centered Practice to the Test at Planned Parenthood — NCT02509767.
• Registry record last updated 2019-09-18; status last verified 2019-08.
• Results first posted 2019-09-18.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

22. Record Summary

The registry record describes a completed, randomized, parallel-group, unmasked phase 4 trial sponsored by Planned Parenthood Federation of America. It compares self-administration of subcutaneous depot medroxyprogesterone acetate with clinic administration, identified as standard care. The brief summary describes female patients ages 15-44 requesting DMPA at two Planned Parenthood affiliates and one year of follow-up.

The primary endpoint is self-reported continuation at one year, assessed by self-administered questionnaire. The posted counts are 108 of 157 in the self-administration arm and 85 of 159 in the clinic-administration arm. The unadjusted risk difference is 0.153, with a 95% confidence interval from 0.047 to 0.259 and p = 0.005.

The registry lists satisfaction and costs as secondary outcomes, but numerical results are not reported for every listed outcome. Missing-data methods, the original sample-size justification, and a multiplicity plan are not reported in the registry record. The primary finding is therefore best read as a positive unadjusted comparison of reported continuation, with uncertainty about its magnitude and limits on broader interpretation.