HIV Rapid Testing & Counseling in Sexually Transmitted Disease (STD) Clinics in the U.S.: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for HIV Rapid Testing & Counseling in Sexually Transmitted Disease (STD) Clinics in the U.S. (NCT01154296), a randomized na study. The primary outcome is STI Incidence.

2. Clinical Question

3. Trial Design

Project Aware was a completed, randomized, parallel-group trial with single masking. It was conducted in STD clinics in the United States and was sponsored by Columbia University. The registry lists the phase as not applicable. The study began in 2010-04, and primary completion was recorded in 2011-07. Total enrollment was 5012.

The two assigned approaches were rapid HIV testing with counseling and rapid HIV testing with information only. Both arms included STI testing and a baseline assessment, followed by outcome assessment at 6 months after randomization. The registry describes the study as multi-center and anticipates approximately 9 clinics. The brief description says recruitment was intended to reflect the gender and minority proportions of the participating clinics; the achieved representativeness of the enrolled sample is not reported in the registry record.

Random allocation supports a comparison of the assigned approaches, but it does not by itself establish that every person enrolled contributed data to every outcome. For the primary outcome, the posted arm counts are 2039 and 2032, while the overall enrollment is 5012. The registry does not explain the difference between those counts or state the analysis population used for the primary comparison. The primary outcome is reported as participants with a binary composite STI result at follow-up.

The registry identifies sexual-risk behaviors, substance use during sex, and cost and cost-effectiveness as secondary areas of interest. Five secondary outcomes are posted, covering numbers of sex acts, unprotected sex acts, partners, unprotected partners, and sex acts with substance use. The posted secondary results include only three of those measures; results for the other listed measures are not reported in the registry record. Details of the original sample-size justification, masking procedures, and allocation implementation are not reported in the registry record.

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: Study personnel made 14,948 approaches to STD clinic patients; some were approached multiple times. Of the 6,239 consenting to be screened, 5028 were eligible (80.6%); 16 of these were not randomized due to: decision to decline (n=3), not returning (n=11), not testing with HIV/STD battery (n=1) and not completing baseline activities (n=1).

Randomization and Intervention

Reasons for not completing this period:

6-month Follow-up

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.

Population: 6,239 patients approached provided consent to be screened. Of these, 5,028 were eligible (80.6%) and 5012 (99.5% of those eligible) were randomized; 16 screened eligible, but were not randomized due to: decision to decline (3), not returning (11), not testing with HIV/STD battery (1) and not completing baseline activities (1).

6. Primary Endpoint

The registry lists the primary outcome as STI Incidence, measured over 6 months post randomization.

The primary endpoint is composite STI incidence at 6 months after randomization. It is a binary measure at the participant level: a person is classified as positive if any tested STI is positive. This combines results across tested infections into a single outcome rather than presenting each infection as a separate primary measure. The specific STIs included in the composite and the testing procedures are not reported in the registry record.

A composite endpoint can provide a single summary of whether participants had any qualifying STI at the follow-up assessment. It can also make the result depend on the particular infections included and how they are tested and combined. Those details matter when interpreting what a positive composite result represents, and they are not reported in the registry record.

For the posted primary outcome, the counseling arm had 250 participants with an event among 2039 participants, and the information-only arm had 226 among 2032. The registry’s definition concerns whether a participant had at least one positive tested STI, not the number of infections or the time until an infection. The result therefore describes the proportion of participants classified as positive at the specified follow-up, rather than a rate over person-time. The registry’s stated primary endpoint gives a common outcome for comparing the randomized approaches, but it does not by itself describe the individual infections, the timing of events, or outcomes beyond the 6-month assessment.

7. Results Posted in the Registry

• Rapid HIV Testing & Information Only (Group 2): 11.1% (226/2032) versus 12.3% (250/2039) on control; risk difference -1.1 percentage points (95% CI -3.1 to 0.8), risk ratio 0.91 (0.77–1.07); unadjusted two-proportion z-test p = 0.258.

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.

Sexual Risk Behavior -- # of Sex Acts

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Rapid HIV Testing & Information Only (Group 2): mean 29.10 versus 28.60 on control; difference 0.50 (95% CI -2.67 to 3.67), standardized effect d = 0.01; z-test p = 0.757.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Rapid HIV Testing & Information Only (Group 2) and the control. The interval gives the range of effects that remain compatible with the data.

Sexual Risk Behavior -- # of Unprotected Sex Acts

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Rapid HIV Testing & Information Only (Group 2): mean 18.30 versus 17.40 on control; difference 0.90 (95% CI -1.90 to 3.70), standardized effect d = 0.02; z-test p = 0.528.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Rapid HIV Testing & Information Only (Group 2) and the control. The interval gives the range of effects that remain compatible with the data.

Sexual Risk Behavior -- # of Partners

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard errors.
• Result:
  • Rapid HIV Testing & Information Only (Group 2): mean 3.00 versus 2.70 on control; difference 0.30 (95% CI 0.08 to 0.52), standardized effect d = 0.08; z-test p = 0.007.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Rapid HIV Testing & Information Only (Group 2) than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The secondary outcomes extend the assessment beyond the primary STI composite to several self-reported sexual-risk behaviors. Five secondary measures are listed in the registry, but results are posted for only three: sex acts, unprotected sex acts, and number of partners. Results for unprotected partners and sex acts with substance use are not reported in the registry record. This incomplete set limits any overall account of the secondary outcome pattern.

The posted measures do not form a single uniform statistical family. The recalculated comparisons are mean differences based on least-squares means, while sponsor-reported results are labeled incidence rate ratios. The registry does not report enough model detail to reconcile these measures or to establish how the sponsor’s rate-based results were produced. Their effect scales and interpretation therefore need to remain distinct.

These outcomes are relevant to the trial’s broader interest in sexual-risk behavior, but they are not substitutes for the primary composite STI endpoint. They also do not establish a mechanism linking reported behavior with STI incidence. The primary result and secondary behavior results address different outcomes and measurement processes, so agreement or disagreement among them would not by itself settle the primary question.

Unadjusted secondary results carry less weight for confirmatory interpretation when several outcomes are assessed. In general, considering multiple comparisons increases the chance that some results may appear notable by chance, especially when there is no reported multiplicity plan. This is a general statistical concern, not evidence that any particular secondary finding is false. The registry’s multiplicity procedures, hierarchy among secondary outcomes, and prespecified analysis plan are not reported. Secondary estimates are consequently best read as exploratory descriptions unless fuller protocol and analysis information establishes a confirmatory role.

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

• Sexual Risk Behavior -- # of Sex Acts
• Sexual Risk Behavior -- # of Unprotected Sex Acts
• Sexual Risk Behavior -- # of Partners
• Sexual Risk Behavior -- # of Unprotected Partners
• Sexual Risk Behavior -- # of Sex Acts With Substance Use

9. Statistical Interpretation

10. Statistical Methods Explained

What does the risk difference describe?

General statistical explanation: A risk difference subtracts the event proportion in one group from the event proportion in the other. It is expressed on the absolute probability scale and uses zero as the value corresponding to equal event risks. The recalculated primary comparison is information-only minus counseling. Its estimate is -0.011, and its confidence interval extends from -0.031 to 0.008. Because the interval includes zero, the data are compatible with a range of possible differences that includes no difference. The estimate alone does not establish a causal mechanism or explain why any difference might arise.

How does a relative measure differ?

General statistical explanation: A risk ratio compares the event risks by division, while an odds ratio compares the odds of an event. Their null value is one rather than zero. These measures can give a different impression from an absolute risk difference because they use a different scale. For the primary outcome, the recalculated risk ratio is 0.907 and the recalculated odds ratio is 0.895; their confidence intervals include one. The registry also reports an adjusted risk ratio, but that adjusted analysis is not the same calculation as either unadjusted measure. The covariates or strata used for adjustment are not reported in the registry record.

What does the p-value add?

General statistical explanation: A p-value describes how unusual data at least as inconsistent with a specified null hypothesis would be if that hypothesis and the test assumptions were true. It is not the probability that the null hypothesis is true, nor does it measure the size or practical importance of an effect. The unadjusted primary p-value is 0.258. A p-value does not replace the estimate and confidence interval, which communicate the direction and range of differences compatible with the analysis. The registry does not report a p-value for its adjusted primary analysis.

Why are the sponsor and recalculated estimates different?

The recalculated primary statistics are simple unadjusted calculations from the posted arm-level event counts. The sponsor’s reported analysis is a Mantel-Haenszel adjusted risk ratio. Adjustment can change an estimate because it uses information beyond the overall event totals. The adjustment factors and full analysis specification are not reported in the registry record, so the adjusted estimate cannot be reproduced from the posted summaries alone. The registry reports an adjusted risk ratio of 1.12 and a 95% confidence interval from 0.94 to 1.33; no p-value is posted for it. The two estimates address related but not identical statistical comparisons.

What do the secondary measures represent?

General statistical explanation: A mean difference compares group averages, whereas an incidence rate ratio compares event rates under a rate-based model. They are not the same type of effect measure. The recalculated secondary comparisons use mean differences based on the posted least-squares means; the sponsor-reported results are incidence rate ratios. The registry does not report the model details needed to determine exactly how the sponsor’s rate ratios were obtained or how they relate to the posted least-squares means. Standard errors are reported with the secondary means, but the registry does not provide full analysis specifications, including the distributional assumptions or handling of repeated observations.

In general, over-dispersion occurs when outcome variability exceeds what a chosen statistical model expects. If present and not accommodated, standard errors and confidence intervals can be misleading. The registry record does not report whether over-dispersion was assessed or how it was handled. This is a general consideration for count-like behavioral outcomes, not a claim about the model used in this trial.

The registry identifies a primary composite outcome and several secondary outcomes, but the statistical plan, covariate adjustment strategy, analysis populations, and missing-data methods are not reported in the registry record. Without those details, the posted estimates can be interpreted descriptively, but the precise planned estimand and analysis choices cannot be verified. The original protocol and sample-size justification are also not reported in the registry record.

11. Confidence Intervals and Precision

A confidence interval describes a range of effect values that are compatible with the observed data and the statistical method used, subject to its assumptions. It conveys uncertainty around an estimate; it is not a guarantee that the true effect lies in the interval. Narrower intervals indicate greater precision on the scale being reported, while wider intervals leave more uncertainty.

For the primary risk difference, the recalculated estimate is -0.011 and the 95% confidence interval is -0.031 to 0.008. Because the interval crosses zero, it includes no difference as well as values on either side of zero. The corresponding unadjusted p-value is 0.258. The risk-ratio interval, 0.766 to 1.074, includes one, as does the odds-ratio interval, 0.740 to 1.084. Those null values correspond to equal risks or odds on their respective scales.

The sponsor’s adjusted risk ratio is 1.12, with a 95% confidence interval from 0.94 to 1.33. That interval includes one. Its adjustment method differs from the unadjusted recalculation, and the registry record does not give enough detail to reproduce the adjusted analysis. The relative direction of the adjusted and unadjusted point estimates should therefore be read in the context of their different methods and reported group ordering, not as a direct numerical contradiction.

Intervals for the secondary estimates also matter because a point estimate alone can make a small or uncertain difference appear more definitive than it is. The secondary measures use different scales and have different confidence intervals; they should not be pooled informally into one conclusion. Confidence intervals do not account for every source of uncertainty, including possible selection from missing follow-up data, model misspecification, or multiple testing. Those issues cannot be fully evaluated because the relevant analysis details are not reported in the registry record.

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 illustrations based on the observed effect, not the original trial’s design calculation. The registry does not report the trial’s own sample-size justification or original design assumptions. For outcomes other than time-to-event outcomes, the figures are participants per arm. Time-to-event planning figures, if present, would instead represent total events; the posted primary and secondary outcomes are not time-to-event measures.

The planning assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Each planning scenario uses the stated fraction of the observed effect. The 80% power column gives the number of participants per arm estimated to provide an 80% chance of detecting the specified effect under those assumptions, if that effect were the true one. The 90% power column gives the corresponding number for a 90% chance. These are planning probabilities under a hypothetical effect and model, not guarantees about a future study.

Rows describing 100%, 75%, and 50% of the observed effect show how the required sample changes when the target effect is smaller than the observed estimate. Smaller effects are harder to distinguish from random variation, so more participants are needed for the same target power under the stated assumptions. This relationship is especially consequential when the observed effect is small or uncertain. The planning values should not be read as the number of participants actually analyzed in Project Aware, nor as evidence that the original study had a particular chance of detecting an effect. These figures are not observed power.

The illustrations simplify real trial planning. They do not include any adjustment for attrition, clustering by clinic, covariate adjustment, multiple outcomes, or other design features; the registry’s stated assumptions do not list those factors. The original protocol’s approach to these issues is not reported in the registry record. Readers should therefore use the figures only to understand the implications of the specified effect sizes and planning assumptions, not as a reconstruction of the investigators’ original design rationale.

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 = 0.123; treatment proportion p₁ = 0.111; average p̄ = 0.117.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.4544 = 0.8906.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.4543 = 0.3824.
4. n = (0.8906 + 0.3824)² / (-0.0114)² = 12,494.7, rounded up to 12,495 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 <- 0.122609122118686                          # control proportion
p1 <- 0.111220472440945                          # 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(1154296)
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 = 12,495 (80% power), 16,727 (90% power)
 75% of observed effect: n per arm = 22,448 (80% power), 30,051 (90% power)
 50% of observed effect: n per arm = 51,035 (80% power), 68,320 (90% power)
power.prop.test: 12494.7 
Simulated power at n = 12,495 per arm: 0.801 (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. Analyses Reported by the Sponsor

The registry’s sponsor-reported primary analysis is a Mantel-Haenszel adjusted risk ratio of 1.12, with a 95% confidence interval from 0.94 to 1.33. A p-value is not reported for this analysis. The recalculated estimate is an unadjusted risk difference of -0.011, with a 95% confidence interval from -0.031 to 0.008 and p = 0.258. These are different effect measures and use different analysis approaches: the recalculation uses the posted aggregate event counts, while the reported analysis is adjusted.

The confidence interval for each analysis includes its respective null value: one for the adjusted risk ratio and zero for the unadjusted risk difference. The registry record does not give the adjustment variables, stratum definitions, or full analysis specification, so the sponsor’s estimate cannot be recreated from the aggregate counts. It also does not report a discrepancy flag for this comparison. Without additional analysis details, the difference in point estimates should not be resolved by treating the two statistics as if they estimated exactly the same quantity.

The sponsor’s analysis is the trial’s reported analysis; the recalculation is a transparent, simple comparison of posted summaries. The registry does not provide enough information to evaluate the adjusted model in detail or to establish why the estimates differ. The two results should be presented with their labels and methods intact rather than collapsed into a single number.

15. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when several statistical hypotheses are examined. In general, the more comparisons considered, the greater the chance that at least one result may appear statistically notable by chance if each is interpreted without accounting for the others. Project Aware lists multiple secondary outcomes, and the posted results include several comparisons. The registry record does not report whether a multiplicity adjustment was planned, whether outcomes were ranked in a prespecified hierarchy, or whether any secondary analysis was designated confirmatory.

The registry describes baseline and 6-month follow-up assessments, but the amount and pattern of missing outcome data are not reported in the registry record. The primary arm counts are 2039 and 2032, while total enrollment is 5012. The registry does not explain the difference between these totals, identify the number of randomized participants with missing primary outcomes, or state how missing data were handled. It is therefore not possible to determine from the posted record whether the primary comparison used all randomized participants or another analysis population.

The registry also does not report the analysis population definition, exclusions after randomization, imputation methods, sensitivity analyses for missing outcomes, or whether the primary analysis followed an intention-to-treat approach. These details affect how a randomized comparison should be interpreted, particularly when follow-up outcomes are unavailable for some participants. Their absence does not establish that the analyses were inappropriate; it limits what can be verified from the registry record.

Finally, the original statistical analysis plan is not reported. The registry does not state the prespecified covariates, subgroup analyses, model diagnostics, or procedures for handling multiple endpoints. As a result, the distinction between planned and post hoc analyses cannot be assessed. These reporting gaps are important for judging robustness and confirmatory strength, but they do not change the numerical estimates posted for the outcomes.

16. 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 1% reporting threshold.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: death, cause unknown (0.0%), victim of homicide, secondary to robbery (0.0%), cancer (0.0%), heart failure (0.0%), metastatic colon cancer (0.0%).

The serious adverse event figures list 2505 people at risk in the counseling group, with 3 serious adverse events, and 2507 at risk in the information-only group, with 2 serious adverse events. These are the registry’s reported counts. The figures describe recorded serious adverse events in the listed risk sets; they do not by themselves establish whether an event was caused by the assigned approach.

The registry lists several serious adverse event terms with a reported value of 0.0%: “Death, cause unknown,” “victim of homicide, secondary to robbery,” “Cancer,” “Heart failure,” and “Metastatic colon cancer.” The meaning and denominator used for those term-specific percentages are not further detailed in the registry record. The deaths fields are not populated, so death counts are not reported in the registry record. Other adverse event information, including non-serious events and event-specific relatedness, is not reported in the registry record.

These safety data should be read as a limited registry summary, not as a complete assessment of all possible harms. The small number of serious events and the absence of detailed event descriptions constrain comparisons. No conclusion about causation or comparative safety can be drawn from these counts alone.

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

The primary result describes the frequency of a binary composite STI outcome at 6 months among participants with posted outcome counts. The unadjusted risk difference is -0.011 for information-only versus counseling, and its 95% confidence interval ranges from -0.031 to 0.008. The interval includes zero, and the unadjusted p-value is 0.258. These findings indicate uncertainty around the difference; they do not establish that the approaches are equivalent, nor do they establish a definitive difference.

The registry’s adjusted analysis reports a risk ratio of 1.12 with a 95% confidence interval from 0.94 to 1.33. That interval includes one. Because the adjustment details are not reported, the adjusted and unadjusted results cannot be fully reconciled from the registry record. Both should be interpreted as comparisons of the assigned approaches for the stated outcome, with their different methods clearly identified.

The outcome is a composite of any tested STI being positive, not a measure of each STI separately, event timing, or long-term health. The posted result does not answer whether counseling changes other outcomes beyond those assessed, or whether the findings apply to settings outside the participating U.S. STD clinics. The registry does not report the specific infections included in the composite, the full testing procedures, or the achieved representativeness of the sample.

Secondary results concern behaviors rather than the primary biological endpoint and are incomplete in the registry record. They should not be taken as direct evidence about the primary outcome or generalized beyond the posted measures. The registry also lacks details on missing data, analysis populations, and multiplicity handling. These limits affect how firmly the estimates can be interpreted, while leaving the reported values themselves unchanged.

Statistical uncertainty is not a clinical recommendation. The posted data alone do not determine what testing or counseling approach an individual or clinic should choose. They describe the trial’s outcomes and the precision of the comparisons that can be calculated or read from the registry.

18. Why This Trial Matters Statistically

This trial illustrates why an intervention comparison needs both an effect estimate and an account of its uncertainty. A group difference is not fully described by a point estimate alone; the confidence interval shows that the primary unadjusted result remains compatible with values on both sides of no difference. The p-value provides a related test summary but does not replace that interval or measure practical importance.

It also demonstrates that adjusted and unadjusted analyses can report different forms of an effect. Here the simple recalculation uses a risk difference from aggregate counts, while the sponsor’s reported analysis is an adjusted risk ratio. The distinction matters: estimates on different scales, based on different models, should not be compared as if they were identical. Reporting the model and adjustment details would make the relationship between these results easier to assess.

The outcome structure is statistically consequential. The primary endpoint combines multiple STI tests into a yes-or-no participant outcome, while the secondary outcomes measure reported behaviors and are represented by more than one statistical measure. This creates distinct interpretive questions about composite endpoints, behavior measurement, and multiple comparisons. The registry record does not supply enough analysis detail to settle all of them.

Finally, the planning illustrations emphasize how sample requirements depend on the target effect and stated assumptions. Smaller target effects require more participants for a given power level under those assumptions. Such calculations are design aids, not retrospective proof that the trial was adequately or inadequately powered. Together, these features make the record useful for examining effect scales, precision, reporting transparency, and the limits of drawing broad conclusions from a single registered trial.

19. 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 specific to the available record constrain interpretation. The primary endpoint is a composite of any positive result across tested STIs, but the specific infections included and testing procedures are not reported in the registry record. The composite therefore cannot be unpacked to determine whether particular infections contributed more than others, or how testing characteristics may have influenced the outcome.

Although total enrollment is 5012, the primary outcome counts are 2039 and 2032. The registry does not explain this difference or report the missing-data pattern, analysis population, exclusions, or imputation approach. Without that information, the completeness of follow-up and the handling of unavailable outcomes cannot be assessed. The registry also does not report whether the analysis followed an intention-to-treat principle.

The adjusted primary analysis lacks reported adjustment variables and full model specifications. The secondary results are also incomplete: five measures are listed, but results are posted for only three. The relationship between the least-squares means and sponsor-reported incidence rate ratios is not explained. Multiplicity procedures and the prespecified status of secondary analyses are not reported.

The study description anticipates approximately 9 STD clinics, but clinic-level results and details on accounting for clustering are not reported in the registry record. The achieved representativeness of the recruited sample is also not reported, despite the stated recruitment aim. Follow-up is specified at 6 months, so the posted primary result does not describe outcomes beyond that assessment. These limitations concern the scope and interpretability of the record; they do not establish that the trial analyses were invalid.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: HIV Rapid Testing & Counseling in Sexually Transmitted Disease (STD) Clinics in the U.S. — NCT01154296.
• Registry record last updated 2014-09-29; status last verified 2014-09.
• Results first posted 2014-09-29.
• 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.

23. Record Summary

Project Aware was a completed, randomized, single-masked, parallel-group trial sponsored by Columbia University. It enrolled 5012 people seeking care or services at U.S. STD clinics and compared rapid HIV testing with RESPECT-2 counseling against rapid testing with information only. The primary endpoint was composite STI incidence at 6 months, defined as any tested STI being positive.

The unadjusted primary risk difference was -0.011, with a 95% confidence interval from -0.031 to 0.008 and p = 0.258. The registry reports an adjusted risk ratio of 1.12 with a 95% confidence interval from 0.94 to 1.33. Secondary behavioral outcomes are only partly reported, and key analysis details concerning missing data, populations, adjustment, and multiplicity are not reported in the registry record.