Evaluation of Peer Telephone Cessation Counseling for Smokers: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluation of Peer Telephone Cessation Counseling for Smokers (NCT01359371), a registered phase not stated study. The primary outcome is Smoking Quit Rate by Number of Calls Received.

2. Clinical Question

The clinical question focuses on whether smoking status differed according to participants’ exposure to volunteer peer calls. That is not the same as asking whether counseling caused a change in smoking: people receiving different numbers of calls may differ in ways that also relate to smoking status. The registry record does not describe random assignment or a control group suitable for a like-for-like comparison, so the reported study question should be read as an evaluation of the implemented counseling rather than a randomized treatment comparison.

Smoking status was assessed around 60 days after discharge, with a stated range from 1 month to 5 months. The outcome description combines information from electronic medical record text fields and volunteer documentation. It also describes different recall windows in those sources: smoking in the past 7 days for the medical record and smoking in the last 24 hours for volunteer documentation. Missing smoking-status data were classified as smoking. These details matter when interpreting what a recorded quit status represents. The registry record does not report the number of calls received, the results by call exposure, or a numerical estimate of the relationship between calls and quitting.

3. Trial Design

This completed study evaluated peer telephone cessation counseling for smokers at the Ann Arbor VA. The registry lists the sponsor as the VA Office of Research and Development and describes the intervention as behavioral. The study began in 2012-06, with primary completion in 2013-01. Enrollment was 131.

Participants were veteran smokers who received the standard-of-care Tobacco Tactics intervention while in the hospital, followed by volunteer peer telephone cessation counseling. The record’s description presents counseling as part of an implemented service that the study set out to evaluate. It does not describe a randomized allocation process. The registry also states that allocation was not stated and that the arms are not a like-for-like control comparison. Thus, the available design description does not support interpreting differences by calls received as randomized causal effects.

The primary outcome is titled “Smoking Quit Rate by Number of Calls Received.” It concerns participant counts and smoking status around 60 days after discharge. The assessment window is described as ranging from 1 month to 5 months after discharge, rather than as a single uniform assessment date. The record lists secondary outcomes concerning participant characteristics by high versus low participation at 60 days post-discharge, attitudes about implementing telephone counseling, and cost per quit of volunteer peer telephone counseling.

The registry lists 4 outcome measures and 3 analyses, but it does not report the analysis methods, call-count categories, outcome counts, or effect estimates. It also does not report a detailed protocol, a sample-size justification, or information about interim analyses. Without those details and the primary results, the completed status indicates that the study record is marked completed, but it does not establish what the evaluation found about quitting or the relationship between calls and smoking status.

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.

6. Primary Endpoint

The registry lists the primary outcome as Smoking Quit Rate by Number of Calls Received, measured over 7-day point prevalence self-reported smoking quit rate 60 days after discharge.

The primary endpoint concerns smoking quit status around 60 days after hospital discharge. Its title links the quit rate to the number of counseling calls received. The outcome description identifies a 7-day point-prevalence self-reported quit measure, meaning that the endpoint concerns smoking status over a recent period rather than continuous abstinence throughout follow-up. A point-prevalence measure can capture a participant’s reported status near the assessment, but by itself it does not show whether that status was maintained during the entire period after discharge.

The registry describes more than one source for assessing status. Electronic medical record text fields recorded whether a participant had smoked in the past 7 days, while volunteer documentation asked whether the participant had smoked in the last 24 hours. Those questions do not use the same recall window. The stated assessment timing also varied, spanning 1 month to 5 months after discharge. Differences in timing or question wording can affect how consistently an endpoint represents smoking status across participants.

When smoking-status data were missing, participants were considered to be smokers. This makes missing status count as not having a recorded quit, rather than treating it as unknown or excluding it from the endpoint. The rule does not reveal the actual status of participants with missing information. The registry record does not report the number classified as quit, the number with missing status, or the results by number of calls received. Accordingly, the endpoint’s definition is available, but its observed result and precision are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The title of the primary outcome frames the analysis around smoking quit status by number of calls received. The record describes the endpoint as a participant count and gives a binary smoking-status measure: a participant is treated as a smoker or as having quit under the stated assessment rule. A binary outcome is commonly summarized by counts and proportions. Comparing such summaries across call exposure groups can describe an association, but the registry record does not provide the group definitions, outcome counts, or statistical analysis used for this study.

What does point prevalence measure?

Point prevalence refers to status during a specified recent period around assessment. It differs from continuous abstinence, which would require evidence about smoking behavior throughout a longer interval. Here, the endpoint description refers to a 7-day point-prevalence self-reported quit rate, while the data-source description also identifies a 24-hour question in volunteer documentation. These are not identical definitions of recent smoking. An analysis that combines them may be affected by which source contributed information for each participant; the registry record does not report how source-specific information was handled or whether results were examined separately by source.

Assessment time also varies. The outcome description places status around 60 days after discharge but states a range from 1 month to 5 months. In general, when outcome assessments occur at different times, the measured status may reflect different durations since intervention and different opportunities for change. The record does not report the distribution of assessment timing or an analysis accounting for timing differences.

How should missing status be understood?

The stated rule classifies participants with missing smoking-status data as smokers. This is a prespecified-looking operational definition in the outcome description, but the record does not say when or how the rule was selected. In general, classifying missing outcomes as not having quit avoids counting an unobserved status as a successful quit. It does not establish that participants with missing information were smoking. The rule can influence the estimated quit proportion, and its impact depends on how many outcomes were missing and how missingness relates to true smoking status. Those counts and relationships are not reported in the registry record.

Missingness can also affect comparisons across call exposure. If missing status differs between participants who received different numbers of calls, the comparison may reflect both the underlying outcome and differences in ascertainment. The record does not report missingness by call exposure or describe sensitivity analyses using alternative assumptions. A sensitivity analysis is a general approach for checking whether conclusions change under plausible alternatives for unobserved outcomes; no such analysis is reported in the registry record.

What can be inferred from comparisons by calls?

In general, an association between call count and quit status is not necessarily a causal effect. Random assignment can help balance measured and unmeasured participant characteristics across treatment groups, but the registry record explicitly says this was not a randomized comparison and that allocation was not stated. Call participation may therefore be related to participant characteristics, access, engagement, or other factors. These are general possibilities, not findings about this study. The record does not describe adjustment variables, matching, stratification, or another method used to address differences between exposure groups.

For a binary endpoint, an analysis might report group-specific counts, proportions, a difference or ratio between proportions, and an uncertainty interval. Each measure answers a somewhat different question, and the chosen method should match the study design and data structure. None of those primary outcome values or methods are reported in the registry record. No effect estimate should be reconstructed without the underlying results.

What do the planning assumptions mean?

The registry’s planning description refers to an illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It describes the effect to detect as a stated fraction of the observed effect. Such calculations are planning illustrations, not observed evidence and not a measure of the probability that a study result is true. The description says that non-time-to-event results are expressed as participants per arm. The registry record does not report the observed effect or the numerical planning results, so the illustration cannot be evaluated from the record alone. These assumptions are also not evidence that the original study used those methods to plan its enrollment.

More generally, the significance level describes a decision threshold under a specified statistical model; it does not measure effect size or clinical importance. A confidence interval communicates uncertainty around an estimate and depends on the data and analysis assumptions. The registry record does not report a confidence interval, an effect estimate, or a primary-outcome test. Without those items, statistical precision and compatibility with different effect sizes cannot be assessed.

10. Exact Estimates for Each Arm

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

R code and output

arm    <- c("Quit Rate With Low Participation in Counseling", "Quit Rate High Participation in Counseling")
n      <- c(25, 106)
events <- c(1, 35)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Quit Rate With Low Participation in Counseling  25  1  4.0  0.1  20.4  0.7  19.5  0.9  19.6
ARM  Quit Rate High Participation in Counseling  106  35  33.0  24.2  42.8  24.8  42.4  24.8  42.5

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 4 outcome measures and 3 analyses. It names secondary outcomes concerning participant characteristics by high versus low participation 60 days post-discharge, attitudes about implementing the telephone counseling, and cost per quit of volunteer peer telephone counseling. The primary outcome is smoking quit status by number of calls received. The record does not report which analyses correspond to which outcomes, whether additional comparisons were made, or whether any adjustment for multiple testing was planned or used.

Multiplicity arises when several outcomes, groups, or analyses are examined. In general, considering more statistical tests can increase the chance of observing an apparently notable result by chance, unless the analysis plan accounts for the set of tests. The registry’s count of outcomes and analyses is not enough to determine the multiplicity burden: the specific comparisons and their results are not reported. No adjustment method or prespecified hierarchy among outcomes is reported in the registry record.

For the primary outcome, the record states that missing smoking-status data were classified as smoking. This rule is important because it treats missing status as not having a recorded quit. The number of missing observations and their distribution across call exposure are not reported in the registry record. The record also does not describe other analysis-population definitions, exclusions, or sensitivity analyses. It is therefore not possible to determine how many participants contributed observed outcome information or how alternative missing-data assumptions would affect the results.

The registry does not report a detailed statistical analysis plan or identify which participants were included in each analysis. Those omissions limit assessment of whether analyses followed a prespecified approach and whether the reported outcome population matched the enrolled cohort. No outcome counts or estimates are available to assess possible bias or the influence of missing data.

12. Safety Results

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

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry reports 0 serious adverse events and 0 other adverse events for the volunteer telephone cessation counseling group. Each category lists 131 participants at risk. These are recorded event counts for the registry’s specified categories; they should not be read as proof that no adverse experiences of any kind occurred. The record does not provide descriptions of non-serious events, methods for collecting adverse-event information, or details about how events were attributed to counseling.

Death information is not reported in the registry record. A missing death count is not the same as a count of zero, so no conclusion about deaths can be drawn from this entry. The record also does not provide a comparison group with which to contextualize the adverse-event counts. As the study was not described as a randomized comparison and the arms were not a like-for-like control comparison, these safety figures are descriptive rather than a comparative estimate of risk.

For interpreting adverse-event data generally, both event counts and the completeness and duration of surveillance matter. Here, the registry gives counts and participants at risk but does not state the surveillance procedures or timing. The reported zeros therefore describe what was entered for these event categories in the registry, not a comprehensive account of all possible safety outcomes.

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

The record establishes that a completed evaluation concerned volunteer peer telephone cessation counseling for veteran smokers who received the standard-of-care Tobacco Tactics intervention while hospitalized. It also specifies a primary outcome focused on smoking quit status around 60 days after discharge and describes the sources used to assess status. The record does not report the primary outcome results, so it cannot establish how many participants were classified as having quit or whether quit status varied with number of calls received.

The absence of reported outcome estimates also means that the magnitude and precision of any association cannot be judged. There is no reported confidence interval or statistical test result for the primary outcome. Enrollment of 131 describes the study cohort, but does not establish how many participants had outcome data, how many were missing, or how participants were distributed across call exposure. The missing-data rule is known, but its practical effect cannot be assessed without those details.

The study’s design description also limits causal interpretation. The registry says this was not a randomized comparison and does not present a like-for-like control comparison. Participants receiving different numbers of calls may differ in other ways, and the record does not describe methods used to address those differences. A relationship between call exposure and smoking status, even if reported elsewhere, would not by itself show that the calls caused the difference.

These limitations do not make the evaluation irrelevant. The record identifies an implemented counseling service, a follow-up outcome, and practical secondary questions about participation, attitudes, and cost per quit. Those are relevant domains for evaluating a service. However, the registry record does not report the results for these outcomes either. Its completed status should not be interpreted as evidence of a particular result. The defensible conclusion is that the study evaluated this service and defined how its primary outcome was assessed, while the posted registry information is insufficient to determine the outcome findings or their uncertainty.

14. Why This Trial Matters Statistically

This study raises statistical questions that are common in evaluations of services delivered in routine clinical settings. Counseling was implemented as part of Tobacco Tactics, and the primary outcome was framed around the number of calls received. In such settings, exposure can vary between participants rather than being assigned by a randomized process. That makes the distinction between association and causation especially important. Differences in call participation may coincide with differences in participant characteristics or engagement, and a descriptive comparison cannot automatically separate those influences.

The endpoint also illustrates why measurement details matter. The registry describes smoking status gathered from electronic medical record text fields or volunteer documentation, with different recall periods across those sources. It specifies a follow-up window from 1 month to 5 months after discharge. Both source and timing can affect the interpretation and comparability of a binary outcome. Clear definitions and transparent reporting help readers understand what an endpoint captures and where measurement variation may enter.

Missing-data handling is another practical issue. The rule counted missing smoking status as smoking, which is a meaningful analytic choice rather than a neutral fact about participants’ actual behavior. Reporting the amount and pattern of missingness, along with sensitivity analyses, would help readers judge the effect of that choice. Those details are not reported in the registry record.

Finally, the evaluation addresses more than a primary smoking outcome: its listed secondary questions include participation, attitudes toward implementation, and cost per quit. For implementation research, these complementary outcomes can matter alongside effectiveness. But they need interpretable estimates and transparent methods. The registry record describes these questions without reporting results, underscoring that a completed study entry is not itself a complete statistical account of what was observed.

15. Limitations

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

The registry record does not include the primary outcome counts or estimates, so the central question about quit status by number of calls cannot be answered from the posted results. It also does not report call-count categories, the distribution of calls, or the number of participants with outcome information. These omissions prevent assessment of the observed effect and its precision.

Outcome ascertainment is not described as uniform: smoking status could come from electronic medical record text fields or volunteer documentation, and the stated recall periods differ. The follow-up timing ranged from 1 month to 5 months after discharge. The record does not report which source was used for each participant, whether the sources were reconciled, or whether timing was considered in analysis. This leaves uncertainty about consistency of measurement across participants.

The registry states that the study was not a randomized comparison and that the arms were not a like-for-like control comparison. It does not describe an adjustment strategy for differences associated with call participation. Consequently, any comparison by calls would be vulnerable to confounding unless addressed by methods not reported in the record. No effect estimates are available to assess even an unadjusted association.

Missing smoking-status data were counted as smoking, but the amount and pattern of missingness are not reported. The record does not identify the analysis population, exclusions, or sensitivity analyses. It lists multiple outcomes and analyses without describing the analysis plan or any multiplicity approach. It also does not report the methods behind the secondary outcomes, including attitudes and cost per quit. These trial-specific reporting gaps restrict interpretation beyond the description of the intervention, outcome definition, and registry status.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Evaluation of Peer Telephone Cessation Counseling for Smokers — NCT01359371.
• Registry record last updated 2020-11-16; status last verified 2020-10.
• Results first posted 2014-12-01.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

19. Record Summary

NCT01359371 is a completed evaluation of peer telephone cessation counseling for veteran smokers at the Ann Arbor VA. The registry lists the VA Office of Research and Development as sponsor, enrollment of 131, a start date of 2012-06, and primary completion in 2013-01. Participants received the standard-of-care Tobacco Tactics intervention while hospitalized, followed by volunteer peer telephone cessation counseling.

The primary outcome concerns smoking quit status around 60 days after discharge, assessed using medical record text fields or volunteer documentation. The registry states that missing smoking-status data were classified as smoking. It lists secondary outcomes about participation, attitudes toward implementation, and cost per quit.

The registry record does not report primary outcome counts, estimates, confidence intervals, or test results. It states that the study was not a randomized comparison and that the arms were not a like-for-like control comparison. Serious and other adverse event counts are each 0; death information is not reported in the registry record.