Penn State TXT2STAYQUIT Study- a Texting Study to Help Hospitalized Smokers Stay Quit: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Penn State TXT2STAYQUIT Study- a Texting Study to Help Hospitalized Smokers Stay Quit (NCT02986711), a randomized na study. The primary outcome is Complete Self-reported Tobacco Abstinence During the Prior 7 Days, as Reported on Telephone Interview, 28 Days After Discharge From Hospital (With Biochemical Verification in a Sub-sample, Exhaled Carbon-monoxide < 10 Parts Per Million)..

2. Clinical Question

The trial focused on whether a brief, automated messaging approach could be evaluated after hospital discharge and whether motivational messages might be associated with a different proportion reporting abstinence than control texts. These are related but distinct aims: testing a means of collecting follow-up information and comparing the posted abstinence outcome. The registry also lists the proportion providing smoking cessation status by text message as a secondary outcome, which speaks to the follow-up collection aim.

The record describes a pilot randomized trial, not a definitive evaluation. The posted results can describe the observed counts and uncertainty for the trial participants, but they do not establish how well the results would generalize to other hospitals or patient groups. The registry does not report detailed eligibility criteria, recruitment methods, participant characteristics, or the intended reach of the intervention. Those details are important when considering which hospitalized smokers the observed results may represent.

3. Trial Design

The registry describes a randomized, single-masked, parallel trial with behavioral interventions. Participants were assigned to motivational text messages or control text messages. The record does not identify which people were masked, so the masking designation cannot establish whether participants, outcome assessors, or another group were unaware of assignment.

The registry lists enrollment of 158 and reports 70 participants in each arm for the posted primary and secondary outcomes. The record does not provide a participant-flow account explaining the relationship between enrollment and the arm counts used for those outcomes, nor does it report how many participants were randomized, received messages, completed follow-up, or contributed data to each analysis. The trial status is terminated. A reason for termination is not reported in the registry record.

The study started in 2013-12 and had primary completion in 2015-04. Its phase is listed as NA. The sponsor is Milton S. Hershey Medical Center. These registry entries describe the recorded design and administrative status; they do not specify why the trial ended or whether the planned recruitment and follow-up were completed as intended.

The two groups differed in the stated content of the text messages. The motivational arm received messages intended to help participants stay quit after leaving hospital. The control arm received messages asking about current smoking status. The registry does not report the message schedule, duration, tailoring, participant engagement rules, or other components of care. The brief summary describes the intended first-month abstinence assessment, and the primary endpoint specifies a telephone interview 28 days after discharge.

The record includes outcome summaries and an unadjusted comparison, but no reported analyses are listed. Details such as the original analysis plan, any planned interim monitoring, sample-size justification, analysis population definitions, and handling of missing outcome data are not reported in the registry record. The sample-size illustrations associated with the posted outcome are based on the observed effect and are not documented as the trial's original design assumptions.

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 Complete Self-reported Tobacco Abstinence During the Prior 7 Days, as Reported on Telephone Interview, 28 Days After Discharge From Hospital (With Biochemical Verification in a Sub-sample, Exhaled Carbon-monoxide < 10 Parts Per Million)., measured over 28 days.

The primary endpoint is the count of participants reporting complete tobacco abstinence during the prior 7 days, assessed by telephone interview 28 days after hospital discharge. The registry describes abstinence as self-reported and notes biochemical verification in a subsample using exhaled carbon monoxide < 10 parts per million. The endpoint is therefore a short-term report of recent abstinence, rather than a measure of smoking behavior over the whole period since discharge.

Using a defined recall period gives the outcome a specific meaning: participants are asked about abstinence during the week before the interview. A telephone assessment allows follow-up after discharge, when participants are no longer in the hospital. The registry's mention of biochemical verification in a subsample indicates an additional way of checking reports for some participants, but the number verified and the verification results are not reported in the registry record.

The posted outcome is expressed as a count of participants in each arm. A count is easy to interpret in relation to the group size, but it does not itself describe how complete follow-up was or whether all randomized participants were included. Participant-level outcome definitions, the treatment of people who could not be reached, and the approach to any missing interview results are not reported in the registry record.

Abstinence is relevant to the study's stated aim of assessing whether messages designed to encourage staying quit could increase the proportion remaining abstinent during the first month after discharge. However, a single assessment at 28 days does not establish longer-term abstinence. The results should be read as evidence about the posted short-term endpoint and its measurement, not as a complete account of subsequent smoking behavior.

7. Results Posted in the Registry

• Motivational Text Messages: 44.3% (31/70) versus 37.1% (26/70) on control; risk difference 7.1 percentage points (95% CI -9.1 to 23.4), risk ratio 1.19 (0.80–1.78); unadjusted two-proportion z-test p = 0.390.

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.

Proportion of Participants Providing Smoking Cessation Status Via Text Message

• 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:
  • Motivational Text Messages: 18.6% (13/70) versus 51.4% (36/70) on control; risk difference -32.9 percentage points (95% CI -47.7 to -18.0), risk ratio 0.36 (0.21–0.62); unadjusted two-proportion z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the proportion with the event is statistically lower for Motivational Text Messages than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The secondary outcome tracks whether participants provided smoking cessation status by text message. Its pattern differs from the primary abstinence comparison: the posted result indicates less text-based status reporting in the motivational-message group than in the control group. This is relevant to the study's stated pilot aim of collecting post-discharge follow-up information by text, but it is not a measure of whether participants were abstinent.

The primary and secondary outcomes answer different questions. The primary result concerns self-reported abstinence at a telephone interview, while the secondary result concerns supplying status by text message. A person might respond by one route without responding by another, and the record does not report how text responses were linked to interview results. It is therefore not possible to use the secondary comparison as a substitute for the primary endpoint, or to determine from the registry whether differences in text response affected the completeness or accuracy of primary outcome measurement.

Because the secondary outcome relates to data collection behavior, it can help identify an implementation issue worth distinguishing from a smoking outcome. At the same time, response differences do not explain why they occurred. The registry does not report reasons for nonresponse, participant feedback, message engagement, or whether the intervention and control arms had different contact procedures beyond the stated message content.

Unadjusted secondary results generally carry less weight than a clearly prespecified primary comparison. When more than one outcome is examined, chance findings become more likely unless the analysis accounts for multiplicity or sets a clear testing hierarchy. A multiplicity plan and analysis hierarchy are not reported in the registry record. The secondary finding is best viewed as an informative pilot signal about status reporting that warrants cautious interpretation, not as confirmatory evidence about abstinence or a demonstrated mechanism.

The contrast between the endpoints also emphasizes the value of separating clinical or behavioral outcomes from feasibility outcomes. Each can be useful, but they require different interpretations and can have different sources of missingness and measurement error. No further secondary endpoints are posted in the record.

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

• Proportion of Participants Providing Smoking Cessation Status Via Text Message

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is binary at the participant level: a person either meets the recorded abstinence definition or does not. The registry reports counts by arm and a comparison as a risk difference. A risk difference expresses the difference between the two group proportions on the absolute probability scale. Unlike a ratio measure, it describes the gap between groups in percentage-point terms when proportions are expressed as percentages. The posted estimate is 0.071, and its confidence interval is -0.091 to 0.234.

What does a confidence interval describe?

In general, a confidence interval is a range calculated by a statistical procedure to represent uncertainty in an estimated effect. Under the method's assumptions, intervals formed in the same way across repeated samples would contain the underlying effect at the stated confidence level at the stated frequency. It is not a range containing a known share of individual participant outcomes, and it is not the probability that the true effect lies within this particular interval. For this trial, the reported interval crosses zero, the value corresponding to no risk difference. Its width also indicates that the point estimate is not highly precise.

What does the p-value add?

The unadjusted p-value for the primary comparison is 0.39. In general, a p-value describes how unusual data at least as incompatible with a specified null model would be if that model and the analysis assumptions were correct. It is not the probability that the null hypothesis is true, the probability that the result happened by chance, or a measure of clinical importance. The registry does not report whether this comparison was prespecified in a formal analysis plan, which test was used, or whether any adjustment was made. The result should therefore be read as the posted unadjusted comparison, not as a fully documented inferential analysis.

Why consider both absolute and relative measures?

The record also posts relative measures: a risk ratio of 1.192 with a 95% confidence interval from 0.797 to 1.783, and an odds ratio of 1.345 with a 95% confidence interval from 0.684 to 2.646. These measures express a comparison on ratio scales, rather than as an absolute difference. A risk ratio compares the group proportions; an odds ratio compares the odds of the outcome. Odds and probabilities are related but are not identical. The risk difference is often directly interpretable as an absolute contrast, while ratio measures can convey proportional change. All three estimates are uncertain, and their intervals include the value representing no association on their respective scales.

The posted values are unadjusted summaries. The registry does not report a covariate-adjusted model, stratification variables, or an analysis accounting for any randomization factors. Randomization supports comparison of groups in expectation, but it does not remove uncertainty in a small pilot sample, guarantee balance on every characteristic, or resolve missing outcome information. Baseline characteristics and their distribution by arm are not reported in the registry record.

How should the secondary outcome be interpreted?

The secondary endpoint is also binary, counting participants who provided smoking cessation status by text message. Its posted risk difference is -0.329, with a 95% confidence interval from -0.477 to -0.180 and an unadjusted p-value of < 0.001. This describes a difference in text-response status, not a direct effect on abstinence. The comparison may inform the feasibility of the texting-based follow-up method, but response behavior and smoking behavior should not be treated as the same outcome.

When several outcomes are evaluated, the chance of finding at least one apparently unusual result can increase if each is assessed without accounting for the others. The registry lists one secondary outcome and the primary endpoint, but it does not report a multiplicity strategy, a hierarchy for interpreting outcomes, or a prespecified family of tests. The secondary p-value is unadjusted; its strength should be considered alongside the pilot aims and the lack of a reported analysis plan rather than as standalone confirmation.

General statistical caution also applies to over-dispersion in outcomes that are more variable than a simple model assumes. Over-dispersion is particularly relevant to count or clustered data, where a basic model may underestimate uncertainty if it assumes too little variability. The posted endpoints are participant counts with binary outcomes, and no dispersion estimate or model-based analysis is reported. There is no basis in the registry record to claim that an over-dispersion adjustment was needed or used.

The trial-specific statistical plan, outcome analysis populations, missing-data methods, and any interim analyses are not reported in the registry record. The posted results therefore support a descriptive interpretation of the arm counts and listed comparisons, with uncertainty, rather than a reconstruction of unreported analytic decisions.

11. Confidence Intervals and Precision

The primary risk-difference estimate is 0.071, and its 95% confidence interval ranges from -0.091 to 0.234. The interval crosses zero, so the posted data are compatible with no difference as well as with differences favoring either group. Its span shows that the estimate is imprecise: the observed point estimate alone gives a much narrower impression than the range of values consistent with the reported interval.

The relative estimates tell a similar broad story. The risk ratio is 1.192, with a 95% confidence interval from 0.797 to 1.783; the odds ratio is 1.345, with a 95% confidence interval from 0.684 to 2.646. Each interval includes its scale's null value. The endpoints differ in how they express contrasts, so their numerical magnitudes should not be compared as if they were the same quantity. Their shared uncertainty is more important than the difference between the scales.

Confidence intervals do not account for every source of uncertainty. They describe sampling uncertainty under the calculation's assumptions. They cannot compensate for unreported participant flow, incomplete outcome data, uncertain measurement, or limitations in generalizing beyond the trial. The record notes biochemical verification in a subsample but does not report its size or results; that leaves uncertainty about how verification relates to the self-reported endpoint.

The secondary status-by-text comparison has a confidence interval from -0.477 to -0.180 for its risk difference. This interval does not cross zero, but the result concerns response by text rather than the primary abstinence endpoint. Its precision on that specific outcome does not remove the uncertainty in the primary comparison or establish a causal explanation for the difference in reporting behavior.

Overall, the primary estimate is not precise enough to distinguish confidently among a range of possible group differences. The interval is a key part of interpretation, not an optional supplement to the point estimate or p-value.

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 sample-size illustrations are planning calculations based on the observed effect, not the original trial design. For these binary outcomes, the entries are participants per arm, not a total across both arms and not total events. The stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each planning row uses the stated fraction of the observed effect as the effect to detect. The trial's own original design assumptions and sample-size justification are not reported in the registry record.

The 80% power column describes the number of participants per arm that a planning calculation estimates would be needed to have an 80% chance of detecting the specified effect under those assumptions, if that effect were the true one. The 90% power column uses a higher target chance of detection and consequently lists more participants per arm for the same effect. These are design illustrations; they are not observed power.

For the primary endpoint, the illustration using 100% of the observed effect lists 742 participants per arm for 80% power and 993 participants per arm for 90% power. Using 75% of the observed effect gives 1,310 and 1,753 participants per arm, respectively; using 50% gives 2,925 and 3,915. Smaller target effects require more participants because a subtler contrast is harder to distinguish from sampling variation.

The secondary endpoint's corresponding illustrations are smaller because they are based on its different observed effect: 32 and 43 participants per arm for 100% of that effect, 61 and 81 for 75%, and 142 and 189 for 50%, at the 80% and 90% targets, respectively. These figures do not establish that the trial was designed or adequately sized for either endpoint. They are sensitive to the observed effect used as the planning input, which may be uncertain in a pilot trial.

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 = 0.371; treatment proportion p₁ = 0.443; average p̄ = 0.407.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.6948 = 1.3618.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.6930 = 0.5832.
4. n = (1.3618 + 0.5832)² / (0.0714)² = 741.5, rounded up to 742 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 <- 0.371428571428571                          # control proportion
p1 <- 0.442857142857143                          # 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(2986711)
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 = 742 (80% power), 993 (90% power)
 75% of observed effect: n per arm = 1,310 (80% power), 1,753 (90% power)
 50% of observed effect: n per arm = 2,925 (80% power), 3,915 (90% power)
power.prop.test: 741.5 
Simulated power at n = 742 per arm: 0.796 (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

The registry record does not report a multiplicity adjustment, a prespecified hierarchy of outcomes, or a testing strategy that explains how the primary and secondary comparisons were to be interpreted together. The primary comparison has an unadjusted p-value, and the secondary comparison is also unadjusted. When several outcomes are assessed, treating each nominal test as if it were the only analysis can increase the chance of a false-positive finding across the set. The extent of that issue depends on the planned family of tests, which is not described.

Missing-data methods are not reported in the registry record. The posted outcome summaries list 70 participants per arm, while enrollment is 158. The record does not explain participant flow, whether the arm counts refer to everyone randomized or only those with available outcomes, how unavailable telephone interviews were handled, or whether missing participants were classified in any particular way. It would be inappropriate to assume a complete-case, intention-to-treat, or other analysis population without that information.

The record also does not report a participant-level analysis set, protocol deviations, or exclusions. Such details matter because conclusions can depend on who contributes outcome information and how missing outcomes are treated. The primary endpoint is self-reported by telephone, with biochemical verification in a subsample, but the record does not give the verification subsample size or specify how verification results were incorporated into the endpoint.

No interim analyses, stopping rules, or monitoring procedures are reported in the registry record. The terminated status alone does not explain whether stopping related to recruitment, feasibility, administration, or another reason. A reason for termination and any consequences for the planned analyses are not reported. These gaps limit reconstruction of the intended inferential framework and counsel against reading the unadjusted comparisons as the result of a fully documented confirmatory analysis.

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 0% reporting threshold.

The registry reports zero serious adverse events among 70 participants in the motivational text-message group and zero among 70 participants in the control group. It also reports zero other adverse events and zero deaths in each of those groups. No serious adverse-event terms are listed.

These figures describe what was recorded for the participants represented in the adverse-event summaries. They do not establish that no adverse events occurred outside the recorded categories, that every participant was observed for the same duration, or that the trial could detect uncommon events. The record does not report adverse-event definitions, collection procedures, follow-up duration for safety, or the participant flow underlying the group counts.

Because the study is a small pilot and the posted safety summaries contain no events, they offer limited information about comparative safety. The absence of recorded events should not be interpreted as proof that either approach has no risk. The registry does not provide further safety analysis or explain whether any events were assessed as related to the interventions.

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

The posted primary result is an uncertain comparison of self-reported abstinence at 28 days after discharge. The motivational-message group had a higher observed abstinence count than the control group, but the risk-difference confidence interval includes no difference and extends in both directions. The unadjusted p-value is 0.39. Taken together, these statistics do not provide a precise estimate of the difference, and they do not establish that the messaging approach increased abstinence.

That interpretation does not mean the study has no value. Its stated aims included piloting post-discharge follow-up by text as well as evaluating a possible relapse-prevention message approach. The secondary outcome on providing status by text bears on the follow-up method, though it is distinct from abstinence and should not be treated as a proxy for it. Pilot results can help clarify measurement and implementation questions even when a primary treatment comparison remains uncertain.

The record does not report the original sample-size rationale, analysis populations, missing-data methods, multiplicity plan, detailed participant flow, or a reason for termination. These omissions make it difficult to judge how closely the posted analyses followed an intended protocol or how outcome availability may have shaped the results. The registry also does not report participant characteristics sufficient to assess how representative the trial was of other hospitalized smokers.

The primary assessment concerns abstinence during the prior 7 days at a 28-day interview, not sustained abstinence over longer periods. Biochemical verification was specified for a subsample, but the subsample size and findings are not reported. These measurement limits constrain what can be inferred about smoking behavior beyond the recorded endpoint.

Accordingly, the results are descriptive evidence from a pilot comparison, with notable uncertainty. They do not establish longer-term effects, explain differences in response behavior, or determine whether the approach would perform similarly in other populations or settings. They should be understood as a record of the outcomes and comparisons posted for this trial rather than a definitive evaluation.

17. Why This Trial Matters Statistically

This trial illustrates why a behavioral intervention study may need to distinguish the outcome of interest from the process used to measure it. The primary endpoint concerns abstinence reported in a telephone interview; the secondary endpoint concerns sending smoking status by text. These are not interchangeable. A difference in follow-up response can matter for feasibility and may affect how outcome data are obtained, while still not answering whether abstinence differs between groups.

The primary comparison also illustrates why estimates need to be read with their uncertainty. The observed risk difference is positive, but the 95% confidence interval crosses zero and covers a broad range of possible group differences. A point estimate and a p-value alone would not convey the same information. The interval makes clear that the pilot results do not tightly determine the magnitude or direction of the underlying contrast.

The contrast between the primary and secondary outcomes shows how different questions can yield different patterns in one study. The secondary comparison may be relevant to the feasibility of text-based collection, but it is unadjusted and appears alongside a primary outcome. Without a reported multiplicity plan, its statistical evidence should be interpreted cautiously. Keeping the outcome meanings and analysis roles distinct helps prevent a secondary feasibility signal from being mistaken for proof about the primary behavioral outcome.

Finally, the record highlights the importance of complete reporting. Participant flow, missing-data procedures, analysis populations, and original design assumptions would help readers understand the relation between enrollment, outcome counts, and statistical conclusions. Their absence does not erase the posted findings, but it limits how fully they can be assessed. This is especially consequential in a pilot trial, where feasibility and measurement are central aims alongside estimation of an intervention effect.

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.

Several limitations specific to the registry record constrain interpretation. Although enrollment is listed as 158, each arm's posted outcome summary contains 70 participants. A flow diagram or accounting of randomized participants, follow-up availability, and analyzed participants is not reported. The record does not state whether participants without a recorded outcome were excluded, treated as smoking, or handled by another method.

The primary endpoint depends on self-report in a telephone interview. Biochemical verification is specified in a subsample, but the number of participants verified, selection approach, results, and influence on the reported endpoint are not reported in the registry record. The endpoint captures the prior 7 days at the 28-day assessment, so it does not describe abstinence across the full period since discharge or later outcomes.

The study is identified as a pilot and has terminated status. The reason for termination and whether the planned recruitment or follow-up was completed are not reported. Baseline characteristics, detailed eligibility criteria, message schedule, intervention engagement, and care received outside the messages are also not reported, limiting assessment of applicability and implementation.

Statistical reporting is incomplete for a detailed appraisal. The registry does not report the original sample-size justification, analysis populations, missing-data approach, prespecified model or test, multiplicity plan, or interim analyses. The listed comparisons are unadjusted, and the outcome counts alone cannot resolve these omissions. The one secondary outcome addresses text response, which is conceptually different from abstinence and should not be interpreted as confirming the primary result.

These limitations are reporting limitations as well as design considerations. They do not prove that the study was conducted incorrectly, but they restrict what can be concluded from its registry record.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Penn State TXT2STAYQUIT Study- a Texting Study to Help Hospitalized Smokers Stay Quit — NCT02986711.
• Registry record last updated 2018-12-19; status last verified 2018-12.
• Results first posted 2018-09-21.
• 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

NCT02986711 is the Penn State TXT2STAYQUIT pilot randomized trial of brief automated smoking cessation support for smokers discharged from hospital. The registry describes a parallel, single-masked behavioral study comparing motivational text messages with control texts that asked about current smoking status. Enrollment is listed as 158, and the trial status is terminated.

The primary outcome is the count reporting complete tobacco abstinence during the prior 7 days at a telephone interview 28 days after discharge, with biochemical verification specified in a subsample. The posted arm summaries list 70 participants per group. The observed comparison favors the motivational-message group by point estimate, but its confidence interval includes no difference and the unadjusted p-value is 0.39.

The secondary outcome is providing smoking cessation status by text message. The record does not report participant flow, missing-data methods, analysis populations, a multiplicity plan, the original sample-size justification, or the reason the trial was terminated. The findings are best read as pilot outcome and follow-up information with substantial limits on precision and interpretation.