Decision Support for Smoking Cessation in Young Adults With Severe Mental Illness: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Decision Support for Smoking Cessation in Young Adults With Severe Mental Illness (NCT01779440), a randomized na study. The primary outcome is Number of Participants Who Utilized Smoking Cessation Treatment.

2. Clinical Question

3. Trial Design

This was a randomized, parallel-group trial with no masking. The registry lists the phase as not applicable. It records an enrollment of 58 participants and a completed study. The listed start date is 2013-01-01, and the primary completion date is 2018-02-22. The sponsor was Dartmouth-Hitchcock Medical Center.

Participants were assigned to an Electronic Decision Support System or a control computer program. The intervention was a web-based program intended to motivate, educate, and engage people with severe mental illness in evidence-based smoking cessation treatment. The comparator was a computer program aimed at educating participants about smoking cessation treatment. The registry does not describe the allocation sequence generation or concealment procedures, so those details are not reported in the registry record.

For the primary endpoint, the registry reports 27 participants in the Electronic Decision Support System group and 23 in the control group. The primary outcome timeframe was 14 week follow-up. The secondary abstinence outcome also has 27 and 23 participants listed by group, with a timeframe of 14 weeks. The safety record lists 30 participants at risk in the intervention group and 28 in the control group. The reasons that the outcome and safety denominators differ are not reported in the registry record.

Although the registry records 58 enrolled participants, the endpoint records do not give a full account of all enrolled participants’ outcome status. The record does not report the analysis population definition, participant flow, withdrawals, or the handling of missing outcome data. It also does not report details of treatment exposure, adherence, or follow-up procedures beyond the stated outcome timeframes. These omissions limit how fully the trial conduct and the relationship between enrollment and analyzed participants can be evaluated.

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

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.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants Who Utilized Smoking Cessation Treatment, measured over 14 week follow-up.

The primary endpoint counts participants who utilized smoking cessation treatment by 14 week follow-up. The registry says utilization was established through clinician confirmation of any engagement in behavioral smoking cessation treatment and/or smoking cessation medication treatment. It is therefore a count of participants meeting a treatment-engagement definition, rather than a measure of how much treatment they received, how consistently they used it, or whether they stopped smoking.

This endpoint is relevant to the stated aim of engaging young smokers with severe mental illness in cessation care. The registry background describes interest in quitting alongside limited use of combination treatments and notes the need for ways to engage smokers with severe mental illness in treatment. A clinician-confirmed engagement outcome can capture whether a participant connected with a cessation treatment, including behavioral support or medication treatment, without treating program exposure itself as proof of treatment use.

The endpoint is binary at the participant level: each participant either met the utilization definition or did not. The posted group values are counts, and the reported comparison expresses the difference in the proportion meeting that definition. The endpoint does not establish the amount, quality, or duration of treatment received. It also does not, by itself, measure abstinence. Biologically confirmed abstinence was listed separately as a secondary outcome, with a timeframe of 14 weeks. The registry does not report further details about the confirmation procedure or the specific criteria used to classify treatment utilization.

7. Results Posted in the Registry

• Electronic Decision Support System: 7.4% (2/27) versus 4.3% (1/23) on control; risk difference 3.1 percentage points (95% CI -9.9 to 16.0), risk ratio 1.70 (0.16–17.60); unadjusted two-proportion z-test p = 0.650.

8. Secondary Efficacy Endpoints

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

Number of Participants With Biologically Confirmed Abstinence

• 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:
  • Electronic Decision Support System: 14.8% (4/27) versus 0.0% (0/23) on control; risk difference 14.8 percentage points (95% CI 1.4 to 28.2); unadjusted two-proportion z-test p = 0.054.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Electronic Decision Support System and the control. The interval gives the range of effects that remain compatible with the data.

The registry lists biologically confirmed abstinence at 14 weeks as the secondary endpoint. Its observed group pattern differs from the primary treatment-utilization result: the posted abstinence counts are 4 in the intervention group and 0 in the control group. The recalculated risk difference is 0.148, with a 95% confidence interval from 0.014 to 0.282, and an unadjusted p-value of 0.054. The registry does not report a sponsor analysis for this endpoint.

The primary endpoint measures treatment engagement, whereas abstinence is a distinct outcome. Engagement in cessation treatment does not itself establish abstinence, and an abstinence result does not explain what treatment a participant received. The two outcomes address related parts of the smoking cessation pathway, but they should not be treated as interchangeable or as evidence that one result confirms the other. The primary endpoint remains the trial’s stated primary measure.

The secondary finding is less definitive than a single planned primary analysis because it is secondary, based on sparse counts, and presented without a registry-reported sponsor analysis. The record does not describe whether the statistical plan accounted for examining more than one outcome or any other comparisons. When multiple outcomes are examined, the chance of seeing an unusual result by chance can increase; a prespecified multiplicity approach can help address that general issue. Without a reported plan, the amount of adjustment, if any, cannot be determined.

The reported unadjusted p-value and confidence interval are useful descriptions of the posted comparison, but they do not establish how the finding would behave under a fully documented analysis plan or in another sample. The pattern can be noted as a secondary observation while giving greater weight to the prespecified primary outcome and recognizing the limitations in the registry’s analysis details.

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

• Number of Participants With Biologically Confirmed Abstinence

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is binary at the participant level: the registry counts participants who met the clinician-confirmed treatment-utilization definition. A risk is the proportion of participants in a group who experience the event of interest. The risk difference subtracts the control-group risk from the intervention-group risk. A positive value therefore indicates a higher observed event proportion in the intervention group, while a negative value indicates a higher proportion in the control group. The recalculated primary risk difference is 0.031.

How should the confidence interval be understood?

A confidence interval describes the uncertainty around an estimated effect under the statistical procedure used to calculate it. It is not a range that guarantees the true effect lies within its endpoints. For the primary risk difference, the interval extends from -0.099 to 0.160. Because this interval includes zero, the data are compatible with no difference as well as with effects in either direction. The broad span relative to the estimate signals limited precision. The registry record does not identify the method used to construct the recalculated interval, so no more specific claim about that procedure is warranted.

What does the reported test contribute?

The registry reports a chi-squared analysis for the primary comparison, with p=0.65. A p-value describes how compatible the observed data are with a specified null model of no group difference, assuming that model and the test’s conditions are appropriate. It is not the probability that the null hypothesis is true, and it does not quantify the size or clinical importance of an effect. The p-value should be read together with the estimated difference, its confidence interval, and the sparse event counts. The registry does not report additional details of the chi-squared test, such as whether any correction was used.

The recalculated estimate is a simple unadjusted comparison based on the posted summary counts. It does not adjust for participant characteristics or other variables. The registry record does not report an adjusted model for the primary endpoint. The sponsor’s reported test is therefore a separate description of the registry analysis, while the recalculation gives an unadjusted effect estimate and interval from the group summaries.

Why do sparse binary outcomes require care?

When few participants meet an outcome, each event contributes substantially to the estimated group proportions. Estimates can consequently be unstable, and confidence intervals can be wide. Standard procedures for binary outcomes can also behave differently when event counts are sparse, especially if an outcome count is zero in a group. The secondary endpoint has no recorded abstinence events in the control group, so estimates and tests for that outcome should be read with attention to the small counts and the method used. Details of the sponsor’s secondary statistical procedure are not reported in the registry record.

Over-dispersion is a general issue in count data when the observed variability exceeds what a chosen model assumes. It can make standard errors too small if ignored. The primary endpoint is recorded as a participant count with a binary event definition, and the registry gives no evidence that an over-dispersed count model was used or was needed. This general consideration should not be mistaken for a claim about the trial’s analysis.

How do the secondary estimates differ in role?

The secondary endpoint records biologically confirmed abstinence at 14 weeks. Its recalculated risk difference is 0.148, with a confidence interval from 0.014 to 0.282, and its unadjusted p-value is 0.054. It is an unadjusted summary comparison, not an adjusted analysis. The registry does not post a sponsor-reported analysis for this outcome. The recorded interval and p-value should be considered as the reported estimates, without inferring that they were produced by the same statistical procedure. The endpoint’s secondary status, small event counts, and unreported multiplicity plan all affect the weight appropriate for that result.

The registry does not state the original analysis plan, the handling of missing observations, the analysis population, or whether any interim analyses were conducted. Those matters are not reported in the registry record. As a result, the posted summary statistics permit a limited comparison of recorded group outcomes but do not fully document the trial’s statistical workflow.

11. Confidence Intervals and Precision

Precision is the degree to which an estimate is concentrated around a range of plausible values. The primary risk difference is 0.031, and its 95% confidence interval runs from -0.099 to 0.160. The interval is wide enough to include a negative difference, no difference, and a positive difference. The primary estimate is therefore uncertain in both magnitude and direction. The posted event counts are sparse, which contributes to the limited information available for estimating the group contrast.

The confidence interval is more informative about uncertainty than the point estimate alone. The point estimate gives a single summary of the observed contrast, but it cannot show how much the estimate could vary with another sample from the same underlying setting. The interval does not mean that every value within it is equally plausible, nor does it account for sources of uncertainty that are not represented by the calculation, such as missing outcomes or departures from the analysis plan.

For biologically confirmed abstinence, the risk difference is 0.148, with a confidence interval from 0.014 to 0.282. The interval is entirely above zero as posted, but the event counts are still limited, including 0 events in the control group. Its unadjusted p-value is 0.054. The registry does not report a sponsor analysis for this endpoint or explain the relationship between the interval and test procedures. The estimate should therefore be read as a secondary finding with considerable uncertainty, not as a precise standalone conclusion.

Confidence intervals do not measure the importance of an outcome, and they do not resolve limitations in study conduct or reporting. In this trial, the outcome denominators differ from the enrollment count, while participant flow and missing-data handling are not reported in the registry record. The intervals describe statistical uncertainty in the posted comparisons; they cannot show whether unrecorded or missing outcomes would change the estimates.

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 primary effect, not a record of the trial’s original design assumptions. The stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The effect to detect is set at the stated fraction of the observed effect. The figures are participants per arm, not total events.

The 80% power column gives the illustrative number of participants per arm for a design that would have an 80% chance of detecting the specified effect under those assumptions, if that effect were the true effect and the statistical model were appropriate. The 90% power column gives the corresponding planning number for a 90% chance. These are design-planning probabilities, not guarantees that a future study will detect the effect.

The rows consider planning for 100% of the observed effect, 75% of the observed effect, and 50% of the observed effect. The listed requirements rise as the target effect becomes smaller: for 100% of the observed effect, the figures are 927 participants per arm for 80% power and 1,240 participants per arm for 90% power; for 75% of the observed effect, they are 1,548 and 2,071; and for 50% of the observed effect, they are 3,253 and 4,355. Smaller effects need more participants because they are harder to distinguish from random variation.

These values are not observed power. They are planning illustrations calculated from the observed effect, and the original trial’s sample-size justification and design assumptions are not reported in the registry record. The registry record does not state that these planning figures were used to set enrollment. They should not be read as an assessment of what the completed trial was capable of proving.

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 = 0.043; treatment proportion p₁ = 0.074; average p̄ = 0.059.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.3326 = 0.6519.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.3319 = 0.2794.
4. n = (0.6519 + 0.2794)² / (0.0306)² = 926.5, rounded up to 927 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 <- 0.0434782608695652                          # control proportion
p1 <- 0.0740740740740741                          # 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(1779440)
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 = 927 (80% power), 1,240 (90% power)
 75% of observed effect: n per arm = 1,548 (80% power), 2,071 (90% power)
 50% of observed effect: n per arm = 3,253 (80% power), 4,355 (90% power)
power.prop.test: 926.5 
Simulated power at n = 927 per arm: 0.807 (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 reports a sponsor analysis of the primary comparison using a chi-squared method, with p=0.65. The unadjusted re-calculation from the posted group counts gives a risk difference of 0.031, a 95% confidence interval from -0.099 to 0.160, and p=0.65. The same p-value is reported for the sponsor analysis and the unadjusted re-calculation, and the registry record does not flag a discrepancy.

The sponsor analysis provides the reported test result. The recalculation adds an unadjusted effect estimate and confidence interval derived from the group summaries; it should not be mistaken for an adjusted model or a replacement for details of the sponsor’s analysis. The registry does not report a sponsor effect estimate or confidence interval for the primary endpoint. It also does not give enough methodological detail to establish that the sponsor’s test and the recalculated interval use identical procedures.

For the secondary abstinence outcome, the registry does not list a sponsor-reported analysis. The posted comparison is therefore limited to the group counts and the unadjusted recalculation. The record does not report a secondary analysis plan or the method used for a sponsor test of that endpoint. These distinctions matter: the primary comparison has a reported sponsor test that agrees in p-value with the recalculation, while the secondary endpoint has no corresponding sponsor analysis listed.

15. Multiplicity, Missing Data and Analysis Populations

The registry identifies a primary endpoint and one secondary endpoint. It reports a chi-squared p-value for the primary endpoint and an unadjusted p-value for the recalculated secondary comparison, but it does not describe a multiplicity strategy. It is not reported in the registry record whether the trial’s analysis plan adjusted for testing more than one outcome, whether outcomes were ranked in a testing sequence, or whether other planned analyses were conducted. Without those details, the secondary result should not be interpreted as if it were the sole planned test.

Multiplicity is a general statistical concern: as the number of questions examined increases, the chance of obtaining at least one apparently unusual result by chance may also increase. Approaches such as prespecifying a primary endpoint, adjusting inference, or using a defined testing hierarchy can help control that concern. The record names a primary outcome, but the broader statistical plan and any adjustment procedure are not reported in the registry record.

The handling of missing data is also not reported. The trial enrollment is 58, while the endpoint group sizes and safety at-risk counts do not use the same denominators. The record does not provide a participant flow account or explain exclusions, withdrawals, unavailable outcomes, or whether missing data were imputed. It is therefore not possible to determine whether the posted comparisons follow an intention-to-treat approach, a complete-case approach, or another analysis population definition.

The record does not state whether analyses were adjusted for baseline characteristics, whether outcome definitions were finalized before analysis, or whether interim analyses took place. These details are not reported in the registry record and should not be inferred from the posted endpoint summaries. Their absence limits assessment of the risk of selective analysis and the relationship between the recorded comparisons and any original protocol.

These uncertainties do not invalidate the posted counts, but they constrain what can be concluded from them. They are particularly relevant when interpreting a secondary outcome and when relating outcome denominators to enrollment. A fuller account of prespecified analyses, participant disposition, and missing-data handling would be needed to assess those issues more completely.

16. 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 5% reporting threshold.

The safety record lists 30 participants at risk in the Electronic Decision Support System group and 28 in the control group. It records 0 serious adverse events, 0 other adverse events, and 0 deaths in each group. The serious-event terms list is empty.

These entries describe what the registry record reports for the listed at-risk groups. They do not establish that no adverse experiences occurred outside the categories or reporting procedures used, and they do not show that the groups have identical safety profiles. The record does not provide adverse-event definitions, severity criteria, collection methods, or the observation period for these counts. It also does not explain why the at-risk numbers differ from the endpoint group sizes.

With no events recorded in either group, the posted figures offer limited information for comparing event rates. A zero count in a trial does not prove that an event cannot occur, and the listed sample sizes are limited. The safety figures should therefore be read as a report of no recorded serious or other adverse events and no deaths in the registry’s stated at-risk groups, not as proof of absence of risk.

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

The primary result describes a small observed difference in clinician-confirmed smoking cessation treatment utilization between the randomized groups at 14 week follow-up. The recalculated risk difference is 0.031, while the confidence interval from -0.099 to 0.160 includes no difference and effects in either direction. The registry’s chi-squared analysis reports p=0.65. Taken together, the posted primary results do not establish a clear group difference in treatment utilization.

This finding is not proof that the programs are equivalent. An equivalence conclusion would require a defined equivalence margin and an analysis designed for that question; neither is reported in the registry record. Nor does the result prove that the intervention has no effect. The estimate is uncertain, and the endpoint counts are sparse. The result indicates that the available primary comparison does not distinguish a group difference clearly, not that all possible effects have been ruled out.

The secondary abstinence comparison has a different observed pattern, but its status and reporting limit the strength of inference. It is based on a small number of events, has no sponsor analysis listed, and appears without a reported multiplicity plan. It cannot be used to overturn the primary endpoint or to claim that the intervention caused abstinence. It is a secondary finding that may warrant careful evaluation in a study with a prespecified analysis plan and adequate information.

The results apply to the recorded study groups, outcomes, and follow-up periods. They do not establish effects on long-term abstinence, health outcomes, or all young people with severe mental illness. The registry does not report detailed eligibility criteria, treatment adherence, participant flow, or missing-data handling, further limiting generalization and interpretation.

The safety entries record no serious or other adverse events and no deaths in the stated at-risk groups. Those counts do not establish the absence of risk, especially given the limited number of participants and missing detail on event collection. Overall, the record supports a cautious description of observed outcomes and their uncertainty, rather than a broad judgment about treatment effectiveness or safety.

18. Why This Trial Matters Statistically

This trial raises an important statistical question about how to evaluate an intervention intended to engage a population in care. The primary endpoint is not smoking cessation itself; it is clinician-confirmed use of behavioral treatment and/or cessation medication treatment. Keeping that distinction clear helps prevent a treatment-engagement result from being mistaken for evidence about abstinence or longer-term health outcomes.

The contrast between the two endpoints also illustrates why outcome hierarchy matters. The primary treatment-utilization comparison is inconclusive in the posted data, while the secondary abstinence comparison has a more favorable observed pattern but sparse events and no sponsor analysis listed. A secondary finding can be informative, but its weight depends on prespecification, the number of questions examined, and the analysis plan. Those details are not reported in the registry record.

The trial also demonstrates how a randomized design can still yield limited precision when outcome events are uncommon and analyzed group counts are small. The point estimate alone is not enough: its confidence interval communicates that a range of effects remains compatible with the primary data. Planning illustrations based on the observed effect require substantially larger per-arm samples than the endpoint groups recorded here, particularly when planning to detect smaller effects. Those illustrations are not the original design justification.

For clinical researchers, the record highlights the value of transparent participant flow, clear definitions of analysis populations, and detailed reporting of missing outcomes and planned analyses. Without those details, even simple group counts leave important questions unanswered about who contributed data and how the results were selected and evaluated. Statistical interpretation depends not only on the calculated estimates but also on the design and reporting context that gives them meaning.

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 are specific to the available trial record. Although enrollment is listed as 58, the primary and secondary endpoint group sizes are 27 and 23, and the safety record lists 30 and 28 participants at risk. The registry does not explain these denominator differences, provide participant flow, or report whether the endpoint analyses included all randomized participants. The effect of missing or excluded observations therefore cannot be assessed.

The primary outcome is a count based on clinician-confirmed treatment engagement, but further operational details are not reported. The record does not describe the confirmation procedure, the amount or duration of treatment, or how use of behavioral treatment and medication treatment was classified. The secondary outcome is biologically confirmed abstinence, but the specific confirmation method and abstinence criteria are not reported in the registry record.

The record identifies randomization, a parallel design, and no masking, but does not provide the sequence-generation or allocation-concealment methods. It does not report detailed eligibility criteria, baseline group characteristics, adherence information, or the content and delivery details of the control program. These omissions limit evaluation of group comparability, intervention exposure, and applicability to populations beyond the recorded participants.

Statistical reporting is also incomplete. The primary sponsor-reported result is a chi-squared p-value, but no sponsor effect estimate or interval is listed. No sponsor analysis is listed for the secondary endpoint. The original sample-size justification, analysis populations, missing-data strategy, multiplicity approach, adjusted analyses, and interim-analysis plan are not reported in the registry record. These limits call for restrained interpretation of both the primary and secondary comparisons.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Decision Support for Smoking Cessation in Young Adults With Severe Mental Illness — NCT01779440.
• Registry record last updated 2018-06-27; status last verified 2018-05.
• Results first posted 2018-06-27.
• 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

The registry record describes a completed, randomized, parallel-group trial with no masking, sponsored by Dartmouth-Hitchcock Medical Center. It enrolled 58 participants and compared a web-based Electronic Decision Support System with a control computer program intended to educate people about smoking cessation treatment. The primary outcome was clinician-confirmed use of behavioral cessation treatment and/or medication treatment at 14 week follow-up. The secondary outcome was biologically confirmed abstinence at 14 weeks.

The primary comparison records 2 participants meeting the treatment-utilization outcome in the intervention group and 1 in the control group. The registry reports a chi-squared p-value of 0.65; the unadjusted recalculation gives a risk difference of 0.031 with a 95% confidence interval from -0.099 to 0.160. The secondary result is based on sparse counts and has no sponsor analysis listed. Participant flow, missing-data handling, the original sample-size justification, and the broader statistical plan are not reported in the registry record.