Preference-adaptive randomization in comparative effectiveness studies

Heterogeneity in the Effects of Reward- and Deposit-based Financial Incentives on Smoking Cessation

RATIONALE

Targeting different smoking cessation programs to smokers most likely to quit when using them could reduce the burden of lung disease.

OBJECTIVES

To identify smokers most likely to quit using pure reward-based financial incentives or incentive programs requiring refundable deposits to become eligible for rewards.

METHODS

We conducted prespecified secondary analyses of a randomized trial in which 2,538 smokers were assigned to an $800 reward contingent on sustained abstinence from smoking, a refundable $150 deposit plus a $650 reward, or usual care.

MEASUREMENTS AND MAIN RESULTS

Using logistic regression, we identified characteristics of smokers that were most strongly associated with accepting their assigned intervention and ceasing smoking for 6 months. We assessed modification of the acceptance, efficacy, and effectiveness of reward and deposit programs by 11 prospectively selected demographic, smoking-related, and psychological factors. Predictors of sustained smoking abstinence differed among participants assigned to reward- versus deposit-based incentives. However, greater readiness to quit and less steep discounting of future rewards were consistently among the most important predictors. Deposit-based programs were uniquely effective relative to usual care among men, higher-income participants, and participants who more commonly failed to pay their bills (all interaction P values < 0.10). Relative to rewards, deposits were more effective among black persons (P = 0.022) and those who more commonly failed to pay their bills (P = 0.082). Relative to rewards, deposits were more commonly accepted by higher-income participants, men, white persons, and those who less commonly failed to pay their bills (all P < 0.05).

CONCLUSIONS

Heterogeneity among smokers in their acceptance and response to different forms of incentives suggests potential benefits of targeting behavior-change interventions based on patient characteristics. Clinical trial registered with www.clinicaltrials.gov (NCT 01526265).

Time to selected quit date and subsequent rates of sustained smoking abstinence

In efforts to combat tobacco dependence, most smoking cessation programs offer individuals who smoke the choice of a target quit date. However, it is uncertain whether the time to the selected quit date is associated with participants' chances of achieving sustained abstinence. In a pre-specified secondary analysis of a randomized clinical trial of four financial-incentive programs or usual care to encourage smoking cessation (Halpern et al. in N Engl J Med 372(22):2108-2117, doi: 10.1056/NEJMoa1414293 , 2015), study participants were instructed to select a quit date between 0 and 90 days from enrollment. Among those who selected a quit date and provided complete baseline data (n = 1848), we used multivariable logistic regression to evaluate the association of the time to the selected quit date with 6- and 12-month biochemically-confirmed abstinence rates. In the fully adjusted model, the probability of being abstinent at 6 months if the participant selected a quit date in weeks 1, 5, 10, and 13 were 39.6, 22.6, 10.9, and 4.3%, respectively.

Equipoise across the patient population: optimising recruitment to a randomised controlled trial

BACKGROUND

This paper proposes a novel perspective on the value of qualitative research for improving trial design and optimising recruitment. We report findings from a qualitative study set within the OPEN trial, a surgical randomised controlled trial (RCT) comparing two interventions for recurrent bulbar urethral stricture, a common cause of urinary problems in men.

METHODS

Interviews were conducted with men meeting trial eligibility criteria (n = 19) to explore reasons for accepting or declining participation and with operating urologists (n = 15) to explore trial acceptability.

RESULTS

Patients expressed various preferences and understood these in the context of relative severity and tolerability of their symptoms. Accounts suggest a common trajectory of worsening symptoms with a particular window within which either treatment arm would be considered acceptable. Interviews with clinician recruiters found that uncertainty varied between general and specialist sites, which reflect clinicians' relative exposure to different proportions of the patient population.

CONCLUSION

Recruitment post referral, at specialist sites, was challenging due to patient (and clinician) expectations. Trial design, particularly where there are fixed points for recruitment along the care pathway, can enable or constrain the possibilities for effective accrual depending on how it aligns with the optimum point of patient equipoise. Qualitative recruitment investigations, often focussed on information provision and patient engagement, may also look to better understand the target patient population in order to optimise the point at which patients are approached.

TRIAL REGISTRATION

ISRCTN Registry, ISRCTN98009168 . Registered on 29 November 2012.

Current Practice of Pharmacological Thromboprophylaxis for Prevention of Venous Thromboembolism in Hospitalized Children: A Survey of Pediatric Hemostasis and Thrombosis Experts in North America

Pharmacological thromboprophylaxis (pTP) is the most effective intervention to prevent venous thromboembolism (VTE) in hospitalized adults. High-quality studies investigating the role of pTP in children are lacking. The aim of this study is to understand pediatric hematologists' current practices of pTP prescription and to explore their opinion about universal adoption of pTP for high-risk hospitalized children. An electronic survey was sent to members of Hemostasis and Thrombosis Research Society of North America. The response rate was 47.3% (53/112). VTE was perceived as a major hospital acquired complication by all and 96% (51/53) prescribed pTP in select cases. Majority would consider prescribing pTP for personal history of thrombosis, inheritance of severe thrombophilic conditions, and teen age. The majority of respondents (55%, 29/53) were either not in support of or uncertain about the universal adoption of pTP policy for high-risk hospitalized children. In total, 62% of respondents (33/53) did not support the use of pTP for central venous lines. Respondents reported on the presence of pharmacological (32%, 17/53) and mechanical (45%, 24/53) thromboprophylaxis policies at their institutions. Pediatric hematologists considered pTP a useful intervention to prevent VTE and prescribed pTP in select cases. Universal adoption of pTP was not supported. Wide variability in clinical practice was observed.

Randomized trial of four financial-incentive programs for smoking cessation

BACKGROUND

Financial incentives promote many health behaviors, but effective ways to deliver health incentives remain uncertain.

METHODS

We randomly assigned CVS Caremark employees and their relatives and friends to one of four incentive programs or to usual care for smoking cessation. Two of the incentive programs targeted individuals, and two targeted groups of six participants. One of the individual-oriented programs and one of the group-oriented programs entailed rewards of approximately $800 for smoking cessation; the others entailed refundable deposits of $150 plus $650 in reward payments for successful participants. Usual care included informational resources and free smoking-cessation aids.

RESULTS

Overall, 2538 participants were enrolled. Of those assigned to reward-based programs, 90.0% accepted the assignment, as compared with 13.7% of those assigned to deposit-based programs (P<0.001). In intention-to-treat analyses, rates of sustained abstinence from smoking through 6 months were higher with each of the four incentive programs (range, 9.4 to 16.0%) than with usual care (6.0%) (P<0.05 for all comparisons); the superiority of reward-based programs was sustained through 12 months. Group-oriented and individual-oriented programs were associated with similar 6-month abstinence rates (13.7% and 12.1%, respectively; P=0.29). Reward-based programs were associated with higher abstinence rates than deposit-based programs (15.7% vs. 10.2%, P<0.001). However, in instrumental-variable analyses that accounted for differential acceptance, the rate of abstinence at 6 months was 13.2 percentage points (95% confidence interval, 3.1 to 22.8) higher in the deposit-based programs than in the reward-based programs among the estimated 13.7% of the participants who would accept participation in either type of program.

CONCLUSIONS

Reward-based programs were much more commonly accepted than deposit-based programs, leading to higher rates of sustained abstinence from smoking. Group-oriented incentive programs were no more effective than individual-oriented programs. (Funded by the National Institutes of Health and CVS Caremark; ClinicalTrials.gov number, NCT01526265.).