Mailing strategies and costs of recruiting heavy smokers in CARET, a large chemoprevention trial

Our plain-English summary of Mailing strategies and costs of recruiting heavy smokers in CARET, a large chemoprevention trial, by B. Valanis, J. Blank, A. Glass (Controlled Clinical Trials, 1998).

The study

• Authors: B. Valanis, J. Blank, A. Glass
• Journal: Controlled Clinical Trials
• Published: 1998;19(1):25-38
• Type of article: Randomized trial
• Cited by: 38 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Recruitment costs represent a major portion of the budget for large clinical trials during the initial years of the study. Further, the rate of recruitment affects allocation of resources in future years. To learn about the costs and yields of recruiting from different populations and under different mailing strategies, we monitored recruitment yields of eligible heavy smokers for the Carotene and Retinol Efficacy Trial (CARET) at the Portland Study Center. Yields from the mailings, measured by response rate, percent of potential participants randomized, and related costs per randomization varied both by mailing strategy and by population targeted. Yield and cost varied significantly across population sources. Less variation was observed among various mailing strategies. Tracking the recruitment process yield provided useful information that allowed us to adjust recruitment approaches and achieve our randomization goals quickly and economically.

In plain English

This paper described how the Portland, Oregon, center of CARET recruited heavy smokers by mail. CARET was a trial testing beta-carotene plus vitamin A against lung cancer in heavy smokers and asbestos-exposed workers. The paper did not study asbestos exposure or disease outcomes. Between January 1989 and March 1992, the center mailed recruitment packets to 172,739 households, about 288,000 people. Overall, 37% of eligible smokers were randomized. That was 1.1% of the people mailed, less than half the 3.2% yield first projected. Kaiser Permanente members returned questionnaires most often (38%) and people from Department of Motor Vehicles lists least often (3.5%). In a randomized test, an advance postcard significantly raised questionnaire return and completion but did not significantly increase the share randomized. The postage options were compared by splitting mailings non-randomly. Among them, cost per randomized participant ranged from $58 for Kaiser nonprofit-rate mailings to $169 for a Blue Cross first class mailer. The authors concluded that tracking recruitment yield let them adjust their approach and meet their goals quickly and economically. They said they could not tell whether the results apply outside the U.S. Northwest.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Descriptive analysis of mail recruitment at one center of a randomized chemoprevention trial. It included one randomized test (advance postcard versus none) and non-randomized comparisons of postage types and source populations.
• Who was studied: Households sent CARET recruitment mailings by the Portland, Oregon, study center from January 1989 to March 1992: 172,739 households, about 288,000 individuals. Sources were Kaiser Permanente members, Blue Cross/Blue Shield of Oregon members, smokers from earlier research studies, known smokers (smoking cessation groups and a purchased mailing list), and Department of Motor Vehicles lists. The paper covers recruitment of heavy smokers, not the trial's asbestos-exposed worker cohort.
• Exposure: No asbestos or other health exposure was studied. The things compared were mailing strategies (advance postcard; regular first class, first class nonprofit, single-page first class mailer, and bulk-rate postage) and source populations.
• Main results:
  • Overall, 37% of smoker eligibles were randomized. This was 1.1% of the estimated population mailed, less than half the 3.2% yield initially projected.
  • Response varied by source: 38% of the Kaiser Permanente population returned an eligibility questionnaire, compared with 3.5% of the Department of Motor Vehicles population.
  • The Department of Motor Vehicles source had the lowest randomization rate: 0.3% of those mailed were randomized.
  • In the randomized test, an advance postcard did not significantly improve the percent of eligibles randomized or the percent of the population randomized. Its higher questionnaire return and completion rates were statistically significant.
  • Within the Kaiser Permanente population, first class postage gave no advantage over nonprofit postage for identifying eligibles.
  • Once eligible participants were identified, all mailing methods had similar enrollment and randomization rates among the eligibles.
  • A first household recruitment packet mailing, including postage, cost from $1.24 (bulk rate) to $1.59 (first class), using 1990 costs.
  • Cost per eligible smoker ranged from $24 (Kaiser Permanente nonprofit mailings) to $60 (Blue Cross/Blue Shield first class mailer). Cost per randomization for the same two groups was $58 and $169.
  • The authors estimated that recruiting 4000 smokers would cost $230,000 with the Kaiser Permanente nonprofit approach and $674,000 with the Blue Cross first class mailer approach, a difference of $444,000.
• The authors' conclusion: The authors concluded that tracking recruitment yield gave them information that let them adjust recruitment approaches and reach their randomization goals quickly and economically.
• Limitations the authors state:
  • Postage strategies were compared by splitting mailings non-randomly, because of limited computer programming resources.
  • The authors could not objectively compare the effect of public media advertising on yield, because it overlapped with remailings and new population sources.
  • The authors could not say whether the results generalize to populations outside the U.S. Northwest.
  • Age and gender were the only demographic variables available for comparing the Kaiser Permanente and Blue Cross populations.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer.

Medical terms in this study, explained in our Lexicon: Clinical Trial.

Related studies

• Research cost analyses to aid in decision making in the conduct of a large prevention trial, CARET. Carotene and Retinol Efficacy Trial — M.D. Thornquist, N. Urban, et al. (1993)
• Recruitment for the beta-carotene and retinol efficacy trial (CARET) to prevent lung cancer in smokers and asbestos-exposed workers — G.S. Omenn, G. Goodman, et al. (1992)
• CARET, the beta-carotene and retinol efficacy trial to prevent lung cancer in asbestos-exposed workers and in smokers — G.S. Omenn, G. Goodman, et al. (1991)
• Stopping the active intervention: CARET — D.J. Bowen, M. Thornquist, et al. (2003)
• Lobe of origin and histologic type of lung cancer associated with asbestos exposure in the Carotene and Retinol Efficacy Trial (CARET) — C.A. Brodkin, J. McCullough, et al. (1997)
• Methylation-derived Neutrophil-to-Lymphocyte Ratio and Lung Cancer Risk in Heavy Smokers — L. Grieshober, S. Graw, et al. (2018)

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