Monetary versus nonmonetary incentives for TB skin test reading among drug users

In a prior study, we reported that monetary incentives were effective in increasing return for tuberculosis (TB) skin test reading. The purpose of this study was to compare the effects of monetary versus nonmonetary incentives and a theory-based educational intervention on return for TB skin test reading in a sample of newly recruited active injection and crack cocaine users, and to determine the prevalence of TB infection in this sample.

Active injection drug and/or crack cocaine users (n = 1,078), recruited using street outreach techniques, were skin tested for TB. They were randomly assigned to 1 of 5 experimental treatment conditions: $10 cash, grocery store coupons, bus tokens/fast-food coupons, motivational education, or usual encouragement to return. Nonmonetary incentives had a $10 value, and all incentives were provided at return for skin test reading.

Ninety-five percent of those who received $10 returned for skin test reading compared to 86% of those who received grocery store coupons and 83% of those who received either bus tokens or fast-food coupons. In contrast, only 47% of those who received the educational session and only 49% of those who received usual encouragement returned for skin test reading. The prevalence of a positive tuberculin test was 21%, and was similar for crack cocaine and injection drug users.

Nonmonetary and monetary incentives dramatically increased the return rate for TB skin test reading among drug users who are at high risk of TB infection. Nonmonetary incentives were somewhat less effective than monetary incentives.