COMPARISON OF 3 COMPOSITE COMPLIANCE INDEXES IN A TRIAL OF SELF-ADMINISTERED PREVENTIVE THERAPY FOR TUBERCULOSIS IN HIV-INFECTED UGANDAN ADULTS

Compliance;with tuberculosis preventive therapy in a randomized placeb o-controlled trial in 2736 HIV-infected Ugandans was measured using ur inary isoniazid metabolite testing, clinic attendance, and self-report . Overall, 77% of urine tests were positive, subjects kept 85% of thei r scheduled visits while on therapy, and 69% reportedly never forgot t o take their medication. Different strategies were used for constructi ng three composite compliance indices in active arms: (1) an unweighte d index of the summed scores on scaled compliance measures; (2) a weig hted index using weights obtained from a survey of experts on tubercul osis; and (3) a statistically weighted index using principal component s analysis. Composite indices were evaluated for reliability, validity , and practical utility. Understanding of the regimen, study arm, subs equent follow-up, tuberculosis status, and urine spot-check result wer e associated with composite compliance scores. The unweighted index in this study performed as well as the weighted indices. (C) 1998 Elsevi er Science Inc.