Adherence behaviors in research protocols: comparison of two interventions.

The effectiveness of an enhanced preparation intervention was compared with the standard preparation intervention for accuracy in overnight urine specimen collections. The sample consisted of 179 individuals with type I insulin-dependent diabetes mellitus (IDDM). Subjects were assigned randomly to an enhanced or standard preparation group. The enhanced preparation included written instructions, a reminder to post instructions in the bathroom, a toilet seat cover with a reminder to save urine, and a nurse-initiated telephone call to review the instructions. The standard preparation included written instructions and a telephone number to call with any questions. For subjects without previous collection experience, significantly fewer inaccurate collections were reported in the enhanced preparation group than in the standard group (chi 2 = 4.61, P < .05). There were no differences in collection accuracy between enhanced and standard groups for subjects with collection experience (chi 2 = .4598, P > .05).