Compliance to multiple interventions in a high risk population.

Purpose: Assess compliance with study medications and examine reasons for noncompliance. Individuals with peripheral arterial disease present the clinician with a unique combination of symptoms and therapeutic needs; the treatment of this population has not been adequately studied.

Methods: The Arterial Disease Multiple Intervention Trial was a randomized double-blind placebo-controlled trial that randomized 468 participants to a combination of antioxidants, niacin and warfarin or matching placebos. Men and women (mean age 65 yrs) with peripheral arterial disease and low-density lipoprotein (LDL) < 190 mg/dl were enrolled and followed for one year. Compliance to the study medications was measured by pill count for each medication. An overall measure of compliance was determined by combining pill counts from all study visits.

Results: Mean overall pill counts ranged from 88 to 94% in the eight treatment groups. No statistically significant differences were found in mean pill counts over time or between active and placebo groups. History of coronary artery disease and number of follow-up visits were associated with higher overall pill counts while low compliance during screening was associated with lower counts during follow-up. Participants with an overall mean pill count < 80% had more adverse events compared to those with a higher count. Side effects were reported as the reason for missing pills significantly more often in the active versus placebo niacin group.

Conclusions: Individuals with peripheral arterial disease were able to comply with the complex drug regimen. The ability of this drug combination to reduce cardiovascular events and improve quality of life warrants study.