Prevalence of nonadherence with maintenance mesalamine in quiescent ulcerative colitis

There are scant data regarding outpatient adherence in quiescent ulcerative colitis aside from patients enrolled in controlled clinical trials. We conducted a prevalence study to determine the medication adherence rate of maintenance therapy and to identify possible risk factors for nonadherence.

Outpatients with clinically quiescent ulcerative colitis for >6 months on maintenance mesalamine (Asacol, Procter and Gamble, Cincinnati, OH) were eligible. Patients were interviewed regarding disease history, and demographics were obtained from medical records. Refill information for at least 6 months was obtained from computerized pharmacy records. Adherence was defined as at least 80% consumption of supply dispensed. Using nonadherence as the outcome of interest, stratified analysis and regression modeling were used to identify significant associations.

Data were complete for the 94 patients recruited. The overall adherence rate was found to be 40%. The median amount of medication dispensed per patient was 71% (8-130%) of the prescribed regimen. Nonadherent patients were more likely to be male (67% vs 52%, p < 0.05), single (68% vs 53%, p = 0.04), and to have disease limited to the left side of the colon versus pancolitis (83% vs 51%, p < 0.01). Sixty-eight percent of patients who took more than four prescription medications were found to be nonadherent versus only 40% of those patients taking fewer medications (p = 0.05). Age, occupation, a family history of inflammatory bowel disease, length of remission, quality-of-life score, or method of recruitment (telephone interview vs clinical visit) were not associated with nonadherence. Logistic regression identified that a history of more than four prescriptions (odds ratio [OR] 2.5 [1.4-5.7]) and male gender (OR 2.06 [1.17-4.88]) increased the risk of nonadherence. Two statistically significant variables, which were protective against nonadherence, were endoscopy within the past 24 months (OR 0.96 [0.93-0.99]) and being married (OR 0.46 [0.39-0.57]).

Nonadherence is associated with multiple concomitant medications, male gender, and single status. These patient characteristics may be helpful in targeting those patients at higher risk for nonadherence.