Purpose: Adherence to oral 5-Aminosalicylates (5ASAs) among patients with ulcerative colitis (UC) prevents relapses and can reduce resource utilization and costs. The degree to which the cost of 5ASA use among adherent patients is offset by reduced resource utilization in other sectors may be dependent on clinical characteristics of the patients selected.
Method: Insurance claims from the PharMetrics Integrated Outcomes Database were analyzed. We identified two cohorts of patients: (1) aged 18 or older with ≥ 1 claim for an UC diagnosis (ICD-9 556.xx) between June 1997 and August 2005 and with ≥30 days of oral 5ASA treatment plus at least one additional claim for UC to confirm the diagnosis (N=3,085); and (2) patients in (1) plus use of corticosteroids (proxy for active patients) within 12 months following 5ASA initiation (N=1,693). Patients had continuous enrollment for ≥6 months prior to and ≥12 months following 5ASA initiation. Cumulative exposure to oral 5ASAs over a 12-month period was calculated using the Medication Possession Ratio (MPR), defined as total 5ASA days supplied during the period divided by 365 days. Patients with an MPR of at least 0.80 were classified as adherent. UC-specific and all-cause resource utilization and costs were computed over the 12-month follow-up period.
Result: Adherent patients in group 1 had similar UC-related costs compared to non-adherent patients, but lower total costs ($9,849 vs. $11,281, P<0.01). Adherent patients in Group 2 also had similar UC-related costs compared to non-adherent patients but much lower total costs ($11,331 vs. $15,177, P<0.01). Further, UC-related and all-cause inpatient costs were lower among adherent patients compared to non-adherent patients in both groups, with the greater reduction of inpatient costs observed in Group 2. Adherent patients also had significantly lower costs of UC-related surgeries and emergency department visits in both groups compared to non-adherent patients.
Conclusion: Adherence with 5-ASAs for ulcerative colitis patients reduces total all-cause resource utilization and associated costs, particularly in inpatient cost sectors such as hospitalization, surgery and emergency department visits. The impact of medication adherence on total resource utilization and cost also varies on underlying characteristics including diagnostic confirmation and disease activity. Future research should investigate how adherence could improve QoL for patients with ulcerative colitis by reducing inpatient services, such as hospitalization and surgery.
Candidate for the Lee B. Lusted Student Prize Competition