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P113. Factors affecting Swedish patients' refill adherence and persistence to adalimumab therapy

Y. Liu1, M. Yang2, P.M. Mulani2, J. Soderberg3, J. Petersson4, J. Chao2

1University of Missouri-Kansas City, Kansas City, MO, United States; 2Abbott Laboratories, Abbott Park, IL, United States; 3Lund University, Malmö, Sweden; 4Abbott Scandinavia, Solna, Sweden

Aim: To examine factors affecting refill adherence and persistence to adalimumab therapy in Swedish patients with Crohn's disease (CD).

Materials and Methods: This was a retrospective cohort study of the Swedish National Board of Health and Welfare database of dispensing records of adalimumab from July 6, 2005, to September 30, 2009, for patients with CD. For each patient, the medication possession ratio (MPR) was calculated as the days of supply dispensed (excluding the last dispensing record) divided by the number of days between the first and last dispensing records. Then patients were identified as adherent (MPR ≥ 0.8) vs. non-adherent (MPR < 0.8). A logistic regression was conducted, where the outcome variable was adherence (yes/no) and the independent variables included age group, gender, dispensing device, prescriber's specialty, and prescriber's practice setting. A patient was considered non-persistent if the gap between any 2 dispensing records minus the days of supply dispensed with the former record was greater than 180 days. A Cox proportional-hazards model was conducted, where the outcome variable was non-persistence (yes/no) and the independent variables were the same as in the logistic regression. Kaplan–Meier survival analyses were performed to compare cumulative incidence of non-persistence for independent variables.

Results: Of 1083 patients, the average MPR was 0.93 with an average follow-up time of 445 days, where 790 (89%) were identified as adherent (MPR ≥ 0.8) and 837 (77%) were identified as persistent. The 1-year Kaplan–Meier persistency rate was 82%. Compared with those using a syringe, patients using a pen as the dispensing device were more likely to be adherent, with an odds ratio (OR) of 1.78 (95% CI: 1.14, 2.78). Patients whose prescribers worked in a gastroenterology center were more likely to be adherent than patients whose prescribers worked in an internal medicine center, with an OR of 1.70 (95% CI: 1.04, 2.79). In addition, patients using a pen were less likely to be non-persistent than those using a syringe, with a hazard ratio (HR) of 0.74 (95% CI: 0.56, 0.97). Patients whose prescribers worked in a gastroenterology center were less likely to be non-persistent than patients whose prescribers worked in an internal medicine center, with an HR of 0.64 (95% CI: 0.48, 0.86). Compared with female patients, male patients were less likely to be non-persistent, with a HR of 0.75 (95% CI: 0.57, 0.97). Furthermore, Kaplan–Meier survival analyses revealed similar results.

Conclusions: Use of the adalimumab pen as the dispensing device and being treated in a gastroenterology center had a positive impact on Swedish patients' refill adherence and persistence to adalimumab. Male patients had better persistency.