Adherence to clotting factors among persons with hemophilia A or B

ObjectiveEvaluate adherence to clotting factor treatment and associated outcomes for patients with hemophilia using an integrated delivery database.MethodsThis was a retrospective, observational study tracking patients between 2006 and 2011. Patients with diagnosis codes for hemophilia were identified. Bleeding and complication rates were annualized over the study period. Medication adherence was assessed using prescription claims for clotting factors by examining sequential time periods of 180 days for each patient's continuous enrollment. Adherence within the time period was calculated using the 'days supply' field divided by 180 days. Under the assumption that severe patients should be treated prophylactically, patients were considered adherent within the time period if the ratio of 'days supply' to observed days was 60% or greater.ResultsA total of 207 patients (74.9 and 25.1% hemophilia A and B, respectively) met the inclusion/exclusion criteria. There were 101 (48.8%) mild, 32 (15.5%) moderate, and 74 (35.7%) severe patients with hemophilia. The percentage of time periods where adherence to clotting factors was 60% or greater was 14% (SD = 28%) for mild disease, 21% (SD = 32%) for moderate disease, and 51% (SD = 36%) for severe disease. Among patients with severe disease, 27 (36.5%) were adherent ≤30% of time periods, 22 (29.7%) adherent 31–70% of the time periods, and 25 (33.8%) were adherent ≥71% of time periods. Joint bleeding episodes and hospitalizations were uncommon events among the three groups.ConclusionsAmong patients with severe disease, the majority (66.2%) were adherent <70% of the time.