Adherence to Lipid Lowering Drugs in Patients with Schizophrenia

Abstract

The risks of cardiovascular disease (CVD) and overall mortality due to CVD are elevated in patients suffering from schizophrenia. The mortality rates in this population are at least twice higher than in general population and CVD is responsible for as much as 50% of the excess mortality. Despite the importance of medication adherence for the effective treatment of dyslipemia, little research has examined adherence with lipid lowering drugs in schizophrenia. First, Basque healthcare databases (e-osabide) were searched to identify patients with the International Classification of Diseases, Ninth Revision, Clinical Modifications (ICD-9-CM) diagnostic codes for schizophrenia (295*). We then collected data on all outpatient prescription medications funded by the autonomous drug benefit plan record (PRESBIDE database) in the province of Araba, (Basque Country) Spain. Adherence to lipid lowering drugs was calculated using the medication possession ratio (the sum of the days’ supply for all fills of lipid lowering during previous 8 months, divided by the number of days in the time period=8 months). Patients that were admitted to any acute health care hospital during the study period were excluded. A total of 769 patients (65% male) with schizophrenia were found. In 28 of them lipid lowering drugs were prescribed, but 6 patients were discarded because they were admitted to an acute care hospital during the study period. Of the 22 studied patients, 18 were male. Mean age was 51.8± 9.7 years. The most frequently prescribed drug was atorvastatin (14 patients) followed by simvastatin (4), fenofibrate (3) and pravastin (1). The proportion of patients with adherence>80% was 20/22 (90.9%). Both patients with a suboptimal adherence were male. The proportion of schizophrenic patients with good adherence to hypolipemiants in our setting is high. Nevertheless, overestimation of adherence values using this method cannot be ruled out.