UK cost-consequence analysis of aripiprazole in schizophrenia: diabetes and coronary heart disease risk projections (STAR study)

Patients with schizophrenia experience elevated rates of morbidity and mortality, largely due to an increased incidence of cardiovascular disease and diabetes. There is increasing concern that some atypical antipsychotic therapies are associated with adverse metabolic symptoms, such as weight gain, dyslipidaemia and glucose dysregulation. These metabolic symptoms may further increase the risk of coronary heart disease (CHD) and diabetes in this population and, subsequently, the cost of treating these patients' physical health. The STAR study showed that the metabolic side effects of aripiprazole treatment are less than that experienced by those receiving standard-of-care (SOC). In a follow-up study the projected risks for diabetes or CHD, calculated using the Stern and Framingham models, were lower in the aripiprazole treatment group. Assuming the risk of diabetes onset/CHD events remained linear over 10 years, these risks were used to estimate the difference in direct and indirect cost consequences of diabetes and CHD in schizophrenia patients treated with aripiprazole or SOC over a 10-year period. Diabetes costs were estimated from the UKPDS and UK T(2)ARDIS studies, respectively, and CHD costs were estimated using prevalence data from the Health Survey of England and the published literature. All costs were inflated to 2007 costs using the NHS pay and prices index. The number of avoided diabetes cases (23.4 cases per 1,000 treated patients) in patients treated with aripiprazole compared with SOC was associated with estimated total (direct and indirect) cost savings of A 37,261,293 pound over 10 years for the UK population. Similarly, the number of avoided CHD events (3.7 events per 1,000 treated patients) was associated with estimated total cost savings of A 7,506,770 pound over 10 years. Compared with SOC, aripiprazole treatment may provide reductions in the health and economic burden to schizophrenia patients and health care services in the UK as a result of its favourable metabolic profile.