The impact of non-compliance on the cost-effectiveness of pharmaceuticals:A review of the literature

Non-compliance with drug therapies not only limits their effectiveness, but in some instances, is associated with grave clinical sequelae and substant ial economic burden. It is important, therefore, to consider non-compliance in economic evaluations. A review of pharmacoeconomic evaluations, which h ave applied sensitivity analysis to non-compliance rates, was undertaken to evaluate the impact of non-compliance on the cost-effectiveness of differe nt drug therapies. Although 22 evaluations satisfied the inclusion criteria , additional information was obtained from the authors of most studies, as the published details were inadequate. The majority of evaluations assumed altered effectiveness owing to reduced compliance in the absence of support ive clinical evidence. Because of the disparity in the nature of the outcom es, the measures of non-compliance and the time horizon of the studies eval uated, it was not possible to compare the magnitude of the impact of non-co mpliance among different drug-disease combinations. However, it was evident that non-compliance always results in a reduction in efficacy, but its imp act on costs varied substantially. The importance of incorporating measures of compliance is highlighted, as failing to account for 'real world' compl iance rates in pharmacoeconomic evaluations may lead to selection of sub-op timal treatment strategies. Copyright (C) 2001 John Wiley & Sons, Ltd.