New clinical insights into chronic obstructive pulmonary disease and their implications for pharmacoeconomic analyses

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of death and disability worldwide, but before the development of several new pharmacological treatments little could be done for COPD patients. Recognition that these new treatments could significantly improve the prognosis for COPD patients has radically changed clinical management guidelines from a palliative philosophy to an aggressive approach intended to reduce chronic symptoms, improve quality of life and prolong survival. These new treatments have also sparked interest in COPD cost-effectiveness research. Most COPD cost-effectiveness studies have been based on clinical trial populations, limited to direct medical costs, and used standard analysis methods such as Markov modelling, and they have usually found that newer therapies have favourable cost effectiveness. However, new insights into the clinical progression of COPD bring into question some of the assumptions underlying older analyses. In this review, we examine clinical factors unique to COPD and recent changes in clinical perspectives that have important implications for pharmacoeconomic analyses. The main parameters explored include (i) the high indirect medical costs for COPD and their relevance in assessing the societal benefits of new therapy; (ii) the importance of acute deteriorations in COPD, known as exacerbations, and approaches to modelling the cost benefit of exacerbation reduction; (iii) quality/utility instruments for COPD; (iv) the prevalence of co-morbid conditions and confounding between COPD and co-morbid disease utilization; (v) the limitations of Markov modelling; and (vi) the problem of outliers.