Mortality associated with tiotropium mist inhaler in patients with chronic obstructive pulmonary disease: systematic review and meta-analysis of randomised controlled trials

Sonal Singh, Yoon K. Loke, Paul L. Enright, Curt D. Furberg

Research output: Contribution to journalArticlepeer-review

211 Citations (Scopus)


While informal care is a significant part of non-market economic activity, its value is rarely acknowledged, perhaps reflecting a lack of market data. Traditional methods to value such care include opportunity and replacement cost. This study is the first to employ the discrete choice experiment methodology to value informal care tasks. A monetary value is estimated for three tasks (personal care, supervising and household tasks). The relationship between time spent on formal and informal care is also modelled and preference heterogeneity investigated using the Latent Class Model. Complementarity between supervising tasks and formal care is observed. Monetary compensation is important, with willingness to accept per hour values ranging from £0.38 to £0.83 for personal care, £0.75 for supervising and £0.31 to £0.6 for household tasks. Heterogeneity in preferences is observed, with monetary compensation being important for younger people, but insignificant for older individuals. Such heterogeneity is important at the policy level. Values are lower than those generated by opportunity cost and replacement cost methods, perhaps because of the limited ability of revealed preference methods to capture broader aspect of utility. Differences with contingent valuation methods are also observed, suggesting future research should investigate the external validity of the different methods.
Original languageEnglish
Article numberd3215
JournalBritish Medical Journal (BMJ)
Publication statusPublished - 14 Jun 2011

Cite this