Modeling lifetime costs and health outcomes attributable to secondhand smoke exposure at home among Korean adult women

PURPOSE The aim of this research is to estimate lifetime costs and health consequences for Korean adult women who were exposed to secondhand smoke (SHS) at home. METHODS A Markov model was developed to project the lifetime healthcare costs and health outcomes of a hypothetical cohort of Korean women who are 40 years old and were married to current smokers. The Korean epidemiological data were used to reflect the natural history of SHS-exposed and non-exposed women. The direct healthcare costs (in 2014 US dollars) and quality-adjusted life years (QALYs) were annually discounted at 5% to reflect time preference. The time horizon of the analysis was lifetime and the cycle length was 1 year. Deterministic and probabilistic sensitivity analyses were conducted. RESULTS In the absence of SHS exposure, Korean women will live 41.32 years or 34.56 QALYs before discount, which corresponded to 17.29 years or 15.35 QALYs after discount. The SHS-exposed women were predicted to live 37.91 years and 31.08 QALYs before discount and 16.76 years and 14.62 QALYs after discount. The estimated lifetime healthcare cost per woman in the SHS non-exposed group was US$11 214 before the discount and US$2465 after discount. The negative impact of SHS exposure on health outcomes and healthcare costs escalated as the time horizon increased, suggesting that the adverse impact of SHS exposure may have higher impact on the later part of the lifetime. The result was consistent across a wide range of assumptions. CONCLUSION Life expectancy might underestimate the impact of SHS exposure on health outcomes, especially if the time horizon of the analysis is not long enough. Early intervention on smoking behaviour could substantially reduce direct healthcare costs and improve quality of life attributable to SHS exposure.