Economic Evaluation of Disease Management Program : A Cases Study of Open Heart Surgery

Abstract

This study aimed to analyze the cost effectiveness for open heart surgery in disease management program compared with usual care. This study analyzed the cost effectiveness for coronary bypass grafting (CABG) in the 60 years old patients and open heart surgery for patients with valvular heart disease in 40 years old patients. Decision Analysis Model was used to calculate life expectancy, quality-adjusted life expectancy (QALY), lifetime cost and incremental cost-effectiveness ration (ICER). The disease management program was assumed to increase the proportion of patients receiving the surgery by 30% and reduce the proportion of patients who received delayed surgery by 40% when compared with usual care. Mortality rate in the first year of the surgery was based on the clinical data of Queen Sirikit Heart Center of the Northeast, Khon Kaen University. Mortality rate in the second year after surgery and thereafter was obtained from published literatures. Cost data were abstracted from electronic databases of Maharat Nakhonratchasima Hospital and obtained from DGR system. Quality of life data were based on the study of quality of life outcome measured by EuroQol VAS among patients with open heart surgery under the disease management program. Time horizons were 20 years for CABG and 40 years for VHD surgery. Compared to usual care, CABG under the disease management program improved life expectancy and QALY, and was more costly. Life expectancy were 9.83 and 9.36 years which were equivalent to 6.29 and 5.82 QALYs for disease management program and usual care, respectively. An ICER of the disease management program as compared with usual care was 17,276 Baht per QALY. For surgery in VHD, compared with usual care, the disease management program also improved life expectancy and QALY, and was more costly. Life expectancy were 13.17 and 11.54 years which were equivalent to 11.54 and 7.35 QALYs for the disease management program and usual care, respectively. An ICER of the disease management program as compared with usual care was 5,904 Baht per QALY. A cost effectiveness acceptability curve, based on Monte Carlo simulation suggests that at a willingness to pay (WTP) threshold of more than 15,000 Baht per QALY, more than 50% of CABG in the disease management program will be cost effective. For the surgery for VHD, at a WTP threshold of more than 10,000 Baht per QALY, more than 50% of surgery for VHD under the disease management program will be cost effective. Based on the WHO cost-effectiveness threshold, open heart surgery under the disease management program is considered the cost-effectiveness management when compared to usual care.