Cost-effectiveness and cost-utility analysis of outpatient follow-up frequency in relation to three-year mortality in discharged patients with bipolar disorder

There is a lack of clarity in terms of cost-effectiveness and cost-utility comparisons across different outpatient (OPD) follow-up patterns in discharged patients with bipolar disorder (BD). In this study, adult patients hospitalised for BD treatment (n = 1,591) were identified from the National Health Insurance Research Database in Taiwan. With survival as the effectiveness measure and quality-adjusted life years (QALYs) as the utility measure, a cost-effectiveness and cost-utility analysis was conducted over the 3-year follow-up period by post-discharge frequency of OPD visits. Compared to those making 1-7, 8-12 and 18 or more OPD visits, BD patients making 13-17 OPD visits within the first year after discharge had the lowest psychiatric and total healthcare costs over the follow-up period. With survival status as the effectiveness outcome, making 13-17 OPD visits was more likely to be the cost-effective option, as revealed by incremental cost-effectiveness ratios. Cost-utility analysis demonstrated that having 13-17 OPD visits was probably the more cost-effective option when considering QALYs; for instance, if society was willing to pay NTD1.5 million for one additional QALY, there was a 75.2% (psychiatric costs) to 77.4% (total costs) likelihood that 13-17 OPD visits was the most cost-effective option. In conclusion, post-discharge OPD appointments with a frequency of 13-17 visits within the first year were associated with lower psychiatric and total healthcare costs in the subsequent 3 years. Having an adequate outpatient follow-up frequency was likely to be cost-effective in the management of discharged patients with BD in this real-world setting.