This study was undertaken to estimate the cumulative incidence rate of rheumatoid arthritis (RA) in the Taiwanese population ages 16-84 years, and life expectancy, loss of life expectancy, and lifetime health care expenditures for incident RA in Taiwan after 2003, when biologics began to be prescribed.
We obtained all claims data for the period 1999 to 2016 from the National Health Insurance program of Taiwan, and validated the data against the Catastrophic Illness Registry to establish the study cohort. We estimated the survival function for RA and extrapolated to lifetime using a rolling-over algorithm. For every RA case, we simulated sex-, age-, and calendar year-matched referents from vital statistics and estimated their life expectancy. The difference between the life expectancy of the referent and the life expectancy of the RA patient was the loss of life expectancy for the RA patient. Average monthly health care expenditures were multiplied by the corresponding survival rates and summed up throughout the lifetime to calculate the lifetime health care expenditures.
A total of 29,352 new RA cases were identified during 2003-2016. There was a decreasing trend in cumulative incidence rate in those ages 16-84 for both sexes. Mean life expectancy after diagnosis of RA was 26.3 years, and mean lifetime cost was $72,953. RA patients had a mean loss of life expectancy of 4.97 years. Women with RA survived 1-2 years longer than men with RA of the same age, which resulted in higher lifetime expenditures for the former. Since the life expectancy for women in Taiwan was 6-7 years higher than that for men, the loss of life expectancy for women with RA was higher than that for men with RA. Annual health care expenditures were similar for both sexes.
Our findings indicate that since biologics became available, RA patients have lived longer and had higher lifetime expenditures, which should be monitored and evaluated for cost-effectiveness.