Rheumatoid arthritis prevalence, incidence, and mortality rates: a nationwide population study in Taiwan

Abstract

There are few nationwide population studies on the epidemiology of rheumatoid arthritis (RA). Here, we present the epidemiologic features and mortality rates of RA in Taiwan. The catastrophic illness registry of the Taiwan National Health Insurance Research Database and the National Death Registry of Taiwan were used to estimate the incidence and prevalence of RA and its associated mortality rates. All-cause and cause-specific standardized mortality ratios (SMRs) were calculated and compared to the corresponding ratios of the general population in 2002. The study comprised 15,967 incident RA cases (3,562 men; 12,405 women) occurring from 2002 through 2007. The annual incidence of RA was 15.8 cases (men, 10.1; women, 41.0) per 100,000 population. The period prevalence was 97.5 cases (men, 37.4; women, 159.5) per 100,000 population. During 67,010 person-years of follow-up, 985 deaths (372 men; 613 women) were identified, and this corresponded to a crude mortality rate of 14.7 deaths (men, 25.0; women, 11.8) per 1,000 person-years. Compared to female patients, male patients had a higher risk for mortality (log-rank test, p < 0.001). RA patients had an SMR of 1.25 (95 % confidence interval [CI], 1.18-1.33) for all-cause mortality. Compared to the general population, RA patients of both genders in this cohort had a significantly higher risk of mortality from infection (SMR, 2.49) and gastrointestinal diseases (SMR, 1.76). RA incidence and prevalence were higher in women than in men. Mortality was higher in men than in women. Compared to the general population, RA patients had a higher risk of death, particularly from infection and gastrointestinal diseases.