Contemporary prevalence estimates for giant cell arteritis and polymyalgia rheumatica, 2015

Objective There are no estimates of the prevalence of giant cell arteritis (GCA) or polymyalgia rheumatica (PMR) in a US population in the current millennium. The purpose of this study was to estimate the 2015 prevalence of GCA and PMR in a US population-based setting. Methods Cohorts of incident GCA in 1950–2009 and incident PMR in 1970–2014 were previously identified among residents of Olmsted County, Minnesota. Prevalence estimates were obtained from the age-, sex-, and calendar year-specific incidence rates and adjusted to the US white 2010 population aged ≥50 years. Confidence intervals (CI) were computed using bootstrap sampling. Results There were 248 incident cases of GCA in 1950–2009 and 790 cases of PMR in 1970–2014. The overall age- and sex-adjusted prevalence rate of GCA on January 1, 2015 was 204 (95% CI: 161–254) per 100,000 population aged ≥50 years. GCA prevalence rate in women was 304 (95% CI: 229–375) and in men was 91 (95% CI: 46–156) per 100,000 population. The overall age and sex adjusted prevalence rate of PMR on January 1, 2015 was 701 (95% CI: 651–750) per 100,000 population. PMR prevalence rate in women was 870 (95% CI: 787–957) and in men was 508 (95% CI: 426–589) per 100,000 population. Conclusion Prevalence rates of GCA and PMR in 2015 are similar to previously published prevalence estimates in the late 1990s. The health burden of these diseases among older persons continues to be substantial and reflects the need for continued efforts to better manage it.