Despite a stable incidence of ANCA-associated vasculitis in southern Sweden, the prevalence of the condition has increased, according to a population-based study spanning a 23-year period.
From 1997 to 2019, the incidence remained constant at approximately 30 cases per 1 million population, with a prevalence of 428 cases per 1 million population on January 1, 2020.
“The prevalence is the highest ever reported in [ANCA-associated vasculitis], indicating improved management and, therefore, survival,” Jens Rathmann, MD, of Lund University in Lund, Sweden, and colleagues wrote in RMD Open.
The study population included 623,872 adults in 2019. During the 23-year study period, 374 patients with a median age of 67.5 years were diagnosed with new-onset ANCA-associated vasculitis. The incidence was 30.3, 30.4, and 29.5 cases per 1 million population in 1997-2003, 2004-2011, and 2012-2019, respectively, the investigators reported. The incidence increased with age and was highest among individuals aged 70-84 years (96 cases per 1 million). The study also revealed a higher prevalence in men than women (479.7 vs 377.8 cases per 1 million).
Further, the study revealed a seasonal variation in ANCA-associated vasculitis diagnosis. The highest number of cases were diagnosed in March and May (37 cases in each month), followed by April (36 cases). ANCA-associated vasculitis was 38% more likely to be diagnosed in spring compared with winter. “A plausible pathophysiologic mechanism is that respiratory infection during winter may trigger the onset of [ANCA-associated vasculitis] a few months later,” the authors wrote.
Rathmann J, Segelmark M, Englund M, Mohammad AJ. Stable incidence but increase in prevalence of ANCA-associated vasculitis in southern Sweden: a 23-year study. RMD Open. Published online March 9, 2023. doi:10.1136/rmdopen-2022-002949
This article originally appeared on Renal and Urology News