Incidence, prevalence and risk of stroke in patients with Takayasu arteritis: a nationwide population-based study in South Korea

Background Takayasu arteritis (TAK) is a disease associated with increased risk of cardiovascular complications. We aimed to evaluate the incidence, prevalence and risk of stroke in patients with TAK. Methods Data from 1065 patients were obtained from a national database (2010-2018). The annual incidence and prevalence per 100 000 persons were estimated using the registration population in the midst of every year, and the standardised incidence ratio (SIR) of stroke was compared with the general population based on the data from the 2006 national report for cardiovascular and cerebrovascular diseases. Age-adjusted incidence rate ratio (IRR) of stroke based on the time interval after diagnosis was also calculated. A time-dependent Cox regression was conducted to investigate predictive factors of stroke. Results The overall incidence rate of TAK ranged between 0.2 and 0.3/100 000 person-years annually; the prevalence of TAK gradually increased, reaching 3.25/100 000 person-years in 2018. Seventy-three (6.9%) patients experienced stroke during follow-up, and the risk of developing stroke was higher than the general population (overall SIR 7.39, 95% CI 5.79 to 9.29; men: SIR 5.70, 95% CI 2.84 to 10.20; women: SIR 7.06, 95% CI 5.41 to 9.05). Most stroke events (90.9%) were cerebral infarction for men, whereas the proportion of cerebral infarction was lower (62.9%) in women. Over half of stroke events occurred within 6 months after diagnosis, and stroke was more common within 6 months of diagnosis compared with after 3 years in women (IRR 13.46, 95% CI 6.86 to 26.40). In Cox regression analysis, age was the sole predictor of stroke (adjusted HR 1.02, 95% CI 1.00 to 1.04, p=0.043). Conclusions The annual incidence of TAK was similar to the previous studies from Asia, and the risk of stroke increased in TAK. Different patterns of subtype and incidence of stroke were found according to sex, although age was the only predictor.