Risk of kidney failure in patients with systemic sclerosis: a nationwide population-based study

Objective Data from a decade ago have shown that patients with systemic sclerosis (SSc) have a higher risk of kidney failure than the general population. However, as the incidence of kidney failure due to SSc has been declining, the comparative risk of kidney failure between patients with SSc and the general population could have changed over time. We investigated the risk of kidney failure in patients with SSc compared with the general population, up to more recent years. Methods This was a nationwide population-based study using the Korean National Health Insurance Service database. Patients with claims data for SSc between 2010 and 2017 (n=2591) and 1:5 age-matched and sex-matched controls (n=12 955) were selected. The index date was the earliest date of claim for SSc between 2010 and 2017. The follow-up duration was from the index date to 2019. The adjusted HRs (aHRs) and 95% CI for kidney failure were estimated using multivariable Cox proportional hazard models. Results Over 5.2 +/- 2.6 years, the incidence rates of kidney failure in patients with SSc and controls were 2.88 and 0.35 per 1000 person-years, respectively. Patients with SSc had a significantly higher risk of kidney failure than controls (aHR=7.244, 95% CI=4.256 to 12.329). The effect size was larger in patients diagnosed with SSc between 2014 and 2017 (aHR=9.754, 95% CI=3.254 to 29.235) than in those diagnosed before 2010 (aHR=6.568, 95% CI=2.711 to 15.571) or between 2010 and 2013 (aHR=6.553, 95% CI=2.721 to 15.781). Conclusion The risk of kidney failure remains higher in patients with SSc than in the general population.