A national registry study of patient and renal survival in adult nephrotic syndrome

Abstract Introduction We aimed to determine mortality rate, cause of death and rate of end-stage kidney disease (ESKD) in adults with nephrotic syndrome. Methods We conducted a national registry-based study, including all 522 adults who had a kidney biopsy for nephrotic syndrome in Scotland in 2014-2017. We linked the Scottish Renal Registry to death certificate data. We performed survival and Cox proportional hazards analyses, accounting for competing risks of death and ESKD. We compared mortality rates with those in the age- and sex-matched general population. Results 372 patients had primary nephrotic syndrome; 150 had secondary nephrotic syndrome. 110 patients (21%) died during a median follow-up of 866 days. In patients with primary nephrotic syndrome, observed vs. population three-year mortality was 2.1% (95%CI 0.0–4.6%) vs. 0.9% (0.8–1.0%) in patients aged under 60 years and 24.9% (18.4–30.8) vs. 9.4% (8.3–10.5) in over-60s. In secondary nephrotic syndrome this discrepancy was 17.1% (5.6–27.2) vs. 1.1% (0.9–1.2) in under-60s and 49.4% (36.6–59.7) vs. 8.1% (6.6–9.6) in over-60s. In primary nephrotic syndrome, cardiovascular causes accounted for 28% of deaths, compared to 18% in the general population. 80 patients (15%) progressed to ESKD. Incidence of ESKD by three years was 8.4% (95%CI 4.9–11.7) in primary and 35.1% (24.3–44.5) in secondary nephrotic syndrome. Early remission of proteinuria and the absence of early acute kidney injury were associated with lower rates of death and ESKD. Conclusions Adults with nephrotic syndrome have high rates of death and ESKD. Cardiovascular causes account for excess mortality in primary nephrotic syndrome.