Background Few population-based data exist about adults with primary nephrotic syndrome.
Methods To evaluate kidney, cardiovascular, and mortality outcomes in adults with primary nephrotic syndrome, we identified adults within an integrated health care delivery system (Kaiser Permanente Northern California) with nephrotic-range proteinuria or diagnosed nephrotic syndrome between 1996-2012. Nephrologists reviewed medical records for clinical presentation, laboratory findings, and biopsy results to confirm primary nephrotic syndrome and assigned etiology. We identified a 1:100 time-matched cohort of adults without diabetes, diagnosed nephrotic syndrome, or proteinuria as controls to compare rates of end-stage kidney disease (ESKD), cardiovascular outcomes, and death through 2014, using multivariable Cox regression.
Results We confirmed 907 cases of primary nephrotic syndrome (655 definite and 252 presumed cases of focal segmental glomerulosclerosis [FSGS, 40%], membranous nephropathy [40%], and minimal change disease [20%]). Mean age was 49 years; 43% were women. Adults with primary nephrotic syndrome had higher adjusted rates of ESKD (adjusted hazard ratio [aHR], 19.63; 95% confidence interval [95% CI], 12.76 to 30.20), acute coronary syndrome (aHR 2.58; 95% CI, 1.89 to 3.52), heart failure (aHR 3.01; 95%CI, 2.16 to 4.19), ischemic stroke (aHR 1.80; 95%CI,1.06 to 3.05), venous thromboembolism (aHR 2.56; 95%CI, 1.35 to 4.85), and death (aHR 1.34; 95%CI, 1.09 to 1.64) versus controls. Excess ESKD risk was significantly higher for FSGS and membranous nephropathy than for presumed minimal change disease. The three etiologies of primary nephrotic syndrome did not differ significantly in terms of cardiovascular outcomes and death.
Conclusions Adults with primary nephrotic syndrome experience higher adjusted rates of ESKD, cardiovascular outcomes, and death, with significant variation by underlying etiology in risk for developing ESKD.
