Twenty-year Follow-up of Patients With Epidemic Glomerulonephritis due to Streptococcus zooepidemicus in Brazil.

Introduction: Post-streptococcal glomerulonephritis (PSGN) has a good prognosis in children, but few studies have evaluated the long-term renal outcomes in adults with PSGN.

Methods: In a follow-up study, 47 predominantly adult patients with PSGN due to group C Streptococcus zooepidemicus were reassessed 20 years after an outbreak in Nova Serrana, Brazil. We evaluated clinical characteristics, renal outcomes, and the trajectory of the estimated glomerular filtration rate (eGFR) by the creatinine-based chronic kidney disease-epidemiology collaboration equation from 5 follow-up assessments. Logistic regression and mixed-effects regression were used in the analysis.

Results: After 20 years, the participants' mean age was 56.6±15.1 years. Thirty-four (72%) patients had hypertension, 21 (44.7%) had eGFR <60 ml/min per 1.73 m2 , 8 of 43 (18.6%) had urine protein-to-creatinine ratio >150 mg/g, and 25 (53%) had CKD (low eGFR and/or increased proteinuria). Increasing age was associated with CKD (odds ratio: 1.07; 95% confidence interval [CI]: 1.02-1.13; P  = 0.011) in multivariate analysis. The mean eGFR decline in the last 11 years of follow-up was -3.2 ml/min per 1.73 m2 per year (95% CI: -3.7 to -2.7). Older age at baseline (coefficient -1.05 ml/min per 1.73 m2 per year; 95% CI -1.28 to -0.81; P  < 0.001), and hypertension 5 years after the outbreak (coefficient -7.78 ml/min/1.73 m2 ; 95% CI -14.67 to -0.78; P  = 0.027) were associated with lower eGFR during the whole study period.

Conclusion: There was a marked worsening of renal function and a high prevalence of CKD and hypertension after 20 years of PSGN outbreak. Long-term follow-up is warranted after PSGN, especially among older patients.