Effect of overweight/obesity on recovery after post-infectious glomerulonephritis.

Background: Children with post-infectious glomerulonephritis (PIGN) rapidly recover and have excellent long-term outcomes. After encountering several overweight/obese children with persistent urinary abnormalities during recovery from PIGN, we conducted this retrospective study to determine if overweight/obese status prolonged time to resolution of renal abnormalities after PIGN. Methods: Records of 20 children with PSGN evaluated between 1/98 and 12/05 were abstracted for demographics, clinical and laboratory data. Primary outcome measures were time to resolution of hypertension, proteinuria, microhematuria, and low complement C3. The effect of overweight/obese status on outcomes was determined using Kaplan Meier Survival and the log-rank test. Results: The median age was 8 years; 30% were overweight/obese. At presentation, 17 (85%) were hypertensive, 10 (50%) had impaired glomerular filtration (GFR), and 18 (90%) had proteinuria. At last follow-up (median 2.8 months) 12% had hypertension, 55% had microhematuria, 5% had proteinuria but none had low GFR. Median time to normalize was: 30 days (GFR), 45 days (blood pressure), 6 weeks (C3) and 6 months (microhematuria). Log rank test showed that proteinuria-, hypertension-, and hematuria-free survival were all lower in children who were overweight/obese although none of the differences were statistically significant. Time to normalization of C3 was shorter in obese/ overweight children. Conclusion: In conclusion, overweight/obese children appear to have greater residual renal injury after PIGN. The earlier C3 normalization in overweight/ obese children may indicate that the adverse effect of weight on recovery is from hemodynamic rather than inflammatory factors. Close follow-up of overweight/obese children who develop PIGN is warranted to ensure optimal long-term outcomes.