Prevalence of hyperfiltration among US youth/young adults with overweight and obesity: A population‐based association study

OBJECTIVE: Determine prevalence of hyperfiltration (high estimated glomerular filtration rate "eGFR" >95th percentile for age/sex) among youth and association with BMI classification. METHODS: With the use of 1999 to 2016 National Health and Nutrition Examination Survey data from 12‐ to 29‐year‐olds, data for serum creatinine and thresholds for high eGFR were normed using a metabolically healthy subsample (no albuminuria, healthy weights, normal blood pressures, blood glucoses, lipids, and liver enzymes). Logistic regression examined the association of BMI classification (healthy weight, overweight, and obesity classes 1‐3) with hyperfiltration (eGFR > 95th percentile for age/sex), adjusted for diabetes and other covariates. RESULTS: Of 12‐ to 29‐year‐olds (N = 18 698), 27.4% (n = 5493) met criteria for entry into the "healthy subsample" and contributed data to derive normative values for serum creatinine/hyperfiltration thresholds. In the full sample, hyperfiltration prevalence in 12‐ to 29‐year‐olds classified as healthy‐weight, overweight, and obesity classes 1 to 3 was 4.9%, 4.7%, 6.5%, 8.7%, and 11.8%, respectively (P < .001). In multivariable analysis, obesity classes 2 and 3 were associated with greater likelihood of hyperfiltration (adjusted ORs for class 2: 1.5, 95% CI, 1.1‐2.1; and for class 3, 2.1, 95% CI, 1.5‐2.9). Diabetes also was associated with hyperfiltration (AOR, 4.0; 95% CI, 2.2‐7.4). CONCLUSION: Obesity classes 2 to 3 are associated with hyperfiltration in youth. Age/sex‐specific norms for creatinine and hyperfiltration thresholds may aid recognition of kidney dysfunction early.