The Association Between Metabolic Syndrome, Hyperfiltration, and Long-Term GFR Decline in the General Population
Erikka W. Bystad, Vidar T.N. Stefansson, Björn O. Eriksen, Toralf Melsom
Abstract
IntroductionOne-quarter of adults worldwide fulfill the criteria of metabolic syndrome (MetS). MetS increases the risk of diabetes, chronic kidney disease (CKD), and cardiovascular disease. However, the association between MetS, hyperfiltration, and long-term GFR decline in the general population is unknown.MethodsIn the Renal Iohexol Clearance Survey (RENIS), we investigated 1551 people aged 50-63 years, representative of the general population without diabetes, cardiovascular disease, or kidney disease. The GFR was measured using iohexol clearance at baseline and twice during 11 years of follow-up. Hyperfiltration at baseline was defined as an absolute GFR (ml/min) above the 90th percentile adjusted for sex, age, and height, as these variables correlate with nephron number. MetS was defined as increased waist circumference and two risk factors among hypertension, hyperglycemia, elevated triglycerides, and low HDL-cholesterol levels. The GFR decline rate was calculated using linear mixed models.ResultsMetS was associated with hyperfiltration at baseline (OR 2.4 [95% CI; 1.7 – 3.5], p<0.001) and a steeper GFR decline rate during follow-up (-0.30 [-0.43 to -0.16] mL/min/1.73 m2/year). Compared to those without Mets, GFR decline was -0.83 (95% CI, -1.13 to -0.53) mL/min/1.73 m2/year in those with Mets and baseline hyperfiltration and -0.15 (-0.30 to 0.00) in those Mets without hyperfiltration, p = 0.2 for interaction.ConclusionsIn the non-diabetic general population, those with MetS had an increased odds ratio of hyperfiltration and steeper long-term GFR decline. Randomized controlled trials are needed to explore whether treatment of hyperfiltration can prevent loss of GFR in persons with MetS.