Insulin sensitivity measured with euglycemic clamp is independently associated with glomerular filtration rate in a community-based cohort

Abstract

Objective: To investigate the association between insulin sensitivity and glomerular filtration rate (GFR) in the community, with pre-specified subgroup analyses in normoglycemic individuals with normal GFR.

Research Design and Methods: We investigated the cross-sectional association between insulin sensitivity (M/I, assessed using euglycemic clamp) and cystatin C-based GFR in a community-based cohort of elderly men (Uppsala Longitudinal Study of Adult Men, ULSAM; n=1070). We also investigated whether insulin sensitivity predicted the incidence of renal dysfunction at a follow-up examination after 7 years.

Results: Insulin sensitivity was directly related to GFR (multivariable-adjusted regression coefficient for 1-unit higher M/I 1.19, 95% CI 0.69-1.68, p<0.001) after adjusting for age, glucometabolic variables (fasting plasma glucose, fasting plasma insulin, 2-hour glucose after an oral glucose tolerance test), cardiovascular risk factors (hypertension, dyslipidemia, smoking), and lifestyle factors (BMI, physical activity, consumption of tea, coffee and alcohol). The positive multivariable-adjusted association between insulin sensitivity and GFR remained statistically significant also in participants with normal fasting plasma glucose, normal glucose tolerance and normal GFR (n=443, p<0.02). In longitudinal analyses, higher insulin sensitivity at baseline was associated with lower risk of impaired renal function (GFR<50ml/min/1.73 m²) during follow-up independently of glucometabolic variables (multivariable-adjusted odds ratio for 1-unit higher of M/I 0.58, 95% CI 0.40-0.84, p<0.004).

Conclusion: Our data suggest that impaired insulin sensitivity may be involved in the development of renal dysfunction at an early stage, prior to the onset of diabetes or pre-diabetic glucose elevations. Further studies are needed in order to establish causality.