Lower urinary connective tissue growth factor levels and incident CKD stage 3 in the general population.

BACKGROUND: Connective tissue growth factor (CTGF) is involved in the development and progression of kidney diseases, including diabetic nephropathy and kidney fibrosis, but also may have a role in mesangial repair after injury. It is unknown whether, in the general population, urinary CTGF levels are associated with a decrease in estimated glomerular filtration rate (eGFR) to

STUDY DESIGN: Nested case-control.

SETTING & PARTICIPANTS: 100 cases of incident CKD stage 3 and 100 age-and sex-matched controls in the Framingham Heart Study; 141 cases and 135 age-, sex-, and race-matched controls in the Atherosclerosis Risk in Communities (ARIC) Study. Controls had eGFR ≥60 mL/min/1.73 m(2) at follow-up in both studies.

PREDICTORS: Urinary CTGF concentrations.

OUTCOMES: Incident CKD stage 3, defined as eGFR

MEASUREMENTS: Stored urine samples from Framingham Heart Study and ARIC were measured for CTGF. Covariates were obtained from Framingham Heart Study and ARIC participant examinations.

RESULTS: In the Framingham Heart Study, the median baseline urinary CTGF concentration was lower in cases (1.35 ng/mL) than controls (2.35 ng/mL; paired t test, P

LIMITATIONS: Observational study; causality cannot be inferred.

CONCLUSIONS: Lower urinary CTGF concentrations precede the onset of CKD stage 3 in the general population. Further work is required to fully characterize how CTGF level influences risk of CKD.