Metabolic Syndrome Linked to Kidney Disease

George Thomas, from the Department of Nephrology and Hypertension at Glickman Urological and Kidney Institute, Cleveland Clinic in Cleveland, Ohio, and colleagues write, "Observational studies have reported an association between MetS and microalbuminuria or proteinuria and CKD with varying risk estimates." "We aimed to systematically review the association between MetS, its components, and development of microalbuminuria or proteinuria and CKD."

The investigators searched MEDLINE (1966 to October 2010), SCOPUS, and the Web of Science for relevant studies. Inclusion criteria were prospective cohort studies that reported the development of microalbuminuria or proteinuria and/or CKD, with confidence intervals (CIs), in participants with MetS. A random-effects model allowed pooling of risk estimates for an estimated glomerular filtration rate (eGFR) of less than 60 mL/minute/1.73 m² extracted from individual studies. The small number of studies reporting proteinuria precluded pooling these outcomes.

There were 11 studies identified, enrolling a total of 30,146 participants, that met inclusion criteria. The meta-analysis showed a significant association between MetS and the development of an eGFR of less than 60 mL/minute/1.73 m² (odds ratio [OR], 1.55; 95% confidence interval [CI], 1.34 - 1.80). As the number of components of MetS increased, the strength of the observed association also increased (P value for trend = .02).

Senior author Sankar D. Navaneethan, MD, also from Cleveland Clinic, in a news release stated that, "Primary care physicians may need to consider using metabolic syndrome as a marker to identify patients at higher risk of developing kidney disease."

For individual components of MetS, the ORs for the development of an eGFR of less than 60 mL/minute/1.73 m² in patients with MetS were 1.61 for elevated blood pressure (95% CI, 1.29 - 2.01), 1.27 for elevated triglycerides (95% CI, 1.11 - 1.46), 1.23 for low high-density lipoprotein (HDL) cholesterol levels (95% CI, 1.12 - 1.36), 1.19 for abdominal obesity (95% CI, 1.05 - 1.34), and 1.14 for impaired fasting glucose levels (95% CI, 1.03 - 1.26). There were 3 studies showing that MetS was associated with increased risks for the development of microalbuminuria or overt proteinuria.

"MetS and its components are associated with the development of eGFR <60 ml/min per 1.73 m₂ and microalbuminuria or overt proteinuria," the study authors write.

"Studies targeting the interrelated individual risk factors included in MetS with either medications or life style interventions have been shown to slow the progression of CKD," the study authors conclude. "Our results emphasize the need to identify individuals with the constellation of these metabolic risk factors earlier and consider multidisciplinary interventions, particularly lifestyle modifications, to retard the development of CKD."

Published online August 18, 2011, Clin J Am Soc Nephrol.