Metabolic Syndrome Exacerbates Kidney Disease in Black Patients

SAN DIEGO—The metabolic syndrome significantly increases the risk for worsening kidney disease in black patients with high blood pressure (BP), according to new data presented at the American Society of Nephrology annual meeting that showed a 38% increased risk of progressive chronic kidney disease (CKD) in hypertensive blacks who have the metabolic syndrome.

The implication of this finding is that treatments that can reduce the severity of metabolic syndrome may also slow the rate of progressive kidney disease, particularly in black patients, who are at significantly increased risk of progressing to end-stage renal disease (ESRD), according to lead investigator Janice Lea, MD, of Emory University, Atlanta.

“This is the first study to look at this issue in this way,” Dr Lea told IMWR.

The data in this study came from a large study of antihypertensive treatments in 842 black patients (mean age, 54.6 years; 40% women). Baseline mean values were body mass index (BMI), 30.6 kg/m2; glomerular filtration rate, 45.6 mL/min; and serum creatinine, 2.0 mg/dL.

At study onset, 25% of the patients met the criteria for the metabolic syndrome diagnosis by having at least 3 of these 5 conditions: high blood glucose, low high-density lipoprotein cholesterol concentration, high triglycerides, obesity, and high BP.

Participants were randomized to 1 of 2 BP goals, and to 1 of 3 BP regimens.

At 4 years of follow-up, patients with the metabolic syndrome had significantly higher rates of progressive kidney disease, which was defined as continued decline in kidney function, ESRD, or death. The risk for progressive kidney disease was 38% among the black patients with the metabolic syndrome, even after adjusting for age, sex, obesity, and initial kidney function.

On their own, none of the individual metabolic syndrome risk factors was related to progressive CKD. The increased risk associated with the metabolic syndrome was unaffected by which BP treatment the patients received.

“The clinical implications…are that the metabolic syndrome needs to be considered a new target for treating patients with chronic kidney disease, and more studies are needed to explore this with…insulin resistance,” said Dr Lea.

Dr Lea emphasized that previous studies have linked the metabolic syndrome to an increased risk of CKD, but it had been unclear whether the metabolic syndrome contributes to the progression of established CKD.

“Researchers have looked at blood pressure, and they looked at diabetes rates, but we have not until now looked at the composite of metabolic syndrome in African Americans. So, this is an important study,” Dr Lea said. “If we can reduce the severity of metabolic syndrome through diet and medication, it may help to reduce the rate of ­progressive kidney disease and thus delay ESRD and the need for dialysis therapy.”