Metabolically healthy obese and overweight patients are at higher risk for developing chronic kidney disease (CKD) than similarly healthy adults of normal weight, according to a Korean study titled “Metabolically Healthy Obesity and Development of Chronic Kidney Disease: A Cohort Study” and published in the Annals of Internal Medicine.
The risk for chronic kidney disease (CKD) among obese people without weight-related metabolic abnormalities, called metabolically healthy obesity, has largely been unexplored. Yet, CKD’s “prevalence is increasing worldwide along with the growing prevalence of obesity and metabolic disease,” the authors wrote according to a news release. “Indeed, obesity — mediated by hypertension, insulin resistance, hyperglycemia, dyslipidemia, and other metabolic abnormalities — is a major risk factor for CKD … metabolically healthy obese persons seem to have a favorable profile with no metabolic abnormalities.”
To investigate the risk for incident CKD across categories of body mass index (BMI) in a large cohort of metabolically healthy men and women, Yoosoo Chang, MD, PhD from the Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine in South Korea, and colleagues conducted a prospective study in 62,249 patients identified through the Kangbuk Samsung Health Study. Patients with metabolic malfunctions or kidney disease were excluded from the analyses.
Metabolic health was defined as the absence of a metabolic syndrome component and insulin resistance of less than 2.5. Body weight groups were classified as underweight (those with a BMI < 18.5 kg/m2), normal weight (BMI of 18.5–22.9 kg/m2), overweight (BMI of 23–24.9 kg/m2)and obese (BMI of 25 kg/m2).
All patients were followed from baseline until their last screening or until they were diagnosed with CKD. During a follow-up of 369,088 person-years, the researchers identified 906 incident CKD cases.
The differences in five-year CKD incidence among underweight, overweight, and obese patients in comparison to normal-weight patients were −4.0, 3.5, and 6.7 cases per 1,000 persons, respectively. These associations were consistently seen in all patient groups.
“In this large cohort study of metabolically healthy Korean adults, being overweight or obese was associated with increased CKD risk compared with being normal weight,” Dr. Chang and colleagues wrote. “The association between [metabolically healthy obesity] and CKD was consistently seen in all prespecified clinical subgroups, including participants without low-grade inflammation or fatty liver. Furthermore, the association could not be explained by the residual levels of metabolic factors in [metabolically healthy obese] participants. Our study … adds to an increasing body of evidence that [metabolically healthy obesity] is not a harmless condition.”
The researchers advised doctors to counsel metabolically healthy obese patients on their increased risk of developing CKD, as well as concerning healthy weight and lifestyle changes.