Obese adults with nondialysis-dependent chronic kidney disease (CKD) who experience rapid weight loss coupled with increasing systolic blood pressure and decreasing serum albumin have a higher risk of death, investigators report.
Using data from 2831 obese adults in the Chronic Renal Insufficiency Cohort Study (CRIC), investigators identified 6 weight loss phenotypes with distinct trajectories of body mass index (BMI), serum albumin, and systolic blood pressure. Class 6 had the highest 5-year all-cause mortality rate of 6.8%. It was characterized by steep and early BMI loss of more than 20%, initially stable then rising systolic blood pressure, and early decline in serum albumin followed by increasing levels. The class 6 group, accounting for 7% of the cohort, had a 1.9-fold increased risk for death compared with healthy weight individuals, Meera Nair Harhay, MD, MSCE, of Drexel University College of Medicine in Philadelphia, Pennsylvania, and colleagues reported in Kidney International Reports.
Class 3, accounting for 37% of patients, was the most common. It was characterized by a less than 5% decline in BMI, small increase in systolic blood pressure, and small increase in albumin level. The class 3 group had the lowest 5-year mortality rate at 1.5%.
The class 6 vs class 3 group were younger (60 vs 61 years), majority female (56% vs 47%), and had higher baseline BMI (37.2 vs 35.5 kg/m2), serum albumin (3.9 vs 3.8 g/dL), and systolic blood pressure (127 vs 125 mm Hg). Class 6 patients also had a lower mean estimated glomerular filtration rate (eGFR): 39.3 vs 48.9 mL/min/1.73m2 and greater CKD burden, reflected by low exercise participation and intensity. The groups had similar daily caloric intake, protein intake, and lipid profiles.
Adults who rapidly lost more than 10% of BMI generally had higher death risks than those with more modest BMI loss.
In a secondary analysis examining percentage change in fat-free mass, patients with BMI loss coupled with transient or sustained loss in fat-free mass, a proxy for muscle mass, had higher death risk. Greater muscle losses are found among patients with unintentional weight loss, a domain of the physical frailty phenotype, the investigators noted.
“Our study suggests that whether weight loss is required or desired by adults with CKD and obesity, they should also be monitored with respect to concurrent changes in hemodynamics, nutrition, and body composition.”
Harhay MN, Kim Y, Milliron BJ, Robinson LF; CRIC Study Investigators. Obesity weight loss phenotypes in CKD: Findings from the Chronic Renal Insufficiency Cohort study. Kidney Int Rep. 8(7):1352-1362. doi:10.1016/j.ekir.2023.04.022