Cognition linked to BMI, cerebral oxygenation in CKD

Cognitive changes in patients with chronic kidney disease (CKD) appear to correlate with accompanying changes in body mass index (BMI) and cerebral regional oxygen saturation (rSO₂), reports a recent longitudinal study.

Sixty-eight CKD patients (mean age 68.8 years, 72 percent men) participated in the present study. Cerebral rSO₂ was measured using a real-time saturation monitor, while the mini-mental state examination (MMSE) was used to evaluate cognitive function.

Patients were followed-up after a median of 364 days, after which the MMSE scores were significantly higher as opposed to baseline (p=0.022). Cognitive impairment, as qualified by MMSE scores, were also less prevalent at follow-up than at the index date, though the difference did not achieve significance.

Specifically, researchers noted significant increases in the scores regarding the domain of orientation (p=0.02) and calculation (p=0.046) domains of MMSE, while small but significant reductions were reported for orientation of time (p=0.03).

Multivariable linear regression analysis revealed that changes in BMI were significantly and positively correlated with cognitive changes from baseline (standardized coefficient, 0.260, 95 percent confidence interval [CI], 0.023–0.088; p=0.023). The same was true for cerebral rSO₂ (standardized coefficient, 0.345; 95 percent CI, 0.045–0.208; p=0.003). Serum albumin was also associated with changes in MMSE but only in unadjusted analysis (r, 0.268; p=0.027).

“Further prospective studies, with a larger number of CKD patients and a longer observational period, are needed to clarify whether maintaining BMI and cerebral oxygenation improves or prevents deterioration of cognitive function in CKD patients without dialysis therapy,” the researchers said.