Association of 24-Hour Ambulatory Blood Pressure Patterns with Cognitive Function and Physical Functioning in CKD

Hypertension is highly prevalent in patients with CKD as is cognitive impairment and frailty, but the link between them is understudied. Our objective was to determine the association between ambulatory BP patterns, cognitive function, physical function, and frailty among patients with nondialysis-dependent CKD.

Ambulatory BP readings were obtained on 1502 participants of the Chronic Renal Insufficiency Cohort. We evaluated the following exposures: (1) BP patterns (white coat, masked, sustained versus controlled hypertension) and (2) dipping patterns (reverse, extreme, nondippers versus normal dippers). Outcomes included the following: (1) cognitive impairment scores from the Modified Mini Mental Status Examination of <85, <80, and <75 for participants <65, 65-79, and ≥80 years, respectively; (2) physical function, measured by the short physical performance battery (SPPB), with higher scores (0-12) indicating better functioning; and (3) frailty, measured by meeting three or more of the following criteria: slow gait speed, muscle weakness, low physical activity, exhaustion, and unintentional weight loss. Cognitive function and frailty were assessed at the time of ambulatory BP (baseline) and annually thereafter. SPPB was assessed at baseline logistic and linear regression and Cox discrete models assessed the cross-sectional and longitudinal relationship between dipping and BP patterns and outcomes.

Mean age of participants was 63±10 years, 56% were male, and 39% were black. At baseline, 129 participants had cognitive impairment, and 275 were frail. Median SPPB score was 9 (interquartile range, 7-10). At baseline, participants with masked hypertension had 0.41 (95% CI, -0.78 to -0.05) lower SPPB scores compared with those with controlled hypertension in the fully adjusted model. Over 4 years of follow-up, 529 participants had incident frailty, and 207 had incident cognitive impairment. After multivariable adjustment, there was no association between BP or dipping patterns and incident frailty or cognitive impairment.

In patients with CKD, dipping and BP patterns are not associated with incident or prevalent cognitive impairment or prevalent frailty.