Blood Pressure Variability and Frailty in End-Stage Kidney Disease

Background

High blood pressure variability (BPV) is a predictor of cardiovascular events and all-cause mortality in people with end-stage kidney disease (ESKD) and a marker of aging in geriatric populations. Nevertheless, the relationship between BPV and geriatric syndromes, such as frailty, in people with ESKD is not well understood.

Objective

To examine the association between very short-term BPV and frailty in people with ESKD and receiving hemodialysis.

Design

Cross-sectional study.

Setting

Three dialysis units in the United Kingdom.

Participants

Sixty-nine people receiving hemodialysis (median age=62.0 years, interquartile range [IQR]=19.0; 52.2% male; median dialysis vintage=1.1 years, IQR=2.4).

Measurements

Systolic and diastolic BPV were recorded using continuous, non-invasive BP monitoring (Task Force Monitor). The very low, low, and high frequency components of BPV (VLF-BPV, LF-BPV, and HF-BPV), as well as the power spectral density (PSD-BPV) and low frequency/high frequency ratio of BPV (LF/HF-BPV) were analyzed. Frailty was evaluated using the Fried frailty phenotype.

Results

Twenty-six (37.7%) participants were classified as frail and 43 (62.3%) as non-frail. Frail participants had higher median systolic (2.1, IQR=5.2 mmHg² vs. 1.1, IQR=1.6 mmHg², p=0.002) and diastolic HF-BPV (0.9, IQR=2.3 mmHg² vs. 0.5, IQR=1.0 mmHg², p=0.048) compared to their non-frail counterparts. In addition, frail participants had higher median systolic VLF-BPV (3.2, IQR=12.5 mmHg² vs. 2.0, IQR=2.4 mmHg², p=0.012), LF-BPV (2.0, IQR=3.8 mmHg² vs. 1.1, IQR=2.0 mmHg², p=0.016), and PSD-BPV (6.6, IQR=27.6 mmHg² vs. 4.5, IQR=5.9 mmHg², p=0.005) compared to the non-frail participants. In age- and sex-adjusted logistic regression analyses, only systolic VLF-BPV (odds ratio [OR]=1.13, 95% confidence interval [CI]:1.01–1.26, p=0.035), HF-BPV (OR=1.26, 95%CI:1.01–1.57, p=0.044), and PSD-BPV (OR=1.06, 95%CI:1.01–1.12, p=0.029) were associated with increased odds of being frail.

Conclusion

Higher systolic BPV is associated with frailty in people receiving hemodialysis. Beat-to-beat assessments of BPV through continuous, non-invasive BP monitoring may be useful in evaluating frailty in ESKD populations.