Are Mid-Dialysis Handgrip Strength Measurements Reliable and Reproducible? A Comparison to Predialysis Handgrip Strength Measurements

Abstract

Objective: Handgrip strength (HGS) is an important predictor of nutritional status. Current guidelines recommend measurement of HGS predialysis; however, this may be impractical, and measurement often occurs during hemodialysis (HD). This study aimed to determine the reliability, reproducibility, and agreement of HGS values pre- and mid-dialysis. Design and methods: Participants were recruited from 4 Australian HD units (n = 48). Eligible participants were stable on HD for at least 3 months and not acutely unwell. HGS was measured in triplicate on the nonfistula arm before dialysis and 2 hours into dialysis for 3 consecutive weeks. Nutritional status and frailty were assessed via subjective global assessment and the fatigue, resistance, aerobic, illnesses, loss of weight questionnaire, respectively. Bland-Altman plots were used to determine agreement between pre- and mid-dialysis measures. Linear mixed models were used to determine differences between pre- and mid-dialysis values controlling for confounders. Results: HGS measures were statistically but not clinically greater predialysis compared to mid-dialysis (19.7 ± 12.9 vs. 18.8 ± 13.6 kg, P = .0433, mean difference 0.5 kg). Bland-Altman plots demonstrated an acceptable level of agreement between pre- and mid-dialysis HGS measures, suggesting no systematic bias in HGS. The influence of confounders (gender, age, dialysis vintage, frailty status, nutritional status, ultrafiltration rate, degree of fluid overload, diabetes, peripheral vascular disease, and weight) on the differences between pre- and mid-dialysis measures was not statistically significant. Conclusion: This study found that HGS taken either pre- or mid-dialysis was reliable and reproducible. Given the agreement between pre- and mid-dialysis HGS measures, HGS measured mid-dialysis may be used for nutritional assessment of HD patients.