Handheld dynamometry testing during dialysis: intra and inter-rater reliability study.

Abstract

Objective: The aim was to assess the intra and inter-rater reliability of the handheld dynamometry testing of lower limb muscles during hemodialysis.

Methods: This is a cross-sectional study including subjects undertaking hemodialysis for at least 3 months. Handheld dynamometer measurements of hip and ankle muscle strength (N) were registered on 4 different occasions, 2 trials by raters A and 2 by raters B, to evaluate the intra and inter-rater reliability. Bland-Altman plots were constructed to examine the agreement between raters by scoring the difference between raters against the mean of both raters' scores. The intraclass correlation coefficient (ICC) was used to assess relative intra-rater and inter-rater reliability. Absolute reliability was assessed with the minimal detectable change (MDC).

Results: Fifty-six participants (median age, 67 years) data showed high to very high relative reliability (ICCs 0.75 to 0.98). Regarding the intra-rater absolute reliability, MDC⁹⁰ values ranged from 27.0 to 41.6.5 N (0.14 to 0.26 N/Kg m²) for hip muscles but increased for ankle muscles. Inter-rater values were wider. The mean difference between trials ranged narrowly across the two-time points for raters A (1.0 - 19.3 N) and for raters B (1.3 - 11.4 N). The mean difference between raters ranged from 2.4 to 13.5 N. The Bland-Altman plot revealed a systematic bias for raters A in ankle plantar flexion. .

Conclusions: The assessment of the hip flexion and abduction strength during dialysis with a handheld dynamometer is reliable and safe. Normalized data provides more reliable results.