Study on the prevalence of sarcopenia and dynapenia in outpatient hemodialysis patients in urban areas of Japan: a multicenter cross-sectional study.

Participants were not randomly selected, so the four groups were not balanced for age and sex and the sample may not represent haemodialysis patients more generally. Only 37 women took part, and the authors say this was too few for reliable statistical analysis, so little can be concluded about women. Everyone was measured once, so the study cannot show whether weakness comes before muscle loss or whether treating one prevents the other. Data on cognitive function, education, socioeconomic status and where people lived were not collected, and the study period was short. All three dialysis centres belong to a single medical corporation in the Tokyo and Yokohama area, so the rates may not apply to other settings.

The authors state that they received no funding and declare no conflicts of interest.

Do not read the 28.8% figure for dynapenia as showing that weakness is a stage on the way to muscle loss, or that spotting it early prevents anything. Everyone was measured once, so the study can say how common these states were, not what happens next. The sample was also not randomly selected, so the rates may not match your own dialysis unit.