Effect of Self-Reported Distress Thermometer Score on the Maximal Handgrip and Pinch Strength Measurements in Hemodialysis Patients

Abstract

Background: Muscle weakness is a risk factor for mortality in hemodialysis (HD) patients. Muscle strength measurements are routinely used as a screening tool but depend on patient cooperation and motivation. We wished to determine whether measuring maximal voluntary muscle strength was affected by patient self-reported distress. Methods: We measured pinch strength (PS) and handgrip strength (HGS) in 382 adult HD patients with a corresponding self-reported distress thermometer (DT) scores. Postdialysis body composition measurements were made using multifrequency bioelectrical assessments and patients assessed for frailty. Results: Mean age was 66.4 ± 14.9 years, with 238 males (62%), 48% diabetic, and dialysis vintage 36 (15–75) months. The mean DT score was 4.4 ± 3.3, with a frailty score of 4.6 ± 1.5. On multivariable analysis, DT scores were associated with frailty (β = 0.35, P = .003), prescription of aspirin for cardiac disease (β = 1.0, P = .004), lean body mass (β = 0.04, P = .004), and negatively with age (β = −0.05, P < .001), hematocrit (β = −8.2, P = .004), and maximum PS (β = −1.4, P = .003). Conclusion: Paradoxically higher self-reported DT scores were associated with younger age and lean body mass. As such, younger healthier, rather than more comorbid, patients may have greater expectations for their health and therefore report more distress. We found no association between DT scores and HGS, and as such, although HGS is a voluntary test, it appears to be a robust test independent of patient stresses. However, PS was lower in patients with higher DT scores, and as such, greater care may be required in interpreting these measurements.