Impact of Physical Activity on Dialysis and Nondialysis Days and Clinical Outcomes Among Patients on Hemodialysis.

OBJECTIVE: Patients undergoing hemodialysis (HD) have different physical activity (PA) patterns on HD and non-HD days. Nonetheless, whether these differences are associated with clinical outcomes remains unclear. We examined the association of PA levels on HD and non-HD days with cardiovascular (CV) hospitalizations and mortality. METHODS: Outpatients undergoing HD from 2002 to 2019 were retrospectively enrolled. The number of steps performed over 3 HD days and 4 non-HD days was recorded via accelerometry. Outcomes were all-cause mortality and a composite of CV hospitalizations and mortality. Patients were divided into two groups, each according to the median number of steps performed on HD (2371 steps/day) and non-HD days (3752 steps/day). Further, we categorized them into 4 groups according to each median values: "more active on HD/more active on non-HD (MM)," "more active on HD/less active on non-HD (ML)," "less active on HD/more active on non-HD (LM)," and "less active on HD/less active on non-HD (LL)." Cox and mixed-effects Poisson regression models were used for these outcomes. RESULTS: We analyzed 512 patients (median follow-up, 3.4 years). Higher PA on HD (hazard ratio [HR], 0.59; 95% confidence interval [CI], 0.54-0.65), and non-HD (HR, 0.84; 95% CI, 0.80-0.88) was associated with lower mortality risk, respectively. Further, the ML group (HR, 1.20; 95% CI, 1.13-1.28), LM group (HR, 1.82; 95% CI, 1.53-2.17), and LL group (HR, 1.83; 95% CI, 1.65-2.02) had higher mortality risks than the MM group. Associations of PA with multiple CV hospitalizations and mortality were similar to those between PA and mortality. CONCLUSIONS: Higher PA on HD and non-HD days was associated with lower risks of CV hospitalizations and mortality. However, higher PA levels on either HD or non-HD days alone did not improve clinical outcomes.

Modified Creatinine Index and Clinical Outcomes of Hemodialysis Patients: An Indicator of Sarcopenia?

OBJECTIVE: Sarcopenia (especially muscle mass assessed using gold standard techniques) has been suggested as a poorer predictor of mortality than muscle function in patients undergoing hemodialysis. Appropriate methods to estimate muscle mass for use as a good predictor of clinical outcomes remain to be established. We investigated whether the modified creatinine index (mCI), which is a surrogate marker of muscle mass, could predict mortality and cardiovascular (CV) hospitalizations independent of muscle function and other confounders in patients on hemodialysis. DESIGN AND METHODS: In this retrospective study, outpatients (n = 542; mean age, 65.3 years; 60% men; median dialysis vintage, 29 months; mean BMI, 22.0 kg/m2) undergoing hemodialysis were investigated. The mCI, handgrip strength, and gait speed were assessed and related to all-cause mortality and a composite of CV hospitalizations and all-cause mortality. Cox proportional and mixed-effects negative binomial models were fit for mortality and the composite outcomes. RESULTS: Patients were followed up for a median 3 years (interquartile range: 1.5-5.7). Each per SD increase of mCI (HR:0.63, 95% CI:0.62-0.65), handgrip strength (HR:0.51, 95% CI:0.48-0.54), and gait speed (HR:0.60, 95% CI:0.56-0.64) were significantly associated with lower all-cause mortality rates after adjusting for covariates. The mCI was consistently found to be an independent predictor of mortality after additional adjustment for handgrip strength or gait speed. Furthermore, sarcopenic conditions [i.e., lower mCI, and lower handgrip strength (HR:3.79, 95% CI:2.09-6.87) or slower gait speed (HR:4.20, 95% CI:2.38-7.41)] were significantly associated with a higher risk of mortality after adjusting for covariates. Associations of mCI with multiple CV hospitalizations and mortality were similar to those between mCI and mortality. CONCLUSION: The mCI was a good predictor of clinical outcomes and was comparable to muscle function, including handgrip strength and gait speed. The mCI is likely to provide additional diagnostic and prognostic values for sarcopenia in patients on hemodialysis.

Perceived difficulty in activities of daily living and survival in patients receiving maintenance hemodialysis.

PURPOSE: Most patients receiving hemodialysis have perceived difficulty in mobility tasks, such as basic activities of daily living (ADL), ambulation, and walking up or down stairs, even if they can ambulate independently. Perceived difficulty in performing ADL (ADL difficulty) is reportedly a useful predictor of mortality in older community-dwelling people. However, very few studies have examined the association of ADL difficulty with clinical outcomes in patients receiving hemodialysis. This study aimed to identify the association between ADL difficulty related to mobility tasks of lower limbs and all-cause mortality in patients receiving hemodialysis who are able to ambulate independently. METHODS: This retrospective study analyzed 300 clinically stable outpatients (median age, 65.0 years) receiving hemodialysis. ADL difficulty was evaluated at baseline with a novel questionnaire developed for patients receiving hemodialysis. Lower scores indicated lower ADL, i.e., greater ADL difficulty. The patients were divided into two groups by the median ADL score: a higher ADL group and a lower ADL group. The association between ADL difficulty and all-cause mortality was estimated by Cox regression analyses. RESULTS: Median follow-up duration was 58 months. The incident rates were 0.02 per person-year in the higher ADL group and 0.06 per person-year in the lower ADL group (P < 0.001). After adjusting for the effects of clinical characteristics, the hazard ratio for all-cause mortality in the lower ADL group was 2.70 (95% confidence interval 1.57-4.64) compared with that in the higher ADL group. CONCLUSIONS: Perceived difficulty in mobility tasks was independently associated with all-cause mortality among ambulatory patients receiving hemodialysis.