Low level of self-reported physical activity in ambulatory patients new to dialysis

Abstract

Physical inactivity contributes to the frailty and the decline in function that develops over time among patients with end-stage renal disease. We assessed physical activity among 1547 ambulatory patients new to dialysis in the United States Renal Data System Comprehensive Dialysis Study. We used a self-reporting Human Activity Profile that included Maximal and Adjusted Activity Scores and compared results to established norms by age and gender. Physical activity was found to be extremely low with scores for all age and gender categories below the 5th percentile of healthy individuals and 95% of patients had scores consonant with low fitness. Older age, female gender, diabetes, atherosclerotic disease, and a low level of education were associated with lower activity scores assessed by univariate and multivariable linear regression analysis. Higher serum albumin, creatinine, and lower body mass index, but not hemoglobin levels, were associated with greater physical activity. By multivariable analysis, patients on hemodialysis using a catheter reported lower levels of physical activity compared to those on peritoneal dialysis, hemodialysis using an arteriovenous fistula, or with a graft. Lower Maximal and Adjusted Activity Scores were associated with poor physical function and mental health. Hence, physical activity is distressingly low among patients new to dialysis. Thus, strategies to enhance activity in these patients should be explored.

Figure 1. Human Activity Profile (HAP) scores among men and women in the Comprehensive Dialysis Study (CDS) compared with norms for healthy individuals

The black boxes represent the 25th to 50th percentile; gray boxes represent the 50th to 75th percentile; lines above and below extend to the 99th and 1st percentile, respectively. In each figure, scores are shown by age group, beginning with age <40 and progressing by decade to age 70+ years. Within each age group, normative data are represented on the left and CDS participants’ data are plotted on the right. (a, b) Maximum Activity Scores (MAS) and (c, d) Adjusted Activity Scores (AAS) for men and women are shown.

Figure 2. Unadjusted and adjusted Human Activity Profile (HAP) scores according to quartiles of hemoglobin and erythropoietin use

(a) In HAP scores according to quartiles of hemoglobin, the black bars represent the first quartile of hemoglobin (≤8.9 g/dl), diagonally striped bars the second quartile (9.0–10.1 g/dl), horizontally striped bars the third quartile (10.2–11.2 g/dl), gray bars the fourth quartile (≥11.2 g/dl), and white bars those with missing hemoglobin values. (b) In HAP scores based on erythropoietin use, the black bars represent those who did not receive erythropoietin before starting dialysis, gray bars represent those receiving erythropoietin, and white bars those whose receipt of erythropoietin was unknown. AAS, Adjusted Activity Score; MAS, Maximum Activity Score.