The effect of a 12 month intradialytic exercise intervention on function, quality of life, nutritional status and clinical status

Haemodialysis (HD) patients are reported to have low levels of physical function, poor quality of life, protein energy wasting and inflammation, which negatively impact on morbidity and mortality. Exercise has previously been used as an intervention in HD patients; however the majority of previous studies have been of short duration and utilised moderate or high intensities requiring individual supervision of each exercise session. These studies recruited young patients with low levels of comorbidity and primarily focused on changes in VO2max/peak. This limits the ability to generalise findings to the wider prevalent HD population. The aims of the present study were therefore to determine whether a low to moderate intensity intradialytic exercise intervention with broad applicability, could over a 12 month period improve functional status and in turn quality of life, nutritional status and clinical status in a prevalent HD population in Scotland. Patients were recruited from NHS Fife, to a non-randomised controlled study and followed a progressive intradialytic aerobic exercise programme. One exercise session was conducted with individual supervision and two sessions with general supervision from dialysis staff. Outcome measures included measures of function (sit to stand, timed up and go, and handgrip), quality of life (SF36v2), nutritional status (anthropometric measurements, dual frequency bioelectrical impedance analysis, dietary intake and appetite) and clinical status (dialysis adequacy, biochemistry, high sensitivity C-reactive protein, blood pressure, medications). Measurements were taken at 6 time points: -1, 0, 3, 6, 9 and 12 months. 25 patients (mean age 56 + 11.4 years) volunteered for the intervention and 13 patients (mean age 60.8 + 14.6 years) volunteered as controls. At baseline groups demonstrated functional impairment, poor quality of life, and low fat free mass and had evidence of low grade inflammation. 25 patients completed 3 months of the exercise intervention, 20 completed 6 months, 16 completed 9 months and 13 patients completed 12 months. Of the 13 control patients 6 remained at 3 months and 5 at 6 months. In the exercise group, significant improvements were observed in all measures of function and 6 out of 8 physical and psychosocial quality of life domains. Anthropometric measures of fat free mass increased. Clinical status improved significantly seen as reductions in systolic blood pressure and prescribed erythropoietin stimulating agent doses. These improvements were observed in the intervention group at 3 and 6 months. No improvements were observed in the control group. Improvements in the majority of outcome measures were also seen in the intervention group at 6 and 12 months. These results suggest that the introduction of a low to moderate intensity intradialytic exercise programme requiring minimal individual supervision is feasible and provides clinically significant improvements in function from 3 months onwards. Such improvements are accompanied by higher quality of life scores and improved aspects of nutritional and clinical status.