Effects of Exercise on Cognitive Function in Patients With CKD

Individuals who have chronic kidney disease (CKD) are at risk for cognitive impairment. Physical activity may improve cognitive function. Therefore, Ellen Bradshaw and colleagues wanted to determine the efficacy of exercise in improving cognitive function in people with CKD and the potential harm exercise might cause. They conducted a systematic review and meta-analysis of randomized controlled trials.  

The literature review identified randomized controlled trials that enrolled patients with CKD and included an exercise intervention that worked large-muscle groups and a validated outcome measure of cognitive function. The analyses included 19 trials and 1,160 participants.  

The researchers first assessed harm from exercise. There were 94 reports of harm in the intervention groups and 83 in control groups.  

Next, they conducted a random-effects meta-analysis with subsequent planned subgroup analyses to examine heterogeneity between CKD stages and treatments; different exercise types, durations, and intensities; and different outcome methodologies. This was followed by rating the quality of the evidence.  

In the primary analysis, exercise was shown to have a statistically significant, although small, effect on cognition in patients with CKD (effect size, 0.22; 95% CI, 0.00-0.44; P=.05). However, the quality of the evidence was low. The subgroup analyses revealed that the type of exercise moderated its effect on cognition (χ2=7.62; P=.02), with aerobic exercise having only positive effects (effect size, 0.57; 95% CI, 0.21-0.93; P=.002).  

In conclusion, the effects of exercise on cognitive function were small but clinically significant. The effects were also positive, particularly in the case of aerobic exercise. Although the quality of evidence in this study was rated as low, exercise may be recommended to prevent cognitive decline. The authors note that studies are needed to determine the intensity and duration of exercise required to maximize the efficiency of such exercise interventions. 

Source: Clinical Journal of the American Society of Nephrology