Effect of Long-term Exercise Training on Physical Performance and Cardiorespiratory Function in Adults With CKD: A Randomized Controlled Trial

Abstract

Rationale & objective: The safety and efficacy of long-term exercise training in reducing physical functional loss in older adults with advanced CKD and comorbidity is uncertain.

Study design: Multicenter, parallel group, randomized controlled trial.

Settings & participants: Adults 55 years and older with estimated glomerular filtration rate (eGFR) of 15 to <45 mL/min/1.73 m² enrolled from centers in Baltimore and Boston.

Intervention: Twelve months of in-center supervised exercise training incorporating majority aerobic but also muscle strengthening activities or a group health education control intervention, randomly assigned in 1:1 ratio.

Outcome: Primary outcomes were cardiorespiratory fitness and submaximal gait at 6 and 12 months quantified by peak oxygen consumption (Vo₂peak) on graded exercise treadmill test and distance walked on the 6-minute walk test, respectively. Secondary outcomes were changes in lower extremity function, eGFR, albuminuria, glycemia, blood pressure, and body mass index.

Results: Among 99 participants, the mean age was 68 years, 62% were African American, and the mean eGFR was 33 mL/min/1.73 m²; 59% had diabetes, and 29% had coronary artery disease. Among those randomized to exercise, 59% of exercise sessions were attended in the initial 6 months. Exercise was well tolerated without excess occurrence of adverse events. At 6 months, aerobic capacity was higher among exercise participants (17.9 ± 5.5 vs 15.9 ± 7.0 mL/kg/min, P = 0.03), but the differences were not sustained at 12 months. The 6-minute walk distance improved more in the exercise group (adjusted difference: 98 feet [P = 0.02; P = 0.03 for treatment-by-time interaction]). The exercise group had greater improvements on the Timed Up and Go Test (P = 0.04) but not the Short Physical Performance Battery (P = 0.8).

Limitations: Planned sample size was not reached. Loss to follow-up and dropout were greater than anticipated.

Conclusions: Among adults aged ≥55 years with CKD stages 3b-4 and a high level of medical comorbidity, a 12-month program of in-center aerobic and resistance exercise training was safe and associated with improvements in physical functioning.

Funding: Government grants (National Institutes of Health).

Trial registration: Registered at ClinicalTrials.gov with study number NCT01462097.

Keywords: Advanced CKD; adverse event; aerobic capacity; aging; cardiorespiratory fitness; chronic kidney disease (CKD); exercise; modifiable risk factor; physical function; physical performance; randomized clinical trial (RCT); renal function; resistance training; safety; treadmill.

Figure 1 –

CONSORT diagram

Figure 2a and 2b.

Effect of Exercise training vs. Health education on V0₂peak (A) and 6 minute walk (B)

Figure 2a and 2b.

Effect of Exercise training vs. Health education on V0₂peak (A) and 6 minute walk (B)