ABSTRACT
BACKGROUND AND OBJECTIVES: Exercise capacity is impaired at a younger age in CKD patients than in the general population. This study examined the reliability of the Duke Activity Status Index (DASI) questionnaire as a measure of exercise capacity in medically stable adults with stage 3-4 CKD (estimated GFR [eGFR], 15-59 ml/min per 1.73 m(2)). DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Peak oxygen uptake (VO(2)peak), estimated from DASI responses and cardiopulmonary exercise test measurements, was obtained at baseline and 6 months in a derivation sample (n=23) and once in a validation sample (n=20). Bland-Altman analysis and linear mixed models were used to estimate bias, concordance correlation coefficients, and intraclass correlation coefficients as the proportion of the variance due to participant (intertest reliability) and method (test-retest reliability). RESULTS: The two samples were homogeneous with respect to age (mean 60 ± 14 years), eGFR (35.5 ± 15 ml/min per 1.73 m(2)), male sex (53%), and diabetes (56%). Mean measured VO(2)peak was 16.5 ± 4 ml/kg per min. The DASI questionnaire overestimated VO(2)peak by 4.3 ml/kg per min. Intertest reliability was 53% when eGFR was ≥35 ml/min per 1.73 m(2) (median) and 60% when eGFR was <35 ml/min per 1.73 m(2) (P<0.01). Test-retest reliability was 81% when eGFR was <35 ml/min per 1.73 m(2) and 71% when eGFR was ≥35 ml/min per 1.73 m(2) (P<0.01). CONCLUSIONS: The DASI questionnaire may be a reliable measure of exercise capacity in CKD patients, especially when eGFR is <35 ml/min per 1.73 m(2). Larger prospective studies are needed to determine its prognostic value.
Subject(s)
Exercise Tolerance , Health Status Indicators , Health Status , Kidney Diseases/diagnosis , Kidney Diseases/physiopathology , Surveys and Questionnaires , Aged , Alberta , Chronic Disease , Cross-Sectional Studies , Exercise Test , Female , Glomerular Filtration Rate , Humans , Kidney/physiopathology , Linear Models , Male , Middle Aged , Observer Variation , Oxygen Consumption , Predictive Value of Tests , Reproducibility of Results , Severity of Illness IndexABSTRACT
BACKGROUND: Patients with chronic kidney disease (CKD) have impaired performance in physical tasks, lower health-related quality of life and high cardiovascular morbidity and mortality. Moderate intensity exercise has been shown to provide cardiovascular and metabolic benefits in healthy individuals and patients without CKD. Long-term exercise training is recommended as a vital component in the management of a number of chronic diseases. This randomized controlled pilot project examined the effects of exercise in predialysis CKD patients. METHODS: Ten patients were randomized to 12 months of exercise (EX) and 10 to standard care (CT). We compared the difference between the two groups in physical impairment (VO(2peak) and endurance time [ET]), arterial stiffness (augmentation index [AI]) and health-related quality of life (EuroQol EQ-5D and Short Form-36 questionnaires) (all measured at baseline and 12 months). RESULTS: The difference between EX and CT was statistically significant for VO(2peak) (3.59 ml O(2)/kg/min; 95% CI 0.92, 6.26; P = 0.01), ET (10.97 min; 95% CI 4.34, 17.59; P = 0.003) and AI (-11.7%; 95% CI -18.79, -4.61; P = 0.003). Clinically important changes were noted in EQ-5D and SF-36. CONCLUSIONS: This study suggests that long-term exercise training improves physical impairment, arterial stiffness and health-related quality of life in patients with predialysis CKD. A larger randomized trial is required to examine the impact of exercise on markers of cardiovascular risk and quality of life in predialysis CKD patients.
