Abstract
Background and Aims
Patients with chronic kidney disease (CKD) often present with reduced physical activity and exercise performance due to a number of factors relevant to co-existing disturbances of the cardiac, nervous and muscular systems. Cardiopulmonary exercise testing (CPET) is widely applied in daily clinical practice used for clinical evaluation of exercise intolerance and related symptoms (i.e. dyspnea, fatigue), as well risk stratification, and other applications in several medical fields.
Method
This is a systematic review and meta-analysis of studies which used CPET technology in adult patients with CKD to examine cardiopulmonary reserve in individuals with versus individuals without CKD. The primary outcome was peak oxygen uptake (VO2peak). Literature search involved PubMed, Web of Science and Scopus databases; manual search of article references and of grey literature was also performed. Newcastle-Ottawa Scale was applied to evaluate the quality of retrieved studies.
Results
From an initial 4944 literature records, we identified 29 studies fulfilling the inclusion criteria; of these, 25 studies with complete data including 2213 participants were included in final meta-analysis. Peak oxygen uptake (VO2peak) was significantly lower in CKD patients compared to controls without CKD (standardized-mean-difference, SMD:-1.40, 95%CI[-1.68, -1.13]) (Figure). Oxygen consumption at anaerobic threshold (VO2AT) (SMD:-1.06, 95%CI[-1.34, -0.79]), maximum workload (weighted-mean-difference, WMD:-58.26, 95%CI[-74.14, -42.38]) and respiratory exchange ratio (RER) (WMD:-0.02, 95%CI[-0.05, 0.01]) were also impaired in CKD patients compared to non-CKD individuals. In 3 studies comparing patients with CKD versus patients with heart failure without CKD VO2peak was higher in the former (WMD:6.60, 95%CI[3.02, 10.18]). Sensitivity analyses confirmed the robustness of these findings.
Conclusion
VO2peak and other commonly analyzed CPET variables were lower in CKD patients compared to controls, indicating reduced functional cardiopulmonary reserve in the former. In contrast, CKD patients performed better when compared patients with heart failure.
Using the 6-min Walk Test to Monitor Peak Oxygen Uptake Response to Cardiac Rehabilitation in Patients With Heart Failure
