Exercise test with constant workload versus incremental test in individuals with cardiovascular disease: systematic review and meta-analysis

Abstract

Funding Acknowledgements Type of funding sources: None. OnBehalf Research Group on Cardiovascular Health and Exercise - gepCARDIO Introduction Cardiovascular disease is the main cause of morbidity and mortality worldwide, accounting for about 31% of deaths, in addition to leading to disabilities and worsening quality of life. The diagnosis of the disease and the response to treatments can be evaluated with functional tests. The most used are the incremental tests, such as the cardiopulmonary exercise test, a reference standard for diagnostic evaluation and exercise prescription. Constant workload tests or endurance tests report the efforts in daily activities and are especially applied to assess the effects of therapeutic procedures, such as physical training and drug therapy. Porpuse: Compare incremental exercise tests with constant workload tests for the assessment of functional performance in response to therapeutic interventions in individuals with cardiovascular disease. Methods: The systematic review was registered on the PROSPERO (CRD42020190214). The search was conducted in July 2020, in ten databases (PubMed, Scopus, Web of Science, Embase, CINAHL, LILACS, PEDro, SPORTDiscus, Livivo and Cochrane Library), and the Google Scholar search. Combinations of terms of related to the PECO strategy were used: (P) individuals with cardiovascular disease undergoing therapeutic procedure; (E) who were exposed to the evaluation with constant workload test; (C) compared to an incremental exercise test; (O) to assess functional capacity outcomes. Results: 9.453 studies were identified, of which 24 were included in the qualitative analysis and 19 in the meta-analysis. The interventions found were exercise training (71%) and drug therapy (29%). Heart failure was the prevalent diagnosis (54%), followed by coronary artery disease (17%). The constant workload test showing an improvement of 83% (MD 8.62, 95% CI 5.85–11.38) in test duration. The incremental tests showed changes of 12% (MD 1.98, 95% CI 5.85–11.38) for oxygen uptake, and 23% (MD 2.15, 95% CI 1.60–2.71) in oxygen uptake at the anaerobic threshold. In the comparisons between the tests performed in the meta-analysis, the duration of the constant workload test was more responsive than the oxygen uptake in the incremental test (SMD 1.59, 95% CI 0.88 - 2.29). In the analysis of subgroups of clinical diagnosis, the constant workload test was more responsive in the groups of heart failure, coronary artery disease and peripheral arterial disease. In the analysis by type of intervention, the studies with constant workload test also showed superior results. Conclusion: Tests with constant workload are more responsive in detecting changes in functional capacity in individuals with cardiovascular disease after a therapeutic intervention. Future studies with better methodological quality are recommended to increase the certainty of the evaluated evidence. Constant workload tests may have more use in clinical practice, facilitating the assessment of functional outcomes for cardiac patients.