Submitted: Assessing Cardiorespiratory Fitness in Clinical Rehabilitation: Validity of Field Exercise Tests and Patient-Reported Questionnaires

Hits: 23
  • Publication status: Submitted
  • Type of study: Validation
  • Journal: To be determined

  • Meijer, R. ORCID iD

    Schep, G. ORCID iD

    Regis, M. ORCID iD

    Jager de, Fm. ORCID iD

    Weemaes, A. ORCID iD

    Bongers, B. ORCID iD

    Pol van de - Franse, L ORCID iD

    Savelberg, H. ORCID iD

    Hooff van, M. ORCID iD

  • Affiliations: Maastricht University, Maastricht University Medical Center, Máxima Medical Centre, The Netherlands Cancer Institute, Tilburg University
  • Population: Oncology, Cardiac, Chronic Heart Failure

Objective: This cross sectional study evaluated criterion and construct validity of field exercise tests and patient-reported questionnaires to estimate cardiorespiratory fitness (CRF) compared with cardiopulmonary exercise testing (CPET). It also aimed to identify the best alternative for CPET to evaluate CRF in clinical rehabilitation. 
Design: All patients performed CPET, the steep ramp test (SRT), the 6-minute walk test (6-MWT) and completed the Duke activity status index (DASI), veterans-specific activity questionnaire (VSAQ), and FitMáx© questionnaire (FitMáx) within 42 days in which no change in CRF was expected. Work rate at peak exercise at the steep ramp test (SRT-WRpeak, in W/kg), distance walked at the 6-MWT (6-MWD, in m), and oxygen uptake at peak exercise (VO2peak, in ml/kg/min) estimated by patient-reported questionnaires were compared with the objectively measured VO2peak during CPET. Moreover, SRT-WRpeak, 6-MWD, and questionnaire-estimated VO2peak were compared to each other.  
Setting: Two physical therapy departments.
Participants: Sixty-nine patients (57% female) with cardiopulmonary or oncologic conditions  with a median (IQR) age of 58 (46-66) years. 
Interventions: Exercise rehabilitation. 
Main outcome measures: Pearson’s correlation between CPET-VO2peak and SRT-WRpeak, 6-MWD, and questionnaire-estimated VO2peak.
Results: Correlations of SRT-WRpeak and 6-MWD with CPET-VO2peak were r=0.83 (95% confidence interval (CI) 0.73-0.89) and r=0.43 (95% CI 0.21-0.60), respectively. Correlations of the DASI-VO2peak, VSAQ-VO2peak, and FitMáx-VO2peak with CPET-VO2peak were r=0.36 (95% CI 0.13-0.55), r=0.43 (95% CI 0.22-0.61), and r=0.76 (95% CI 0.64-0.84), respectively. 
Conclusions: Both SRT-WRpeak and FitMáx-VO2peak showed a strong correlation with CPET-VO2peak. The 6-MWD, DASI-VO2peak and VSAQ-VO2peak showed a poor correlation with CPET-VO2peak. Consequently, the SRT and FitMáx are considered the best alternative field exercise test and patient-reported questionnaire to estimate CRF when CPET is not feasible or considered redundant.