Cardiorespiratory Fitness, Physical Activity, and Quality of Life in Patients with McArdle Disease

Background This study sought to determine whether health-related quality of life (HRQoL) could be related to cardiorespiratory fitness (CRF) and/or physical activity (PA) in patients with McArdle disease and to compare the CRF and HRQoL data obtained with normative data for age- and sex-matched healthy subjects. Methods Eighty-one adult patients with McArdle disease underwent aerobic capacity testing to determine peak oxygen uptake (VO2peak), among other variables. HRQoL (Short Form 36-Item Health Survey questionnaire version 2 (SF-36 version 2)) and PA (International Physical Activity Questionnaire) questionnaires were completed by 45 of the patients. HRQoL and VO2peak data were compared with published normative data. Results Positive correlations were observed between VO2peak and leisure time PA versus the physical component summary score and scores for several domains of the SF-36 questionnaire after adjusting for age, body mass index, and disease severity (R values, 0.42-0.68; all P < 0.01). In a regression analysis, the physical component summary score was directly linked to VO2peak (B = 1.28; 95% confidence interval, 0.78-1.78; P < 0.001; R-2 = 0.422). The mean VO2peak recorded for patients with McArdle disease was 57% lower than the normative value (17.1 5.3 vs 40.0 +/- 9.5 mLkg(-1)min(-1), respectively; P < 0.001). All patients showed a CRF below their age-/sex-matched normality value and scored clinically lower in the physical component summary and in most SF-36 domains compared with the Spanish general population. Conclusions Patients showed a consistent link between higher physical HRQoL scores and higher CRF. Patients fulfilling leisure time PA recommendations showed higher CRF and physical HRQoL scores than those not meeting guideline recommendations. According to normative data for healthy subjects, CRF and physical HRQoL are severely impaired in adult patients with McArdle disease.