Reduced peak oxygen uptake and implications for cardiovascular health and quality of life in patients with schizophrenia

BACKGROUND Peak oxygen uptake (VO(2peak)) is a strong predictor of cardiovascular disease (CVD) and all-cause mortality, but is inadequately described in patients with schizophrenia. The aim of this study was to evaluate treadmill VO(2peak), CVD risk factors and quality of life (QOL) in patients with schizophrenia (ICD-10, F20-29). METHODS 33 patients, 22 men (33.7 ± 10.4 years) and 11 women (35.9 ± 11.5 years), were included. Patients VO(2peak) were compared with normative VO(2peak) in healthy individuals from the Nord-Trøndelag Health Study (HUNT). Risk factors were compared above and below the VO(2peak) thresholds; 44.2 and 35.1 ml·kg⁻¹·min⁻¹ in men and women, respectively. RESULTS VO(2peak) was 37.1 ± 9.2 ml·kg⁻¹·min⁻¹ in men with schizophrenia; 74 ± 19% of normative healthy men (p < 0.001). VO(2peak) was 35.6 ± 10.7 ml·kg⁻¹·min⁻¹ in women with schizophrenia; 89 ± 25% of normative healthy women (n.s.). Based on odds ratio patients were 28.3 (95% CI = 1.6-505.6) times more likely to have one or more CVD risk factors if they were below the VO(2peak) thresholds. VO(2peak) correlated with the SF-36 physical functioning (r = 0.58), general health (r = 0.53), vitality (r = 0.47), social function (r = 0.41) and physical component score (r = 0.51). CONCLUSION Men with schizophrenia have lower VO(2peak) than the general population. Patients with the lowest VO(2peak) have higher odds of having one or more risk factors for cardiovascular disease. VO(2peak) should be regarded as least as important as the conventional risk factors for CVD and evaluation of VO(2peak) should be incorporated in clinical practice.