Exploring the association between socioeconomic status and cardiopulmonary exercise testing measures: A cohort study based on routinely collected data.

BACKGROUND

Cardiopulmonary exercise testing (CPET) provides objective measures of cardiorespiratory fitness and can support surgical risk stratification. As socioeconomic status is a factor known to influence patient health and outcomes, we analysed how CPET-derived measures vary across levels of socioeconomic status in patients being considered for elective surgery.

METHODS

A database of patients who underwent CPET between 2011 and 2024 was analysed. Measures including oxygen consumption (V̇O₂) at gas exchange threshold (GET), peak V̇O₂, and ventilatory equivalent for carbon dioxide (VE/V̇CO₂) were compared across socioeconomic deprivation quintiles. Multivariable linear and logistic regression models assessed the effects of age, sex, body mass index (BMI), Revised Cardiac Risk Index (RCRI), and deprivation quintiles on CPET measures. Hierarchical regression models incorporating the Indices of Deprivation (IoD) domains and Access to Healthy Assets and Hazards (AHAH) scores determined whether wider social determinants of health explained the variance in CPET measures.

RESULTS

A total of 3344 patients (2476 male) were included, referred prior to procedures in vascular (2006), colorectal (650), upper GI (267), urology (205), and other (216) surgical specialties. Lower socioeconomic status was associated with younger age (p < 0.001), higher BMI (p = 0.022), higher smoking prevalence (p < 0.001), and RCRI ≥3 (p = 0.013). CPET measures were lower in the most deprived quintile (Q1) compared to the least (Q5): mean GET was 11.0 vs. 11.5 ml·kg-1·min-1 and peak V̇O2 was 14.8 vs. 16.3 ml·kg-1·min-1 (p < 0.05). Deprivation remained an independent predictor of lower GET and peak V̇O2, even after adjustment. Several IoD and AHAH domains explained small but significant variance in CPET measures.

CONCLUSION

Patients from more deprived areas exhibit risk factors for poor health and lower cardiorespiratory fitness as measured by CPET. These findings add to our understanding of socioeconomic disparities in physiological reserve among surgical patients and may support the need for more holistic approaches to peri-operative care.