Gender based Prediction Equation to assess Aerobic Capacity in Chronic Obstructive Pulmonary Disease patients with Infection

This study investigates the prognostic role of functional assessment in chronic obstructive pulmonary disease (COPD) patients with infection, emphasizing the six-minute walk test (6MWT) as a practical substitute for cardiopulmonary exercise testing (CPET). The 6MWT is simple, inexpensive, and safer for patients unable to perform CPET, making it valuable in low-resource settings. While reduced six-minute walk distance (6MWD) is linked with COPD severity, its role in predicting infection-related exacerbations remains underexplored.

COPD is a progressive, irreversible disease marked by airflow limitation and frequent infections. It causes reduced lung function, exercise intolerance, and poor quality of life. Smoking is the main cause, though pollution, occupational exposures, and genetics also contribute. Exacerbations worsen prognosis and strain healthcare systems, especially where diagnostic tools are limited.

In this study, 80 clinically stable patients with infection-related exacerbations were evaluated using spirometry and the 6MWT. Peak oxygen uptake (VO₂ max) was estimated from walking distance. Demographic variables, body mass index, and symptom burden (mMRC and Borg scales) were recorded. Data were analyzed with non-parametric statistics and regression models.

The cohort was mostly middle-aged, with severe airflow limitation and a slight male predominance. Emphysema was the most common phenotype. The 6MWT revealed clear exertional limitation, with Borg scores indicating breathlessness. Walking distance strongly correlated with VO₂ max (r² > 0.95) and FEV₁/FVC (r = 0.731, p < 0.001). Gender explained most variance in VO₂ max, reflecting physiological differences in lung function and muscle mass. Both low and high BMI negatively affected performance, suggesting a U-shaped link between body composition and exercise capacity.

Clinically, results emphasize the complementary role of functional testing with spirometry. The 6MWT is reproducible, requires minimal infrastructure, and is ideal where CPET is unavailable. Gender-specific predictive equations developed in this study support individualized rehabilitation and safer exercise prescriptions. Embedding such models into digital platforms could extend monitoring to community and home care.

In conclusion, integrating 6MWT with spirometry provides a reliable, field-friendly approach for predicting aerobic capacity and managing infection-related exacerbations in COPD. This combined strategy supports personalized care, especially in resource-limited settings, and has potential to improve patient outcomes while reducing disease burden.