Predictors of asthma-chronic obstructive pulmonary disease overlap syndrome in patients with chronic obstructive pulmonary disease from a tertiary care center in India.

BACKGROUND

There is dearth of literature on asthma-chronic obstructive pulmonary disease overlap syndrome (ACOS) in India. The aim was to compare clinical characteristics between patients with ACOS and non-ACOS COPD and to identify clinical predictors of ACOS in patients with COPD.

METHODS

We conducted a retrospective study by reviewing data collected from patients performing spirometry at our hospital. Those with postbronchodilator FEV/FVC <70% were included in the study. Among them, those with significant reversibility (change in FEVor FVC by 12% and 200 ml postbronchodilator) were diagnosed with ACOS and the rest were considered to have non-ACOS COPD. Data on the 2 groups were compared and statistical analysis was performed.

RESULTS

Out of a total of 324 patients, 100 of them had postbronchodilator FEV/FVC <70%. Of them, 45 and 55 were diagnosed with ACOS and non-ACOS COPD, respectively. Patients with ACOS had significantly higher postbronchodilator FVC volumes and FVC % predicted values (P < 0.05), had higher reported wheeze (P = 0.02) and ankle edema (P < 0.05), were more likely to be smokers (P = 0.01) with lower smoking index (P = 0.03), and had frequent (≥2) ER visits (P = 0.04). However, very frequent (≥3 per year) hospital admissions (P < 0.01) with higher rates of invasive mechanical ventilation (P = 0.02), and pulmonary hypertension diagnosed by two-dimensional echocardiography (P < 0.01) were significantly higher in the non-ACOS group. The two groups did not differ with respect to history of atopy, family history of wheeze, compliance to inhaler therapy, or blood absolute eosinophil counts.

CONCLUSION

Our study highlights how the ACOS phenotype may clinically differ from their counterparts elsewhere, making it a clinical challenge to identify them in India.