Objective
The objective of this study was to differentiate between the various epidemiological, clinical, radiological, laboratory and prognostic characteristics of Tobacco smoke (TS) associated and Bio mass fuel (BMF) associated COPD. BMF associated COPD is a major cause of morbidity and mortality in the developing world. A large population especially in rural India still uses coal and indigenous gas stoves which lead to a large amount of air pollution. Current western literature does not distinguish between the characteristics of TS and BMF associated COPD.
Method
80 patients with COPD, defined using the GOLD spirometry criteria, were studied. 40 patients had significant exposure to smoked tobacco. 40 patients were never smokers, but had been exposed to BMF for at least 5–10 years, mostly for domestic cooking exposure. Both the groups were compared for various parameters.
Results
92.5% (37/40) in the smoking group were males. 85% (34/40) in the BMF group were females. The average age of the TS group at the time of diagnosis was 58 years, in the BMF group the average age of diagnosis was 69 years. All females from the BMF group were uneducated and 88.2 (30/34) were brought to medical attention for the first time with an acute exacerbation. In the TS group the average FEV1 value (% age predicted) was 52%. In the BMF group the average FEV1 was better at 64% predicted. 65% (26/40) patients were on inhaled therapy for their disease as compared to 30% (12/40) in the BMF were on any kind of inhaled therapy. 97.5 (39/40) in the TS group knew that Tobacco smoking could lead to COPD. In the BMF group only 17.5% (7/40) knew that BMF exposure could lead to respiratory disease. 72.5 (29/40) in the TS group had associated Cardiovascular and metabolic disorders, this was 22.5 (9/40) in the BMF group. The patients in both the groups were equally dyspnic at presentation, with an average MMRC of 3, depicting that most patients with COPD present to health care facilities late in our country. Both the groups had an average exacerbation of 2/year, over the 2 years of study period, However, the TS group had a higher number of ICU admissions and worse exacerbations (10 in TS group vs 3 in BMF group). On HRCT Thorax BMF COPD had lesser percentage emphysema (low attenuation areas). The BMF group had a higher prevalence of associated Bronchiectasis on CT scans (53% vs 18%). Post discharge the TS group had higher adherence to the prescribed drugs and hospital follow up as compared to the BMF group (70% vs 45%).
Conclusions
BMF associated COPD is a unique group of COPD patients encountered in rural India. Majority of these patients are females, who are exposed to large a corpus of inhaled smoke via indigenous stoves and wood fire used for cooking. The health seeking behaviour of this group is worse than the classical TS COPD, as indicated by late age of first presentation, first presentation in exacerbation and poor post discharge follow up. Despite having better lung functions and less cardiovascular morbidities most of these patients are equally dyspnic and exacerbate at the same rates as their smoker counterparts. This special subgroup of COPD patients needs to be identified and treated early, for more favourable outcomes.