SPIROMETRIC SCREENING OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE IN SMOKERS PRESENTING TO TERTIARY CARE CENTRE

Objective: To determine the frequency of Chronic Obstructive Pulmonary Disease (COPD) by spirometric screening in smokers presenting to tertiary care center. Design: This Cross sectional study was carried out at the Medical department, Civil Hospital Hyderabad from April 2006 to September 2006. The main outcome variables were frequency of COPD in smokers, presenting symptoms and proportion of COPD severity classification. Results: The mean age of the clients was 39.77±6.30 years. The main symptoms of the study population were 75 (75%) patients have cough, 53 (53%) have sputum and 34 (34%) have dyspnoea. The spirometric results showed 39 (39%) smokers had study diagnosis of COPD with 19 (19%) had mild,12 (12%) had moderate and 8 (8%) smokers had severe obstruction. Conclusion: The prevalence of COPD in smokers using spirometry in our population is high (39%) as compared to international studies. This showed a great need and desire of screening for COPD in target population of smokers in our setting. Although effectiveness of screening in terms of smoking cessations and delay of progression of COPD should be calculated in order to make it national guideline.


Introduction:
Chronic Obstructive Pulmonary Disease (COPD) is a global problem.According to World Bank reports it accounts for 29 million disability-adjusted life-years (DALYS) and 1 million years of life are lost per annum around the world. 1 Many studies have shown COPD prevalence to be around 10 to 15% in smokers. 1 A US based study has showed 4 in 5 patients with COPD are current or former smokers. 2 Literature on COPD screening for smokers in primary care remains controversial.But there is increasing evidence to show that spirometric screening and frequency determination of people with moderate or severe COPD in smokers can significantly improves rates of smoking cessation as compared to rates of cessation in the otherwise general population. 3r literature review clearly suggests weakness of epidemiological data in our country.Thus we planned to determine the frequency of COPD in smokers using spirometry as a standard technique.

Methodology:
We conducted a cross sectional study in department of Medicine Civil Hospital Hyderabad from April 2006 to September 2006 in smokers presenting to tertiary care center.The sample size of the study was 100 patients selected through non probability purposive sampling.The inclusion criteria were all males who are current smokers of age >30 years with smoking history of more than seven pack years, giving informed consent were included.Whereas factory workers, those living near the factories and exposed to chemicals like exposures to coal mine dust, cotton dust, silica and grain dust were excluded in the study.Patients of ischemic heart disease, having myocardial infarction in the last one month or having chest pain at rest or on exertion were also excluded from the study.Finally patients with co-morbidities like diabetes and TB., debilitating diseases, very old age (>60 years), previously diagnosed as COPD, taking treatment for COPD were also excluded from the sample.
The main outcome variable of the study was presence of COPD.The effect modifiers were controlled by strict exclusion criteria.The close-ended questionnaire along with proper training of the co-researchers minimizes interviewer bias.
All the selected patients were interviewed by co researcher.COPD was confirmed by spirometry performed by trained technician of at least five years experience.A study diagnosis of COPD was defined as airway obstruction as measured by FEV1/FVC <0.70 measured by trained technician.
The severity of COPD was also diagnosed using Global Initiative for Chronic Obstructive Pulmonary disease (GOLD) by a trained technician in front of coresearcher.The classification cutoffs were mild FEV1/ FVC<0.70 (FEV1 > 80% predicted), moderate FEV1/ FVC < 0.70 (50% < FEV1 < 80% predicted), severe FEV1/FVC < 0.70 (30% > FEV1 < 50% predicted) and very severe FEV1/FVC < 0.70 (FEV1 < 30% predicted or FEV1 < 50% predicted plus chronic respiratory failure) The data was entered and analyzed in SPSS 12.The quantitative variables include age, age of starting smoking, number of cigarettes smoked per day, expressed as means and S.D. The qualitative variables include sex, occupation, presenting symptoms (cough, sputum and dyspnoea), COPD along with its severity classification (mild, moderate, severe and very severe obstruction), were expressed as percentages.No analytical test was applied.

Results:
The mean age of the clients was 39.77±6.30years.There were 4 (4%) businessmen, 3 (3%) teachers, 7(7%) drivers, 14 (14%) farmers, 48 (48%) laborers and 24 (24%) shopkeepers ( Currently COPD is the 12th leading cause of disability worldwide expected to be fifth by 2020. 1 Globally, smoking is a major cause of COPD and symptoms typically present in mid to later life. 7Smoking is a major risk factor of COPD and increases with aging due to changes in pulmonary function. 8A study conducted by Trofor has showed that smoking cessation as mandatory and beneficial in COPD. 9e results of this study showed higher frequency of COPD in smokers (39%).Further 19 (19%) smokers had mild obstruction, 12 (12%) smokers had moderate obstruction and 8 (8%) smokers had severe obstruction.
There are many studies that have shown high prevalence of COPD in smokers. 2,3,10study showed 34.9% of people diagnosed with COPD were smokers compared with 22.4% of those without. 11In a study by Gingter COPD prevalence in smokers was 6.9%. 12A study conducted in Turkey showed 6.9% of the participants (general population) were found to have COPD with the prevalence of COPD was 18.1% in current smokers. 13A study in Japan showed overall, 22.5% of patients were current smokers. 14A study by Pelkonen showed approximately one-quarter of smokers can be affected by clinically significant chronic obstructive pulmonary disease. 9study was conducted in Israel that showed COPD prevalence of about 22% in smokers. 15A study in China showed the smoking rate among COPD patients was significantly higher than that among the controls. 16A study by Godoy showed that about 57 (36.1%) smokers met the criteria for COPD out of 158 smokers. 10A study in China showed the overall prevalence of COPD (in the general population) was 8.2%. 17A study conducted by Tatsumi also showed 15 % of chronic smokers may develop COPD. 18r study has also showed a higher prevalence COPD of around 39% in smokers.But few studies have also shown a very low prevalence of COPD in smokers. 1,12ur study only included male patients the justification was studies have shown COPD to be more frequently occurred in males than females mostly due to predominance of smoking in males. 19,20Another study has showed the presence of COPD was significantly lower among women compared to men. 21study in Israel has showed that there was no correlation between pack-years smoking and development of COPD, but there was a relative correlation of pack-years smoking and severity of COPD, particularly in the older group. 15Our study also showed decrease in FEV1/FVC (severe COPD) with increase in pack years (see The main limitation of the study was a hospital based study not true representative of smokers in general community.But then it would be more advisable and feasible to perform screening in those smokers approaching at a tertiary center.So our results can be used in developing screening strategies to all smokers presenting to tertiary hospitals.The other limitation was, we were unable to control the effect of atmospheric pollution in developing COPD in our target population of smokers.But as our main objective was to provide rationale for screening by determining frequency of COPD in smokers and not association.Thus it does not affect our study objective and outcomes.

Conclusion:
The higher prevalence of COPD in smokers clearly showed the effectiveness and a rationale to conduct screening in the most target group (smokers).But father studies with larger and more multi centric settings involving health economic models should be conducted in order to develop national recommended guidelines in future.

Table - III
Table-I).The mean age of starting smoking of the patients was 22.35±5.34years.The mean number of cigarettes smoked per day was 17.65±5.70cigarettes.According to the interpretation of Spirometric results, 61 (61%) smokers had normal spirometry whereas 39 (39%) smokers had study diagnosis of COPD.Using the about 19 (19%) smokers had mild obstruction, 12 (12%) smokers had moderate obstruction and 8 (8%) smokers had severe obstruction none have very severe obstruction.The main symptoms of the study population were cough (75, 75%), sputum (53, 53%) and dyspnoea (34, 34%) respectively (Table-II).Finally the distribution of mean outcome of spirometry according to severity of smoking history is shown in Table-III.Distribution of mean outcome of spirometry according to severity of smoking history (n=100)