The cost-effectiveness of mini peak expiratory flow as a screening test for chronic obstructive pulmonary disease among the Bangkok elderly.

This study aims to explore the cost-effectiveness of Mini Peak Expiratory Flow (miniPEF) as a screening test for Chronic Obstructive Pulmonary Disease (COPD) among the elderly in 124 urban communities around Siriraj Hospital, using the gold standard of diagnosis based on the guidelines of the Thoracic Society of Thailand. There were 3,094 subjects who participated and completed all the tests. The results showed that the cut-off miniPEF percentage of predicted value of highest average accuracy was 62 per cent. The sensitivity was 72.7 per cent (95% CI 67.0-78.6) and the specificity was 81.1 per cent (95% CI 79.7-82.5) The cost of screening 19 elderly to detect one case of COPD is 923 baht, with a false negative rate of 1.9 per cent (95% CI 1.3-2.5%) and a false positive rate of 17.5 per cent (95% CI 15.4-19.6%). It is suggested that measuring a miniPEF is regarded as one of the cost-effective screening tests for COPD in the elderly.

The most cost-effective screening method for chronic obstructive pulmonary disease among the Bangkok elderly.

Our previous studies demonstrated the high prevalence and incidence of Chronic Obstructive Pulmonary Disease (COPD) among the Bangkok elderly, as well as the cost-effectiveness of a questionnaire, chest radiography, and mini peak expiratory flow rate (miniPEF) as screening tools. This final study aimed to identify the most cost-effective screening method among individual, serial and parallel combinations of the above tools, based on the guidelines for diagnosing COPD of the Thoracic Society of Thailand. There were 3,094 elderly aged 60 years and over in 124 urban communities around Siriraj Hospital who participated and completed all the tests. The results showed that the most cost-effective screening method was the miniPEF at cut-off percentage of 62 per cent of predicted value. This needed to screen 19 elderly people at a cost of 923 baht to detect one case of COPD, with a false negative rate of 1.9 per cent (95%CI 1.3-2.5), a false positive rate of 17.5 per cent (95%CI 15.4-19.6). The questionnaire is the alternative choice of screening tool.

The cost-effectiveness of a questionnaire as a screening test for chronic obstructive pulmonary disease among the Bangkok elderly.

This study aimed to explore the cost-effectiveness of using a questionnaire as a screening test for Chronic Obstructive Pulmonary Disease (COPD) among the Bangkok elderly residing around Siriraj Hospital. The gold standard used for diagnosing COPD followed the guidelines of the Thoracic Society of Thailand. The questionnaire consisted of 10 questions on smoking status, respiratory symptoms and previous history of pulmonary tuberculosis. There were 3,094 elderly who participated, completed the questionnaire, and underwent spirometry as well as chest radiography in the community. The results showed that elderly individuals who are smokers (> 0.5 pack-year) or have ever experienced sudden cough with chest oppression or dyspnea when the weather changes or who have expectorated more than two tablespoons of sputum would be suspected of having COPD with a sensitiviy of 81.4 per cent (95% CI 79.4-83.4), specificity of 62.2 per cent (95% CI 60.4-64.0) false negative rate 1.2 per cent (95% CI 0.7-1.7) and false positive rate 38 per cent (95% CI 35.3-40.7) and subsequently required spirometry and chest X-ray for definitive diagnosis. The test needed to screen 17 elderly individuals to detect one COPD case at a cost of 1,538 baht. This questionnaire is also a self-assessment tool for COPD screening among the elderly in order to encourage them to seek for early medical attention and it is recommended that this should be publicized via the mass media.

The cost-effectiveness of chest radiography as a screening test for chronic obstructive pulmonary disease among the Bangkok elderly.

Regular screening with chest radiography (CXR) in an annual physical check up of the elderly is most frequently practiced. This study aimed to identify the CXR indices and the cost-effectiveness of CXR as a screening test for Chronic Obstructive Pulmonary Disease (COPD) among the elderly in 124 urban communities of Bangkok around Siriraj Hospital. The gold standard for diagnosing COPD followed the guidelines of the Thoracic Society of Thailand. There were 3,094 subjects who participated, completed spirometry and a CXR. The selected nine indices from PA and lateral CXR for diagnosing COPD were based on the presence of hyperinflation. The positive criteria of each index were reported. The cut-off point of best average accuracy ie, Z score of the CXR was 0.07 with a sensitivity of 75.9 per cent (95% CI 70.2-81.6%), specificity of 72.4 per cent (95% CI 70.8-74.0%) and the best average accuracy of 74.1 per cent (95% CI 72.5-75.7%) whereas the cost-effective cut-off point of a Z score of CXR as a screening test for COPD was 0.04 at the lowest grand total cost. The cost to detect one case of COPD was 2,008 baht and needed to screen 17 elderly. It is suggested that CXR is probably not a suitable screening test for COPD in the elderly due to the complicated derivation of the CXR indices. However, its efficacy may be of some value in in-office diagnosis of COPD.

The prevalence and incidence of COPD among urban older persons of Bangkok Metropolis.

COPD substantially affects the national healthcare resource and healthcare cost especially among the older persons. Identifying the accurate prevalence and incidence reflects the scale of problem posed by COPD. This epidemiological study using the criteria for diagnosing COPD based on ratio of FEV1.0/FVC less than 70 per cent and the reversibility of less than 15 per cent increase of post bronchodilator FEV1.0 in the absence of parenchymal lesions and cardiomegaly in CXR (PA and lateral view) revealed the prevalence (1998) of COPD among the 3094 older persons aged 60 years and over in the communities of Bangkok Metropolis 10 km around Siriraj Hospital was 7.11 per cent (95% CI: 6.21-8.01), whereas the incidence (1999) of COPD was 3.63 per cent (95% CI: 2.83-4.43). Both the prevalence and the incidence were increased with increasing age.The disease occurred predominantly among male smokers. The distribution of mild : moderate : severe COPD in the prevalence study was 5.6:2.2:1. The current findings also suggest that tobacco smoking is the prime important cause of COPD and the indoor pollution especially cooking smoke is not significant. In particular, the unexpectedly high incidence compared with prevalence in this population probably represents the warning message to the national policy maker for prompt and effective health promotion and disease prevention to prevent further social and economic loss.

Differential cell analysis in bronchoalveolar lavage from various pulmonary diseases.

To obtain characteristics of cellular responses of the lung to various disease processes, we analyzed the cells in bronchoalveolar lavage fluid retrieved from various lung lesions. Patients affected with five groups of pulmonary diseases were included in this study. These were pulmonary tuberculosis (21), malignancy (7), interstitial lung disease (11), bacterial pneumonia (10), and invasive fungal infection (7). Diagnoses were made from histopathological or microbiological evidence and were followed by compatible clinical courses. We compared total cell counts, alveolar macrophages, neutrophils, and lymphocytes in both percentages and absolute numbers to the values in the normal population reported in previous studies. Comparisons within each disease were also made. Compared to the normal population reported in previous increased percentages of neutrophils and lymphocytes in nearly all groups. However, if the comparison was made among the five groups, only the bacterial pneumonia had a significantly higher total cell count, absolute count and percentage of neutrophils. A value of more than 50% neutrophils gave sensitivity and specificity as 80% and 89%, respectively, in differentiatind bacterial pneumonia from other diseases. No parameter was demonstrated as useful in distinguishing between nonbacterial conditions. In conclusion, increases in the percentage of neutrophils and lymphocytes were discovered in nearly all pulmonary diseases. The markedly increased percentage of neutrophils in bacterial pneumonia may be useful as adjunctive evidence in the diagnostic process in some special conditions.