Associations among serum folate, waist-to-hip ratio, lipid profile, and eating habits with homocysteine in an elderly Thai population.

A lower serum folate level is common in older populations and is associated with increased serum homocysteine concentration. In turn, an elevated homocysteine level is associated with increased risk of cardiovascular disease and age-related diseases. Contemporary studies of folate and dietary risk factors for cardiovascular disease among the elderly population in Thailand are lacking. This cross-sectional study aimed to investigate the relationships among serum folate, homocysteine level, and nutritional status in the elderly Thai. Three hundred individuals, aged 60 years and over, underwent anthropometric and physiological measurements, and biochemical parameters, and eating habits were also determined. Folate insufficiency was found in approximately 35% of subjects. Folate and homocysteine showed a significant inverse correlation. Serum homocysteine levels rose with increasing age. Folate deficiency and high waist-to-hip ratio were associated with 7-fold and 2.5-fold increased risk for hyperhomocysteinemia, respectively. There were positive correlations between homocysteine and waist-to-hip ratio and systolic blood pressure, but a negative correlation between homocysteine and high-density lipoprotein (r = -0.239, p < 0.01), which are markers for cardiovascular disease risk. Folate negatively correlated with body mass index, waist-to-hip ratio, and diastolic blood pressure, but positively with high-density lipoprotein (r = 0.162, p < 0.01). Investigation of eating habits showed that low consumption of green leafy vegetables and high consumption of sugary foods were associated with high homocysteine levels. Given associations between nutritional status and cardiovascular disease confirmed in this study, nutrition education, holistic health promotion, and appropriate behavioral modification of eating habits represent important measures for preventing premature cardiovascular disease in the elderly Thai population.

The immunogenicity of the intradermal injection of seasonal trivalent influenza vaccine containing influenza A(H1N1)pdm09 in COPD patients soon after a pandemic.

The antibody responses of a reduced-dose intradermal seasonal influenza vaccination have never been studied in COPD patients soon after a pandemic. A total of 149 COPD patients (60 y of age or older) were randomized to receive trivalent influenza vaccine (Sanofi-Pasteur, France) either 9 µg of hemagglutinin (HA) per strain split into 2-site intradermal (ID) injections via the Mantoux technique or one intramuscular (IM) injection of 15 µg of HA per strain. The geometric mean titers, seroconversion factors, seroconversion rates and seroprotection rates for influenza A(H3N2) and B administered through the ID injection (n = 75) were similar to those obtained with the IM injection (n = 74) 4 weeks post-vaccination. The antibody responses for influenza A(H1N1)pdm09 administered through the ID injection were lower than those obtained with the IM injection, but all of these responses met the 3 criteria proposed by the Committee for Proprietary Medicinal Products (CPMP) for annual re-licensure. The seroprotection rates 4 weeks post-vaccination for influenza A(H1N1)pdm09 were 64.0% (95%CI 52.7-74.0%) in the ID group vs. 78.4% (95% CI 67.6-86.3%) in the IM group (p = 0.053). Influenza-related acute respiratory illness (ARI), diagnosed as a 4-fold rise in HI titers with a convalescent titer > 1:40, and/or the RT-PCR between the ID group (5.3%) and the IM group (8.1%) were not significantly different. The reduced-dose intradermal influenza vaccine may expand vaccine coverage in cases of vaccine shortage.

Experience of percutaneous dilatational tracheostomy by using Grigg's technique in Siriraj Hospital.

BACKGROUND: Percutaneous dilatational tracheostomy (PDT) was increasingly performed after the commercial kit was available in 1985. Several studies showed that PDT was equivalent to surgical tracheostomy considering perioperative and long-term complications and PDT was more cost-effective and provide greater feasibility in terms of bedside capacity and nonsurgical operation. MATERIAL AND METHOD: The data of patients who were performed PDT at Division of Respiratory Disease and Tuberculosis, Department of Medicine, Faculty of Medicine Siriraj Hospital were retrospectively reviewed since March 2007 to December 2011. All procedures were done at bedside in intensive care unit or general ward of internal medicine under intravenous anesthesia. PDT was performed by using Griggs' technique. This technique is based on Seldinger guidewire technique and uses the guidewire dilator forceps (GWDFs) to enlarge the hole in the trachea under flexible bronchoscopic visualization. RESULTS: Ninety-one patients were enrolled with a mean age of 68 years old (range 17-100). Majority of patients had American Society of Anesthesiologist (ASA) classification 3. The most common indication for tracheostomy was failure to wean from the mechanical ventilator (68 patients; 74.7%). Fifty-two procedures (57.1%) were done at intensive care unit and 39 procedures (42.9%) were done at general ward of internal medicine. Mean duration of procedure was 18 minutes (range 5-90). The rate of perioperative complication was 11.0%. Five patients (5.5%) had desaturation and all of them were improved by short disruption of the procedure for ventilatory support. Three patients (3.3%) had moderate bleeding and one (1.1 %) had excessive bleeding that were stopped by electrocauterization and pressure compression. There was 1 serious perioperative complication that was accidental extubation. No perioperative or postoperative mortality that related to procedure was found. CONCLUSION: PDT is a safe procedure and can be performed easily and rapidly at the bedside either in intensive care unit or general ward with closed monitoring. Proper patient selection and attention to technical detail are necessary in maintaining low complication rates.

Epidemiology of sleep-related complaints associated with sleep-disordered breathing in Bangkok, Thailand.

BACKGROUND: This study assesses the prevalence of and risk factors for sleep-related complaints in Bangkok, Thailand. METHODS: A representative sample of the Bangkok population was selected based on results of the 2000 Census. A total of 4680 participants underwent face-to-face interview with a 49-question sleep inventory. RESULTS: Four percent of the total sampled (5.3% of men and 3.5% of women) complained of habitual snoring (>3 nights/week) and excessive daytime sleepiness (>3 days/week) for at least 3 months. These subjects were significantly (p<0.0001) older (41.4 vs. 36.7 years), had greater BMI (26.0 vs. 22.8 kg/m(2)), neck size (34.7 vs. 32.5 cms), and waist circumference (88.0 vs. 78.7 cms). They reported significantly shorter nocturnal sleep time, greater frequency of sleep disturbances and awakenings, unrefreshing sleep, choking during sleep, night sweats, nocturia, and bruxism. There was also a greater prevalence of cardiovascular and endocrine diseases. Multivariate analysis showed that male gender; BMI; waist size; and reports of witnessed apneas, unrefreshing sleep and night sweats were significant predictors of snoring and daytime sleepiness. CONCLUSION: This is the first epidemiologic study investigating sleep-related complaints and associated health morbidities in the Thai population.

The immunogenicity of intradermal influenza vaccination in COPD patients.

We evaluated the immunogenicity of a reduced-dose intradermal trivalent, inactivated, split-virion seasonal influenza vaccine compared to that of a conventional intramuscular vaccination in chronic obstructive pulmonary disease (COPD) patients. One hundred and fifty-six COPD patients randomly received either 0.2 ml (6 microg hemagglutinin (HA) per strain) split into two-site intradermal (ID) injections or a single 0.5 ml (15 microg HA per strain) intramuscular (IM) injection. Geometric mean titers, seroconversion factors, seroconversion rates and seroprotection rates at 4 weeks post-vaccination in the ID group were less than those in the IM group. Only the seroconversion factor to influenza B in the ID group was statistically less than in the IM group (18.8 in the ID group, n=81 versus 37.3 in the IM group, n=75, p=0.045). Nevertheless, each strain of the ID vaccination met all the Committee for Proprietary Medicinal Products (CPMP) criteria. Seroprotection rates were above 60% throughout the year in influenza A (H3N2), for at least 6 months in influenza A (H1N1) and at least 4 weeks in influenza B in both ID and IM groups. The reduced-dose intradermal vaccination may be considered for use in COPD patients in a vaccine shortage situation.

The endobronchial ultrasound-guided transbronchial lung biopsy in peripheral pulmonary lesions.

BACKGROUND: Peripheral pulmonary lesions are technically challenging with conventional bronchoscopy in obtaining tissue diagnosis. The recently developed small-caliber ultrasonographic probe can be introduced via the working channel of a flexible bronchoscope to localize peripheral pulmonary lesions (PPLs) prior to transbronchial lung biopsy (TBLB). The endobronchial ultrasound-guided transbronchial lung biopsy (EBUS-TBLB) is a new diagnostic method for the diagnosis of pulmonary lesions in our center. OBJECTIVE: To evaluate the diagnostic yield of EBUS-TBLB in pulmonary lesions. STUDY DESIGN: A prospective cross-sectional study. MATERIAL AND METHOD: We enrolled 152 patients with pulmonary lesions that were beyond the segmental bronchus and had no evidence of endobronchial lesion, who underwent bronchoscopy in our center. With EBUS assisted, transbronchial lung biopsy was performed after localizing and measuring distance from the tip of bronchoscope to the lesion. The diagnostic yield was calculated. RESULTS: The pulmonary lesions were visible on EBUS image in 98.7% of cases. The overall diagnostic yield of EBUS-TBLB was 66.4%. The diagnostic yield in the infiltrative and mass lesions were 86.4% and 63.1%, respectively. The lesions which EBUS probe located within it were diagnosed by EBUS-TBLB about 74.8%. The benign and malignant lesions were diagnosed by EBUS-TBLB about 81.1% and 58.6%, respectively. The average EBUS time was 3.55 +/- 2.29 minutes. No complication of EBUS and transbronchial lung biopsy were observed in this study. CONCLUSION: EBUS-TBLB is a safe procedure for diagnosing pulmonary lesions. Our results indicate that the EBUS-TBLB improves the diagnostic yield compared to conventional brochoscopy.

Outcome of medical thoracoscopy.

BACKGROUND: Medical thoracoscopy is a common procedure for pulmonologists working in Europe but is still unpopular in South East Asia with few medical centers in Thailand performing this procedure. We report our outcome of medical thoracoscopy based upon 10 years experience. MATERIAL AND METHOD: Medical thoracoscopy was first performed in our unit in 1998. The early indication was undiagnosed pleural effusion. Other indications which were empyema, pneumothorax and talc pleudrage were carried on for the last 3 years. The patients' demographic data, indication for medical thoracoscopy, procedures, complication and outcome were recorded and analyzed separately. RESULTS: During 1998 to 2007, there were 142 procedures of medical pleuroscopy performed. There were 86 procedures for the indication of undiagnosed pleural effusion. The diagnostic yield was 95.2%. The malignancy was recovered by thoracoscopy in 45.35% of procedure. For indication of talc pleurodesis, there were 22 patients with 3 who had early failure of pleurodesis because of trapped lung. After mean follow up of 124 days, 17 patients did not have recurrence of pleural effusion. 15 patients who had loculated pleural effusion were done medical thoracoscopy. Operations were successful in only 6 patients. For indication of pneumothorax 5 out of 6 procedures were successful after mean follow up of 167 days. In 12 empyema patients, mean hospital admission was 9.1 days after thoracoscopy. There was no serious complication from the procedure. DISCUSSION: There are many indications for medical thoracoscopy and the experience of the performer is the important factor determining success of the procedure. In undiagnosed pleural effusion, our result was comparable to other studies in the past in which the rate of malignancy was around 40-60%. The result of talc pleudrage was also comparable with the need to improve the diagnosis of trapped lung to prevent the unnecessary medical thoracoscopy. The result was excellent in patients who came for pleurodesis indicated in pneumothorax also in empyema but number of patient was still low. The problem was in loculated pleural effusion from malignancy which showed high failure rate. The early pleurodesis in malignant pleural effusion before it became loculated should be considered. CONCLUSION: Outcome of medical thoracoscopy varies from various indications. The success rate was high and decreasing in undiagnosed pleural effusion, pneumothorax, empyema and talc pleurodesis in malignant effusion. Great skill was needed to perform medical thoracoscopy in loculated malignant pleural effusion

Asthma, bronchial hyper-responsiveness and Chlamydophila (Chlamydia) pneumonia infection in adult Thai population.

BACKGROUND: The associations between Chlamydophila (Chlamydia) pneumonia infection and chronic asthma or bronchial hyper-responsiveness (BHR) have been inconclusive. OBJECTIVE: We aimed to determine the association between C. pneumonia infection and asthma as well as BHR in the adult Thai population. MATERIAL AND METHOD: This nested case-control study retrieved the data from a nation-wide Respiratory Health Survey (2001-02) in the adult population (age 20-44 year) in Thailand. Each subject underwent questionnaire interview, spirometry, bronchoprovocative test, skin prick test for common aeroallergens and venous blood collection. Subjects with BHR (n = 79) including those with asthma (n = 52), were randomly selected as cases. Subjects without BHR or asthma were also randomly selected as the control (n = 137). We used the stored serums for the C. pneumonia serologic assay including IgA, IgG and IgM by microimmunofluorescence (MIF) technique. RESULTS: There is no significant relationship between chronic Chlamydia infection (IgG > or = 1:512 and IgA > or = 1:40) and BHR or asthma. Higher IgM was found in subjects with BHR when compared with the control group (p = 0.04). The IgM titer > or = 1:10 was associated with BHR with borderline significance (odds ratio 1.98; 95% CI 0.98-4.00; p = 0.05). Logistic regression analysis revealed no evidence of confounding effects for age, sex and atopy. However mite allergy seems to be an effect modifier of the relationship between the recent Chlamydia infection and BHR. CONCLUSION: The present study does not support the hypothesis about the association between persistent C. pneumonia infection and chronic asthma. However the recent infection may be related with bronchial hyper-responsiveness particularly in those without allergy to house dust mite.

Optimal use of advanced technology.

The Asian Pacific Society of Respirology held its 13th Congress in Bangkok, Thailand, between 19 and 22 November 2008. It was attended by over 1500 delegates from around the world, particularly well represented by delegates from the Asia Pacific Rim. The congress was highlighted by an excellent scientific program, preceded by an educational course on pulmonary laboratory practices and several postgraduate courses. Office bearers representing the American Thoracic Society, European Respiratory Society and American College of Chest Physicians, among others, made significant contributions, further enhancing the high-quality faculty.

Recovery of heart rate variability in patients with moderate to severe obstructive sleep apnea after 6-month continuous positive airway pressure treatment.

OBJECTIVE: To evaluate the effect of long-term treatment with continuous positive airway pressure (CPAP) on the heart rate variability (HRV) of obstructive sleep apnea (OSA) patients. MATERIAL AND METHOD: Patients with moderate to severe OSA who had never used CPAP treatment were enrolled. Short recording HRV analysis was performed at baseline then at one, three, and six months after CPAP treatment. The measurement included low frequency HRV (LF), high frequency HRV (HF), low frequency to high frequency ratio (LHR), and standard deviation of R-R intervals (SDNN). All domains were measured both during spontaneous and deep breathing. RESULTS: There were 10 patients in the present study, all were men with the mean age of 45 years, mean body mass index 29.3 kg/m2, mean apnea-hypopnea index 60.9 events/hour, and mean average CPAP usage 4.8 hours/night. The HRV showed no significant change after one and three months of CPAP treatment. At 6 months, the only significant change was the SDNN measured after deep breathing (28.80 +/- 9.83 vs. 34.43 +/- 14.23 millisecond, p = 0.032). CONCLUSION: One aspect of heart rate variability in moderate to severe obstructive sleep apnea patients was improved after six month's continuous positive airway pressure treatment.

Comparison of clinical and polysomnographic characteristics of non-obese and obese patients with obstructive sleep apnea.

OBJECTIVE: To compare the clinical features, anthropometric indices, and polysomnographic data between different body mass index (BMI) subgroups of obstructive sleep apnea (OSA) patients. MATERIAL AND METHOD: The authors reviewed the data from OSA patients in Siriraj Sleep Clinic from April 2005 to September 2006. Objective measurement for sleepiness (Epworth Sleepiness Scale, ESS), anthropometric measurements [body mass index (BMI), neck circumference, thyromental distance, Mallampati S score, and occlusion pattern] and polysomnographic recordings [apnea/hypopnea index (AHI) during REM and NREM periods, respiratory arousal index, periodic leg movement index, minimal oxygen saturation, total sleep time with oxygen saturation <90%, and desaturation index] were collected. The patients were stratified into the non-obese group and obese group if their BMI was <27 or > or =27 kg/m2 respectively. RESULTS: Of the total 158 patients, 71 were non-obese and 87 were obese, no difference in mean age and sex was observed, but more patients with hypertension and coronary artery disease were noted in the obese group. Mean ESS was not different between the 2 groups. In anthropometric measurements, the obese group had statistically significant large neck circumference (41.6 +/- 3.5 cm vs. 37.0 +/- 2.9 cm, p<0.001), but the nonobese group had a shorter thyromental distance (56.4 +/- 11.7 mm vs. 61.4 +/- 11.2 mm, p=0.006), with no significant difference in Mallampatis score and occlusion pattern. In polysomnographic data, the obese group had statistical significantly more severity of various indices except for AHI during the REM period and the periodic limb movement index. CONCLUSION: Non-obese obstructive sleep apnea patients have more bony structural change than the obese ones as demonstrated by shorter thyromental distance. But degree of abnormalities during sleep was less severe in nearly all aspects.

Factors determining the severity of pulmonary function impairment in silicotic patients.

OBJECTIVE: Silicosis is the most common occupational lung disease in Thailand. Determinants of pulmonary function impairment in Thai silicotic patients have not been mentioned before. MATERIAL AND METHOD: The present study was conducted in silicotic patients who attended the Siriraj Occupational Lung Clinic in the year 2006. Patients were classified according to the forced expiratory volume in one second (FEV1) into the severe impairment group (< 50% predicted) and the non-severe group (FEV1 > 50% predicted) which includes normal FEV1. Comparison between the two groups in terms of demographic characteristics, smoking history, history of pulmonary tuberculosis, and radiographic features were assessed. RESULTS: Thirty-four patients of which 24 were female (70.6%) had an overall mean age of 53.7 years. Seven patients (20.6%) had severe impairment, four were female, three were smokers, and two had a history of pulmonary tuberculosis. All of the severe impairment patients had nodule profusion in category 2 and had large opacity. Only the presence of large opacity was significantly associated with the severity of pulmonary function impairment (p = 0.002). CONCLUSION: Only the presence of large opacity in a chest radiograph can determine the severity of pulmonary function impairment in Thai silicotic patients.

Prevalence of bronchial hyperresponsiveness and asthma in the adult population in Thailand.

OBJECTIVES: We conducted a nationwide cross-sectional survey of respiratory health in adults aged 20 to 44 years during 2001 to 2002 to determine the prevalence of bronchial hyperresponsiveness (BHR) and asthma in the adult Thai population. DESIGN: Subjects were selected by a multistage stratified random sampling. The stratification was done on geographic area, age group, and sex. Subjects were interviewed with questionnaires and underwent spirometric testing. Methacholine challenge tests were performed on all subjects without contraindication to determine BHR defined as the provocative concentration of methacholine producing a 20% fall in FEV(1) < or = 8 mg/mL. Definite asthma was defined as BHR present with any asthma symptom within the past 12 months or demonstrated reversible airflow obstruction. Current diagnosed asthma was defined as previous physician-diagnosed asthma and any asthma symptom within the past 12 months or currently receiving asthma medication. RESULTS: The study population was from 20 provinces of five geographic regions of Thailand and included 1,882 women and 1,572 men. The prevalence of BHR was 3.31% (95% confidence interval [CI], 2.68 to 3.94). However, if subjects with positive reversibility test results were included, the prevalence increased to 3.98% (95% CI, 3.30 to 4.67). The prevalence of definite asthma was 2.91% (95% CI, 2.32 to 3.50), whereas the prevalence of current diagnosed asthma by the questionnaire interview was 2.15% (95% CI, 1.66 to 2.63). The kappa index of the agreement between both definitions of asthma was 0.40, indicating poor to fair agreement. CONCLUSION: The prevalence of BHR and asthma in the adult Thai population is relatively low as compared with western countries.

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 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 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.

Comparison between specified percentage and fifth percentile criteria for spirometry interpretation in Thai patients.

OBJECTIVES: The present study was conducted to determine the degree of agreement between the interpretation of spirometry using a specified percentage of predicted value (SPC) and the fifth percentile (FPC) as the cut off between normal and abnormal. METHODOLOGY: Spirometric values were collected for 1754 subjects attending the respiratory service at Siriraj Hospital between February 2000 and April 2001. These values included forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC, maximal mid-expiratory flow (FEF25-75%) and peak expiratory flow (PEF). A comparison of results between SPC and FPC was performed. The SPC cut-off values for FVC, FEV1, FEV1/FVC, FEF25-75% and PEF were 80% predicted, 80% predicted, 70%, 65% predicted and 80% predicted, respectively. The FPC cut-off values were calculated from reference equations for the Thai population. Inter-rater agreement was calculated as the kappa score. RESULTS: High kappa scores were obtained for FVC (0.84), FEV1 (0.88) and FEF25-75% (0.80). However, poor agreement was found for FEV1/FVC (0.72) and PEF (0.61). When the cut-off values for SPC were modified to 90% of predicted values for FEV1/FVC and to 65% of predicted values for PEF, agreement was substantially improved to 0.92 and 0.89, respectively. CONCLUSIONS: Interpretation by SPC using cut-off values of 80% predicted for FVC and FEV1 and 65% predicted for FEF25-75% resulted in good agreement with FPC. However, the SPC cut-off values for FEV1/FVC and PEF should be modified to 90% predicted and 65% predicted, respectively.