Bronchiectasis

Study objectives: To validate the Hong Kong Chinese version of the St. George Respiratory Questionnaire (SGRQ-HK) in patients with bronchiectasis.

Design and setting: Outpatients (93 patients; 61 women; mean age [[+ or -] SD], 59.0 [+ or -] 14.2 years) were assessed at baseline by the SGRQ-HK, the Hong Kong Chinese version of the 36-item short form health survey (SF-36-HK), and the hospital anxiety and depression scale (HADS). Forty randomly selected patients also were reassessed at 2 weeks for repeatability. Seventy-two patients were further reassessed at 6 months for responsiveness.

Measurements and results: Cronbach [alpha] coefficients, which reflected internal consistency, were > 0.7 for all SGRQ-HK components except for symptoms ([alpha] = 0.59), and the intraclass correlation coefficients between baseline and the 2-week follow-up visits were between 0.80 and 0.94 (p > 0.05). SGRQ-HK component scores and total scores correlated with all the component scores of the SF-36-HK and the HADS (p < 0.02). SGRQ-HK component scores and total scores correlated with the scores of the SF-36-HK and the HADS, confirming the concurrent validity. All SGRQ-HK scores correlated negatively with FE[V.sub.1], FVC, and arterial oxygen saturation (p < 0.005), while the activity score correlated with the Karnofsky performance scale and the number of bronchiectatic lobes (p < 0.001). SGRQ-HK scores positively correlated with Borg scale scores, exacerbation frequency, and 24-h sputum volumes (p < 0.03). Patients with 24-h sputum volumes of [greater than or equal to] 10 mL or < 10 mL had significantly different SQRG-HK component scores and total scores (p < 0.002), although this sensitivity was not displayed by scores on the HADS or the SF-36-HK. Patients with 25% reductions in 24-h sputum volumes had significant improvements in SGRQ-HK activity scores, impact scores, and total scores (p < 0.02), but not in other quality-of-life measures or clinical parameters, indicating the responsiveness of the SGRQ-HK.

Conclusion: The SGRQ-HK is a valid and sensitive instrument for determining quality of life in bronchiectasis patients.

Key words: bronchiectasis; hospital anxious and depression scale; MOS short form-36; quality of life; St. George Respiratory Questionnaire

Abbreviations: HADS = hospital anxiety and depression scale. ICC = intraclass correlation coefficient; KPS = Karnofsky performance scale., Sa[O.sub.2] = arterial oxygen saturation; SF-36-HK = Hong Kong Chinese version of the 36-item short form health survey; SGRQ = St. George Respiratory Questionnaire; SGRQ-HK = Hong Kong Chinese version of St. George Respiratory Questionnaire; 6MWD = 6-min walking distance

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Bronchiectasis is a common respiratory disease among Chinese people. Similar to COPD patients, patients with bronchiectasis also experience chronic sputum production, recurrent exacerbations, and progressive lung destruction. (1) Most patients undergo a slow, progressive deterioration over decades. The evaluation of lung function does not fully reflect the impact of the disease on a patient and, therefore, should be supplemented by using quality-of-life questionnaires. (2) Because structural markers such as the number of bronchiectatic lung lobes and measurements of lung function parameters are unlikely to show a response to effective therapy, disease activity markers such as 24-h sputum volume measurement and exacerbation frequency are more important surrogate end points for the assessment of treatment efficacy. Disease activity markers, however, do not necessarily reflect the overall impact of an illness on an individual patient. Although treatment with inhaled corticosteroids, low-dose erythromycin, the early administration of antibiotics for exacerbations of bronchiectasis, and the practice of regular chest physiotherapy are effective in ameliorating inflammatory and other disease activities in patients with bronchiectasis, (3-5) little is known about the effects of these modes of treatment on the overall well-being of an individual patient. Trials of potential therapeutic agents should, therefore, not only include assessments of disease activity markers, but also quality-of-life parameters.

The St. George Respiratory Questionnaire (SGRQ),has been used to assess the quality of life in patients with asthma, COPD, [[alpha].sub.1]-antitrypsin deficiency, interstitial lung diseases, and, very recently, bronchiectasis. Test-retest reliability, validity, and sensitivity have been demonstrated in these patients. (6-10) The SGRQ is a standardized, disease-specific, self-administered, health status instrument consisting of 50 items grouped under three components, namely, symptoms, activity, and impact. (7) The eight items in the symptom component assess the frequency of cough, sputum production, and dyspnea, and the duration and frequency of attacks of dyspnea or wheeze. The 16 items in the activity component identify physical activities that induce dyspnea or that are affected by dyspnea. The 26 items in the impact component broadly assess the impact of the disease on different aspects of social and emotional functions, and on expectations for health. The response to each item is in the form of "true" or "false" answers for the activity and impact components. Component scores are calculated using empirically determined weights attached to each item, (11) and a total score is calculated based on the responses to all items. A higher SGRQ score, either the total score or individual component score, represents a poorer quality of life.

The SGRQ has been translated to into many other languages and has been validated for use in some languages and cultural backgrounds. (10,12-16) However, validation and translation into Chinese, particularly for use in patients with bronchiectasis, has not been accomplished. We have, therefore, undertaken this prospective study to validate a Hong Kong Chinese version of the SGRQ (SGRQ-HK) in 93 stable patients with bronchiectasis.

MATERIALS AND METHODS

Translation Procedure

The SGRQ was translated into Chinese and then back-translated into English using the methodology employed by a Spanish translation and validation study. (12) The process involved the translation of the first version by a bilingual person, followed by a review by a committee of professionals (ie, two respiratory physicians, one respiratory nurse, and one research assistant). Back-translation into English and a comparison with the original version were performed by another bilingual person, and the translation then was reviewed and adjusted by the committee. During the examination of the translated Chinese version of SGRQ, seven words and three phrases were judged to contain ambiguous wording and were replaced before the first Chinese version was produced. This Chinese translation was back-translated into English, which was judged to contain no literal difference from the original version except in one aspect. In the process of translating the questionnaire from English to Hong Kong Chinese, a substitution of exercise items such as "gardening" and "playing golf" by "hiking" and "playing Tai-chi," respectively, was performed to adapt terminology to the local culture. This version then underwent pilot testing on eight randomly selected patients with stable idiopathic bronchiectasis (five women and three men; mean [[+ or -] SD] age, 66.4 [+ or -] 10.5 years; FE[V.sub.1], 78.0 [+ or -] 0.3% predicted; FVC, 1.8 [+ or -] 0.2% predicted; mean 24-h sputum volume, 15.7 [+ or -] 17.5 mL; mean exacerbation frequency, 4.4 [+ or -] 5.9 per year; mean number of lung lobes affected, 1.8 [+ or -] 0.8). None of the eight bronchiectasis patients reported any difficulty in understanding or answering the questions. Therefore, the SGRQ-HK was adopted as the final version of the questionnaire.

Study Design

The SGRQ-HK and its back-translation (available from the authors) were assessed in a three-part study on Hong Kong Chinese patients with bronchiectasis. Following the general principle, our validation of the SGRQ-HK entailed the determination of whether there were grounds for trusting that it measured what it was intended to measure, and that it was useful. Validity was examined as concurrent validity, which reflected the empirical association with external criteria such as other established instruments; and construct validity, which reflected the theoretical relationship of the items to each other and to the hypothetical scales. Two elements of construct validity, namely, item-scale convergent validity and discriminant validity, also were examined. The former described the prediction of observations and the conformation of the observations to the predictions, while the latter identified items that should be of poor correlation. Reliability and repeatability were assessed, addressing the random variability associated with measurements. Sensitivity assessments measured the ability to detect differences between patients or groups of patients. Finally, responsiveness, which reflected the ability to detect changes when a patient's condition improved or deteriorated, was assessed. (17)

The reliability (ie, repeatability and internal consistency), validity, sensitivity, and responsiveness of the SGRQ-HK were, therefore, assessed in this cohort. One of the three components was a cross-sectional study, which consisted of a battery of assessments completed by each patient on recruitment. The data were used to examine the reliability, construct validity (comprised of item-scale convergent validity and discriminant validity), concurrent validity, and the sensitivity of the SGRQ-HK. The second component was a longitudinal study, which entailed reassessment of patients at 2 weeks for comparison with baseline assessments for examination of the test-retest reliability (ie, repeatability) of the SGRQ-HK. The repeatability of the SGRQ-HK was assessed at this stage as the patients were expected to show no significant changes in overall health status at 2 weeks. The third component was used to determine the responsiveness of the SGRQ-HK to changes by comparing the results at 6 months with those obtained at baseline.

Patients with proven bronchiectasis that had been diagnosed by high-resolution CT scanning were recruited from the specialist respiratory outpatient clinics of the University of Hong Kong, and written informed consent was obtained from each patient. The number of lung lobes (including lingula as an individual lobe) affected by bronchiectasis was determined by a thoracic radiologist who examined the high-resolution CT scan of each patient using standard criteria. (18) Inclusion criteria included the following: daily sputum expectoration; absence of other respiratory or unstable systemic diseases; and steady-state bronchiectasis (ie, a < 20% alteration of the 24-h sputum volume, reductions in FE[V.sub.1] and FVC, and the absence of deterioration in respiratory symptoms for at least 3 weeks prior to baseline assessment). Exclusion criteria included unreliable clinic attendance and a refusal to provide a written consent. (4) All patients were interviewed in the same clinic room by the same respiratory physician, research nm, se, and research assistant each time. At each clinic visit, clinical, physiologic, and quality-of-life parameters were assessed. At 2 weeks, when no changes in quality-of-life parameters were expected, the SGRQ-HK was administered again to a subgroup of 40 randomly selected patients to assess the repeatability of the questionnaire. Finally, patients were reassessed at 6 months when the aforementioned assessment was repeated. The study protocol had approval from the institutional ethics committee.

Health-Related Quality-of-Life Questionnaires

Two health-related questionnaires, the Hong Kong Chinese version of the 36-item short form health survey (SF-36-HK) and the hospital anxiety and depression scale (HADS), (18,19) were simultaneously applied to the study population along with the SGRQ-HK. The SF-36-HK consists of 36 items that are categorized into the following eight multi-item scales: physical functioning; limitations due to physical health problem (role-physical); bodily pain; general health; vitality; social functioning; limitations due to emotional health problems (role-emotional); and mental health. Higher scores represent better health status. The SF-36-HK has been translated, validated, and normalized according to the guidelines of the International Quality of Life Assessment Project. (19) HADS, which was designed to eliminate the effects of the somatic symptoms of physical illness, was used to assess the emotional status of each of the patients. HADS contains 14 items, gives separate scores for anxiety and depression, and also has recently been translated into Chinese and validated in Hong Kong. (20)

The three instruments were administered by the research assistant, in random order, in Cantonese, to each patient. All patients were interviewed to ensure that they could understand and answer the questions. Face-to-face interviews were necessary because of the high level of illiteracy among older Hong Kong Chinese people. (21) If a patient could not answer a question after adequate explanation, the corresponding answer was defined as missing.

Clinical and Physiologic Parameters

At each visit, the patients were directly questioned on the presence of respiratory symptoms, including cough, dyspnea, hemoptysis, sputum production, chest pain, and wheezing, were examined physically. The number of exacerbations occurring in the preceding 12 months and during the study also was determined, by the same physician, for each patient by meticulous history taking and review of clinical charts. An exacerbation was defined as subjective and persistent (ie, for [greater than or equal to] 24 h) deterioration of at least three respiratory symptoms, including cough, dyspnea, hemoptysis, increased sputum purulence or volume, and chest pain (with or without fever [ie, temperature of [greater than or equal to] 37.5[degrees]C]), radiographic deterioration, systemic disturbances, or deterioration in physical signs in the chest, including crackles and dullness on auscultation and percussion). (4) Sputum was collected every 24 h on 3 successive days immediately before each visit, and the mean 24-h sputum volume was determined. (4)

At each visit, lung function parameters, resting oxygen saturation, Karnofsky performance scale (KPS) score, Borg score, and 6-min walking distance (6MWD) were determined for each patient. Spirometry (model 2200 spirometry unit; Sensor-Medics; Yorba Linda, CA) was carried out between 10 and 11 AM using standard protocols. FE[V.sub.1] and FVC were determined. Resting arterial oxygen saturation (Sa[O.sub.2]) was determined on the index finger with a pulse oximeter (model 4500; Invivo Research Inc; Orlando, FL) for all patients after a 15-min rest and while breathing room air. The KPS (range, 0 to 100 [0, dead; 100, normal]) and the 12-point Borg scale for dyspnea (0, nothing at all; 10, maximal intensity of dyspnea sensation) were determined by the same physician 15 min after the patient had settled in the same clinic room at each visit. The 6MWD was determined for each patient by the same physician, who walked with the patient. The walking was performed in a quiet and air-conditioned corridor that had a level and smooth covered floor. All walks were scheduled at least 2 h after meals and in the morning. The 6MWD was measured to the nearest meter for each subject. (22)

Data Analysis

Data were analyzed using appropriate software (SPSS, version 10.0; SPSS; Chicago, IL). Descriptive statistics were used to summarize the demographic and clinical characteristics of the patient population. Spearman rank correlation coefficients were determined for all correlation analyses, except those involving FE[V.sub.1], FVC, Sa[O.sub.2], 6MWD, and 24-h sputum volume, which displayed normal distribution on data inspection and, thus, were analyzed using the Pearson correlation. A p value of < 0.05 was taken to be statistically significant.

The percentage of missing data was determined as the number of missing items in each component divided by the total number of items in that particular component for each patient. The ceiling and floor percentages of each of the components were used to assess the potential sensitivity of SGRQ-HK in patients with bronchiectasis. Ceiling and floor percentages were determined as the percentage of patients with the best or worst possible scores in a particular component, respectively. The score for each of the items was correlated with the three component scores and the total scores to determine whether its original placement within a particular component (ie, the hypothesized component) was correct. Scaling success rates (ie, the percentage of items in each one of the three components [symptoms, activity, and impact]) that correlated higher or significantly higher with their hypothesized component than with the other two components, were computed for each of the components.

Item-scale convergent validity and discriminant validity, which are elements of scale construct validity, of the SGRQ-HK were examined by comparing the item-scales correlation. Convergent validity was supported if an item correlated (r [greater than or equal to] 0.4) with the component it was hypothesized to belong to. Discriminant validity was supported whenever a correlation between an item and its hypothesized component was higher than its correlation with the other two components. (17) The internal consistency of the questionnaire was tested by determining the Cronbach [alpha] coefficient. A minimum of 0.7 for Cronbach [alpha] coefficients, as suggested by Nunnally and Bernstein, (23) was adopted as the minimum reliability coefficient for group comparison. Test-retest reliability, which measured the ability of the SGRQ-HK to produce consistent scores over a short period of time (ie, at 2 weeks), and the intraclass correlation coefficient (ICC), were determined.

Concurrent validity of the SGRQ-HK was assessed by comparing its component and total scores with SF-36-HK and HADS scores, and with the clinical and physiologic parameters obtained during baseline assessment. The sensitivity of the SGRQ-HK to detect disease severity was determined using the 24-h sputum volume during baseline examination. The responsiveness of the SGRQ-HK was assessed comparing data at 6 months with those obtained at baseline.

RESULTS

Subject Demography and Clinical Characteristics

Altogether, 93 bronchiectasis patients (mean [[+ or -] SD] age, 59.0 [+ or -] 14.2 years; women, 61; current smokers, 2; ex-smokers, 17; and never-smokers, 74) were recruited prospectively between May 1999 and June 2000. The clinical characteristics of these patients are outlined in Table 1. Most of these patients had idiopathic bronchiectasis (75 patients), and the remaining patients had developed bronchiectasis due to pulmonary tuberculosis (11 patients), IgG deficiency (1 patient), diffuse panbronchiolitis (1 patient), Kartagener syndrome (2 patients), measles (1 patient), and pneumonia (2 patients). The 6-month study was attended by 72 patients as the remaining cases declined to be interviewed or defaulted repeatedly after the initial assessment.

Scale Construct Validity and Internal Consistency

The scale construct validity, internal consistency, Cronbach [alpha] coefficients, and the percentage of missing data for each of the SGRQ-HK components are shown in Table 2. The percentage of missing data for the SGRQ-HK symptom component score was 2.7% if question 6 in section 1 ("How long did the worst attack of chest trouble last?") was excluded, as this was an optional item. Moreover, the scaling success rate was relatively low for the symptom component. None of the patients achieved the worst possible score (ie, highest or ceiling score) in all three SGRQ-HK components, although 11.7% achieved the best possible score (ie, lowest or floor score) in the activity component. The internal consistency, as measured by the Cronbach [alpha] coefficient, was > 0.7 in all the components of the SGRQ-HK except for the symptom component ([alpha] = 0.59).

Test-Retest Reliability (Repeatability)

Table 3 shows the mean component scores and total scores of the SGRQ-HK obtained for 40 patients to whom the questionnaire was administered twice, during the baseline visit and at 2 weeks. The scores of all SGRQ-HK components were not significantly different between the two visits (p > 0.05). The ICCs were high for all components and ranged from 0.80 to 0.94.

Concurrent Validity

The SGRQ-HK component scores and total scores significantly correlated with the scores of SF-36-HK and HADS (Table 4). The correlation was highest between the activity score of the SGRQ-HK and the physical function score of the SF-36-HK (r = -0.78), and between the impact score of the SGRQ-HK and the general health score of the SF-36-HK (r = -0.63).

Table 5 shows the results of the correlation analysis between the SGRQ-HK component and total scores, and the clinical parameters. FE[V.sub.1], FVC, and Sa[O.sub.2] values correlated negatively with all SGRQ-HK component scores and total scores. The 6MWD correlated negatively with the activity scores and total scores, while the KPS correlated negatively with the activity, impact, and total scores of the SGRQ-HK. Borg scale scores, 24-h sputum volume measurements, and exacerbation frequency significantly correlated with all component and total scores of the SGRQ-HK (p < 0.005), while the number of bronchiectatic lung lobes had similar correlations, except with the activity score (p = 0.18).

Sensitivity

To test the sensitivity of the SGRQ-HK to detect disease activity or severity, patients were categorized according to their 24-h sputum volume as < 10 mL and [greater than or equal to] 10 mL (Table 6). The mean SGRQ-HK component scores and total scores were significantly higher among patients with 24-h sputum volumes [greater than or equal to] 10 mL than with their counterparts. Only two of eight SF-36-HK scores (ie, bodily pain and general health) were significantly different between the patients with 24-h sputum volumes [greater than or equal to] 10 mL and their counterparts. Similarly, none of the HADS scores were significantly different between these two subgroups of bronchiectasis patients.

Responsiveness

Table 7 compares the results of various parameters at baseline and at 6 months in 72 patients who attended the follow-up assessment. There were no significant changes in lung function measurements, Sa[O.sub.2] values, Borg scale scores, KPS scores, 24-h sputum volumes, or exacerbation frequencies (p > 0.05). However, SGRQ-HK symptom and total scores, but not activity or impact scores, showed significant reduction at 6 months compared with baseline (p < 0.05).

Table 8 shows the results of a comparison between the mean changes in the scores on the SGRQ-HK for patients who had reductions in sputum volume by > 25% (ie, improved volumes) at 6 months and their counterparts. The mean activity, impact, and total scores of the SGRQ-HK showed a significant difference between patients who scores improved and those whose scores did not.

DISCUSSION

The original SGRQ was developed in 1990 by Jones et al (7) to quantify the impact of disease on the health and well-being of patients with COPD. Since then, the SGRQ has been translated into many languages and has been validated for use in different ethnic groups. To date, several adaptation and validation studies have been published in non-English populations. (10,12-16,24) These studies were performed on Swedish, Spanish, Japanese, and American-English speaking populations, and have independently validated the reliability and sensitivity of the translated versions. (10,12-14) The original SGRQ also has been validated for use in other airway diseases such as asthma, (25) COPD, (26) and bronchiectasis. (6) While other quality-of-life instruments, such as the chronic respiratory disease questionnaire and airway questionnaire 20/30, are also available for the assessment of quality of life in patients with COPD and asthma, (27,28) the SGRQ is the only validated instrument in the assessment of patients with bronchiectasis. (6) Some studies have shown that patients with bronchiectasis have worse quality of life, as assessed by SGRQ, if they have more severe airway inflammation or sputum colonization by Pseudomonas aeruginosa. (6,29,30) While there is an increasing availability of quality-of-life instruments for the assessment of patients with chronic diseases, only a few quality-of-life measures have been translated and validated for use with Chinese patients (eg, the SF-36-HK, (18) the McGill quality of life questionnaire, (31) and the functional assessment of cancer therapy-general scale (20)). Despite the prevalence of chronic respiratory diseases among Chinese people, no respiratory disease-specific, quality-of-life instrument has been properly translated and validated. The SGRQ-HK that was evaluated in our study is, therefore, the first validated respiratory disease-specific, quality-of-life questionnaire in Chinese.

Similar to the results of a previous study (6) on the validation of the SGRQ in British-English-speaking patients with bronehiectasis, our results also demonstrated highly acceptable reliability, sensitivity, and responsiveness in Chinese patients with stable bronehiectasis. The English study (6) reported that patients with wheezing and exacerbation frequencies of more than six episodes per year had significantly worse SGRQ scores than their counterparts who did not wheeze and had fewer than three exacerbations per year, respectively. However, our results did not show such a pattern. Instead, our data showed that all SGRQ-HK component and total scores significantly correlated with 24 h sputum volume and exacerbation frequency. This is indicative of the importance of these disease activity markers in affecting the quality of life of patients with bronchiectasis. In addition, bronchiectasis patients do not predominantly complain of wheezing but, rather, suffer from sputum production, dyspnea, and chest pain. Our results showed that the presence of the latter two symptoms was independently associated with worse quality of life (ie, high SGRQ-HK symptom scores). (6) Although there were no significant differences in lung function, Sa[O.sub.2] values, Borg scale scores, KPS scores, 24-h sputum volumes, and exacerbation frequencies at baseline and 6 months, the SGRQ-HK symptom scores and total scores were significantly lower at 6 months than at baseline. This suggests that the SGRQ-HK was responsive in detecting a change in the health status in a superior manner to more conventional clinical and physiologic surrogate end points among Chinese patients with bronchiectasis.

We are unclear about the reasons for the relatively low scaling success rate (75%) and Cronbach [alpha] coefficient (0.59) for the symptom component of the SGRQ-HK. However, this low value also has been reported by a similar validation study (15) of an American-English version of the SGRQ among patients with COPD. These low values could have arisen from an inherent inappropriateness of using the SGRQ in assessing patients with bronchiectasis, as the SGRQ originally was designed specifically for COPD patients. However, this is unlikely to be the sole explanation as a validation study of the SGRQ among English patients with bronchiectasis did not report such findings. (6) Not only were our patients older, they also appeared to be less severely affected than were their English counterparts in terms of FE[V.sub.1], FVC, and exacerbation frequency. Although these differences in disease characteristics could have contributed to the discrepancy in our findings from those of the English study, it is also highly possible that there is a strong cultural influence on the impact of bronchiectasis. Our very structured and consistent use of the same researchers to interview the same patients under identical conditions could have been contributory to the high repeatability of the SGRQ-HK, although it is not possible to quantify this contribution.

As reported previously for COPD patients, we found significant correlations between the SGRQ-HK component scores and those of the SF-36-HK in our patients with stable bronchiectasis. (7,9) The physical functioning component of the SF-36-HK strongly correlated with the SGRQ-HK activity score. Apart from bodily pain and general health scores, the SGRQ-HK symptom score had lower correlation coefficients with all the other SF-36-HK scores. This was expected because the SF-36 is a measure of subjective well-being and daily functioning, rather than an indicator of the severity of symptoms. (7,12) The correlation between SF-36-HK and SGRQ-HK scores is also consistent with those reported in previous studies (6,7,9) and shows that these instruments are complementary to each other in the assessment of patients with airway diseases. The use of a generic rather than a disease-specific quality-of-life instrument such as the SF-36 in patients with bronchiectasis might have limited responsiveness, (32) as demonstrated by our results.

A quarter of the world's population is Chinese. Bronchiectasis is a very common respiratory disorder among the Chinese, and the quality of life of affected patients could be severely impaired by disabling symptoms such as chronic sputum production, cough, dyspnea, and recurrent exacerbations. Our validated SGRQ-HK, with its established psychometric properties, should, therefore, be incorporated into future research on this vast patient population.

ACKNOWLEDGMENTS: The authors thank the patients who participated in the study, Christina Yan for patient data extraction, K.M. Lo for technical support, Daniel Fong for expert statistical advice, S.M. Ho for expert translation, and C. Lai of the Chinese University of Hong Kong for expert advice.

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* From the Departments of Medicine (Ms. Chan and Drs. Chan-Yeung, C.L. Lam, W.K. Lam, and Tsang), Diagnostic Radiology (Dr. Ooi), and School of Professional and Continued Education (Dr. Cheung), The University of Hong Kong, Hong Kong, Special Administrative Region.

Manuscript received September 4, 2001; revision accepted June 11, 2002.

Correspondence to: Kenneth W. Tsang, MD, FCCP, Associate Professor and Honorary Consultant Physician, University Department of Medicine, Queen Mary Hospital, The University of Hong Kong, Pokfulam, Hong Kong, Special Administrative Region; e-mail: kwttsang@hku.hk

COPYRIGHT 2002 American College of Chest Physicians
COPYRIGHT 2003 Gale Group