Design and analytic considerations in determining the cost-effectiveness of early intervention in asthma from a multinational clinical trial

Demand for economic and outcomes data in support of drug formulary listing in private and government-sponsored health programs has led to fundamental changes in drug development. In part as a response to these pressures, the pharmaceutical industry has begun to include economic and quality-of-life endpoints in clinical trials with the hope of providing information to answer health policy questions on the economic value of its products. Here, the design and health economic techniques that will be used to analyze the START (inhaled Steroid Treatment As Regular Therapy in early asthma) study-a multinational (31 countries), randomized, placebo-controlled trial of 7240 patients with mild asthma over 3 years-will be presented. START compares the effect of once-daily administration of an inhaled glucocorticosteroid (Pulmicort Turbuhaler to conventional therapy in the management of newly diagnosed asthma, for which the use of this therapy is currently not the standard. The START study will examine both clinical effectiveness (measured as symptom-free days) and asthma-related costs for both treatment arms, aggregated for all patients across all countries. We believe that presenting the analytical plan prior to disseminating the results is an important way of increasing the credibility of economic evaluations. However, using clinical trials for collecting economic data poses several challenges, and the methods for conducting such evaluations are being developed. This paper will present and discuss several methodological options and the current state of the art for conducting economic evaluations alongside multinational clinical trials.

Nitrogen dioxide exposure from domestic gas cooking and airway response in asthmatic women

BACKGROUND

Previous studies have not found a consistent association between exposure to domestic cooking using gas appliances and exacerbation of asthma. We investigated the immediate airflow response to acute exposure from single episodes of gas cooking, and peak airflow variability from continued exposure to repeated episodes of gas cooking in a group of non-smoking asthmatic women.

METHODS

Sixteen adult non-smoking women with mild to severe persistent asthma were studied. The acute short term level of nitrogen dioxide (NO2) during gas cooking episodes and the mean exposure to NO2 from repeated gas cooking episodes were measured over a 2 week period, as well as proxy measures of frequency of cooking on each day and the length of time spent cooking each day. Their asthma status was monitored using peak expiratory flow rates (PEFR) before and after cooking, 2 week self-recorded serial readings of PEFR, respiratory symptom severity score, and use of rescue bronchodilators for acute asthma attacks.

RESULTS

Cooking was significantly associated with an immediate mean fall in PEFR of 3.4% (p=0.015, paired t test). The acute short term NO2 level during cooking was significantly correlated with the fall in PEFR (r=–0.579; p=0.019). The frequency of cooking over a 2 week period was positively correlated with the mean exposure to NO2(r=0.529; p=0.042). Continued exposure to NO2 over a 2 week period was associated significantly with increased frequency of rescue bronchodilator usage for asthma attacks (r=0.597; p=0.031). However, it was negatively associated with PEFR variability (r=–0.512; p=0.051) and respiratory symptom severity score (r= –0.567; p=0.043), probably due to the masking effects of bronchodilator treatment.

CONCLUSIONS

Acute short term exposure to NO2 from single episodes of gas cooking is associated with immediate airflow limitation. Continued exposure from repeated episodes of gas cooking in asthmatic women is associated with greater use of rescue bronchodilators.

Nitrogen dioxide exposure from domestic gas cooking and airway response in asthmatic women

BACKGROUND

Previous studies have not found a consistent association between exposure to domestic cooking using gas appliances and exacerbation of asthma. We investigated the immediate airflow response to acute exposure from single episodes of gas cooking, and peak airflow variability from continued exposure to repeated episodes of gas cooking in a group of non-smoking asthmatic women.

METHODS

Sixteen adult non-smoking women with mild to severe persistent asthma were studied. The acute short term level of nitrogen dioxide (NO2) during gas cooking episodes and the mean exposure to NO2 from repeated gas cooking episodes were measured over a 2 week period, as well as proxy measures of frequency of cooking on each day and the length of time spent cooking each day. Their asthma status was monitored using peak expiratory flow rates (PEFR) before and after cooking, 2 week self-recorded serial readings of PEFR, respiratory symptom severity score, and use of rescue bronchodilators for acute asthma attacks.

RESULTS

Cooking was significantly associated with an immediate mean fall in PEFR of 3.4% (p=0.015, paired t test). The acute short term NO2 level during cooking was significantly correlated with the fall in PEFR (r=-0.579; p=0.019). The frequency of cooking over a 2 week period was positively correlated with the mean exposure to NO2 (r=0.529; p=0.042). Continued exposure to NO2 over a 2 week period was associated significantly with increased frequency of rescue bronchodilator usage for asthma attacks (r=0.597; p=0.031). However, it was negatively associated with PEFR variability (r=-0.512; p=0.051) and respiratory symptom severity score (r= -0.567; p=0.043), probably due to the masking effects of bronchodilator treatment.

CONCLUSIONS

Acute short term exposure to NO2 from single episodes of gas cooking is associated with immediate airflow limitation. Continued exposure from repeated episodes of gas cooking in asthmatic women is associated with greater use of rescue bronchodilators.

The inhaled Steroid Treatment as Regular Therapy in early asthma (START) study: rationale and design

Although the beneficial effects of treatment with inhaled steroids in asthma are widely accepted, the role of early intervention in patients with mild asthma remains unsettled. Conventional efficacy trials are often of short duration and involve highly selected patient populations that exclude many patients typical of those encountered in routine clinical practice. Hence, a large "real-world" effectiveness study is needed to evaluate the benefits of early intervention with inhaled steroids in patients with mild, persistent asthma. In the START (inhaled Steroid Treatment As Regular Therapy in early asthma) study, patients ages 6-60 years, from 31 countries and districts worldwide with mild persistent asthma, have been randomized to once-daily treatment with budesonide, 200 microg (for patients < 11 years) or 400 microg (for patients > or = 11 years), or placebo via Turbuhaler for 3 years. The double-blind treatment period will be followed by a 2-year period of open budesonide treatment. Throughout the study, other asthma medication including glucocorticosteroids can be given as judged appropriate by the investigator. Lung function will be measured by spirometry using standardized techniques at 3-month intervals throughout the study, and bronchodilator reversibility will be measured annually. The primary outcome measures are the time to the first severe asthma-related event during the first 3 years of the study and the change in postbronchodilator forced expiratory volume in 1 second (FEV(1)) from baseline during the entire 5-year study period. These measures have been chosen to reflect the progression of mild asthma toward more severe asthma and the extent of irreversible airflow limitation, which should reflect the degree of airway remodeling.

Clinical management of PCOS

The polycystic ovary syndrome (PCOS) is a heterogeneous condition with genetic predisposition. It is characterized by a myriad of symptoms including oligomenorrhea or amenorrhea, anovulation or infertility, hirsutism or acne. Insulin resistance appears to be an important factor in PCOS though the lack of an etiology has led to symptom oriented therapy which includes lifestyle modification, the use of cyclical progestagens and antiandrogens. Ovulation induction by drug therapy and ovarian drilling aims to treat subfertility in women with PCOS. Therapeutic approaches to PCOS remain an ongoing source of debate. Insulin sensitizing agents may bring new hope in therapy. Future research is aimed at shedding light on the pathophysiology so as to optimize treatment of women with PCOS.

Comparison of different methods of total RNA extraction for viral detection in sputum

Examination of sputum specimens can be used for monitoring airway inflammation by means of immunological and molecular techniques. RNA extraction is essential for measurement of cytokine gene expression and for detection of many viral pathogens in sputum. In this study, three RNA extraction methods used commonly (acid guanidinium thiocyanate-phenol-chloroform extraction, Trizol and RNeasy Mini kit) were compared on the sputum of 14 patients who had chronic obstructive pulmonary disease. The effect of dithiothreitol pre-treatment on sputum RNA extraction was also investigated. The yield and purity of total RNA were determined by spectrophotometry. Reverse transcription-polymerase chain reaction (RT-PCR) results of the house keeping gene (glyceraldehyde-3-phosphate dehydrogenase) and RNA sequences specific to common respiratory viruses were compared. The results showed that (1) total RNA extracted with Trizol had highest yield and purity among the three RNA extraction methods; (2) there was no significant difference among the three RNA extraction methods on the house keeping gene and viral detection by RT-PCR; (3) dithiothreitol pre-treatment did not improve either the purity of total RNA, or RT-PCR signal. Moreover, dithiothreitol treatment reduced significantly the yield of total RNA. The results of the study indicate that the Trizol method appears to be superior for total RNA extraction from sputum, and dithiothreitol pre-treatment does not increase the efficiency of RNA extraction and RNA detection in sputum specimens.

Cytochrome P4501A2 (CYP1A2) activity and lung cancer risk: a preliminary study among Chinese women in Singapore

There is increasing evidence for the role of heterocyclic and other arylamines in carcinogenesis, including lung carcinogenesis. Chinese women have a high rate of lung cancer despite a low smoking prevalence, and studies in this population may provide useful information on risk factors other than smoking. Hepatic CYP1A2 and NAT2 are involved in the metabolism of carcinogenic arylamines, and NAT2 also catalyzes the detoxification pathway for these compounds. In this study, we examined the effect of CYP1A2 activity using a urinary caffeine metabolic ratio assay for 54 Chinese women with newly diagnosed lung cancer (including 28 adenocarcinomas) and 174 hospital controls. Among them, NAT2 genotype was available for 47 cases and 98 controls. There was no effect of CYP1A2 activity on overall risk of lung cancer in the study population [odds ratio (OR) 0.8, 95% confidence interval (CI) 0.4-1.6, adjusted for age at diagnosis, smoking and cruciferous vegetable intake]. For adenocarcinomas, the OR was 1.5, 95% CI 0.6-3.4. After further adjustment for NAT2 acetylator genotype, the OR for adenocarcinoma was 1.8 (95% CI 0.7-4.8). When the combined NAT2/CYP1A2 status was examined, women with slow NAT2 and rapid CYP1A2 activity were at highest risk (adjusted OR 6.9, 95% CI 1.3-37.6) relative to women with rapid NAT2 and slow CYP1A2 activity, for lung adenocarcinoma. While larger studies are needed to confirm or refute these results, they are consistent with a role for heterocyclic arylamines in lung carcinogenesis in this primarily non-smoking population.

Fumes from meat cooking and lung cancer risk in Chinese women

Chinese women are recognized to have a high incidence of lung cancer despite a low smoking prevalence. Several studies have implicated domestic exposure to cooking fumes as a possible risk factor, although the exact carcinogens have yet to be identified. Heterocyclic amines are known carcinogens, which have been identified in cooked meat, and also in fumes generated during frying or grilling of meats. We conducted a case-control study of 303 Chinese women with pathologically confirmed, primary carcinomas of the lung and 765 controls to examine the association between exposure to meat cooking and lung cancer risk. Data on demographic background, smoking status, and domestic cooking exposure, including stir-frying of meat, were obtained by in-person interview while in hospital. The response rates among eligible cases and controls were 95.0 and 96.9%, respectively. The proportion of smokers (current or ex-smokers) among cases and controls was 41.7 and 13.1%, respectively. Adenocarcinomas comprised 31.5% of cancers among smokers and 71.6% among nonsmokers. When cases were compared with controls, the odds ratio (OR) for lung cancer (all subtypes) among ex-smokers was 4.3 [95% confidence interval (CI) 2.7-6.8] and that among current smokers was 5.0 (95% CI, 3.4-7.3). Among smokers, women who reported that they stir-fried daily in the past had a significantly increased risk of lung cancer (adjusted OR, 2.0; 95% CI, 1.0-3.8) and among these women, risk was enhanced for those who stir-fried meat daily (OR, 2.7; 95% CI, 1.3-5.5). Women who stir-fried daily but cooked meat less often than daily did not show an elevated risk (OR, 1.0. 95% CI, 0.5-2.4). Risk was further increased among women stir-frying meat daily who reported that their kitchen was filled with oily fumes during cooking (OR, 3.7; 95% CI, 1.8-7.5). These cooking practices on their own did not increase risk among nonsmokers in our study population. Our results suggest that inhalation of carcinogens, such as heterocyclic amines generated during frying of meat, may increase the risk of lung cancer among smokers. Further studies in different settings are warranted to examine this possibility, which may also help to explain the higher risk observed among women smokers compared with men.

Polymorphisms in the IL4, IL4RA, and FCERIB genes and asthma severity

BACKGROUND

Genetic polymorphisms have been associated with asthma and asthma severity.

OBJECTIVE

We sought to determine whether 3 polymorphisms were associated with severe asthma indicated either by the occurrence of a fatal (or near-fatal) asthma attack or by severe airflow obstruction.

METHODS

We obtained DNA and clinical data from asthmatic subjects who either died or nearly died during an asthma attack and from a group of subjects with mild-to-moderate asthma who had never experienced a fatal or near-fatal asthma episode. These groups were compared with a group of nonatopic nonasthmatic control subjects. The level of airflow obstruction (FEV(1) percent predicted) in the subjects with mild-to-moderate asthma was used as an additional measure of disease severity. The subjects were genotyped for the IL4*C-589T promoter polymorphism and the IL4RA*Q576R and the FCERIB*E237G amino acid substitutions.

RESULTS

The results showed that the FCERIB*E237G and IL4RA*Q576R polymorphisms were not associated with fatal or near-fatal asthma. However, the IL4*-589T allele was significantly increased in the subjects with fatal or near-fatal asthma compared with nonasthmatic subjects (odds ratio [OR], 1.8; P =.02) and subjects with mild-to-moderate asthma (OR, 1.9; P =.02). There was no interaction between the IL4*-589T and IL4RA*576R alleles. Of the 3 polymorphisms, only the IL4RA*576R allele was associated with severe airflow obstruction (OR, 8.2; P =.01).

CONCLUSION

These data suggest that the IL4*-589T allele is a risk factor for life-threatening asthma and that the IL4RA*576R allele is a risk factor for a low level of lung function in asthmatic subjects.

The human bone marrow response to acute air pollution caused by forest fires

Atmospheric pollution increases cardiopulmonary morbidity and mortality by unexplained mechanisms. Phagocytosis of fine particles (PM(10)) by rabbit alveolar macrophages elevates white blood cells (WBC) by releasing precursors from the bone marrow and this could contribute to the pathogenesis of cardiopulmonary disease. The present study examined the association between acute air pollution caused by biomass burning and peripheral WBC counts in humans. Serial measurements of the WBC count made during the 1997 Southeast Asian Smoke-haze (Sep 29, Oct 27) were compared with a period after the haze cleared (Nov 21, Dec 5) using peripheral blood PMN band cells to monitor marrow release. The results showed that indices of atmospheric pollution were significantly associated with elevated band neutrophil counts expressed as a percentage of total polymorphonuclear leukocytes (PMN), with maximal association on zero and 1 lag day for PM(10) and 3, and 4 lag days for SO(2) (p value < 0.000). We conclude that atmospheric pollution caused by biomass burning is associated with elevated circulating band cell counts in humans because of the increased release of PMN precursors from the marrow. We speculate that this response contributes to the pathogenesis of the cardiorespiratory morbidity associated with acute air pollution.

Photodynamic therapy using 5-aminolaevulinic acid for oesophageal adenocarcinoma associated with Barrett's metaplasia

Photodynamic therapy (PDT) is a novel technique for local endoscopic treatment of gastrointestinal neoplasia. Current photosensitisers for PDT may cause prolonged skin phototoxicity. 5-Aminolaevulinic acid (ALA), a precursor of the photosensitiser protoporphyrin IX (PpIX), is more acceptable because of its short half-life and preferential accumulation in mucosa and mucosal tumour. We have treated 12 patients, median age 73 years (range 55-88) with oesophageal adenocarcinoma arising from Barrett's metaplasia (two carcinomas-in-situ, grade 0; 10 carcinomas, grade 1-11A based on endoluminal ultrasound in two and CT scanning in 10 patients). ALA (60 and 75 mg/kg body weight) was given orally in two or five equally divided doses. The PpIX distribution in stomach, normal oesophagus, Barrett's mucosa and carcinoma was measured by quantitative fluorescence photometry. PDT was performed using laser light (630 nm) delivered via a cylindrical diffuser 4-6 h after the first dose of ALA. The patients received one to four sessions of PDT. PpIX accumulation in the mucosa was two to three times that in the lamina propria. The differential distribution between carcinomatous and normal oesophageal mucosa was less marked (carcinoma:normal mucosa ratio = 1.4). Higher doses of ALA increased PpIX accumulation in all tissues but did not increase the differential PpIX distribution between tumour and normal oesophageal mucosa. After PDT using ALA (ALA/PDT), all mucosa showed superficial white necrotic changes and the histology confirmed fibrinoid necrosis. One patient with carcinoma-in-situ had the tumour eradicated after one treatment with no recurrence at 28 months. Another patient with a small T1 tumour required four ALA/PDT treatments, and died of other disease after 36 months. There was no evidence of recurrence. The tumour bulk in the other carcinomas was not significantly reduced. ALA/PDT has a potential for the eradication of small tumours but careful patient selection with endoluminal ultrasound is needed when using ALA/PDT to treat oesophageal cancer.

Temporal trends and ethnic variations in asthma mortality in Singapore, 1976-1995

BACKGROUND

A study was undertaken to examine temporal trends and ethnic differences in the asthma mortality rate in Singapore.

METHODS

Asthma mortality rates in Singapore were estimated from vital data for the years from 1976 to 1995. Trends in sex and age specific (5-14, 15-34, 35-59, 60+ years) rates were obtained for four periods (1976-80, 1981-85, 1986-90, 1991-95) and for Chinese, Malay, and Indian subjects for the years when these data were available (1989-95).

RESULTS

An increase in asthma mortality was observed in children aged 5-14 years from 0.21 per 100,000 person years in 1976-80 to 0.72 per 100,000 person years in 1991-95. No increases were noted in the other age groups but a small decrease was observed in the 1991-95 period for the 35-59 year age group. Marked ethnic differences in mortality rates were observed. In the group aged 5-34 years the asthma mortality rates were 0.5 per 100,000 in Chinese subjects, 1.3 per 100,000 in Indians, and 2.5 per 100,000 in Malay subjects. Similar 2-4 fold differences were observed in all other age groups.

CONCLUSIONS

Apart from genetic factors, environmental exposures and medical care factors which influence asthma prevalence and severity are most likely to be the causes of the observed temporal trends and ethnic differences in the asthma mortality rate in Singapore, but further studies are needed to elucidate these more fully.

NAT2 slow acetylator genotype is associated with increased risk of lung cancer among non-smoking Chinese women in Singapore

Among non-smokers, the factors resulting in lung carcinogenesis are poorly understood. We conducted a hospital-based case-control analysis of 294 Chinese women, of whom 217 were non-smokers, to evaluate the role of polymorphic N-acetyltransferase (NAT2) as a susceptibility factor for the disease. The proportion of slow acetylator genotypes among non-smoking cases (n = 92) and controls (n = 125) was 38.0 and 24.0%, respectively [odds ratio (OR) 2.0, 95% confidence interval (CI) 1.1-3.7]. No effect of NAT2 genotype was seen among smokers. Among non-smokers, the effect was marked for adenocarcinomas (OR 2.1, 95% CI 1.1-4.0). As NAT2 activity is known to modify risk of arylamine-induced carcinogenesis, our results suggest that exposure to arylamines in the environment may play a role in risk of lung cancer among non-smokers.

Hospital acquired pneumonia in the medical intensive care unit--a prospective study

AIM OF STUDY

The aim of the study was to define the prevalence, risk factors, spectrum of organisms and sensitivity patterns, and the outcome in patients with severe hospital acquired pneumonia (HAP) in the Medical Intensive Care Unit (SCU) in a hospital in Singapore.

METHOD

Consecutive patients admitted to the MICU over a 6-month period were studied and assessed daily to determine whether patients had developed HAP based on defined clinical criteria. Sputum or endotracheal aspirate was obtained and results recorded from each patient on admission and every subsequent three days throughout the stay in the MICU. Mortality during hospital stay was the main outcome measure recorded.

RESULTS

A total of 136 patients (150 admissions) were studied; 24 patients were identified as having HAP. The prevalence of HAP was 17% [both ventilator-associated pneumonia (VAP) and pneumonia acquired from the ward (WAP)]. Cerebral disease was the main risk factor for VAP (OR 4.94, 95% CI 1.33-18.4). The spectrum of organisms which caused HAP were polymicrobial, Klebsiella pneumoniae, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus and coagulase negative Staphylococcus. The mortality of patients with VAP and WAP were 72.7% and 76.9% respectively.

CONCLUSION

This study concludes that HAP in the MICU is common with a high mortality. The spectrum of organisms was comparable to previous studies.

Hospitalised low-risk community-acquired pneumonia: outcome and potential for cost-savings

Fine et al. from USA have identified a sub-group of patients with community-acquired pneumonia (CAP) with a low risk of mortality and suggested that it may be cost-effective to manage them as outpatients. The aims of this study were: to evaluate the outcome of low risk CAP patients that were hospitalised in our local setting, and to gauge the number of such patients in order to estimate the potential cost-savings by treating them as outpatients, as well as the safety of such an approach. All patients with CAP admitted to our hospital from 1 April 1997 to 1 March 1998 were enrolled into this prospective cohort study. Low-risk patients were identified, and their hospital outcome compared with other patients. Hospitalisation charges were obtained from the Finance Department. There were 226 patients with CAP. The average age was 64 years with a range of 12 to 96 years. The median hospital stay was 6 days. Mortality was 13.7%. 16.8% required admission to the ICU; none of these were low-risk patients. There were 47 (21%) low-risk patients, and there was no mortality in this group. They had significantly shorter hospital stay (6.4 days versus 10 days) and lower hospitalisation charges ($2,160 versus $5,770) compared to other CAP patients. Only one low-risk patient had a positive blood culture. In conclusion, nearly one-fifth of our CAP admissions consisted of low-risk patients that experienced no mortality, and required a significantly shorter hospitalisation. The management of such patients who are young (< or = 50 years), with no serious co-morbidities in an outpatient setting may be a cost-effective strategy, and this group of patients consumed 9% of the total hospitalisation charges for CAP.

Long-term outcome and disease control in near-fatal asthma

Patients who have survived an episode of intubation and mechanical ventilation for acute respiratory failure due to a severe and unresponsive asthmatic attack are considered to have experienced a near-fatal asthma (NFA) attack. Such patients are at a higher risk of similar severe attacks and hence of death in the future. The aims of the study were to: (i) evaluate the outcome; (ii) identify any persistent deficiencies in asthma management, and (iii) assess self-management knowledge in survivors of NFA. Ninety-three consecutive patients who had been treated for NFA in the Intensive Care Unit of an urban teaching hospital in Singapore from 1992 to 1997 were studied. All hospital records were reviewed retrospectively. Survivors were then invited to attend a questionnaire interview and to have lung function tests performed. Of the original cohort (OC) of 93 patients with NFA (mean age 55.2 years), 18 (19% OC) patients (mean age 64 years) had died while in hospital and 75 (81% OC) patients survived the initial episode of NFA and were discharged home (DH). The long-term outcome of this DH group was: 13 patients had died (17% DH) and 62 (83% DH) survived. Of these survivors, 35 were interviewed while 27 declined or were not contactable. This interview yielded the following information: (i) Hospitalisation in the past year: 66% had no hospital admission; of the 31.4% who had 2 or more admissions, most had a further NFA attack. (ii) Health care: The majority of patients (71.4%) were monitored by a single doctor. (iii) Patient knowledge of disease management was deemed good to fair for trigger avoidance (77%), for appropriate drug usage (97%). (iv) Satisfactory inhaler skill (80%). NFA is associated with a high intrahospital and long-term mortality. Although most survivors of NFA appeared to have satisfactory care and a fair understanding of medication usage, a significant minority continue to pose much morbidity and risk for death.

Dithiothreitol has a dose-response effect on cell surface antigen expression

BACKGROUND

The use of Dithiothreitol (DTT) to improve cell dispersion is an integral step in induced sputum examination, which has become an important noninvasive method of assessing airway inflammation. Several studies have shown that sputum treatment with DTT does not affect cell morphology, differential cell counts, and cytokine levels in the supernatant. However, the effect of DTT on cell surface marker expression has not been systematically studied.

OBJECTIVE

We have investigated the effect of different DTT concentrations on antigen expression on peripheral blood cells compared with antigen expression on PBS-treated cells.

METHODS

Peripheral blood from different healthy donors was incubated with either DTT or PBS, washed, and then incubated with different fluorescence-labeled antibodies. Analysis was performed after lysis of erythrocytes on a calibrated flow cytometer. Respective cell populations were identified, and the mean fluorescence intensity of surface-marker expression for each cell population was compared between DTT- and PBS-treated cells.

RESULTS

We found that DTT decreased the expression of CD11a and CD49d on lymphocytes and eosinophils. The expression of CD11a on neutrophils was also decreased after DTT treatment. DTT increased CD11b expression on lymphocytes, neutrophils, and eosinophils. DTT might also have a mild effect on cell activation. It decreased the expression of CD2 on lymphocytes and variably affected the expression of EG2 in eosinophils, although it had no significant effect on HLA-DR expression on lymphocytes.

CONCLUSION

Our findings show that DTT can affect antigen expression on lymphocytes, neutrophils, and eosinophils and suggest the need for further investigation of similar consequences on induced sputum analysis.

The ECG "lead I sign" in cardiac disease--an indicator of coexisting obstructive pulmonary disease

Two patients with co-existing cardiac disease and chronic obstructive pulmonary disease are described. The first patient had Wolff-Parkinson-White syndrome and the second patient had extensive anterior Q wave myocardial infarction. In addition to the distinctive ECG patterns of their cardiac abnormalities, both patients also showed the "lead I sign" which is a highly specific marker of chronic obstructive pulmonary disease. These two patients suggest that even in the presence of cardiac disease, the diagnosis of chronic obstructive pulmonary disease should be strongly suspected when the "lead I sign" is present.

Detection of Mycobacterium tuberculosis DNA using polymerase chain reaction in cutaneous tuberculosis and tuberculids

BACKGROUND

The objective of this study was to explore the role of the polymerase chain reaction (PCR) fo the detection of Mycobacterium tuberculosis DNA as a diagnostic aid in cutaneous tuberculosis using routinely processed skin biopsy specimens.

METHODS AND RESULTS

A wide range of clinical specimens representing different forms of cutaneous tuberculosis and so-called tuberculids were studied. A sensitive and specific PCR assay targeting the sequence IS6110 of Mycobacterium tuberculosis complex was used. The specimens were categorized as follows. 1 Acid-fast bacilli (AFB) positive on biopsy (nine specimens from seven patients who were immunocompromised). PCR was positive in five specimens. Of these, one specimen was culture positive and three specimens were culture negative. 2 AFB negative on biopsy: (a) tuberculosis verrucosa cutis (23 specimens); (b) lupus vulgaris (three specimens); (c) cutaneous tuberculosis clinically suspected (six specimens). PCR was negative in all specimens. 3 Tuberculids.' (a) erythema induratum/nodular vasculitis (20 specimens); (b) papulonecrotic tuberculid (two specimens); (c) erythema nodosum (20 specimens). PCR was negative in all specimens.

CONCLUSIONS

The role of PCR in clinical dermatologic practice, at this stage, may be in differentiating between cutaneous tuberculosis and atypical mycobacterial infections in the context of an immunocompromised patient where AFB can be demonstrated on biopsy and cultures may be negative. In this clinical situation, PCR allows the prompt diagnosis and early institution of appropriate therapy. We have not found PCR to be a useful complement to the clinical and histologic diagnosis of "paucibacillary" forms of cutaneous tuberculosis.

Prevalence of snoring and sleep breathing-related disorders in Chinese, Malay and Indian adults in Singapore

This study investigated the prevalence of snoring and symptoms of sleep breathing-related disorders in the multi-ethnic population of Singapore (3 million people, comprising 75% Chinese, 15% Malay and 7% Indian). A multistaged, area cluster, disproportionate stratified, random sampling of adults aged 20-74 yrs was used to obtain a sample of 2,298 subjects (65% response), with approximately equal numbers of Chinese, Malay and Indian and in each 10 yr age group. An interviewer-administered field questionnaire was used to record symptoms of snoring and breathing disturbances during sleep witnessed by a room-mate and other personal and health-related data. The weighted point estimate (and 95% confidence interval) of the whole population prevalence of snoring was 6.8% (53-83). There were pronounced ethnic differences among Chinese, 6.2% (4.4-8.1); Malay, 8.1% (6.1-10.2) and Indian, 10.9% (85-13.4). The minimum whole population prevalence by the most restricted symptom criteria for defining sleep breathing-related disorder was 0.43% (0.05-0.8%). Similar marked ethnic differences in rates were observed using various symptom criteria. The ethnic differences in sleep breathing symptoms paralleled the differences in body mass index, neck circumference and hypertension, but statistically significant differences remained after adjustment for sex, age and these known associated factors. Marked ethnic differences in snoring and sleep breathing-related disorders were observed in Chinese, Malays and Indians in Singapore, which were only partly explained by known factors of sex, age and body habitus.

The effect of inhaled budesonide on the diurnal variation in airway mechanics, airway responsiveness and serum neutrophil chemotactic activity in Asian patients with predominant nocturnal asthma

The effectiveness of inhaled corticosteroids in the control of daytime symptoms in asthma is well established, but the specific use against nocturnal asthma has not been systematically studied in Asian patients. This study examined the effect of treatment with inhaled budesonide on the nocturnal variation in measurements of airway calibre, bronchial hyperresponsiveness to inhaled histamine and circulating neutrophil chemotactic activity in Asian patients with nocturnal asthma. Thirty patients, with nocturnal asthma, were randomized into a 2-month, double-blind, parallel group study. Twice as many subjects were allocated to the group who received two consecutive months of inhaled budesonide 1600 microg daily as to the group who received placebo followed by budesonide. Spirometry, lung mechanics, bronchial hyperresponsiveness and serum neutrophil chemotactic factor (NCA) were measured at 16.00 h, 22.00 h and at 04.00 h on 3 days and nights, 4 weeks apart before and after either placebo or budesonide. The combined measurements for the two groups at 04.00 h before and after treatment with budesonide were: forced expiratory volume in 1 s (FEV1) mean (SEM) litres 1.34 (0.17) before, 2.00 (0.19) after; thoracic gas volume (TGV) litres 3.05 (0.32) before, 2.25 (0.14) after; specific airway conductance (sGaw) (cmH20.0 sec)(-1) 0.39 (0.07) before, 1.16 (0.17) after; PD20 microg geometric mean 1.16 before, 44.74 after; neutrophil chemotactic activity (NCA) in units of graduations of migration 98.8 (4.2) before, 101 (14.2) after. The data showed that short and intermediate term high dose inhaled budesonide is an effective specific treatment for nocturnal asthma in Asian patients, resulting in marked improvements in symptoms and in lung mechanics, and reductions in the diurnal variations in bronchial hyperresponsiveness, before any change could be demonstrated in a circulating marker of airway inflammation.

Necrotizing fasciitis--an unusual presentation of miliary mycobacterium tuberculosis

We report an immunocompromised patient who presented with necrotizing fasciitis as the initial presentation of miliary tuberculosis. The diagnosis of miliary tuberculosis was delayed resulting in prolonged morbidity and hospital stay. The lesson from this report is that tuberculosis should be recognised as an uncommon cause of necrotizing fasciitis in an immunocompromised patient, especially if the response to prompt and standard initial treatment is unsatisfactory.