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A S Buist

Publications and source records attributed to A S Buist.

At least 19 recordsLinked to original sources
PubMed2006

Global burden of COPD: systematic review and meta-analysis.

The aim of this study was to quantify the global prevalence of chronic obstructive pulmonary disease (COPD) by means of a systematic review and random effects meta-analysis. PubMed was searched for population-based prevalence estimates published during the period 1990-2004. Articles were included if they: 1) provided total population or sex-specific estimates for COPD, chronic bronchitis and/or emphysema; and 2) gave method details sufficiently clearly to establish the sampling strategy, approach to diagnosis and diagnostic criteria. Of 67 accepted articles, 62 unique entries yielded 101 overall prevalence estimates from 28 different counties. The pooled prevalence of COPD was 7.6% from 37 studies, of chronic bronchitis alone (38 studies) was 6.4% and of emphysema alone (eight studies) was 1.8%. The pooled prevalence from 26 spirometric estimates was 8.9%. The most common spirometric definitions used were those of the Global Initiative for Chronic Obstructive Lung Disease (13 estimates). There was significant heterogeneity, which was incompletely explained by subgroup analysis (e.g. age and smoking status). The prevalence of physiologically defined chronic obstructive pulmonary disease in adults aged > or =40 yrs is approximately 9-10%. There are important regional gaps, and methodological differences hinder interpretation of the available data. The efforts of the Global Initiative for Chronic Obstructive Lung Disease and similar groups should help to standardise chronic obstructive pulmonary disease prevalence measurement.

Adult↗
PubMed2005

Inhaled corticosteroids and mortality in chronic obstructive pulmonary disease.

BACKGROUND: Clinical studies suggest that inhaled corticosteroids reduce exacerbations and improve health status in chronic obstructive pulmonary disease (COPD). However, their effect on mortality is unknown. METHODS: A pooled analysis, based on intention to treat, of individual patient data from seven randomised trials (involving 5085 patients) was performed in which the effects of inhaled corticosteroids and placebo were compared over at least 12 months in patients with stable COPD. The end point was all-cause mortality. RESULTS: Overall, 4% of the participants died during a mean follow up period of 26 months. Inhaled corticosteroids reduced all-cause mortality by about 25% relative to placebo. Stratification by individual trials and adjustments for age, sex, baseline post-bronchodilator percentage predicted forced expiratory volume in 1 second, smoking status, and body mass index did not materially change the results (adjusted hazard ratio (HR) 0.73; 95% confidence interval (CI) 0.55 to 0.96). Although there was considerable overlap between subgroups in terms of effect sizes, the beneficial effect was especially noticeable in women (adjusted HR 0.46; 95% CI 0.24 to 0.91) and former smokers (adjusted HR 0.60; 95% CI 0.39 to 0.93). CONCLUSIONS: Inhaled corticosteroids reduce all-cause mortality in COPD. Further studies are required to determine whether the survival benefits persist beyond 2-3 years.

Administration, Inhalation↗
PubMed2005

Caesarean section delivery and the risk of allergic disorders in childhood.

BACKGROUND: The composition of the intestinal flora in young children, if unfavourable, may increase the susceptibility to allergic disorders. Beneficial intestinal microbes originate from the maternal vaginal tract and thus are more likely to be transferred during vaginal births than during Caesarean sections (C-sections). OBJECTIVE: To determine whether children born by C-section have a different risk of allergic disorders compared with those delivered vaginally. We also tested the hypothesis that the risk of allergic disorders is highest for children born after 'repeat C-sections'. METHODS: A retrospective cohort study of 8,953 children aged 3-10 years. Children diagnosed with allergic rhinoconjunctivitis (AR), asthma, atopic dermatitis (AD), or food allergies were identified from the Kaiser Permanente Northwest Region electronic records. The children's sex, birth weight, birth order, postnatal exposure to antibiotics as well as the mothers' age, ethnicity, education, marital status, smoking status during pregnancy, and use of asthma or hayfever medications were identified through the mothers' medical records or through the Oregon Birth Registry. RESULTS: The risk of being diagnosed with AR was significantly higher in the children born by C-section than in those delivered vaginally: adjusted odds ratio (OR)=1.37%, 95% confidence interval (CI)=1.14-1.63. Delivery by C-section was also associated with the subsequent diagnosis of asthma (OR=1.24%, 95% CI=1.01-1.53); this association was gender specific, with a positive association restricted to girls (OR for asthma in girls: OR=1.53%, 95% CI=1.11-2.10; in boys: OR=1.08%, 95% CI=0.81-1.43). There was no significant association between mode of delivery and AD. If children born in a 'repeat C-section' were considered separately the risk of being diagnosed with AR increased further (OR=1.78%, 95% CI=1.34-2.37). The same increase was noted for asthma in girls (OR=1.83%, 95% CI=1.13-2.97) but not in boys. CONCLUSION: Caesarean sections may be associated with an increased risk of developing AR in childhood.

Anti-Infective Agents↗
PubMed2005

A dynamic population model of disease progression in COPD.

To contribute to evidence-based policy making, a dynamic Dutch population model of chronic obstructive pulmonary disease (COPD) progression was developed. The model projects incidence, prevalence, mortality, progression and costs of diagnosed COPD by the Global Initiative for Chronic Obstructive Lung Disease-severity stage for 2000-2025, taking into account population dynamics and changes in smoking prevalence over time. It was estimated that of all diagnosed COPD patients in 2000, 27% had mild, 55% moderate, 15% severe and 3% very severe COPD. The severity distribution of COPD incidence was computed to be 40% mild, 55% moderate, 4% severe and 0.1% very severe COPD. Disease progression was modelled as decline in forced expiratory volume in one second (FEV1) % predicted depending on sex, age, smoking and FEV1 % pred. The relative mortality risk of a 10-unit decrease in FEV1 % pred was estimated at 1.2. Projections of current practice were compared with projections assuming that each year 25% of all COPD patients receive either minimal smoking cessation counselling or intensive counselling plus bupropion. In the projections of current practice, prevalence rates between 2000-2025 changed from 5.1 to 11 per 1,000 inhabitants for mild, 11 to 14 per 1,000 for moderate, 3.0 to 3.9 per 1,000 for severe and from 0.5 to 1.3 per 1,000 for very severe COPD. Costs per inhabitant increased from 1.40 Euro to 3.10 for mild, 6.50 Euro to 9.00 for moderate, 6.20 Euro to 8.50 for severe and from 3.40 Euro to 9.40 for very severe COPD (price level 2000). Both smoking cessation scenarios were cost-effective with minimal counselling generating net savings. In conclusion, the chronic obstructive pulmonary disease progression model is a useful instrument to give detailed information about the future burden of chronic obstructive pulmonary disease and to assess the long-term impact of interventions on this burden.

Aged↗
PubMed2004

COPD exacerbations: the importance of a standard definition.

Efforts to assess the efficacy of new therapies in the treatment of acute exacerbations of chronic obstructive pulmonary disease (COPD) have been hampered by the lack of a widely agreed and consistently used definition. A variety of definitions have been used in clinical studies, based on changes in patient symptoms or the requirement for antibiotic therapy, oral steroids or hospitalisation. To date, none of these definitions have been assessed in detail for their reliability, responsiveness and validity determined. Considerable heterogeneity in the aetiology and manifestation of COPD exacerbations makes identification and quantification of defining symptoms extremely difficult. New approaches are therefore being sought with a view to identifying a serum or tissue marker that can be used as a valuable diagnostic tool. Improvements in data recording will also contribute to the accuracy of data retrieval and assessment. If we are to progress to a level of sophistication seen in the diagnosis and management of other diseases, it is evident that considerable research efforts will be required to improve our understanding of COPD exacerbations and develop a standard definition for these events, thereby facilitating the assessment of therapeutic approaches.

Ambulatory Care↗
PubMed2003

Dietary vitamin C intake is inversely related to cough and wheeze in young smokers.

We aimed to investigate whether dietary vitamin C intake, an important antioxidant, is inversely related to self-reported respiratory symptoms in young adults of a community. A random sample of 4300 subjects, aged 20-44 years, living in Bergen, Norway, received a postal questionnaire on respiratory symptoms; 80% responded. Vitamin C intake (mg per week) was estimated from a food-frequency questionnaire asking how often the subject, during the last year, had consumed units of orange juice, oranges, potatoes, carrots and tomatoes. Significant differences in the intake of vitamin C were observed across smoking categories with current smokers having the lowest intake, while there was no variation by gender, age or occupational dust exposure. Dietary vitamin C intake was in univariate analyses inversely related to "morning cough", "chronic cough", "wheeze" and "wheeze ever". After adjusting for gender, age, body mass index, "occupational exposure" pack-years as well as having and stratified on smoking habits in multiple logistic regression analyses, the relationship between dietary vitamin C intake and "cough" and "wheeze" tended to be associated to smoking. The odds ratio (OR) for "morning cough" was 0.68 (95% CI: 0.35-0.95), "chronic cough" OR 0.69 (95% CI: 0.47-1.04) and "wheeze ever" OR 0.75 (95% CI: 0.56-1.01) in current-smokers with dietary vitamin C intake in the upper (> or =395 mg/ week) vs. the lower (<209 mg/week) tertile. The OR for "wheeze" was 0.56 (95% CI: 0.35-0.88) in ex-smokers. The magnitude ofthese effects remained after excluding subjects with supplementary vitamin C intake (n=199) from the statistical analyses. Among young Norwegian adults, having a low prevalence of asthma and high prevalences of smoking-related respiratory symptoms, dietary vitamin C intake may act as an antioxidant and thereby reduce cough and wheeze in smokers having high oxidant stress.

Adult↗
PubMed2003

Lung function and mortality in the United States: data from the First National Health and Nutrition Examination Survey follow up study.

BACKGROUND: A study was undertaken to define the risk of death among a national cohort of US adults both with and without lung disease. METHODS: Participants in the first National Health and Nutrition Examination Survey (NHANES I) followed for up to 22 years were studied. Subjects were classified using a modification of the Global Initiative for Chronic Obstructive Lung Disease criteria for chronic obstructive pulmonary disease (COPD) into the following mutually exclusive categories using the forced expiratory volume in 1 second (FEV(1)), forced vital capacity (FVC), FEV(1)/FVC ratio, and the presence of respiratory symptoms: severe COPD, moderate COPD, mild COPD, respiratory symptoms only, restrictive lung disease, and no lung disease. Proportional hazard models were developed that controlled for age, race, sex, education, smoking status, pack years of smoking, years since quitting smoking, and body mass index. RESULTS: A total of 1301 deaths occurred in the 5542 adults in the cohort. In the adjusted proportional hazards model the presence of severe or moderate COPD was associated with a higher risk of death (hazard ratios (HR) 2.7 and 1.6, 95% confidence intervals (CI) 2.1 to 3.5 and 1.4 to 2.0), as was restrictive lung disease (HR 1.7, 95% CI 1.4 to 2.0). CONCLUSIONS: The presence of both obstructive and restrictive lung disease is a significant predictor of earlier death in long term follow up.

Adult↗
PubMed2003

Similarities and differences between asthma and chronic obstructive pulmonary disease: treatment and early outcomes.

There are now many guidelines that provide direction for the diagnosis and management of asthma and chronic obstructive pulmonary disease (COPD). However, both diseases are still underdiagnosed (or misdiagnosed) and undertreated. There is considerable evidence that treatment with anti-inflammatory drugs reduces morbidity and mortality in asthma. The evidence is growing regarding their effect on slowing the remodelling that occurs in subsets of asthmatics. COPD is more challenging. There are no disease-modifying drugs available yet that will change the natural history of COPD. However, there is overwhelming evidence that smoking cessation will slow the progression of disease. Until better drugs are available for the treatment of COPD, emphasis must be placed on primary and secondary prevention by reducing exposure to noxious agents (cigarette smoke in particular). Inhaled corticosteroids appear to have a place in the management of severe chronic obstructive pulmonary disease, perhaps by decreasing the frequency of exacerbations.

Asthma↗
PubMed2002

Guidelines for the management of chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is a respiratory condition characterized by progressive decline in lung function. It imposes a considerable burden on patients, healthcare services and society that is likely to increase in the future. It is, therefore, important to ensure that this disease is managed as effectively as possible. In many therapeutic areas, management guidelines have been developed in an attempt to ensure that physicians are aware of optimal disease management and cost-effective use of healthcare resources. Such guidelines are usually prepared by consensus among clinical experts or following a systematic review of the evidence. However, there are a number of barriers to the implementation of treatment guidelines, including the sheer weight of guidelines in all therapeutic areas, a focus on scientific knowledge rather than on clinical practice, lack of trust in the recommendations, practical considerations (e.g. time, resources, budget) and failure to include the perspective of patients. The management guidelines most likely to be implemented are those that are quick and easy to use, relevant to the user's practice and from a credible source. In COPD, over 40 guidelines have been developed, mainly by local respiratory societies as a result of local expert consensus. The guidelines developed by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) are evidence-based and have the backing of international experts. Local implementation plans have been developed to help ensure that GOLD recommendations are implemented in practice. In all COPD guidelines, however, lung function measures feature prominently with limited reference to outcome measures of interest to patients and healthcare payers (e.g. frequency of exacerbations requiring hospitalization). Low expectations among physicians and patients may also impair implementation. In conclusion, guidelines may improve the management of COPD, but the main challenge is to ensure implementation.

Communication↗
PubMed2002

Patterns of lung function in asymptomatic nonsmoking men and women in the People's Republic of China.

PURPOSE: To evaluate patterns of lung function in healthy, working Chinese men and women in different geographic areas of the People's Republic of China (PRC). METHODS: We conducted lung function tests on 2926 asymptomatic, never smoking Chinese men and women aged 35-56 years residing in or around Beijing and Guangzhou. Within each of these locations, separate urban and rural samples were recruited. RESULTS: Age and height adjusted lung function was greater in Beijing than in Guangzhou, and within each city for residents of rural vs. urban areas. Among women, estimated rates of lung aging were greater in Beijing than in Guangzhou, and in urban vs. rural areas. Both FEV(1) and FVC exhibited a curvilinear association with body mass index. CONCLUSIONS: Lung function data from this largely working cohort exhibited marked geographic and urban-rural differences in this never smoking, adult Chinese cohort. Such variation is not uncommon and may reflect differences in body size, diet, and environmental and occupational exposures across these different settings. Caution should be used in applying published reference equations to populations from different parts of the PRC.

Adult↗
PubMed2002

Risk of over-diagnosis of COPD in asymptomatic elderly never-smokers.

The Global Initiative for Chronic Obstructive Lung Disease (GOLD) has defined stage I chronic obstructive pulmonary disease (COPD) as forced expiratory volume in one second/forced vital capacity (FEV1/FVC)% <70% and a FEV1% predicted of >80%. Stage 2 has been defined as FEV1/FVC <70% and a FEV1% pred of <80%. The authors examined the extent of COPD misdiagnosis using this definition in healthy, never-smoker, asymptomatic adults aged >70 yrs in Bergen, Norway. A respiratory questionnaire was mailed to a random sample of 2,871 persons aged >70 yrs. In a random, well-defined subgroup of 208 never-smoker respondents with no current respiratory disease and significant dyspnoea or heart disease/hypertension complicated with dyspnoea, 71 were able to perform an acceptable spirometry. Approximately 35% of these healthy, elderly never-smokers had an FEV1/FVC% of <70% and would be classified as having at least a stage 1 COPD. This percentage increased with age and in those aged >80 yrs approximately 50% would be classified as having COPD and approximately one-third would have an FEV1 of <80% pred (stage 2 COPD). The estimated 5th percentile of FEV1 was consistently <80% pred. The Global Initiative for Chronic Obstructive Lung Disease criteria will probably lead to a significant degree of over-diagnosis of chronic obstructive pulmonary disease in those aged >70 yrs. The criteria used to define the various stages of chronic obstructive pulmonary disease need to be age-specific.

Aged↗
PubMed2001

Sustained-release bupropion for pharmacologic relapse prevention after smoking cessation. a randomized, controlled trial.

BACKGROUND: Smoking relapse is common after successful pharmacologic treatment for smoking cessation. No previous studies have examined long-term drug therapy used expressly for prevention of smoking relapse. OBJECTIVE: To evaluate the efficacy of bupropion to prevent smoking relapse. DESIGN: Randomized, placebo-controlled trial. PARTICIPANTS: 784 healthy community volunteers who were motivated to quit smoking and who smoked at least 15 cigarettes per day. INTERVENTION: The participants received open-label, sustained-release bupropion, 300 mg/d, for 7 weeks. Participants who were abstinent throughout week 7 of open-label treatment were randomly assigned to receive bupropion, 300 mg/d, or placebo for 45 weeks and were subsequently followed for an additional year after the conclusion of the medication phase. Participants were briefly counseled at all follow-up visits. At the end of open-label bupropion treatment, 461 of 784 participants (58.8%) were abstinent from smoking. MEASUREMENT: Self-reported abstinence was confirmed by an expired air carbon monoxide concentration of 10 parts per million or less. RESULTS: The point prevalence of smoking abstinence was significantly higher in the bupropion group than in the placebo group at the end (week 52) of drug therapy (55.1% vs. 42.3%, respectively; P = 0.008) and at week 78 (47.7% vs. 37.7%; P = 0.034) but did not differ at the final (week 104) follow-up visit (41.6% vs. 40.0%). The median time to relapse was significantly greater for bupropion recipients than for placebo recipients (156 days vs. 65 days; P = 0.021). The continuous abstinence rate was higher in the bupropion group than in the placebo group at study week 24 (17 weeks after randomization) (52.3% vs. 42.3%; P = 0.037) but did not differ between groups after week 24. Weight gain was significantly less in the bupropion group than in the placebo group at study weeks 52 (3.8 kg vs. 5.6 kg; P = 0.002) and 104 (4.1 kg vs. 5.4 kg; P = 0.016). CONCLUSIONS: In persons who stopped smoking with 7 weeks of bupropion treatment, sustained-release bupropion for 12 months delayed smoking relapse and resulted in less weight gain.

Adult↗
PubMed2001

Insight into patient dissatisfaction with asthma treatment.

BACKGROUND: Measures of patient satisfaction or dissatisfaction with treatment are increasingly being used as indicators of quality of care. As these measures become more widely used, it is important to know if patient dissatisfaction is associated with important processes or outcomes of medical care. METHODS: Survey of patient-reported asthma management issues using the Asthma Therapy Assessment Questionnaire in a large health maintenance organization in the Pacific Northwest. Associations between patient dissatisfaction with asthma treatment and patient-reported measures of asthma control, patient-provider communication, and belief in asthma medications (self-efficacy) were examined. RESULTS: Of the 5181 adult members with asthma enrolled in the health maintenance organization, 30% indicated dissatisfaction with current treatment. Dissatisfaction was higher among patients with a higher number of asthma control problems, patient-provider communication problems, or belief in medication problems (eg, failure to believe their medications are useful and inability to take asthma medications as directed). The odds of dissatisfaction with treatment were 2.8 (95% confidence interval [CI], 2.4-3.3; P<.001) for asthma control problems, 2.0 (95% CI, 1.6-2.6; P<.001) for communication problems, and 8.0 (95% CI, 6.7-9.5; P<.001) for belief in medication problems compared with patients without these perceived problems. CONCLUSION: Patient dissatisfaction with treatment may be related to important asthma disease management issues.

Adult↗
PubMed2001

Experience of Black participants in the Lung Health Study smoking cessation intervention program.

This paper evaluates the hypothesis that Black smokers will respond differently than Whites to a smoking cessation intervention program where no adjustments are made in recognition of cultural differences. The responses of Black smokers who were recruited into the Lung Health Study (LHS) to the smoking cessation intervention are described. Black quit rates are compared with those of Whites. The LHS enrolled 5887 men and women smokers, aged 35-60 years, of whom 3923 were randomized to a group cessation intervention and 1964 to usual care. Blacks and Whites from six clinics who had complete covariate data (200 Blacks and 2868 Whites) were compared on baseline smoking characteristics and subsequent smoking cessation outcomes. Logistic models were constructed to adjust for baseline smoking variables and demographic characteristics to evaluate the effect of treatment group on smoking cessation among Blacks and Whites. At baseline, Blacks reported smoking fewer cigarettes than Whites, but had higher mean levels of salivary cotinine. The adjusted odds ratio of quitting at 1 year for the smoking intervention group vs. the usual care group was 1.48 for Blacks and 5.99 for Whites. This difference between Blacks and Whites was highly significant (p = 0.002). Across 5 years, the adjusted odds ratios of quitting were 1.87 for Blacks and 3.34 for Whites (p = 0.06). Although the treatment effect was stronger for Whites than for Blacks, over the 5 years of the study there was a significant treatment effect for Blacks. Indicators of physical dependence on nicotine at baseline were inconsistent in indicating whether Blacks were more dependent. We conclude that Blacks and Whites differed significantly in their response to the LHS group smoking intervention program.

Adult↗
PubMed2001

Correlates of peak expiratory flow lability in elderly persons.

OBJECTIVE: To determine the correlates of the lability of peak expiratory flow (PEF) in the elderly. METHODS: A community sample of 4,581 persons > or = 65 years old from the Cardiovascular Health Study completed an asthma questionnaire and underwent spirometry. During a follow-up examination of the cohort, 1,836 persons agreed to measure PEF at home twice daily for 2 weeks, and 90% successfully obtained at least 4 days of valid measurements. PEF lability was calculated as the highest daily (PEF maximum - PEF minimum)/mean PEF. RESULTS: Mean PEF measured at home was accurate when compared to PEF determined by spirometry in the clinic. Mean PEF lability was 18% in those with current asthma (n = 165) vs 12% in healthy nonsmokers (upper limit of normal, 29%). Approximately 26% of those with asthma and 14% of the other participants had abnormally high PEF lability (> 29%). After excluding participants with asthma, other independent predictors of high PEF lability included black race, current and former smoking, airway obstruction on spirometry, daytime sleepiness, recent wheezing, chronic cough, emphysema, and wheezing from lying in a supine position. Despite having a lower mean PEF, those reporting congestive heart failure (n = 82) did not have significantly higher PEF lability. CONCLUSIONS: Measurement of PEF lability at home is highly successful in elderly persons. PEF lability > or = 30% is abnormal in the elderly and is associated with asthma.

Aged↗