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Biomedical subjects

Don D Sin

Publications and source records attributed to Don D Sin.

At least 37 records · Page 2Linked to original sources
PubMed2005

The relationship between reduced lung function and cardiovascular mortality: a population-based study and a systematic review of the literature.

STUDY OBJECTIVES: Conditions that give rise to reduced lung function are frequently associated with low-grade systemic inflammation, which may lead to poor cardiovascular outcomes. We sought to determine the relationship between reduced FEV1 and cardiovascular mortality, independent of smoking. DESIGN: Longitudinal population-based study and a meta-analysis of literature. SETTING: Representative sample of the general population. PARTICIPANTS: Participants of the first National Health and Nutrition Examination Survey Epidemiologic Follow-up Study who were 40 to 60 years of age at baseline assessment (n = 1,861). MEASUREMENTS AND RESULTS: We compared the risk of cardiovascular mortality across quintiles of FEV1. Individuals in the lowest FEV1 quintile had the highest risk of cardiovascular mortality (relative risk [RR], 3.36; 95% confidence interval [CI], 1.54 to 7.34). Compared to FEV1 quintile 1, individuals in quintile 5 had a fivefold increase in the risk of death from ischemic heart disease (RR, 5.65; 95% CI, 2.26 to 14.13). We also performed a systematic review of large cohort studies (> 500 participants) that reported on the relationship between FEV1 and cardiovascular mortality (12 studies; n = 83,880 participants). Compared to participants in the highest FEV1 category, those with reduced FEV1 had a higher risk of cardiovascular mortality (pooled RR, 1.77; 95% CI, 1.56 to 1.97). CONCLUSIONS: There is strong epidemiologic evidence to indicate that reduced FEV1 is a marker for cardiovascular mortality independent of age, gender, and smoking history.

Adult↗
PubMed2005

Chronic obstructive pulmonary disease as a risk factor for cardiovascular morbidity and mortality.

Chronic obstructive pulmonary disease and other disorders, associated with reduced lung function, are strong risk factors for cardiovascular events, independent of smoking. Overall, when the lowest quintile of lung function, as measured by FEV1 is compared with the highest quintile, the risk of cardiovascular mortality increases by approximately 75% in both men and women. Having symptoms of chronic bronchitis alone increases the risk of coronary deaths by 50%. Reduced ratio of FEV1 to FVC by itself is a modest independent risk factor for coronary events, increasing the risk by 30%. However, if patients have ventricular arrhythmias, the risk of coronary events is increased twofold, suggesting that the cardiotoxic effects of obstructive airways disease are amplified in those who have underlying cardiac rhythm disturbances. In general, for every 10% decrease in FEV1, all-cause mortality increases by 14%, cardiovascular mortality increases by 28%, and nonfatal coronary event increases by almost 20%. These data indicate that chronic obstructive pulmonary disease is a powerful, independent risk factor for cardiovascular morbidity and mortality.

Cardiovascular Diseases↗
PubMed2005

Effects of corticosteroids on systemic inflammation in chronic obstructive pulmonary disease.

Patients with chronic obstructive pulmonary disease (COPD) are predisposed to atherosclerosis and coronary artery disease, but the underlying mechanisms are unclear. Although there is wide acceptance that atherosclerosis is related to systemic inflammation, the cause(s) and mechanism(s) of pulmonary inflammation in stable COPD remain unknown. Infectious (bacterial and viral) as well as noninfectious agents can cause acute exacerbations in COPD, and they intensify local and systemic inflammation. Although it is not known how systemic inflammation develops in stable COPD, there is good evidence to suggest that it occurs and that the intensity of systemic inflammation is linked to the severity of airflow obstruction. We postulate that systemic inflammation provides the linkage between COPD and atherosclerosis. Inhaled corticosteroids have been shown to improve health outcomes in COPD, but the mechanism by which this occurs is a pivotal and challenging question that has yet to be answered. To prove the concept that inhaled corticosteroids could suppress systemic inflammation (as exemplified by serum C-reactive protein [CRP] levels), a double-blind, placebo-controlled clinical trial was conducted in a group of patients with mild to moderate COPD. We found that withdrawal of inhaled corticosteroids increased serum CRP levels, and that reintroduction of inhaled fluticasone could suppress CRP levels.

Androstadienes↗
PubMed2005

Inhaled corticosteroids in chronic obstructive pulmonary disease: is there a clinical benefit?

Chronic obstructive pulmonary disease (COPD) is a serious illness that affects over 5% of the adult population. It is one of the few conditions for which the mortality and morbidity are still increasing. Experts expect COPD to become the third leading cause of death and the fifth leading cause of disability worldwide by the year 2020. Thus far, the only treatments that have been shown to make a difference to survival are smoking cessation and the use of oxygen supplements for those who are hypoxaemic at rest. The use of inhaled corticosteroids as monotherapy or in combination with a long-acting beta2-adrenoceptor agonist for COPD is controversial. Experimental data indicate that the inflammatory process in COPD may be resistant to the anti-inflammatory effects of corticosteroids. However, several large clinical studies have shown that inhaled corticosteroids in relatively high doses (e.g. budesonide 800 microg/day or fluticasone propionate 1 mg/day) reduce exacerbations by 20-30% and improve the health status of COPD patients by a similar amount compared with placebo. Withdrawal of inhaled corticosteroids may increase clinical exacerbation rates by 50% in COPD patients and by 2-fold in those with severe disease. Combined therapy with inhaled corticosteroids and long-acting beta2-adrenoceptor agonists may be superior to individual component therapy in reducing exacerbations. However, these medications must be used cautiously, as they have been associated with certain adverse effects. Inhaled corticosteroids, for instance, increase the risk for dysphonia and oral thrush by 2- to 3-fold. Skin bruising is also more common in users than in non-users of inhaled corticosteroids. On balance, for those with moderate-to-severe COPD and those who experience frequent exacerbations, judicious use of inhaled corticosteroids alone or in combination with long-acting beta2-adrenoceptor agonists appears reasonable.

Administration, Inhalation↗
PubMed2005

Management of asthma among community-based primary care physicians.

BACKGROUND: Despite significant improvements in asthma treatment and the dissemination of national and international guidelines for asthma management, there are ongoing concerns that suboptimal care is being provided for patients with asthma. OBJECTIVE: To determine the current practice patterns of asthma care among primary care physicians. DESIGN: A cross-sectional study. SETTING: Province of Alberta, Canada (population: 3 million people). PARTICIPANTS: Patients, 5 years of age or older, who had a physician's diagnosis of asthma, and had at least two visits for asthma between 1996 and 2001. MEASUREMENT AND RESULTS: Charts of 3072 distinct patients (from 45 unique primary care physicians) were reviewed. Previous emergency department visits or hospitalizations were experienced by 20% of the sample. A total of 25% of patients had documented evidence that they had performed spirometry. More than half of the patients had no documented evidence that they had received any form of asthma education; only 2% of the charts indicated that patients received a written action plan. Two thirds of the patients were prescribed an inhaled steroid within 6 months of the last clinic visit. CONCLUSIONS: Our study indicates a gap in the provision of asthma education, written action plans, and spirometric testing for patients diagnosed with asthma among primary care physicians.

Adolescent↗
PubMed2004

Effects of increased primary care access on process of care and health outcomes among patients with asthma who frequent emergency departments.

PURPOSE: Many asthmatic patients discharged from emergency departments do not have timely follow-up visits with a primary care physician. This study was conducted to determine the effectiveness of a health professional-based intervention in improving process of care and health outcomes among asthmatic patients discharged from emergency departments. METHODS: We enrolled 125 asthmatic patients, aged 5 through 50 years, from the emergency department of a community-based hospital; 62 patients were assigned to usual care and 63 to enhanced care. Enhanced care consisted of usual care plus employment of a coordinator to make follow-up appointments with the patient's primary care physician with at least one reminder telephone call to the patient. RESULTS: At 6 months of follow-up, mean (+/- SD) asthma and pediatric quality-of-life scores were higher in the enhanced care group than in the usual care group (5.7 +/- 1.2 units vs. 5.0 +/- 1.3 units, P = 0.01). The enhanced care group also had a higher rate of follow-up office visits (78% [n = 44] vs. 60% [n = 33], P = 0.003), were more likely to have written action plans (46% [n = 26] vs. 25% [n = 14], P = 0.02), and had fewer asthma symptoms (1.8 +/- 1.1 units vs. 2.2 +/- 1.3 units, P = 0.09). However, these differences disappeared by 12 months of follow-up. CONCLUSION: A simple intervention wherein a health professional facilitates follow-up visits can improve the process of care and health outcomes of high-risk asthmatic patients. However, the effect of this intervention is time limited and largely wears off by 12 months.

Adolescent↗
PubMed2004

Pharmacological management to reduce exacerbations in adults with asthma: a systematic review and meta-analysis.

CONTEXT: Over the last 2 decades, many new pharmacological agents have been introduced to reduce the growing morbidity associated with asthma, but the long-term effects of these agents on exacerbations are unclear. OBJECTIVE: To systematically review and quantitatively synthesize the long-term effects of inhaled corticosteroids, long-acting beta2 agonists, leukotriene pathway modifiers/receptor antagonists, and anti-IgE therapies on clinical outcomes and particular clinically relevant exacerbations in adult patients with chronic asthma. DATA SOURCES: MEDLINE, EMBASE, and Cochrane databases were searched to identify relevant randomized controlled trials and systematic reviews published from January 1, 1980, to April 30, 2004. We identified additional studies by searching bibliographies of retrieved articles and contacting experts in the field. STUDY SELECTION AND DATA EXTRACTION: Included trials were double-blind, had follow-up periods of at least 3 months, and contained data on exacerbations and/or forced expiratory volume in 1 second. The effects of interventions were compared with placebo, short-acting beta2 agonists, or each other. DATA SYNTHESIS: Inhaled corticosteroids were most effective, reducing exacerbations by nearly 55% compared with placebo or short-acting beta2 agonists (relative risk [RR], 0.46; 95% confidence interval [CI], 0.34-0.62; P<.001 for heterogeneity). Compared with placebo, the use of long-acting beta2 agonists was associated with 25% fewer exacerbations (RR, 0.75; 95% CI, 0.64-0.88; P =.43 for heterogeneity); when added to inhaled corticosteroids, there was a 26% reduction above that achieved by steroid monotherapy (RR, 0.74; 95% CI, 0.61-0.91; P =.07 for heterogeneity). Combination therapy was associated with fewer exacerbations than was increasing the dose of inhaled corticosteroids (RR, 0.86; 95% CI, 0.76-0.96; P =.65 for heterogeneity). Compared with placebo, leukotriene modifiers/receptor antagonists reduced exacerbations by 41% (RR, 0.59; 95% CI, 0.49-0.71; P =.44 for heterogeneity) but were less effective than inhaled corticosteroids (RR, 1.72; 95% CI, 1.28-2.31; P =.91 for heterogeneity). Use of monoclonal anti-IgE antibodies with concomitant inhaled corticosteroid therapy was associated with 45% fewer exacerbations (RR, 0.55; 95% CI, 0.45-0.66; P =.15 for heterogeneity). CONCLUSIONS: Inhaled corticosteroids are the single most effective therapy for adult patients with asthma. However, for those unable or unwilling to take corticosteroids, the use of leukotriene modifiers/receptor agonists appears reasonable. Long-acting beta2 agonists may be added to corticosteroids for those who remain symptomatic despite low-dose steroid therapy. Anti-IgE therapy may be considered as adjunctive therapy for young adults with asthma who have clear evidence of allergies and elevated serum IgE levels.

Adrenergic beta-Antagonists↗
PubMed2004

Effects of fluticasone on systemic markers of inflammation in chronic obstructive pulmonary disease.

Systemic inflammation is present in chronic obstructive pulmonary disease (COPD), which has been linked to cardiovascular morbidity and mortality. We determined the effects of oral and inhaled corticosteroids on serum markers of inflammation in patients with stable COPD. We recruited 41 patients with mild to moderate COPD. After 4 weeks during which inhaled corticosteroids were discontinued, patients were assigned to fluticasone (500 mcg twice a day), oral prednisone (30 mg/day), or placebo over 2 weeks, followed by 8 weeks of fluticasone at 500 mcg twice a day and another 8 weeks at 1,000 mcg twice a day. Withdrawal of inhaled corticosteroids increased baseline C-reactive protein (CRP) levels by 71% (95% confidence interval [CI], 16-152%). Two weeks with inhaled fluticasone reduced CRP levels by 50% (95% CI, 9-73%); prednisone reduced it by 63% (95% CI, 29-81%). No significant changes were observed with the placebo. An additional 8 weeks of fluticasone were associated with CRP levels that were lower than those at baseline (a 29% reduction; 95% CI, 7-46%). Inhaled and oral corticosteroids are effective in reducing serum CRP levels in patients with COPD and suggest their potential use for improving cardiovascular outcomes in COPD.

Administration, Inhalation↗
PubMed2004

The relationship between birth weight and childhood asthma: a population-based cohort study.

BACKGROUND: Because obesity promotes inflammation and imposes mechanical constraints to the airways, a high birth weight may be a risk factor for asthma in childhood. However, to our knowledge, few studies have examined this potential relationship. OBJECTIVE: To determine the relationship between high birth weight and risk of emergency visits for asthma during childhood. DESIGN: Population-based cohort study. SETTING: Alberta, Canada. PARTICIPANTS: All neonates born at term (> or =37 weeks) between April 1, 1985, and March 31, 1988, in Alberta (N = 83,595). We divided the cohort into birth-weight categories: low (<2.5 kg), normal (2.5-4.5 kg), or high (>4.5 kg). The cohort was observed prospectively for 10 years.Main Outcome Measure Comparison of risk of emergency visits for asthma over 10 years across the birth-weight categories. RESULTS: Neonates born with a high birth weight had a significantly increased risk of emergency visits for asthma during childhood compared with neonates born with a normal birth weight (relative risk [RR], 1.16; 95% confidence interval [CI], 1.04-1.29). The relationship between birth weight and emergency visits for asthma beyond a birth weight of 4.5 kg was linear, such that every increment of 0.10 kg in birth weight was associated with an additional 10% (95% CI, 2%-19%) increase in the risk of emergency visits for asthma. Other factors associated with an elevated risk for emergency asthma visits during childhood included male sex (RR, 1.26; 95% CI, 1.22-1.30), aboriginal status (RR, 1.20; 95% CI, 1.11-1.29), and low-income status (RR, 1.11; 95% CI, 1.06-1.16). CONCLUSIONS: A high, but not low, birth weight is a risk factor for increased emergency visits during childhood. The risk increases linearly beyond a birth weight of 4.5 kg.

Alberta↗
PubMed2004

Economic evaluation of a community-based pulmonary rehabilitation program for chronic obstructive pulmonary disease.

Pulmonary rehabilitation has been demonstrated to be efficacious in chronic obstructive pulmonary disease (COPD), however, its cost-effectiveness is largely unknown. The present study determined the cost-effectiveness of a community-based pulmonary rehabilitation program for COPD patients with mild, moderate, and severe disease. We compared the direct costs (in Canadian dollars) and disease-specific quality of life (measured by the St. George's Respiratory Questionnaire, SGRQ) of patients with COPD (N = 210) who enrolled in the rehabilitation program in Edmonton, Canada one year before and after completion of the program. To determine temporal trends in health service utilization between 2000 and 2002 we used similar data from 592 COPD patients from the same region who did not participate in the rehabilitation program. We found that the health status of patients enrolled in the program improved significantly following pulmonary rehabilitation, irrespective of the severity of disease (total SGRQ score improved by 4.85%, p = 0.001). The total direct cost per 100 person-years of follow-up before the program was $122,071 (SE = 29,566); after the program it was $87,704 (SE = 26,146). The average reduction of total costs before and after the program was $34,367 per 100 person-years or approximately $344 per person per year (p = 0.02). Over one-year, pulmonary rehabilitation was associated with decreased health service utilization, reduced direct costs and improved health status of COPD patients. This suggests that pulmonary rehabilitation is cost-effective for patients with relatively high utilization of emergency and hospital-based services.

Aged↗
PubMed2004

Why do some countries publish more than others? An international comparison of research funding, English proficiency and publication output in highly ranked general medical journals.

National factor(s) influencing publication output in the highest ranked medical journals are largely unknown. We sought to examine the relationship between national research funding and English proficiency on publication output. We identified all original research articles appearing in the five highest ranked general medical journals between 1997 and 2001. Using the country of the corresponding author as the source nation for each article, we determined a standardized publication rate across developed nations. We used multiple regression techniques to determine the influence of national expenditures on research and scores from the Test of English as a Foreign Language (TOEFL), a surrogate for English proficiency, on publication output. There was a significant relationship of national spending on research and TOEFL scores to publication output of developed countries (p = 0.04; p < 0.01, respectively). These two variables explained approximately 71.5% of the variation in publication rate across developed nations around the world (R = 0.85; p < 0.01). Normalized for population size, English-speaking nations and certain northern European countries such as Denmark, The Netherlands, Switzerland, and Sweden had the highest rate of publication in the five highest ranked general medical journals, while Asian countries had generally low rates of publication. Research spending and English proficiency were strongly associated with publication output in the highest ranked general medical journals. While these data cannot be considered definitive due to their observational nature, they do suggest that for English-language medical journals, research funding and English proficiency may be important determinants of publication.

Bibliometrics↗
PubMed2004

Alberta Strategy to Help Manage Asthma (ASTHMA): a provincial initiative to improve outcomes for individuals with asthma.

As society struggles with escalating healthcare costs, and a general increase in the prevalence as well as the morbidity of common chronic conditions such as asthma and diabetes, patient health management programs offer new opportunities to improve the process of care, create efficiencies in the healthcare system and enhance the outcomes of patients suffering from these conditions.

Alberta↗
PubMed2004

Combination therapy of inhaled corticosteroids and long-acting beta2-adrenergics in management of patients with chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) affects over 5% of the adult population and is the only major cause of death in the United States where morbidity and mortality are increasing. Clinically, COPD is characterized by irreversible airflow obstruction and airway inflammation that eventually lead to dyspnea, cough and sputum production. Long-acting beta(2)-agonists (LABAs) are effective in reducing patient symptoms through their bronchodilatory action on airway smooth muscle. More importantly, when LABAs are given in conjunction with inhaled corticosteroids, they appear to provide added benefits for patients. While the mechanisms for this observation are not entirely clear, there is emerging evidence to indicate that LABAs and corticosteroids attenuate different but complementary components of the inflammatory cascade related to COPD. Moreover, LABAs and corticosteroids may beneficially interact to prevent downregulation of beta(2)-receptors in airway cells (and thereby preventing tachyphylaxis) and to facilitate translocation of glucocorticoid receptors into the nucleus of inflammatory cells (thereby, amplifying the anti-inflammatory activity of the corticosteroid). Regardless of the mechanism, several large, high-quality randomized controlled clinical trials indicate that combination therapy of LABA with inhaled corticosteroids improves patient symptoms, and reduces exacerbations by a third (compared to placebo). More importantly, combination therapy produces superior health outcomes than mono-therapy with inhaled corticosteroids or LABA, suggesting added clinical benefits of these two compounds in COPD. This article will present a comprehensive overview of the currently available clinical evidence for the use of combination therapy as well as the potential mechanisms of their actions in COPD.

Administration, Inhalation↗
PubMed2003

Contemporary management of chronic obstructive pulmonary disease: scientific review.

CONTEXT: The care of patients with chronic obstructive pulmonary disease (COPD) has changed radically over the past 2 decades, and novel therapies can not only improve the health status of patients with COPD but also modify its natural course. OBJECTIVE: To systematically review the impact of long-acting bronchodilators, inhaled corticosteroids, nocturnal noninvasive mechanical ventilation, pulmonary rehabilitation, domiciliary oxygen therapy, and disease management programs on clinical outcomes in patients with COPD. DATA SOURCES: MEDLINE and Cochrane databases were searched to identify all randomized controlled trials and systematic reviews from 1980 to May 2002 evaluating interventions in patients with COPD. We also hand searched bibliographies of relevant articles and contacted experts in the field. STUDY SELECTION AND DATA EXTRACTION: We included randomized controlled trials that had follow-up of at least 3 months and contained data on at least 1 of these clinical outcomes: health-related quality of life, exacerbations associated with COPD, or death. For pulmonary rehabilitation, we included studies that had a follow-up of at least 6 weeks. Using standard meta-analytic techniques, the effects of interventions were compared with placebo or with usual care. In secondary analyses, the effects of interventions were compared against each other, where possible. DATA SYNTHESIS: Long-acting beta2-agonists and anticholinergics (tiotropium) reduced exacerbation rates by approximately 20% to 25% (relative risk [RR] for long-acting beta2-agonists, 0.79; 95% CI, 0.69-0.90; RR for tiotropium, 0.74; 95% CI, 0.62-0.89) in patients with moderate to severe COPD. Inhaled corticosteroids also reduced exacerbation rates by a similar amount (RR, 0.76; 95% CI, 0.72-0.80). The beneficial effects were most pronounced in trials enrolling patients with FEV1 between 1 L and 2 L. Combining a long-acting beta2-agonist with an inhaled corticosteroid resulted in an approximate 30% (RR, 0.70; 95% CI, 0.62-0.78) reduction in exacerbations. Pulmonary rehabilitation improved the health status of patients with moderate to severe disease, but no material effect was observed on long-term survival or hospitalization rates. Domiciliary oxygen therapy improved survival by approximately 40% in patients with PaO2 lower than 60 mm Hg, but not in those without hypoxia at rest. The data on disease management programs were heterogeneous, but overall no effect was observed on survival or risk of hospitalization. Noninvasive mechanical ventilation was not associated with improved outcomes. CONCLUSIONS: A significant body of evidence supports the use of long-acting bronchodilators and inhaled corticosteroids in reducing exacerbations in patients with moderate to severe COPD. Domiciliary oxygen therapy is the only intervention that has been demonstrated to prolong survival, but only in patients with resting hypoxia.

Adrenergic beta-Agonists↗
PubMed2003

Contemporary management of chronic obstructive pulmonary disease: clinical applications.

The presentation of chronic obstructive pulmonary disease (COPD) usually is insidious, and many patients are undiagnosed until the disease is far advanced. Therefore, the early use of spirometry is recommended for anyone who is suspected to have COPD. In the early stages of the disease, the patient is only mildly symptomatic (cough and sputum production). As COPD becomes more advanced, functional impairment in the form of chronic dyspnea occurs and acute exacerbations of symptoms become more frequent, contributing to overall morbidity and mortality. The single most important known causative factor of COPD is cigarette smoking. Smoking cessation remains, therefore, the mainstay of COPD therapy. In patients with advanced disease, symptomatic treatment with the regular use of either short- or long-acting sympathomimetic and/or anticholinergic bronchodilators, singly or in combination, should be added to smoking cessation and influenza and pneumococcal vaccination therapies. An inhaled corticosteroid, either alone or more commonly in combination with a long-acting bronchodilator, can further reduce exacerbations and improve the health status of these patients. Furthermore, patients with severe COPD, particularly those who are debilitated, should be considered for pulmonary rehabilitation because these programs have been proven useful in maintaining, or in some cases improving, health status for these patients. Finally, correction of resting arterial hypoxemia with oxygen therapy for more than 15 h/d prolongs survival of COPD patients for those with a resting PaO2 lower than 55 to 60 mm Hg.

Aged↗