Andrea S. Gershon

Global asthma prevalence in adults: findings from the cross-sectional world health survey

BackgroundAsthma is a major cause of disability, health resource utilization and poor quality of life world-wide. We set out to generate estimates of the global burden of asthma in adults, which may inform the development of strategies to address this common disease.MethodsThe World Health Survey (WHS) was developed and implemented by the World Health Organization in 2002-2003. A total of 178,215 individuals from 70 countries aged 18 to 45 years responded to questions related to asthma and related symptoms. The prevalence of asthma was based on responses to questions relating to self-reported doctor diagnosed asthma, clinical/treated asthma, and wheezing in the last 12 months.ResultsThe global prevalence rates of doctor diagnosed asthma, clinical/treated asthma and wheezing in adults were 4.3%, 4.5%, and 8.6% respectively, and varied by as much as 21-fold amongst the 70 countries. Australia reported the highest rate of doctor diagnosed, clinical/treated asthma, and wheezing (21.0%, 21.5%, and 27.4%). Amongst those with clinical/treated asthma, almost 24% were current smokers, half reported wheezing, and 20% had never been treated for asthma.ConclusionsThis study provides a global estimate of the burden of asthma in adults, and suggests that asthma continues to be a major public health concern worldwide. The high prevalence of smoking remains a major barrier to combating the global burden of asthma. While the highest prevalence rates were observed in resource-rich countries, resource-poor nations were also significantly affected, posing a barrier to development as it stretches further the demands of non-communicable diseases.

Identifying Individuals with Physcian Diagnosed COPD in Health Administrative Databases

Chronic Obstructive Pulmonary Disease (COPD) is a common chronic respiratory disease responsible for significant morbidity and mortality. Population-based health administrative databases provide a powerful and unbiased way of studying COPD in the population, however, their ability to accurately identify patients with this disease must first be confirmed. The objective was to validate population-based health administrative definitions of COPD. Previously abstracted medical records of adults over the age of 35 randomly selected from primary care practices in Ontario, Canada were reviewed by an expert panel to establish if an individual did or did not have a diagnosis of COPD. These reference designations were then linked to each individuals respective health administrative database record and compared with predefine health administrative data definitions of COPD. Concepts of diagnostic test evaluation were used to calculate and compare their test characteristics. The most sensitive health administrative definition of COPD was 1 or more ambulatory claims and/or 1 or more hospitalizations for COPD that yielded a sensitivity of 85.0% (95% confidence interval 77.0 to 91.0) and a specificity of 78.4% (95% confidence interval 73.6 to 82.7). As number of ambulatory claims in the definition increased, sensitivity decreased and specificity increased. Individuals with COPD can be accurately identified in health administrative data, and therefore it may be used to create an unbiased population cohort for surveillance and research. This offers a powerful means of generating evidence to inform strategies that optimize the prevention and management of COPD.

Lifetime risk of developing chronic obstructive pulmonary disease: a longitudinal population study

BACKGROUND Although chronic obstructive pulmonary disease (COPD) is one of the most deadly, prevalent, and costly chronic diseases, no comprehensive estimates of the risk of developing COPD in the general population have been published. We aimed to quantify the lifetime risk of developing physician-diagnosed COPD in a large, multicultural North American population. METHODS We did a retrospective longitudinal cohort study using population-based health administrative data from Ontario, Canada (total population roughly 13 million). All individuals free of COPD in 1996 were monitored for up to 14 years for three possible outcomes; diagnosis of COPD by a physician, reached 80 years of age, or death. COPD was identified with a previously validated case definition based on COPD health services claims. The cumulative incidence of physician-diagnosed COPD over a lifetime adjusted for the competing risk of death was calculated by a modified survival analysis technique. Results were stratified by sex, socioeconomic status, and whether individuals lived in a rural or urban setting. FINDINGS A total of 579,466 individuals were diagnosed with COPD by a physician over the study period. The overall lifetime risk of physician-diagnosed COPD at age 80 years was 27·6%. Lifetime risk was higher in men than in women (29·7%vs 25·6%), individuals of lower socioeconomic status than in those of higher socioeconomic status (32·1%vs 23·0%), and individuals who lived in a rural setting than in those who lived in an urban setting (32·4%vs 26·7%). INTERPRETATION About one in four individuals are likely to be diagnosed and receive medical attention for COPD during their lifetime. Clinical evidence-based approaches, public health action, and more research are needed to identify effective strategies to prevent COPD and ensure that those with the disease have the highest quality of life possible. FUNDING Government of Ontario, Canada.

Trends in Chronic Obstructive Pulmonary Disease Prevalence, Incidence, and Mortality in Ontario, Canada, 1996 to 2007: A Population-Based Study

BACKGROUND Chronic obstructive pulmonary disease (COPD) is a preventable and treatable disease with a prevalence of more than 10% worldwide among adults 40 years and older. Whether this amount has been increasing, decreasing, or stable over time remains unknown. METHODS A longitudinal cohort study using population-based, health administrative data from 1991 to 2007 was conducted in Ontario, Canada. Individuals with COPD were identified using a previously validated health administrative case definition of COPD. Annual COPD prevalence, incidence, and all-cause mortality rates were estimated from 1996 to 2007. RESULTS The prevalence of COPD increased by 64.8% between 1996 and 2007. The age- and sex-standardized COPD prevalence rate increased from 7.8% to 9.5%, representing a relative increase of 23.0% (P < .001). The age- and sex-standardized incidence decreased from 11.8 per 1000 adults to 8.5 per 1000 adults, representing a relative decrease of 28.3% (P < .001). Finally, the age- and sex-standardized all-cause mortality rate decreased from 5.7% to 4.3%, representing a relative decrease of 24.0% (P < .001). CONCLUSIONS Our findings indicate a substantial increase in COPD prevalence in the last decade, with more of the burden being shifted from men to women. Effective clinical and public health strategies are needed to prevent COPD and manage the increasing number of people living longer with this disease.

Obstructive Sleep Apnea and Incident Diabetes. A Historical Cohort Study

RATIONALE Despite emerging evidence that obstructive sleep apnea (OSA) may cause metabolic disturbances independently of other known risk factors, it remains unclear whether OSA is associated with incident diabetes. OBJECTIVES To evaluate whether risk of incident diabetes was related to the severity and physiologic consequences of OSA. METHODS A historical cohort study was conducted using clinical and provincial health administrative data. All adults without previous diabetes referred with suspected OSA who underwent a diagnostic sleep study at St. Michaels Hospital (Toronto, Canada) between 1994 and 2010 were followed through health administrative data until May 2011 to examine the occurrence of diabetes. All OSA-related variables collected from the sleep study were examined as predictors in Cox regression models, controlling for sex, age, body mass index, smoking status, comorbidities, and income. MEASUREMENTS AND MAIN RESULTS Over a median follow-up of 67 months, 1,017 (11.7%) of 8,678 patients developed diabetes, giving a cumulative incidence at 5 years of 9.1% (95% confidence interval, 8.4-9.8%). In fully adjusted models, patients with apnea-hypopnea index (AHI) greater than 30 had a 30% higher hazard of developing diabetes than those with AHI less than 5. Among other OSA-related variables, AHI in rapid eye movement sleep and time spent with oxygen saturation less than 90% were associated with incident diabetes, as were heart rate, neck circumference, and sleep time. CONCLUSIONS Among people with OSA, and controlling for multiple confounders, initial OSA severity and its physiologic consequences predicted subsequent risk for incident diabetes.

Cardiovascular Safety of Inhaled Long-Acting Bronchodilators in Individuals With Chronic Obstructive Pulmonary Disease

IMPORTANCE Chronic obstructive pulmonary disease (COPD) is a common and deadly disease. Long-acting inhaled β-agonists and anticholinergics, first-line medications for COPD, have been associated with increased risk of cardiovascular outcomes. When choosing between the medications, patients and physicians would benefit from knowing which has the least risk. OBJECTIVE To assess the association of these classes of medications with the risk of hospitalizations and emergency department visits for cardiovascular events. DESIGN We conducted a nested case-control analysis of a retrospective cohort study. We compared the risk of events between patients newly prescribed inhaled long-acting β-agonists and anticholinergics, after matching and adjusting for prognostic factors. SETTING Health care databases from Ontario, the largest province of Canada, with a multicultural population of approximately 13 million. PARTICIPANTS All individuals 66 years or older meeting a validated case definition of COPD, based on health administrative data, and treated for COPD from September 1, 2003, through March 31, 2009. EXPOSURE New use of an inhaled long-acting β-agonist or long-acting anticholinergic. MAIN OUTCOME AND MEASURES An emergency department visit or a hospitalization for a cardiovascular event. RESULTS Of 191 005 eligible patients, 53 532 (28.0%) had a hospitalization or an emergency department visit for a cardiovascular event. Newly prescribed long-acting inhaled β-agonists and anticholinergics were associated with a higher risk of an event compared with nonuse of those medications (respective adjusted odds ratios, 1.31 [95% CI, 1.12-1.52; P < .001] and 1.14 [1.01-1.28; P = .03]). We found no significant difference in events between the 2 medications (adjusted odds ratio of long-acting inhaled β-agonists compared with anticholinergics, 1.15 [95% CI, 0.95-1.38; P = .16]). CONCLUSIONS AND RELEVANCE Among older individuals with COPD, new use of long-acting β-agonists and anticholinergics is associated with similar increased risks of cardiovascular events. Close monitoring of COPD patients requiring long-acting bronchodilators is needed regardless of drug class.

Proton pump inhibitors and the risk of hospitalisation for community-acquired pneumonia: replicated cohort studies with meta-analysis

Objective Previous observational studies suggest that the use of proton pump inhibitors (PPIs) may increase the risk of hospitalisation for community-acquired pneumonia (HCAP). However, the potential presence of confounding and protopathic biases limits the conclusions that can be drawn from these studies. Our objective was, therefore, to examine the risk of HCAP with PPIs prescribed prophylactically in new users of non-steroidal anti-inflammatory drugs (NSAIDs). Design We formed eight restricted cohorts of new users of NSAIDs, aged ≥40 years, using a common protocol in eight databases (Alberta, Saskatchewan, Manitoba, Ontario, Quebec, Nova Scotia, US MarketScan and the UKs General Practice Research Database (GPRD)). This specific patient population was studied to minimise bias due to unmeasured confounders. High-dimensional propensity scores were used to estimate site-specific adjusted ORs (aORs) for HCAP at 6 months in PPI patients compared with unexposed patients. Fixed-effects meta-analytic models were used to estimate overall effects across databases. Results Of the 4 238 504 new users of NSAIDs, 2.3% also started a PPI. The cumulative 6-month incidence of HCAP was 0.17% among patients prescribed PPIs and 0.12% in unexposed patients. After adjustment, PPIs were not associated with an increased risk of HCAP (aOR=1.05; 95% CI 0.89 to 1.25). Histamine-2 receptor antagonists yielded similar results (aOR=0.95, 95% CI  0.75 to 1.21). Conclusions Our study does not support the proposition of a pharmacological effect of gastric acid suppressors on the risk of HCAP.

Burden of comorbidity in individuals with asthma.

Background and aims Asthma comorbidity, such as depression and obesity, has been associated with greater healthcare use, decreased quality of life and poor asthma control. Treating this comorbidity has been shown to improve asthma outcomes as well as overall health. Despite this, asthma comorbidity remains relatively under-recognised and understudied—perhaps because most asthma occurs in young people who are believed to be healthy and relatively free of comorbidity. The aim of this study was to quantify empirically the amount of comorbidity associated with asthma. Methods A population-based cohort study was conducted using the health administrative data of the 12 million residents of Ontario, Canada in 2005. A validated health administrative algorithm was used to identify individuals with asthma. Results The amount of comorbidity among individuals with asthma, as reflected in rates of hospitalisations, emergency department visits and ambulatory care claims, was found to be substantial and much greater than that observed among individuals without asthma. Together, asthma and asthma comorbidity (the extra comorbidity found in individuals with asthma compared with those without asthma) were associated with 6% of all hospitalisations, 9% of all emergency room visits and 6% of all ambulatory care visits that occurred in Ontario. Conclusions Asthma comorbidity places a significant burden on individuals and the healthcare system and should be considered in the management of asthma. Further research should focus on which types of asthma comorbidity are responsible for the greatest burden and how such comorbidity should be prevented and managed.

Combination Long-Acting β-Agonists and Inhaled Corticosteroids Compared With Long-Acting β-Agonists Alone in Older Adults With Chronic Obstructive Pulmonary Disease

IMPORTANCE Chronic obstructive pulmonary disease (COPD), a manageable respiratory condition, is the third leading cause of death worldwide. Knowing which prescription medications are the most effective in improving health outcomes for people with COPD is essential to maximizing health outcomes. OBJECTIVE To estimate the long-term benefits of combination long-acting β-agonists (LABAs) and inhaled corticosteroids compared with LABAs alone in a real-world setting. DESIGN, SETTING, AND PATIENTS Population-based, longitudinal cohort study conducted in Ontario, Canada, from 2003 to 2011. All individuals aged 66 years or older who met a validated case definition of COPD on the basis of health administrative data were included. After propensity score matching, there were 8712 new users of LABA-inhaled corticosteroid combination therapy and 3160 new users of LABAs alone who were followed up for median times of 2.7 years and 2.5 years, respectively. EXPOSURES Newly prescribed combination LABAs and inhaled corticosteroids or LABAs alone. MAIN OUTCOMES AND MEASURES Composite outcome of death and COPD hospitalization. RESULTS The main outcome was observed among 5594 new users of LABAs and inhaled corticosteroids (3174 deaths [36.4%]; 2420 COPD hospitalizations [27.8%]) and 2129 new users of LABAs alone (1179 deaths [37.3%]; 950 COPD hospitalizations [30.1%]). New use of LABAs and inhaled corticosteroids was associated with a modestly reduced risk of death or COPD hospitalization compared with new use of LABAs alone (difference in composite outcome at 5 years, -3.7%; 95% CI, -5.7% to -1.7%; hazard ratio [HR], 0.92; 95% CI, 0.88-0.96). The greatest difference was among COPD patients with a codiagnosis of asthma (difference in composite at 5 years, -6.5%; 95% CI, -10.3% to -2.7%; HR, 0.84; 95% CI, 0.77-0.91) and those who were not receiving inhaled long-acting anticholinergic medication (difference in composite at 5 years, -8.4%; 95% CI, -11.9% to -4.9%; HR, 0.79; 95% CI, 0.73-0.86). CONCLUSIONS AND RELEVANCE Among older adults with COPD, particularly those with asthma and those not receiving a long-acting anticholinergic medication, newly prescribed LABA and inhaled corticosteroid combination therapy, compared with newly prescribed LABAs alone, was associated with a significantly lower risk of the composite outcome of death or COPD hospitalization.

The Impact of Infection on Population Health: Results of the Ontario Burden of Infectious Diseases Study

Background Evidence-based priority setting is increasingly important for rationally distributing scarce health resources and for guiding future health research. We sought to quantify the contribution of a wide range of infectious diseases to the overall infectious disease burden in a high-income setting. Methodology/Principal Findings We used health-adjusted life years (HALYs), a composite measure comprising premature mortality and reduced functioning due to disease, to estimate the burden of 51 infectious diseases and associated syndromes in Ontario using 2005–2007 data. Deaths were estimated from vital statistics data and disease incidence was estimated from reportable disease, healthcare utilization, and cancer registry data, supplemented by local modeling studies and national and international epidemiologic studies. The 51 infectious agents and associated syndromes accounted for 729 lost HALYs, 44.2 deaths, and 58,987 incident cases per 100,000 population annually. The most burdensome infectious agents were: hepatitis C virus, Streptococcus pneumoniae, Escherichia coli, human papillomavirus, hepatitis B virus, human immunodeficiency virus, Staphylococcus aureus, influenza virus, Clostridium difficile, and rhinovirus. The top five, ten, and 20 pathogens accounted for 46%, 67%, and 75% of the total infectious disease burden, respectively. Marked sex-specific differences in disease burden were observed for some pathogens. The main limitations of this study were the exclusion of certain infectious diseases due to data availability issues, not considering the impact of co-infections and co-morbidity, and the inability to assess the burden of milder infections that do not result in healthcare utilization. Conclusions/Significance Infectious diseases continue to cause a substantial health burden in high-income settings such as Ontario. Most of this burden is attributable to a relatively small number of infectious agents, for which many effective interventions have been previously identified. Therefore, these findings should be used to guide public health policy, planning, and research.