Jingqin Zhu

Progression from Asthma to Chronic Obstructive Pulmonary Disease. Is Air Pollution a Risk Factor

RATIONALE Individuals with asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS), have more rapid decline in lung function, more frequent exacerbations, and poorer quality of life than those with asthma or COPD alone. Air pollution exposure is a known risk factor for asthma and COPD; however, its role in ACOS is not as well understood. OBJECTIVES To determine if individuals with asthma exposed to higher levels of air pollution have an increased risk of ACOS. METHODS Individuals who resided in Ontario, Canada, aged 18 years or older in 1996 with incident asthma between 1996 and 2009 who participated in the Canadian Community Health Survey were identified and followed until 2014 to determine the development of ACOS. Data on exposures to fine particulate matter (PM2.5) and ozone (O3) were obtained from fixed monitoring sites. Associations between air pollutants and ACOS were evaluated using Cox regression models. MEASUREMENTS AND MAIN RESULTS Of the 6,040 adults with incident asthma who completed the Canadian Community Health Survey, 630 were identified as ACOS cases. Compared with those without ACOS, the ACOS population had later onset of asthma, higher proportion of mortality, and more frequent emergency department visits before COPD diagnosis. The adjusted hazard ratios of ACOS and cumulative exposures to PM2.5 (per 10 μg/m(3)) and O3 (per 10 ppb) were 2.78 (95% confidence interval, 1.62-4.78) and 1.31 (95% confidence interval, 0.71-2.39), respectively. CONCLUSIONS Individuals exposed to higher levels of air pollution had nearly threefold greater odds of developing ACOS. Minimizing exposure to high levels of air pollution may decrease the risk of ACOS.

Chronic disease prevalence in women and air pollution — A 30-year longitudinal cohort study

BACKGROUND Air pollution, such as fine particulate matter (PM2.5), can increase risk of adverse health events among people with heart disease, diabetes, asthma and chronic obstructive pulmonary disease (COPD) by aggravating these conditions. Identifying the influence of PM2.5 on prevalence of these conditions may help target interventions to reduce disease morbidity among high-risk populations. OBJECTIVES The objective of this study is to measure the association of exposure of PM2.5 with prevalence risk of various chronic diseases among a longitudinal cohort of women. METHODS Women from Ontario who enrolled in the Canadian National Breast Screening Study (CNBSS) from 1980 to 1985 (n = 29,549) were linked to provincial health administrative data from April 1, 1992 to March 31, 2013 to determine the prevalence of major chronic disease and conditions (heart disease, diabetes, asthma, COPD, acute myocardial infarction, angina, stroke and cancers). Exposure to PM2.5 was measured using satellite data collected from January 1, 1998 to December 31, 2006 and assigned to resident postal-code at time of entry into study. Poisson regression models were used to describe the relationship between exposure to ambient PM2.5 and chronic disease prevalence. Prevalence rate ratios (PRs) were estimated while adjusting for potential confounders: baseline age, smoking, BMI, marital status, education and occupation. Separate models were run for each chronic disease and condition. RESULTS Congestive heart failure (PR = 1.31, 95% CI: 1.13, 1.51), diabetes (PR = 1.28, 95% CI: 1.16, 1.41), ischemic heart disease (PR = 1.22, 95% CI: 1.14, 1.30), and stroke (PR = 1.21, 95% CI: 1.09, 1.35) showed over a 20% increase in PRs per 10 μg/m(3) increase in PM2.5 after adjusting for risk factors. Risks were elevated in smokers and those with BMI greater than 30. CONCLUSIONS This study estimated significant elevated prevalent rate ratios per unit increase in PM2.5 in nine of the ten chronic diseases studied.

Asthma Deaths in a Large Provincial Health System. A 10-Year Population-Based Study

RATIONALE Individuals with asthma are more likely to die from chronic conditions than the general population. Measuring only mortality with asthma listed as the primary cause of death may lead to an underestimation of total asthma mortality. OBJECTIVES To examine mortality patterns in the asthma population over 10 years, including asthma as the primary cause of death (asthma-specific mortality) and asthma as a secondary, contributing cause of death (asthma-contributing mortality). METHODS Health administrative data from Ontario, Canada were used to identify mortality rates and cause of death in subjects 0 to 99 years of age. Mortality rates were calculated in the asthma and general population from 1999 to 2008. Total asthma mortality was estimated by adding rates of asthma-specific and asthma-contributing mortality for years 2003 to 2008. MEASUREMENTS AND MAIN RESULTS Asthma-specific mortality rates per 100,000 asthma population decreased by 54.4% from 13.6 in 1999 to 6.2 in 2008. In 2008, the asthma population had higher all-cause mortality compared with the general population (rate ratio, 1.3), asthma-specific mortality rates were 60% higher among those in the lowest compared with highest socioeconomic status, and total asthma mortality was fourfold higher than asthma-specific mortality alone (21.6 vs. 5.4 per 100,000). CONCLUSIONS All-cause mortality rates have decreased substantially over the past decade. Compared with the general population, the asthma population has higher all-cause mortality and is more likely to die from comorbid conditions. Total asthma mortality was fourfold higher than asthma-specific mortality, highlighting the importance of comprehensive measurement approaches that include asthma-specific and asthma-contributing mortality.

Outcome of work-related asthma exacerbations in Quebec and Ontario

There are differences in the management of workers with work-related asthma within Canadian provinces. In Quebec, the compensation of a case of occupational asthma is usually based on the positivity of a specific inhalation challenge, whereas in Ontario, the diagnosis is usually based on serial peak expiratory flow (PEF), provocative methacholine concentration causing a 20% decrease in forced expiratory volume in 1 s (PC20) monitoring at and away from work, and specific skin-prick tests (that is, less often on specific inhalation challenges) [1]. We aimed: 1) to compare the delay between the onset of work-related asthma symptoms and the diagnosis of occupational asthma and work-exacerbated asthma between Quebec and Ontario; and 2) to assess and compare the healthcare utilisation in subjects with occupational asthma and work-exacerbated asthma between the provinces before and after the first assessment in two tertiary clinics in Quebec and Ontario that specialise in work-related asthma. Diagnosing work-related asthma decreased asthma-related healthcare utilisation in Quebec and Ontario http://ow.ly/CFrPk

Quality of asthma care under different primary care models in Canada: a population-based study

BackgroundPrevious research has shown variations in quality of care and patient outcomes under different primary care models. The objective of this study was to use previously validated, evidence-based performance indicators to measure quality of asthma care over time and to compare quality of care between different primary care models.MethodsData were obtained for years 2006 to 2010 from the Ontario Asthma Surveillance Information System, which uses health administrative databases to track individuals with asthma living in the province of Ontario, Canada. Individuals with asthma (n=1,813,922) were divided into groups based on the practice model of their primary care provider (i.e., fee-for-service, blended fee-for-service, blended capitation). Quality of asthma care was measured using six validated, evidence-based asthma care performance indicators.ResultsAll of the asthma performance indicators improved over time within each of the primary care models. Compared to the traditional fee-for-service model, the blended fee-for-service and blended capitation models had higher use of spirometry for asthma diagnosis and monitoring, higher rates of inhaled corticosteroid prescription, and lower outpatient claims. Emergency department visits were lowest in the blended fee-for-service group.ConclusionsQuality of asthma care improved over time within each of the primary care models. However, the amount by which they improved differed between the models. The newer primary care models (i.e., blended fee-for-service, blended capitation) appear to provide better quality of asthma care compared to the traditional fee-for-service model.

Characteristics of Individuals Admitted to the Intensive Care Unit for Asthma

Introduction: While asthma mortality and hospitalizations have decreased substantially over the past two decades, asthma prevalence has increased, and a number of individuals still present with severe asthma. As intensive care unit (ICU) admissions can be used as a marker for severe asthma, there is utility in continuing to monitor ICU trends and the descriptive profile of individuals admitted to the ICU. Methods: Health administrative population data from Ontario, Canada, were used to describe ICU admission trends by age group from 2003 to 2012 and the characteristics of those admitted to ICU. Descriptive analyses were performed for both hospitalized patients and ICU patients for age, sex, rurality, neighborhood income quintile and comorbidities. Results: ICU admission rates per 100,000 asthma population decreased steadily over time (56.4 in 2003; 31.1 in 2012), but increased in the 0-4 (73.9 in 2003; 85.9 in 2012) and 5-14 (11.1 in 2003; 18.8 in 2012) age groups. Compared to individuals who were hospitalized only, a greater proportion of older individuals, females, children with other respiratory conditions, and adults with acute myocardial infarction were admitted to the ICU. Conclusions: While the overall rate of ICU admissions has decreased over time, it has increased in children aged 0-14. This study identified high risk groups who are more likely to be admitted to the ICU. These individuals may benefit from targeted interventions to improve asthma control and reduce their future risk of admission to the ICU.

Frequency of health service use in the year prior to asthma death

Abstract Objective: High frequency health service use (HSU) is associated with poorly controlled asthma, and is a recognized risk factor for near-fatal or fatal asthma. The objective of this study was to describe the frequency of HSU in the year prior to asthma death. Methods: Individuals aged 0–99 years who died from asthma from April 1996 to December 2011 in Ontario, Canada were identified as cases. Cases were matched to 4–5 live asthma controls by age, sex, rural/urban residence, socioeconomic status, duration of asthma and a co-diagnosis of COPD. HSU records in the year prior to death [hospitalization, emergency department (ED) and outpatient visits] were assembled. The association of prior HSU and asthma death was measured by conditional logistic regression models. Results: From 1996 to 2011, 1503 individuals died from asthma. While the majority of cases did not have increased HSU as defined in the study, compared to matched live asthma controls, the cases were 8-fold more likely to have been hospitalized two or more times (OR = 7.60; 95% CI: 4.90, 11.77), 13-fold more likely to have had three or more ED visits (OR = 13.28; 95% CI: 7.55, 23.34) and 4-fold more likely to have had five or more physician visits for asthma (OR = 4.41; 95% CI: 3.58, 5.42). Conclusions: Frequency of HSU in the year prior was substantially higher in those died from asthma. Specifically, more than one asthma hospital admission, three ED visits or five physician visits increased the asthma mortality risk substantially and exponentially.

Association Between Inhaled Corticosteroid Use and Bone Fracture in Children With Asthma

Importance Daily use of inhaled corticosteroids is a widely recommended treatment for mild persistent asthma in children. There is concern that, similar to systemic corticosteroids, inhaled corticosteroids may have adverse effects on bone health. Objective To determine whether there is an increased risk of bone fracture associated with inhaled corticosteroid use in children with asthma. Design, Setting, and Participants In this population-based nested case-control study, we used health administrative databases to identify a cohort of children aged 2 to 18 years with a physician diagnosis of asthma between April 1, 2003, and March 31, 2014, who were eligible for public drug coverage through the Ontario Drug Benefit Program (Ontario, Canada). We matched cases of first fracture after asthma diagnosis to fracture-free controls (ratio of 1 to 4) based on date of birth (within 1 year), sex, and age at asthma diagnosis (within 2 years). We used a 1-year lookback period to ascertain history of inhaled corticosteroid use. Multivariable conditional logistic regression was used to obtain an odds ratio (OR) with 95% confidence interval for fracture, comparing no inhaled corticosteroid use vs current, recent, and past use. Exposures Inhaled corticosteroid use during the child’s 1-year lookback period, measured as current user if the prescription was filled less than 90 days prior to the index date, recent user (91-180 days), past user (181-365 days), or no use. Main Outcomes and Measures First emergency department visit for fracture after asthma diagnosis, identified using International Statistical Classification of Diseases and Related Health Problems, 10th Revision codes. Results This study included 19 420 children (61.0% male; largest proportion of children, 31.5%, were aged 6-9 years at their index date). The multivariable regression results did not show a significant association between first fracture after asthma diagnosis and current use (OR, 1.07; 95% CI, 0.97-1.17), recent use (OR, 0.96; 95% CI, 0.86-1.07), or past use (OR, 1.00; 95% CI, 0.91-1.11) of inhaled corticosteroids, compared with no use, while adjusting for sociodemographic factors and other medication use. However, use of systemic corticosteroids in the 1-year lookback period resulted in greater odds of fracture (OR, 1.17; 95% CI, 1.04-1.33). Conclusions and Relevance Systemic corticosteroids, but not inhaled corticosteroids, were significantly associated with increased odds of fracture in the pediatric asthma population.

Risk Factors for Return to the Emergency Department for Asthma: A Population-Based Study

BACKGROUND A substantial proportion of patients with asthma return after being discharged from the emergency department (ED). Given the high economic burden of acute care claims, and the impact on productivity and quality of life, a better understanding of risk factors for ED return is of interest. OBJECTIVE To quantify the rate and determine factors associated with return to the ED for asthma within 1 year of an initial ED visit for asthma. METHODS Individuals aged 5 to 99 years living in Ontario, Canada, with an ED visit for asthma in the period 2008 to 2014 were included. Descriptive statistics were used to compare those with an ED return with those without an ED return. An adjusted modified Poisson regression model was used to estimate the relative risk of ED return for asthma within 1 year after the initial discharge. RESULTS In total, 58,366 individuals met the inclusion criteria. At 1-year follow-up, 12.1% returned to the ED at least once. Younger age, being materially deprived, and having chronic obstructive pulmonary disease were significantly associated with increased risk of ED return within 1 year after the initial visit. CONCLUSIONS Nearly 1 in 8 individuals with a first ED visit for asthma returned to the ED within a year of the initial ED discharge. Targeting those at risk for ED return may help improve health care costs, productivity, and quality of life.

Asthma health services utilisation before, during and after pregnancy: a population-based cohort study

During pregnancy, females with asthma may be at higher risk of exacerbation. The objective of this study was to determine whether females with asthma in Ontario, Canada have increased health services utilisation (HSU) during pregnancy. Rates of asthma-specific, asthma-related and non-pregnancy-related HSU were calculated in a population-based cohort of pregnant females with asthma. Poisson regression with repeated measures was used to determine adjusted rate ratios and 95% confidence intervals of HSU during and 1 year after pregnancy, compared to the year before pregnancy. The cohort consisted of 103 976 pregnant females with asthma. Compared to the year prior to pregnancy, hospitalisation rates per 100 person-months during pregnancy increased 30% for asthma (from 0.016 to 0.020), 24% for asthma-related conditions (from 0.012 to 0.015) and decreased 37% for non-pregnancy-related conditions (from 0.24 to 0.15). Emergency department visits for asthma and asthma-related conditions did not increase significantly during pregnancy. During pregnancy, physician office visits decreased 19% for asthma (from 2.20 to 1.79), 10% for asthma-related conditions (from 9.44 to 8.47) and increased 74% for non-pregnancy-related conditions (from 56.4 to 98.2). Hospitalisations for asthma and asthma-related conditions increased during pregnancy, demonstrating that the overall increase in non-pregnancy-related physician office visits may not meet the primary care needs of pregnant females with asthma. Females in Ontario, Canada have increased hospitalisations and reduced primary care visits for asthma during pregnancy http://ow.ly/9yqi30iUJQM