The course of asthma activity: a population study.

BACKGROUND: Unlike most chronic diseases, which tend to progress over time, asthma is known to persist, possibly resolve, and/or present with any combination of remissions and relapses. As a result, its course has been difficult to characterize and its prognosis difficult to predict. OBJECTIVE: To quantify the proportion of individuals with asthma who have active disease and, of those, the proportion who experience significant gaps in their asthma activity; and to determine factors associated with asthma activity. METHODS: Universal population health administrative databases were used to identify all individuals with asthma living in Ontario, Canada, in 1993 and follow them for 15 years. Active asthma was indicated by 1 or more physician claims for asthma. RESULTS: Of 613,394 individuals with asthma in 1993, 504,851 (82.3%) had active disease in subsequent years. Of those who had complete follow-up, 74.6% experienced a gap of 2 or more years in their asthma activity. Previous asthma claims, older and younger age, and a codiagnosis of chronic obstructive pulmonary disease correlated with greater asthma activity. CONCLUSION: Over 15 years, most individuals with asthma in Ontario, Canada, had active disease that was interspersed by periods of inactivity when they did not require medical attention and were likely in remission. These analyses offer insight into the natural course of asthma activity that may help improve the ability to predict an individual's course of disease.

What is the lifetime risk of physician-diagnosed asthma in Ontario, Canada?

RATIONALE: Asthma is the most common chronic respiratory disease in Canada. The estimates of risk of developing asthma may help researchers and health planners set research agendas, predict the burden of asthma on society, and target the at-risk population for asthma prevention, management, and control. OBJECTIVES: To estimate the lifetime risk of physician-diagnosed asthma. METHODS: All individuals aged 0-79 years living in Ontario, Canada on April 1, 1996 who had not been diagnosed with asthma were monitored for 11 years until March 31, 2007. They were censored when they were diagnosed with asthma, turned age 80 years, or died. The lifetime risk (from birth to age 79 yr) of physician-diagnosed asthma was calculated by a modified survival analysis technique. Results were stratified by sex, rurality, and neighborhood income. MEASUREMENTS AND MAIN RESULTS: Overall, the lifetime risk of physician-diagnosed asthma was 33.9%. Whereas the overall lifetime risk was higher in females (35.0 vs. 32.9%; P < 0.001), the cumulative risk was higher in males in early years. The lifetime risk was higher in individuals living in urban areas (34.5 vs. 30.1%; P < 0.001) or low-income neighborhoods (35.0% in the lowest income quintile vs. 32.2% in the highest; P < 0.001). CONCLUSIONS: Our estimated overall lifetime risk indicates that one of every three individuals in Ontario, Canada has physician-diagnosed asthma during one's lifetime.

Trends in asthma prevalence and incidence in Ontario, Canada, 1996-2005: a population study.

In the 1980s and early 1990s, asthma prevalence increased significantly in most Westernized countries. In more recent years, asthma trends have been less clear, with some studies suggesting that they are still rising and others suggesting that they have stabilized or decreased. A population-based cohort study was conducted to estimate asthma prevalence and incidence trends in one large Canadian province, Ontario. All individuals with asthma living in Ontario, a province of Canada with a multicultural population of approximately 12 million, were identified in universal, population health administrative databases by using a validated health administrative case definition of asthma. Annual asthma prevalence, incidence, and all-cause mortality rates were estimated from 1996 to 2005. During this time, the prevalence of asthma increased by 70.5%. The age- and sex-standardized asthma prevalence increased from 8.5% in 1996 to 13.3% in 2005, a relative increase of 55.1% (P < 0.0001). Asthma incidence rates increased in children by 30.0% and were relatively stable in adults. Overall all-cause mortality decreased. Asthma prevalence in Ontario, Canada, has increased significantly. This is attributable, in part, to an increase in the incidence of asthma in children. Effective clinical and public health strategies are needed to prevent and manage asthma in the population.

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.

Evidence-based performance indicators of primary care for asthma: a modified RAND Appropriateness Method.

PURPOSE: To develop evidence-based performance indicators that measure the quality of primary care for asthma. DATA SOURCES: Cochrane Database of Systematic Reviews, MEDLINE, EMBASE and CINAHL for peer-reviewed articles published in 1998-2008 and five national/global asthma management guidelines. STUDY SELECTION: Articles with a focus on current asthma performance indicators recognized or used in community and primary care settings. Data extraction Modified RAND Appropriateness METHOD: was used. The work described herein was conducted in Canada in 2008. Five clinician experts conducted the systematic literature review. Asthma-specific performance indicators were developed and the strength of supporting evidence summarized. A survey was created and mailed to 17 expert panellists of various disciplines, asking them to rate each indicator using a 9-point Likert scale. Percentage distribution of the Likert scores were generated and given to the panellists before a face-to-face meeting, which was held to assess consensus. At the meeting, they ranked all indicators based on their reliability, validity, availability and feasibility. RESULTS: Literature search yielded 1228 articles, of which 135 were used to generate 45 performance indicators in five domains: access to care, clinical effectiveness, patient centeredness, system integration and coordination and patient safety. The top five ranked indicators were: Asthma Education from Certified Asthma Educator, Pulmonary Function Monitoring, Asthma Control Monitoring, Controller Medication Use and Asthma Control. CONCLUSION: The top 15 ranked indicators are recommended for implementation in primary care to measure asthma care delivery, respiratory health outcomes and establish benchmarks for optimal health service delivery over time and across populations.

How much do health care providers value a community-based asthma care program? A survey to collect their opinions on the utilities of and barriers to its uptake.

BACKGROUND: A comprehensive asthma care program (ACP) based on Canadian Asthma Consensus Guidelines was implemented in 8 primary care sites in Ontario, Canada. A survey was distributed to health care providers' (HCPs) to collect their opinions on the utilities of and barriers to the uptake of the ACP. METHODS: A 39-item self-administered survey was mailed to 184 HCPs and support staff involved in delivering the ACP at the end of implementation. The items were presented in mixed formats with most items requiring responses on a five-point Likert scale. Distributions of responses were analyzed and compared across types of HCPs and sites. RESULTS: Of the 184 surveys distributed, 108 (59%) were returned, and of that, 83 were completed by HCPs who had clinical contact with the patients. Overall, 95% of the HCPs considered the ACP useful for improving asthma care management. Most HCPs favored using the asthma care map (72%), believed it decreased uncertainties and variations in patient management (91%), and considered it a convenient and reliable source of information (86%). The most commonly reported barrier was time required to complete the asthma care map. Over half of the HCPs reported challenges to using spirometry, while almost 40% identified barriers to using the asthma action plan. CONCLUSION: Contrary to the notion that physicians believe that guidelines foster cookbook medicine, our study showed that HCPs believed that the ACP offered an effective and reliable approach for enhancing asthma care and management in primary care.

Examining intra-rater and inter-rater response agreement: a medical chart abstraction study of a community-based asthma care program.

BACKGROUND: To assess the intra- and inter-rater agreement of chart abstractors from multiple sites involved in the evaluation of an Asthma Care Program (ACP). METHODS: For intra-rater agreement, 110 charts randomly selected from 1,433 patients enrolled in the ACP across eight Ontario communities were re-abstracted by 10 abstractors. For inter-rater agreement, data abstractors reviewed a set of eight fictitious charts. Data abstraction involved information pertaining to six categories: physical assessment, asthma control, spirometry, asthma education, referral visits, and medication side effects. Percentage agreement and the kappa statistic (kappa) were used to measure agreement. Sensitivity and specificity estimates were calculated comparing results from all raters against the gold standard. RESULTS: Intra-rater re-abstraction yielded an overall kappa of 0.81. Kappa values for the chart abstraction categories were: physical assessment (kappa 0.84), asthma control (kappa 0.83), spirometry (kappa 0.84), asthma education (kappa 0.72), referral visits (kappa 0.59) and medication side effects (kappa 0.51). Inter-rater abstraction of the fictitious charts produced an overall kappa of 0.75, sensitivity of 0.91 and specificity of 0.89. Abstractors demonstrated agreement for physical assessment (kappa 0.88, sensitivity and specificity 0.95), asthma control (kappa 0.68, sensitivity 0.89, specificity 0.85), referral visits (kappa 0.77, sensitivity 0.88, specificity 0.95), and asthma education (kappa 0.49, sensitivity 0.87, specificity 0.77). CONCLUSION: Though collected by multiple abstractors, the results show high sensitivity and specificity and substantial to excellent inter- and intra-rater agreement, assuring confidence in the use of chart abstraction for evaluating the ACP.

Describing and quantifying asthma comorbidity [corrected]: a population study.

BACKGROUND: Asthma comorbidity has been correlated with poor asthma control, increased health services use, and decreased quality of life. Managing it improves these outcomes. Little is known about the amount of different types of comorbidity associated with asthma and how they vary by age. METHODOLOGY/PRINCIPAL FINDINGS: The authors conducted a population study using health administrative data on all individuals living in Ontario, Canada (population 12 million). Types of asthma comorbidity were quantified by comparing physician health care claims between individuals with and without asthma in each of 14 major disease categories; results were adjusted for demographic factors and other comorbidity and stratified by age. Compared to those without asthma, individuals with asthma had higher rates of comorbidity in most major disease categories. Most notably, they had about fifty percent or more physician health care claims for respiratory disease (other than asthma) in all age groups; psychiatric disorders in individuals age four and under and age 18 to 44; perinatal disorders in individuals 17 years and under, and metabolic and immunity, and hematologic disorders in children four years and under. CONCLUSION/SIGNIFICANCE: Asthma appears to be associated with significant rates of various types of comorbidity that vary according to age. These results can be used to develop strategies to recognize and address asthma comorbidity to improve the overall health of individuals with asthma.

Is large birth weight associated with asthma risk in early childhood?

OBJECTIVE: To determine the association between large birth weight and the risk of developing asthma in early childhood. METHODS: All single live births (n=687 194) born in Ontario between 1 April 1995 and 31 March 2001 were followed until their sixth birthday. Their birth weight was categorised as low (<2.5 kg), normal (2.5-4.5 kg), large (4.6-6.5 kg) or extremely large (>6.5 kg). Poisson regression analysis was used. RESULTS: Compared with normal-birth-weight infants, large-birth-weight infants (2.3% of total) had a slightly lower risk of developing asthma by age 6 after adjusting for confounders (adjusted RR 0.90, 95% CI 0.86 to 0.93). There was a trend towards increased risk of asthma among extremely large-birth-weight infants (RR 1.21, 95% CI 0.67 to 2.19). CONCLUSIONS: Contrary to previous reports, large birth weight was associated with a lower risk for asthma. Instead, a trend towards increased risk of asthma was observed among extremely large-birth-weight infants and interventions to reduce the incidence of extreme large birth weight may help reduce the risk of asthma.

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.

Can an evidence-based guideline reminder card improve asthma management in the emergency department?

OBJECTIVE: Asthma is the most common chronic disease in children. Previous studies described significant variations in acute asthma management in children. This study was conducted to examine whether asthma management in the pediatric emergency department (ED) was improved through the use of an evidence-based acute asthma care guideline reminder card. METHODS: The Pediatric Acute Asthma Management Guideline (PAMG) was introduced to the ED of a pediatric tertiary care hospital in Ontario, Canada. Medical charts of 278 retrospective ED visits (January-December 2002) and 154 prospective visits (July 2003-June 2004) were reviewed to assess changes in acute asthma management such as medication treatment, asthma education, and discharge planning. Logistic and linear regressions were used to determine the effect of PAMG on asthma management in the ED. The propensity score method was used to adjust for confounding. RESULTS: During the implementation of PAMG, patients who visited the ED were more likely to receive oral corticosteroids (Adjusted Odds Ratio [AOR] = 2.26, 95% CI: 1.63-3.14, p < 0.0001) and oxygen saturation reassessment before ED discharge (AOR = 2.02, 95% CI: 1.45-2.82, p < 0.0001). They also received 0.23 (95% CI: 0.03-0.44, p = 0.0283) more doses of bronchodilator in the first hour of ED stay. Improvements in asthma education and discharge planning were noted, but the changes were not statistically significant. CONCLUSIONS: After the implementation of an evidence-based guideline reminder card, medication treatment for acute asthma in the ED was significantly improved; however, asthma education and discharge planning remained unchanged. Future efforts on promoting guideline-based practice in the ED should focus on these components.

Neighborhood income and health outcomes in infants: how do those with complex chronic conditions fare?

OBJECTIVE: To quantify the effect of socioeconomic status (SES) on health outcomes during the first year after newborn discharge among infants with complex chronic conditions (CCCs) insured through a universal health plan. DESIGN: Longitudinal, population-based cohort study. SETTING: Ontario, Canada. PARTICIPANTS: Infants born in hospitals from April 1, 1996, through March 31, 2000. Infants with CCCs were identified from their newborn discharge records. Neighborhood income quintiles were obtained by linking participants' postal codes to census data. MAIN OUTCOME MEASURES: Mortality and hospital admissions in the first year after newborn discharge. Logistic and Poisson regression analyses were used to examine the relationship between neighborhood income quintiles and outcomes, adjusting for important covariates such as low birth weight and rural residence. RESULTS: A total of 512 768 infants were included, of whom 2.3% had CCCs at newborn discharge. Infants with CCCs accounted for 37.8% of deaths and 11.0% of hospitalizations during the first year after the newborn discharge. Infants with CCCs living in the lowest-income neighborhoods had a 1.26-fold higher mortality risk (95% confidence interval, 0.83-1.90; P = .28) and a 1.24-fold higher hospitalization rate (1.09-1.40; P < .001) compared with those living in the highest-income neighborhoods. Although the income gradients associated with mortality and hospitalization were less pronounced among infants with CCCs compared with infants without CCCs, the absolute interquintile risk differences attributable to SES were higher among infants with CCCs. CONCLUSIONS: Despite universal health insurance, SES-related inequality affects hospitalization and, possibly, mortality rates among medically vulnerable infants.

Identifying patients with physician-diagnosed asthma in health administrative databases.

BACKGROUND: Asthma imposes a heavy and expensive burden on individuals and populations. A population-based surveillance and research program based on health administrative data could measure and study the burden of asthma; however, the validity of a health administrative data diagnosis of asthma must first be confirmed. OBJECTIVE: To evaluate the accuracy of population-based provincial health administrative data in identifying adult patients with asthma for ongoing surveillance and research. METHODS: Patients from randomly selected primary care practices were assigned to four categories according to their previous diagnoses: asthma, chronic obstructive pulmonary disease, related respiratory conditions and nonasthma conditions. In each practice, 10 charts from each category were randomly selected, abstracted, then reviewed by a blinded expert panel who identified them as asthma or nonasthma. These reference standard diagnoses were then linked to the patients' provincial records and compared with health administrative algorithms designed to identify asthma. Analyses were performed using the concepts of diagnostic test evaluation. RESULTS: A total of 518 charts, including 160 from individuals with asthma, were reviewed. The algorithm of two or more ambulatory care visits and/or one or more hospitalization(s) for asthma in two years had a sensitivity of 83.8% (95% CI 77.1% to 89.1%) and a specificity of 76.5% (95% CI 71.8% to 80.8%). CONCLUSION: Definitions of adult asthma using health administrative data are sensitive and specific for identifying adults with asthma. Using these definitions, cohorts of adults with asthma for ongoing population-based surveillance and research can be developed.

Risk factors for repeat adverse asthma events in children after visiting an emergency department.

OBJECTIVE: The aim of this study was to identify risk factors for long-term adverse outcomes in children with asthma after visiting the emergency department (ED). METHODS: A prospective observational study was conducted at the ED of a pediatric tertiary hospital in Ontario, Canada. Patient outcomes (ie, acute asthma episodes and ED visits) were measured at baseline and at 1- and 6-months post-ED discharge. Time trends in outcomes were assessed using the generalized estimating equations method. Multiple conditional logistic regressions were used to model outcomes at 6 months and examine the impact of drug insurance coverage while adjusting for confounders. RESULTS: Of the 269 children recruited, 81.8% completed both follow-ups. ED use significantly reduced from 39.4% at baseline to 26.8% at 6 months (P < .001), whereas the level of acute asthma episodes remained unchanged. Children with drug insurance coverage were less likely to have acute asthma episodes (adjusted odds ratio [AOR] = 0.36; 95% CI, 0.15-0.85; P < .02) or repeat ED visits (AOR = 0.45; 95% CI, 0.20-0.99; P < .05) at 6 months. Other risk factors for adverse outcomes included previous adverse asthma events and certain asthma triggers (eg, cold/sinus infection). Washing bed linens in hot water weekly was protective against subsequent acute asthma episodes. CONCLUSIONS: Our study demonstrated significant improvements in long-term outcomes in children seeking acute care for asthma in the ED. Future efforts remain in targeting the sustainability of improved outcomes beyond 6 months. Risk factors identified can help target vulnerable populations for proper interventions, which may include efforts to maximize insurance coverage for asthma medications and strategies to improve asthma self-management through patient and provider education.

Persistence and remission in childhood asthma: a population-based asthma birth cohort study.

OBJECTIVES: To examine and predict the persistence of childhood asthma. DESIGN: Longitudinal population-based cohort study. SETTING: Ontario, Canada. PARTICIPANTS: Children born in 1994 and diagnosed with asthma before age 6 years were followed up until age 11 years. Diagnosis of asthma was defined as 1 asthma hospitalization or 2 asthma physician claims within 3 years prior to age 6 years. MAIN EXPOSURE: Intensity of health services use within 1 year postdiagnosis. MAIN OUTCOME MEASURES: Those who continued to have asthma events (hospitalization and/or physician visit) between ages 6 and 11 years were considered to have "persistent asthma," while others were in "remission." Cumulative rates of health services use for asthma during follow-up were calculated. Logistic regression analysis was used to estimate risks of persistent asthma. RESULTS: The study included 34,216 children diagnosed with asthma before age 6 years. More than half (54.4%) experienced a second asthma health care encounter within 1 year after diagnosis. By age 12 years, nearly half (48.6%) were in remission. Children with asthma hospitalization during the first year postdiagnosis had a 3-fold risk of persistent asthma by age 12 years (95% confidence interval, 2.69-3.39; P < .001). Those with at least 4 physician visits also had a 2.6-fold risk of persistent asthma during follow-up (95% confidence interval, 2.34-2.81; P < .001). CONCLUSION: The concentration of health services use within 1 year following the initial diagnosis of childhood asthma points to the need for attentive follow-up and ongoing management and education strategies in the early years.