Vancouver, BC, Canada: University of British Columbia (doctoral dissertation).
University of British Columbia, Vancouver, BC, Canada
BACKGROUND: Drug therapy is the mainstay medical treatment for asthma patients. Many asthma patients (up to 70%) receive suboptimal drug therapy. Inadequate use of inhaled corticosteroids (ICS) has been associated with increased emergency department (ED) visits and hospital admissions for asthma. To understand patients’ asthma drug use in British Columbia (B.C.) and improve health outcomes, this study describes the burden of asthma, identifies patients who received suboptimal asthma drug regimens according to asthma clinical practice guidelines, and examines the link between regimen optimality and health services utilization for asthma in an entire population with treated asthma in BC from 1996 to 2009.
METHODS: A cohort of 336,901 asthma patients between 5-55 years of age was identified using provincial health services utilization data from 1996 to 2009. Annual patient medication dispensings of short-acting bronchodilators (SABA) with or without ICS were categorized into optimal or suboptimal regimens based on the asthma clinical practice guidelines. The association between regimen optimality and health services utilization was examined in one-year, as well as during a 14-year study period, using logistic regression models and Cox Proportional regression models, respectively.
RESULTS: The prevalence (~2%) and incidence (0.7%) of asthma was stable in patients 5-55 years of age in B.C. from 1996 to 2009. Asthma-related specialist visits, ED visits and hospital admissions declined by over 50% during the study period. In 2009, patients with suboptimal regimens had significantly greater risk of using health services than patients with optimal regimens of SABA and/or ICS. Over time, switching from a suboptimal to an optimal drug regimen was associated with a 30% reduction in the use of hospital services for asthma (hazard ratio (HR) 0.71; 95% CI 0.54-0.93), and a 50% reduction in the use of ED services for asthma (HR 0.49; 95% CI 0.33 -0.73).
CONCLUSIONS: Much of the healthcare burden associated with asthma is preventable by optimizing drug therapy, in particular, with improved ICS adherence. Identifying patients with suboptimal asthma management practices is a critical step in reducing the burden of asthma on the healthcare system and ultimately improving the quality of life of asthma patients.
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