Factors associated with acute health care use in a national adult asthma management program Tze-Pin Ng, MD*; Tow-Keang Lim, MMed†; John Abisheganaden, MMed‡; Philip Eng, MMed§; and Fai-Lam Sin, FRCP¶ Background: The use of acute health care resources for asthma is considerable. Disease severity is an established risk factor, but ethnicity and health care factors are less well studied. Objective: To investigate the independent associations of ethnicity and health care factors with acute resource use for asthma. Methods: Longitudinal data from a national adult asthma management program providing universal access to care were analyzed. Outcome measures were unscheduled physician visits with urgent nebulization, emergency department (ED) visits, and hospitalizations. Results: In multivariate analyses, markers of disease severity were found to be significantly associated with all acute resource use. After controlling for disease severity, ethnicity was associated with increased risk of all acute resource use; Indian (vs Chinese) ethnicity was associated with increased risk of unscheduled physician visits (hazard ratio [HR], 1.32; 95% confidence interval [CI], 1.03–1.70), ED visits (HR, 1.61; 95% CI, 1.12–2.32), and hospitalizations (HR, 1.49; 95% CI, 1.03–2.16). Malay ethnicity was associated with unscheduled physician visits (HR, 1.30; 95% CI, 1.01–1.68) and ED visits (HR, 1.55; 95% CI, 1.09 –2.19). Default of follow-up appointments was associated with unscheduled physician visits (HR, 1.47; 95% CI, 1.08 –2.00), ED visits (HR, 2.35; 95% CI, 1.59 –3.45), and hospitalizations (HR, 1.74; 95% CI, 1.09 –2.76). Poor inhaler technique was associated with ED visits (HR, 1.86; 95% CI, 1.05–3.30) and smoking with unscheduled physician visits (HR, 1.38; 95% CI, 1.09 –1.76). Conclusions: In addition to markers of asthma severity, ethnicity, smoking, discontinuity of care, and self-care behavior are risk factors for acute resource utilization and represent target groups and elements of asthma intervention for improving asthma outcomes. Ann Allergy Asthma Immunol. 2006;97:784–793. INTRODUCTION Despite therapeutic advances, asthma remains an important cause of ill health in the population and consumes consider- able health care service resources. 1 This occurs because many patients who have poorly controlled asthma have frequent relapse of asthma attacks requiring unscheduled visits to physicians, emergency department (ED) visits, or admissions to the hospital. Delineating the factors 2–37 that contribute to increased use of acute health care services for asthma is key to targeted and effective intervention. Clinical and proxy markers of disease severity 13,15,24,30,34 are consistently reported to be important predictive factors. However, the effects of ethnicity and self-care behavior factors are much less under- stood. Ethnicity 13–26 has been reported in population studies to be associated with higher hospitalization rates for asthma. Whether such ethnic disparity in acute services use is attrib- utable to differences in disease severity, socioeconomic sta- tus, health care access, or other factors is not well understood. An estimated 4.5% of the population in Singapore reported a physician diagnosis of asthma in their lifetime, and 2.2% reported experiencing asthma in the current year. 38 It is the fifth most common reason for hospital discharges. 39 Previous population-based studies have documented that in multiethnic Singapore, the prevalence of current asthma in Malays (3.3%) and Indians (4.5%) is higher than that in Chinese people (0.9%). Rates of asthma hospital admissions were higher in Malays (3.3 per 1,000) and Indians (4.1 per 1,000) than in Chinese people (1.2 per 1,000). 40 Also, asthma mortality rates in Malays and Indians were 4 and 2 to 3 times higher, respectively, than in Chinese people. 41 In this prospective open cohort study, we investigated the factors associated with subsequent urgent physician visits, ED visits, and hospital admissions. In particular, we exam- ined whether ethnicity was a risk factor, independent of disease severity and other risk factors, and whether patient self-care behavior and other potentially modifiable factors were associated with acute resource use. * Gerontological Research Programme, Faculty of Medicine, and Depart- ment of Psychological Medicine, National University of Singapore, Singa- pore. † Division of Respiratory Medicine, National University Hospital, National University of Singapore, and Singapore National Asthma Programme, Sin- gapore. ‡ Department of Respiratory Medicine, Tan Tock Seng Hospital, Singapore. § Department of Respiratory Medicine, Singapore General Hospital, Singa- pore. ¶ Department of Medicine, Alexander Hospital. The National Asthma Management Programme (HSDP 01  05) was sup- ported by the Ministry of Health, Singapore. Received for publication July 19, 2006. Accepted for publication in revised form August 7, 2006. 784 ANNALS OF ALLERGY, ASTHMA & IMMUNOLOGY