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A1352 - Predicting Positive Bronchial Challenge Test in Older Adults with Asthma
Author Block: B. J. Polivka1, R. Cavallazzi2, A. Jorayeva2, J. Myers3, B. L. Beatty4, R. J. Folz5; 1School of Nursing, University of Louisville, Louisville, KY, United States, 2University of Louisville, Louisville, KY, United States, 3Pediatrics, University of Louisville, Louisville, KY, United States, 4Department of Medicine/Pulmonary, University of Louisville, Louisville, KY, United States, 5Pulmonary, Critical Care and Sleep Medicine, Case Western Reserve University, Cleveland, OH, United States.
Rationale: Asthma is a chronic inflammatory airway disease characterized by variable airflow limitation. In adults, the prevalence of asthma is about 9%. The diagnosis and evaluation of asthma can especially be challenging in older adults. Many patients with asthma do not demonstrate airflow obstruction nor show bronchodilator reversibility. This study aimed to investigate predictors of a positive bronchial challenge test with methacholine (MCT) in older adults with asthma. Methods: This is an ancillary study to the ongoing “Asthma in Older Adults: Identifying phenotypes and factors impacting outcomes” (NIH, National Institute on Aging). The parent study is a prospective cohort study that longitudinally follows older adults with asthma. This investigation is a diagnostic accuracy study with a cross-sectional design. Non-smoking adults ≥ 60 years with suspected asthma and a negative postbronchodilator response on spirometry were included. All participants underwent a MCT. Standard asthma screening questions and additional clinical questions were evaluated for their positive MCT result predictive value. Results: The majority of the 53 participants in these analyses were female (n=36, 67.9%) and the average age was 66.9±5.3 years, had a body mass index of 31.7, FEV1 of 2.2 liters (91.6% predicted), and fractional exhaled nitric oxide of 25.0 ppb. Most had recurrent attacks of wheezing (n=46, 86.8%), a troublesome cough at night ((n=30, 56.6%), wheeze or cough after exercise (n=40, 75.5%), wheezing or cough when exposed to airborne allergens (n=49, 92.5%), colds that went to their chest or lasted longer than 10 days (n=32, 60.4%) and symptom improvement after receiving appropriate treatment (n=52, 98.1%). Those with a positive MCT (n=32; 60.4%) were more likely to: (1) have recurrent attacks of wheezing (94% vs. 71%; P=.028), and (2) have a history of hypertension (69% vs. 33%, P=.014). After adjustment, recurrent attacks of wheezing (OR=5.5, 95% CI 2.4-7.7, P=.021) and history of hypertension (OR=6.2, 95% CI 3.4-10.6, P=.007) remained significant independent predictors of a positive MCT. Conclusions: With aging of the population, the number of older adults with asthma are projected to increase. Clinicians who care for older patients are often faced with the challenging task of making rapid clinical decisions. Study results revealed that in older adults with suspected asthma, those with recurrent attacks of wheezing and those with a history of hypertension had an increased probability of a positive MCT. Further research is warranted to validate these findings in a larger, more diverse population.