Measuring reversible airflow obstruction and/or methacholine hyper-reactivity in all individuals referred for asthma specialty care
Sunday, March 4, 2018
South Hall A2 (Convention Center)
RATIONALE: Asthma is commonly over-diagnosed. Referral often occurs when primary care management fails, frequently from misdiagnosis.

METHODS: All newly referred individuals, age 12 to 64, with a clinical or administrative asthma diagnosis, seen by one Allergist, were initially evaluated for clinical symptoms compatible with asthma. If compatible, they were requested to get lung function tests (PFTs), and if those tests did not show reversible airflow obstruction, a methacholine challenge (MC), as part of a quality improvement project for maintenance of certification.

RESULTS: There were 171 individuals with an asthma diagnosis seen between 4-2-2013 and 3-25-2014 and followed through 5-31-2017. There were 65 (38.0%) seen for symptoms unrelated to asthma and denied any recent asthma symptoms or therapy. Among the remaining 106 (62%) with asthma-compatible symptoms, 40 (23.4%) either refused PFTs, 8 (20%), or had normal PFTs but declined a MC, 32 (80%). Asthma was confirmed in 25 (14.6%), 22 (88%) by >12% increase in FEV1 and only 3 (12%) by positive MC. There were 41 (24.0%) with asthma-compatible symptoms, completely normal PFTs, and negative MC. Frequent associations with asthma-compatible symptoms included reflux in 40, post-viral cough in 35, ACE inhibitor use in 11, and sleep apnea in 9.

CONCLUSIONS: It was possible to document asthma by clinical symptoms and confirmatory PFTs or MC in only a small minority of individuals with a clinical or administrative diagnosis of asthma referred for specialty care. It was difficult to get both complete PFTs, and if normal, methacholine challenges in all individuals with asthma-compatible symptoms.