Lower physician estimate of underlying asthma severity leads to undertreatment

Background: Asthma undertreatment has been linked to poor outcomes. National guidelines recommend that physicians classify asthma severity based on pretreatment symptoms and titrate care as the disease changes in the individual patient. This study evaluated the extent to which the physician estimate of underlying severity affects a patient's asthma care. Methods: Data used were collected from a cohort of adults with asthma enrolled in managed care. Eligible patients were adults enrolled in managed care with medical encounters coded for asthma. Physicians were eligible if they were main asthma providers. The patient survey covered demographics, symptoms, asthma treatment, and self-management knowledge. Physicians were asked to assess the underlying severity of their patients' asthma. Results: There were 4005 patients with asthma with physician estimates of underlying severity. Of the patients, 70.1% were female (mean age, 44.8 years) and 83.5% were white. Most patients' current asthma symptoms were moderate (39.4%) and severe (50.1%). Most physician estimates of underlying severity were mild (44.6%) and moderate (44.5%). Among those patients reporting moderate symptoms, daily inhaled corticosteroid use was reported in 35.2% when physician estimates were mild, 53.0% when moderate, and 68.1% when severe (P=.001). Rates of peak flowmeter ownership, allergy testing, and self-management knowledge tracked similarly with physician estimates of underlying severity. Conclusions: Physician estimates of underlying asthma severity appear to determine asthma care. For patients with inadequate symptom control, lower physician estimates of underlying severity were associated with care that is less consistent with national guidelines. To improve the quality of asthma care, physicians need to update treatment based on their patients' current symptoms and adapt care accordingly.