Variation in out‐of‐Pocket Spending Among Low‐Income Versus High‐Income Commercially Insured Patients with Asthma

Abstract

Research ObjectivePatient cost‐sharing has been increasing over the past two decades, in particular due to high‐deductible health plans (HDHP). Asthma is a very common, serious, chronic disease in the United States. We analyzed a large, national sample of asthma patients to provide new evidence on OOP spending overall, across types of asthma care, and variation by patient income.Study DesignWe used 11 years (2004‐2014) of enrollment, claims, and geocoded census tract data on income. Annual OOP costs were measured as the sum of actual patient‐paid deductible, coinsurance and copayments on all medical care; spending was adjusted to 2014 dollars using the Medical CPI. Annual asthma OOP spending included OOP payments for asthma services (ie, asthma medications, office and emergency department (ED) visits, and hospitalizations with ICD‐9 codes for asthma, spacers for inhalers, asthma nebulizers). Patient income was measured using the census tract income associated with the patient’s address, and then, patients were categorized into income quintiles based on the distribution of household income across the United States (eg, not within sample). We report the association of OOP spending with patient income based on linear regression models controlling for patient age, sex, state, morbidity and asthma severity (using the Johns Hopkins ACG system), and year; models were stratified by annual HDHP enrollment.Population StudiedAll patients ages 4‐64 years with asthma (defined as having an asthma ICD‐9 diagnosis code for an outpatient or ED visit or hospitalization) in a large, national Commercial and Medicare Advantage claims database (n = 2 018 178).Principal FindingsMore patients in the lowest‐income quintile had a HDHP. Within plan type, levels of spending associated with income quintiles were similar but represented a significantly larger proportion of income for the lowest‐income quintile (Table).ConclusionsBecause patients spent similar amounts of OOP for asthma care, the lowest‐income quintile patients experienced greater cost burden. The majority of OOP asthma spending was on asthma medications, but lowest‐income quintile patients had greater spending on high acuity care than those in higher income quintiles.Implications for Policy or PracticeEfforts should be made to understand whether these differences in cost burden are associated with cost‐related underuse of medications or other adverse outcomes to inform policy and insurance benefit design.Primary Funding SourcePatient‐Centered Outcomes Research Institute.