A comprehensive study of the direct and indirect costs of adult asthma

Background: Asthma is a common and costly health condition, but most estimates of its economic effect have relied on secondary sources with limited condition-specific detail. Objective: We sought to estimate the magnitude of direct and indirect costs of adult asthma from the perspective of society. Methods: We used cross-sectional survey data from an ongoing community-based panel study of 401 adults with asthma originally derived from random samples of northern California pulmonologists, allergist-immunologists, and family practitioners to assess health care use for asthma, to assess purchase of items to assist with asthma care, and to measure work and other productivity losses. Unit costs derived from public-use and proprietary data sources were then assigned to the survey items. Results: Total per-person annual costs of asthma averaged $4912, with direct and indirect costs accounting for $3180 (65%) and $1732 (35%), respectively. The largest components within direct costs were pharmaceuticals ($1605 [50%]), hospital admissions ($463 [15%]), and non-emergency department ambulatory visits ($342 [11%]). Within indirect costs, total cessation of work accounted for $1062 (61%), and the loss of entire work days among those remaining employed accounted for another $486 (28%). Total per-person costs were $2646, $4530, and $12,813 for persons self-reporting mild, moderate, and severe asthma, respectively (P < .0001, 1-way ANOVA). Conclusion: Asthma-related costs are substantial and are driven largely by pharmaceuticals and work loss.