Effect of an Asthma Exacerbation on Medication Adherence

Abstract

Background: Few studies have looked at the effect of an asthma exacerbation on asthma medication adherence.

Objective: To measure asthma medication adherence in the 12 months after an asthma exacerbation and the influence of care type (specialist vs primary care provider) as well as social economic status on adherence.

Methods: We measured portion of days covered (PDC) during the 12 months before and after an exacerbation in a cohort of patients with asthma who were aged 18 years and older. Subanalyses looked at PDC in those who had more than one exacerbation after the sentinel exacerbation, by type of care received (primary care, allergist or pulmonologist, or no care) during both periods and by socioeconomic status (SES), defined as the lower quartile of annual income for the group.

Results: In a cohort of 1,697 patients, PDC improved significantly (from 0.44 to 0.53; P < .001) after an asthma exacerbation. Improvement in PDC was even greater (from 0.45 to 0.57; P < .001) if they had more than one exacerbation after the sentinel exacerbation. Being seen by a specialist after the exacerbation but not before it, resulted in the greatest improvement in PDC (0.17 mean change). Patients not seen by a specialist either before the exacerbation or after had a mean change of just 0.07. Those with a lower SES had an overall lower PDC before the exacerbation (0.37 vs 0.43) but saw a similar improvement in the PDC compared with those in a higher SES (0.09 vs 0.10).

Conclusions: An asthma exacerbation is associated with a significant and sustained effect on medication adherence.

Keywords: Asthma exacerbations; Asthma medication adherence; Specialty care.

Figure 1:

Illustration of proportion of days covered 12 months prior to asthma exacerbation and 12 months after exacerbation by number of exacerbations in 2018, one exacerbation, n=1349; two exacerbations, n=677. Each time point represents month x to month x + 1. Abbreviations: PDC: proportion of days covered

Figure 2:

Illustration of proportion of days covered 12 months prior to asthma exacerbation and 12 months after exacerbation by time from exacerbation and type of care, primary care exclusively, n=936; primary care baseline to specialty care after exacerbation, n=242; specialty care baseline to primary care after exacerbation, n=116; specialty care exclusively, n=186 Abbreviations: PC=Primary care; SC=Specialty care

Figure 3:

Illustration of proportion of days covered 12 months prior to asthma exacerbation and 12 months after exacerbation by time from exacerbation and socioeconomic status (low (n=515) versus higher (n=1510)) Abbreviations: SES=socioeconomic status; PDC=proportion of days covered