Concordance between reported medication taking behavior and prescription instructions for patients with chronic...

Understanding types and frequency of medication taking discrepancies could help design pharmacist interventions to improve adherence, outcomes, and prescribing.

This study aimed to assess concordance between participants' descriptions of chronic obstructive pulmonary disease (COPD) medication taking behaviors and prescription instructions.

Continued analysis of previously collected data. Dispensing data from 35 community pharmacies identified participants at the age of ≥ 40 years, with ≥ 1 COPD maintenance medication in the past year and self-reported COPD. Participants completed a survey of demographics, corticosteroid/antibiotic drug use, and symptom scores. Participants listed each medication and described medication taking behavior. COPD severity was classified by Global Initiative for Chronic Obstructive Lung Disease (GOLD) ABCD categories from exacerbation history and symptoms. Aggregate proportion days covered (PDC) for any 1 maintenance medicine was calculated using 12-month dispensing data. Discrepancies between medication taking and instructions were classified: (1) overuse, (2) underuse, or (3) discontinued by participant (without prescriber knowledge). Descriptive statistics summarized survey results. Chi-square compared discrepancies among long-acting bronchodilators (LABDs), inhaled corticosteroids (ICS), and short-acting bronchodilators (SABDs).

Most participants (N = 709; 27.6% urban, 70.5% rural) were highly symptomatic (GOLD groups B/D = 89.9%) and high risk (groups C/D = 59.2%). Median medication number was 4. Concordance of ICS and LABD taking behavior with prescriber instructions was 80.6% and 81.8%, respectively (P > 0.05). PDC averaged 0.46 ± 0.37; only 28.7% were adherent (i.e., PDC ≥ 0.80). ICS underuse (11.8%) exceeded LABD (5.5%). LABD discontinuation (7.4%) exceeded ICS (2.7%) or SABD (0.6%). SABD overuse (9.3%) exceeded ICS (3.4%) or LABD (4.3%) (P < 0.5 all comparisons).

Although most were highly symptomatic, high risk, and frequently described correct medication taking behavior, overall adherence was very low. Discrepancies included overuse, underuse, and self-discontinuation. Nonadherence and medication taking discrepancies may increase symptoms, exacerbations, and additional medication prescribing. Potential pharmacist strategies include regularly assessing adherence and differentiating intentional versus nonintentional nonadherence to identify and implement patient-specific interventions to encourage medication taking as prescribed.