Increasing pharmaceutical copayments: impact on asthma medication utilization and outcomes

Area of Science:

• Health Services Research
• Pharmacoeconomics
• Respiratory Medicine

Background:

• Changes in pharmacy benefit design can lead to unintended consequences.
• Patient cost-sharing for medications impacts adherence and healthcare utilization.

Purpose of the Study:

• To determine the impact of increased patient copayments for long-term asthma controller (LTC) medications on medication use and healthcare services.
• To analyze how copayment changes affect adherence to inhaled corticosteroids (ICS), ICS plus long-acting beta agonist (COMBO), and leukotriene receptor antagonist (LTRA) therapies.

Main Methods:

• Utilized 2005 MarketScan claims data to identify asthma patients aged 12-64.
• Employed multivariable models to assess associations between copayment changes and LTC consumption and asthma-related visits.
• Categorized patients based on an average copayment increase of ≥ $5 per month of medication supplied.

Main Results:

• A copayment increase of ≥ $5/month resulted in significant reductions in medication supply days: -47.1 for ICS, -35.3 for COMBO, and -47.5 for LTRA.
• Patients with ≥ $5 copayment increases showed significantly more asthma-related outpatient visits and emergency department (ED) visits compared to those with < $5 increases.
• Mean annual copayment changes varied by medication class, with notable increases for ICS, COMBO, and LTRA users in the ≥ $5 group.

Conclusions:

• Even modest increases in average copayments for asthma medications can lead to substantial decreases in medication use.
• Increased copayments for asthma controllers are associated with unintended increases in healthcare service utilization, including outpatient and ED visits.
• Pharmacy benefit design modifications require careful consideration of potential adverse effects on patient adherence and overall healthcare costs.