OBJECTIVES: Health plan claims databases are used extensively for health outcomes research, with prescription claims used as a proxy for drug utilization. Prescription claims may be missing in payer-sourced data due to the use of alternative forms of payment not captured in the database including discount cards, cash, Medicaid and Medicare PartD. This study quantifies the extent of missing prescription claims information for asthma patients when using payer-sourced claims alone and shows how appending with point-of-sale data (POS) may provide a more accurate proxy for utilization.

METHODS: A retrospective cohort study using the payer-sourced PharMetrics® Plus database identified patients with a medical claim having an asthma diagnosis and continuous medical and pharmacy eligibility (CE) between 1/1/19-12/31/20. The patients were then linked to the IQVIA POS database (Longitudinal Access and Adjudicated Data). All prescriptions for inhaled corticosteroid/long-acting beta agonist combinations (ICS/LABA) or oral corticosteroids (OCS) were identified. The merged prescription data were then de-duplicated to identify prescription utilization that was missing when payer-sourced data alone were evaluated. The number of patients with missing claims, the volume of missing claims, and the payment type of those claims were assessed.

RESULTS: Of 856,351 asthma patients with 2-year CE identified using payer-sourced claims alone, 689,709 (80.5%) were linkable to point-of-sale data. Of these, 188,289 (27.3%) had >=1 prescription for ICS/LABA and 347,963 (50.5%) had >=1 prescription for OCS. The merged dataset revealed an additional 9,016 (4.8%) patients with ICS/LABA and 21,136 (6.1%) patients with OCS use. The total estimated proportion of missing claims was 10.9% for ICS/LABA and 11.3% for OCS. The payment type of these missing claims were 7.9% cash/discount cards, 80.4% commercial payers, and 11.6% for government payers.

CONCLUSIONS: Appending health plan claims data with point-of-sale data provides a more complete proxy of the utilization of medications important in the management of asthma patients.