# Treatment Persistence and Variations in Prescribing Oral, Injectable, and Inhaled Corticosteroids: A Population‐Based Drug Utilisation Study

## TL;DR

This study analyzed how corticosteroids are prescribed in primary care, finding that a small group of patients accounts for most prescriptions.

## Contribution

The study introduces a population-based analysis of corticosteroid prescribing patterns and persistence.

## Key findings

- 20% of patients accounted for 80% of oral and inhaled corticosteroid use.
- Older patients with comorbidities were more likely to receive higher doses.
- Persistence rates varied significantly between oral and inhaled corticosteroids.

## Abstract

To examine variation in oral, injectable, and inhaled corticosteroid (CS) prescribing in primary care, exploring treatment persistence and coverage.

We examined patient‐level electronic health records from English general practices in the Clinical Practice Research Datalink Aurum database. We delineated a cohort of new users of oral, injectable, or inhaled CS with prescriptions issued between January 1, 2000, and June 30, 2021. Lorenz curves assessed potential prescribing skewness, and Kaplan–Meier (KM) plots estimated treatment persistence. The Proportion of Patients Covered (PPC) method estimated the proportion of patients still covered by treatment 1 year after initiation.

We observed 1 942 571 CS users across 1471 general practices, with 20% of oral and inhaled CS users accounting for almost 80% of total CS use. Older patients with comorbidities including respiratory diseases (13.5%), skin conditions (5.8%), or inflammatory bowel diseases (1.6%) were more likely to be prescribed higher doses. The KM plots showed that 20% of oral and 50% of inhaled CS users were persistent after one and 2 months, respectively. The PPC method indicated that 30% of oral and 60% of inhaled CS users were covered by treatment 6 months post‐initiation. Some variation was observed when different grace periods were applied. Combined use of oral and inhaled CS was observed for 6.9% of patients.

A fifth of patients receiving CS accounted for over 80% of oral and inhaled CS prescribing in primary care. Identifying these patients is crucial for targeting future interventions to promote patient safety and cost‐effective CS use.