Abstract
OBJECTIVE: To determine the costs and consequences of switching asthma patients, managed in primary care, from a twice-daily inhaled corticosteroid (ICS), to either a once-daily or another twice-daily ICS. DESIGN: This was a case-control study based on an interrogation of the General Practice Research Database in the UK, for patients with a Read code of asthma who were managed between 1990 and 2001, and who had received at least two prescriptions for a twice-daily ICS within 12 months, before switching to a once-daily ICS (cases) or another twice-daily ICS (controls). Data on resource use was collected for one year before and after the switch. Patients were stratified according to whether their treatment step had been stepped up, stepped down or remained unchanged. SETTING: A modelling study performed from the perspective of the UK's National Health Service (NHS). MAIN OUTCOME MEASURES: Compliance with ICS, and the cost of drug and non-drug resource use, for the year before and after the switch. RESULTS: Switching patients managed in primary care to a once-daily ICS increased compliance and reduced NHS costs, irrespective of whether patients' treatment had been stepped up or down. Switching patients to another twice-daily ICS increased compliance to a lesser extent, and increased NHS costs. We believe that this paper offers the first documented association between compliance in asthma and NHS management costs. CONCLUSIONS: Compliance and management costs among patients with asthma managed in primary care appear to be related to both changing treatment and dosing regimen. Within the limitations of our study, the results suggest that patients who are switched to a once-daily ICS rather than another twice-daily preparation are better compliers with their ICS medication. Additionally, patients who become high-compliers after being switched to a once-daily ICS incur lower management costs than patients who become high-compliers after being switched to another twice-daily ICS. These findings should now be investigated further under more controlled conditions.