B D Pethica1, A Penrose, D MacKenzie, J Hall, R Beasley, M Tilyard. 1. Wellington Asthma Research Group, Wellington School of Medicine, University of Otago, Wellington, PO Box 7343, Wellington South, New Zealand. WARG.Sec@wnmeds.ac.nz
Abstract
OBJECTIVE: To determine whether inhaled budesonide and beclomethasone are equipotent in the treatment of asthma in primary care. DESIGN: Retrospective study of computerised clinical records from 28 general practices in New Zealand. SUBJECTS: 5930 patients who received 16 725 prescriptions for inhaled budesonide or beclomethasone from 1 July 1994 to 30 June 1995. SETTING: General practices on the database of the Royal New Zealand College of General Practitioners Research Unit. Linked information from secondary care was available for a subset of the practices. MAIN OUTCOME MEASURE: Mean prescribed daily inhaled corticosteroid dose. RESULTS: The daily prescribed dose was higher for patients receiving inhaled budesonide (mean 979 microg) than beclomethasone (mean 635 microg), a difference of 344 microg (95% confidence interval 313 to 376 microg). This difference was consistent in all age bands and with different types of inhalation device. Evidence of systematic prescribing of higher doses of budesonide to patients with more severe asthma was not found. CONCLUSIONS: In primary care in New Zealand evidence suggests that budesonide is less potent than beclomethasone. Consideration of validated, established, and other possible markers of asthma severity did not support confounding by severity as a reason for the higher prescribed doses of budesonide. Pending further epidemiological evaluation, international asthma guidelines may need to be modified on the equivalence of inhaled corticosteroid doses. Furthermore, the comparative potency of newly developed inhaled steroids in clinical trials will need to be confirmed in appropriately designed epidemiological studies based in general practice.
OBJECTIVE: To determine whether inhaled budesonide and beclomethasone are equipotent in the treatment of asthma in primary care. DESIGN: Retrospective study of computerised clinical records from 28 general practices in New Zealand. SUBJECTS: 5930 patients who received 16 725 prescriptions for inhaled budesonide or beclomethasone from 1 July 1994 to 30 June 1995. SETTING: General practices on the database of the Royal New Zealand College of General Practitioners Research Unit. Linked information from secondary care was available for a subset of the practices. MAIN OUTCOME MEASURE: Mean prescribed daily inhaled corticosteroid dose. RESULTS: The daily prescribed dose was higher for patients receiving inhaled budesonide (mean 979 microg) than beclomethasone (mean 635 microg), a difference of 344 microg (95% confidence interval 313 to 376 microg). This difference was consistent in all age bands and with different types of inhalation device. Evidence of systematic prescribing of higher doses of budesonide to patients with more severe asthma was not found. CONCLUSIONS: In primary care in New Zealand evidence suggests that budesonide is less potent than beclomethasone. Consideration of validated, established, and other possible markers of asthma severity did not support confounding by severity as a reason for the higher prescribed doses of budesonide. Pending further epidemiological evaluation, international asthma guidelines may need to be modified on the equivalence of inhaled corticosteroid doses. Furthermore, the comparative potency of newly developed inhaled steroids in clinical trials will need to be confirmed in appropriately designed epidemiological studies based in general practice.