SPIROMETRY UTILIZATION IN ONTARIO - PRACTICE PATTERNS AND POLICY IMPLICATIONS

Objective: To describe growth and regional variation in the use of spi rometry (flow studies) in Ontario. Design: Retrospective analysis of O ntario Health Insurance Pan (OHIP) fee-for-service billing data for sp irometry from the 1989-90 to 1994-95 fiscal years. Setting: Physicians ' office practices in Ontario. Outcome measures: Number of flow studie s and associated expenditures, number and specialty of physicians perf orming flow studies and the distribution of their billings, number of studies per capita by age group of patients, expenditures by region an d measures of variation among regions. Results: In 1994-95, $14.13 mil lion was spent on flow studies in Ontario. This expenditure increased by 36.9% from 1989-90 to 1994-95, exceeding the overall growth rate of 20.8% for all expenditures under OHIP. Expenditure growth was driven by an increase in the number of physicians performing spirometry rathe r than a higher volume of services performed per physician. The substi tution of flow-volume loops, for which the fee is higher, for simple s pirograms also contributed to expenditure growth. There were wide regi onal variations in spirometry utilization. A small number of general p ractitioners and family physicians accounted for much of the regional variation. Conclusions: The rapid growth in spirometry utilization may stem from the diffusion of inexpensive spirometers in physicians' off ices and from increased awareness of guidelines promoting the use of f low measurements, However, the wide regional variation in utilization may indicate either incomplete implementation of spirometry guidelines or lack of direction on the appropriate frequency of spirometry use. Clearer, evidence-based guidelines and an implementation strategy are needed. Also required is further study of possible inadequate access t o spirometry in low-use regions and inappropriate use in high-use regi ons, where spirometry use is concentrated among a small number of phys icians.