A prescription for improvement? An observational study to identify how general practices vary in their growth in prescribing costs.

OBJECTIVE To identify how some general practices have low growth in prescribing costs relative to other practices. DESIGN Observational study. SETTING Trent region of England. PARTICIPANTS 162 general practices: 54 with low growth in prescribing costs, 54 with average increases in costs, and 54 with large increases in costs. MAIN OUTCOME MEASURES Changes in prescribing costs in therapeutic categories in which it has been suggested that savings can be made. RESULTS There were significant differences between the three groups of practices in terms of their changes in prescribing costs for almost all the variables studied. For the group of practices with lowest growth in costs the most important factors were reducing numbers of prescription items and costs per item; relatively low growth in the costs of "new and expensive" drugs; increasing generic prescribing; and reducing costs for modified release products. This group of practices did not increase costs as much as the others for lipid lowering drugs (P=0.012) and hormone replacement therapy (P=0. 007). The practices with the greatest increases in costs had particularly large increases for proton pump inhibitors, selective serotonin reuptake inhibitors, and modified release products. Compared with the other groups these practices had larger increases in costs for "expensive hospital initiated drugs" (P=0.009). CONCLUSION General practices vary in their growth in prescribing costs in many ways, with growth in costs for "new and expensive" drugs being particularly important.