Evaluating innovation in general practice: a pragmatic framework using programme budgeting and marginal analysis

Background. Innovation in primary care in the UK, in terms of new service developments, is occurring at a fast pace. However, little information is available on the costs and benefits of these changes. Objectives. We aimed to illustrate the use of programme budgeting and marginal analysis (PBMA) as a framework for evaluating innovation in primary care, using an example of practice-based diabetes care. The aim was to examine changes in the use of practice resources and the changes in benefits to patients, following the introduction of a diabetes clinic. Methods. PBMA is a form of pragmatic economic evaluation combining practice data for the 'before' period and data from the literature to model the 'after' period. Results. In 1995/6, the total amount of resources devoted to diabetes care in the two practices was £145,813 (£634 per patient). Of this sum, 62% was allocated to out-patient visits, 28% to prescribing, 5% to hospital admissions, 2% to GP consultations and 2% to tests. The literature suggests that a nurse-run diabetes clinic would result in similar health outcomes and better access for patients. The introduction of such a clinic could potentially save each practice between £2000 and £16,000 per year. This result takes into account a wide range of assumptions about changes in resource use, but does depend on the findings of previous studies. Conclusions. The results of this study show that PBMA is a useful framework for helping practices be accountable and make 'evidence-based' decisions about service innovations in primary care.