The aim of this study is to explore the effects of substitution in out-of-hours primary care. In consecutive stages an extra General Practitioner (GP) is substituted by a Nurse Practitioner (NP) aiming at replacing 3 out of 4 GPs by NPs. Effects are measured in terms of feasibility and cost-efficiency.

Out-of-hours care in the Netherlands is under pressure. Workload for GPs during out-of-hours care is high and there are concerns about maintaining the quality of care. Since 80% of the complaints shown in out-of-hours care is neither complex nor urgent not all patients necessarily have to be seen by a GP.

A previous study (ID: 80-82800-98-227) indicated that shifting care from GPs to NPs is possible in terms of safety and quality of care and resulted in cost savings due to less treatment. In that study 4 GPs and 1 NP provided care in the experimental condition and 5 GPs provided care in the control condition. Based on the results it is hypothesized that NPs are competent to diagnose and treat at least 75% of the complaints shown in out-of-hours primary care. Substituting more GPs by NPs in out-of-hours care will probably lead to more cost savings.

In the current study care delivered and direct healthcare costs are compared between different team compositions. In the experimental condition care is provided by a team of NPs and GPs. The intervention starts with a team of 4 professionals in both the experimental (3 GPs and 1 NP) and the control (4 GPs) condition; in consecutive stages an extra GP is substituted by an NP aiming at replacing 3 out of 4 GPs with by NPs.

Control: 4 GPs

Stage 1: experimental: 3 GPs & 1 NP

Stage 2: experimental: 2 GPs & 2 NPs

Stage 3: experimental: 1 GP & 3 NPs

Both feasibility and cost-efficiency will lead to recommendations on the optimal balance in a team between GPs and NPs.

Inclusion Criteria:

• Patients (with urgencylevel U2, U3, U4, or U5) requesting an appointment at the primary out-of-hours service during the weekend between 10am and 6pm.

Exclusion Criteria:

• None