Shared decision making in primary care: Process evaluation of the intervention in the OPTIMAL study, a cluster...

To analyse the performance of a Shared Decision Making (SDM) intervention, we assessed perceived and experienced SDM in General Practitioners (GPs) and patients with type 2 diabetes (T2DM).

Cluster-Randomised Controlled Trial (cRCT) testing the effect of a decision aid. Opinions and experienced role regarding SDM were assessed in 72 patients and 18 GPs with the SDM-Q-9 (range 0-45) and Control Preferences Scale (CPS, 0-5), and observed SDM with the OPTION5 (0-20). SDM at baseline was compared to 24 months' follow-up using paired t-tests.

At baseline, perceived levels of SDM did not significantly differ between GPs and patients with T2DM (difference of 2.3, p = 0.24). At follow-up, mean patients' perceived level of SDM was 7.9 lower compared to baseline (p < 0.01), whereas GPs' opinions had not changed significantly. After both visits, mean CPS scores differed significantly between patients and GPs. OPTION5 scores ranged between 6 and 20.

Patients and GPs perceived similar baseline levels of SDM. Two years later, patients perceived less SDM, while GPs did not change their opinion. SDM was appropriate immediately after training, but perhaps GPs fell back in old habits over time. We recommend repeated SDM training.