Shared decision making and patient-centeredness for patients with poorly controlled type 2 diabetes mellitus in primary care—results of the cluster-randomised controlled DEBATE trial

BACKGROUND: We investigate whether an educational intervention of GPs increases patient-centeredness and perceived shared decision making in the treatment of patients with poorly controlled type 2 diabetes mellitus? METHODS: We performed a cluster-randomized controlled trial in German primary care. Patients with type 2 diabetes mellitus defined as HbA1c levels ≥ 8.0% (64 mmol/mol) at the time of recruitment (n = 833) from general practitioners (n = 108) were included. Outcome measures included subjective shared decision making (SDM-Q-9; scale from 0 to 45 (high)) and patient-centeredness (PACIC-D; scale from 1 to 5 (high)) as secondary outcomes. Data collection was performed before intervention (baseline, T0), at 6 months (T1), at 12 months (T2), at 18 months (T3), and at 24 months (T4) after baseline. RESULTS: Subjective shared decision making decreased in both groups during the course of the study (intervention group: -3.17 between T0 and T4 (95% CI: -4.66, -1.69; p < 0.0001) control group: -2.80 (95% CI: -4.30, -1.30; p = 0.0003)). There were no significant differences between the two groups (-0.37; 95% CI: -2.20, 1.45; p = 0.6847). The intervention's impact on patient-centeredness was minor. Values increased in both groups, but the increase was not statistically significant, nor was the difference between the groups. CONCLUSIONS: The intervention did not increase patient perceived subjective shared decision making and patient-centeredness in the intervention group as compared to the control group. Effects in both groups might be partially attributed to the Hawthorne-effect. Future trials should focus on patient-based intervention elements to investigate effects on shared decision making and patient-centeredness. TRIAL REGISTRATION: The trial was registered on March 10(th), 2011 at ISRCTN registry under the reference ISRCTN70713571.