Shared Decision Making Between Patients and GPs in the Treatment of Type 2 Diabetes in Primary Care.

Shared Decision Making in Type 2 Diabetes With a Support Decision Tool That Takes Into Account Patient Preferences, Clinical Factors and the Intensity of Treatment: Design of a Cluster Randomised Trial

Background: Less than 20% of type 2 diabetes mellitus (T2DM) patients in different healthcare settings achieve all treatment goals to prevent cardiometabolic disease. A more personalised approach with shared decision making should increase that percentage. Because the ADDITION-Europe study demonstrated two (almost) equally effective treatments but with slightly different intensities, it may be a good starting point to discuss with the patients their diabetes treatment, taking into account both the intensity of treatment, clinical factors and patients' preferences. The aim of the study was to evaluate whether such an approach increases the proportion of treatment goals that T2DM patients achieve.

Methods: In a cluster-randomised trial in 40 primary care practices that participated until 2009 in the ADDITION Study, 150 T2DM patients 60 - 80 years, known with T2DM for 8-15 years, will be included. Practices are randomised a second time, i.e. intervention practices in the ADDITION study could be control practices in the current study and vice versa. For the GPs from the intervention group a 2-hour training in shared decision making (SDM) was developed as well as a decision support tool to use during the consultation. These GPs plan the first visit with the patients to decide on the intensity of the treatment, personalised targets and the priorities of treatment. The control group will continue with the treatment they were allocated to in the ADDITION study (treatment-as-before). Follow-up: 24 months. The primary outcome is the proportion of patients who achieve all three treatment goals (HbA1c, blood pressure, total cholesterol) at 24 months. Secondary outcomes are the proportion of patients who achieve five treatment goals (HbA1c, blood pressure, total cholesterol , body weight, not smoking), evaluation of the SDM process (SDM-Q9), satisfaction with the treatment (DTSQ), wellbeing and quality of life (W-BQ12, ADD QoL-19), health status (SF-36, EQ-5D) and coping (DCMQ). The proportions of achieved treatment goals will be compared between groups by estimating the relative risk of meeting the treatment targets. For the secondary outcomes mixed models will be used.

Discussion: To achieve optimal diabetes care with a higher proportion of achieved individualised treatment goals, the SDM approach including a multi-faceted decision support tool might be useful. An intervention with such a support decision tool is designed.

See brief summary

Inclusion Criteria:

• Two more or less comparable categories of patients are eligible: 1. if diagnosed with T2DM in 2002-2004 by screening, aged between 50-70 years at that time and having participated in the ADDITION-study that ended in 2009; 2. treated for their T2DM in a practice that participated in the ADDITION study, between 60 and 80 years in 2012-2014 and with a T2DM duration between 8 to 15 years.

Exclusion Criteria:

• Patients will be excluded if they have a history of alcoholism, drug abuse, psychosis, personality disorder or another emotional, psychological or intellectual problem that is likely to invalidate informed consent, or limit the ability of the individual to comply with the protocol requirements and patients with a limited life expectancy.