Statistical methods
T2DM, diabetic distress, diabetes
SECONDARY, RECRUITMENT, SENSITIVITY, DIABETES
Patients with T2DM with an HbA1c ≥ 8.0% (64 mmol/mol) at the time of recruitment and complete data at baseline and T4 were eligible for the presented analyses (see Additional file For a description of the sample, we compared the subgroups of patients with shared HbA1c goal and with non-shared HbA1c goal, using t tests and χ² tests for independent samples. For a description of the magnitude of differences, we calculated Cohen’s d as an effect size from the T statistic and the phi coefficient, respectively [For the main analysis, we calculated a multivariable generalized estimating equation (GEE), adjusting for dependencies between patient-level data and affiliation with a specific GP. The criterion was “HbA1c goal missed vs. achieved at T4” and the baseline predictors were “HbA1c as shared vs. non-shared goal”, age, sex, education, partner status, controlled for baseline HbA1c and insulin therapy. We defined an HbA1c goal as “missed” if the measured HbA1c at T4 was > 0.5 above the aspired HbA1c goal at baseline. Research has shown, that a HbA1c reduction of 0.5% is clinically relevant and leads to less absenteeism, diabetes-related hospital admissions and improved quality of life [Sensitivity analyses for this main analysis were performed with regard to (1) including the intervention of the DEBATE trial (control group vs. intervention group) [A secondary question is whether the type of HbA1c goal setting (shared vs. non-shared) is associated not only with goal achievement (main analysis), but also with the overall diabetes outcome. We therefore built a composite score for HbA1c, quality of life, and diabetic distress from z-standardized HbA1c, EQ-5D-3 L, and PAID, both for baseline and T4 (higher score = worse outcome (higher HbA1c/more distress/lower QoL)). We performed a GEE with the T4 composite score as the criterion, the same predictors mentioned above, and controlled for the baseline composite score.The significance level was 0.05. Analyses were performed with SPSS (IBM Corp. Released 2017. IBM SPSS Statistics for Windows, Version 25.0. Armonk, NY: IBM Corp.).