Spillover effects from a type 2 diabetes integrated model of care in 22,706 Australians: an open cohort stepped wedge trial

Many Australian adults are not receiving timely or effective diabetes management to prevent or delay the onset of diabetes related complications. Integrated care, a worldwide trend in healthcare reform, aims to reduce the fragmented delivery of health services and improve outcomes. This study aimed to test whether a specialist-led integrated model of care provided to a small subset of patients in general practices leads to spillover clinical improvements in all patients of the practice with type 2 diabetes. Seventy-two general practice sites (clusters) in New South Wales, Australia received the Diabetes Alliance intervention, creating a non-randomised open cohort stepped wedge trial. The intervention comprised of case conferencing, delivered directly to a small proportion of adults with type 2 diabetes (n = 1,072) of the general practice sites; as well as practice feedback, education and training. Spillover clinical improvements were assessed on all adults with type 2 diabetes within the general practice sites (n = 22,706), using practice level data recorded in the MedicineInsight electronic database, compared before and after the intervention. Outcome measures included frequency of diabetes screening tests in line with the Annual Cycle of Care, and clinical results for weight, blood pressure, HbA1c, lipids, and kidney function. Compared to before Diabetes Alliance, the odds of all practice patients receiving screening tests at or above the recommended intervals were significantly higher for all recommended tests after Diabetes Alliance (odds ratio range 1.41–4.45, p < 0.0001). Significant improvements in clinical outcomes were observed for weight (absolute mean difference: -1.38 kg), blood pressure (systolic − 1.12 mmHg, diastolic − 1.18 mmHg), HbA1c (-0.03% at the mean), total cholesterol (-0.11 mmol/L), and triglycerides (-0.02 mmol/L) (p < 0.05). There were small but significant declines in kidney function. Integrated care delivered to a small subset of patients with type 2 diabetes across a large geographic region has spillover benefits that improve the process measures and clinical outcomes for all practice patients with type 2 diabetes. ACTRN12622001438741; 10th November 2022, retrospectively registered: https://www.anzctr.org.au/ACTRN12622001438741.aspx .