The impact of gender on the long-term morbidity and mortality of patients with type 2 diabetes receiving structured personal care: a 13 year follow-up study

Marlene Ø. Krag, Lotte Hasselbalch, Volkert Siersma, Anni B. S. Nielsen, Susanne Reventlow, Kirsti Malterud, Niels de Fine Olivarius

The aim of this study was to assess gender differences in mortality and morbidity during 13 follow-up years after 6 years of structured personal care in patients with type 2 diabetes mellitus. In the Diabetes Care in General Practice (DCGP) multicentre, cluster-randomised, controlled trial (ClinicalTrials.gov registration no. NCT01074762), 1,381 patients newly diagnosed with type 2 diabetes were randomised to receive 6 years of either structured personal care or routine care. The intervention included regular follow-up, individualised goal setting and continuing medical education of general practitioners participating in the intervention. Patients were re-examined at the end of intervention. This observational analysis followed 970 patients for 13 years thereafter using national registries. Outcomes were all-cause mortality, incidence of diabetes-related death, any diabetes-related endpoint, myocardial infarction, stroke, peripheral vascular disease and microvascular disease. In women, but not men, a lower HR for structured personal care vs routine care emerged for any diabetes-related endpoint (0.65, p = 0.004, adjusted; 73.4 vs 107.7 events per 1,000 patient-years), diabetes-related death (0.70, p = 0.031; 34.6 vs 45.7), all-cause mortality (0.74, p = 0.028; 55.5 vs 68.5) and stroke (0.59, p = 0.038; 15.6 vs 28.9). This effect was different between men and women for diabetes-related death (interaction p = 0.015) and all-cause mortality (interaction p = 0.005). Compared with routine care, structured personal diabetes care reduced all-cause mortality and diabetes-related death in women but not in men. This gender difference was also observed for any diabetes-related outcome and stroke but was not statistically significant after extensive multivariate adjustment. These observational results from a post hoc analysis of a randomised controlled trial cannot be explained by intermediate outcomes like HbA1c alone, but involves complex social and cultural issues of gender. There is a need to rethink treatment schemes for both men and women to gain benefit from intensified treatment efforts.