Setting: National Diabetes Centre, Tonga.

Objective: To describe the diabetes patient profile and disease spectrum, assess the impact of diabetic care and evaluate diabetes-attributable adverse outcomes.

Design: Retrospective descriptive study of patients registered in the National Diabetes Registry from its inception in May 2004 to 2012, and review of the National Deaths Registry (2011–2012).

Results: Of 4653 patients with diabetes mellitus (DM) identified, 95.8% had type 2 DM, 0.2% type 1, 1.2% gestational DM and 2.9% pre-DM. Of the 4409 patients with type 2 DM, 64.7% were female, 82.7% were aged ?40 years, 25.3% had hypertension and 53.3% were obese. Among those in care for >2 years, no positive impact on body mass index or glycosylated haemoglobin could be demonstrated, but there was significant improvement in hypertension control. Morbidity included lower limb amputations in 272 (6.1%) patients. DM was listed as a contributory cause of death due to sepsis (15/30, 50.0%), kidney failure (16/28, 57.1%), stroke (7/16, 43.8%) and ischaemic heart disease (20/59, 33.9%).

Conclusion: DM was associated with high levels of morbidity and mortality. DM care improved hypertension control, but had little impact on other comorbid conditions. Enhanced monitoring and greater patient involvement should improve care; creative strategies are required to prevent and reduce obesity.