Oral Presentation The Annual Scientific Meeting of the Australian Diabetes Society and the Australian Diabetes Educators Association 2013

All-cause and cardiovascular disease mortality in community-based patients with type 1 diabetes: The Fremantle Diabetes Study (#98)

Timothy ME Davis 1 , David G Bruce 1 , Wendy Davis 1
  1. The University of Western Australia, Fremantle, WA, Australia

Background and Aim: Since few studies have assessed prognosis in type 1 diabetes (T1DM), we investigated the relative risk of all-cause and cardiovascular disease (CVD) mortality in community-based patients with T1DM.

Patients and Methods: The longitudinal observational Fremantle Diabetes Study Phase I included 125 T1DM subjects recruited from 1993 to 1996. This cohort and 484 age-, gender-, and postcode-matched non-diabetic residents were followed for validated outcomes to death/census at end-2010.

Results: At baseline, the T1DM patients had a mean±SD age of 42.0±16.0 years, 59% were male, and their median [inter-quartile range] diabetes duration was 11.0 [3.0-21.0] years. During 1,722 person-years of follow-up, 39 (31.2%) died vs 54 (11.2%) of the non-diabetic group over 7,623 person-years. All-cause mortality rates (95% CI) were 22.7 (16.1-31.0) and 7.1 (5.3-9.2) per 1,000 person-years, respectively, a mortality rate ratio (MRR) of 3.20 (2.06-4.92). Age at death was 61.9±13.2 years in the T1DM vs 69.2±13.9 years in the non-diabetic group (P=0.012). For CVD deaths (cardiac, cerebrovascular or sudden), 20 T1DM participants and 19 non-diabetic residents died, with comparative mortality rates of 11.6 (7.1-17.9) and 2.5 (1.5-3.9) per 1,000 patient-years and a MRR of 4.66 (2.36-9.23). In the T1DM group alone, Cox proportional hazards modelling with age as the time-line showed that all-cause mortality was predicted by lower systolic (hazard ratio (95% CI): 0.96 (0.94-0.98)) and higher diastolic blood pressure (1.05 (1.01-1.09)), higher loge(urinary albumin:creatinine ratio) (1.52 (1.24-1.86)) and prior cerebrovascular disease (5.35 (1.99-14.42)). CVD mortality was predicted by higher HbA1c (1.39 (1.03-1.89)), higher loge(serum triglycerides) (2.12 (1.28-3.50)) and, through confounding by indication, taking lipid-modifying medication (3.65 (1.33-10.07)).

Conclusions: These Australian community-based data show that adults with T1DM lose >7 years of life due mainly to increased CVD mortality. Multivariate analyses confirm that longevity in T1DM could be increased by targeting blood pressure, metabolic control and albuminuria.