Comparative mortality and its determinants in community-based people with type 1 diabetes: The Fremantle Diabetes Study Phase i

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The aim of this study was to compare mortality in community-based Australians with type 1 diabetes (T1D), without diabetes, or with type 2 diabetes (T2D). 

Research design and methods

The longitudinal observational Fremantle Diabetes Study Phase I (FDS1) T1D cohort, matched people without diabetes from the FDS1 catchment area, and matched FDS1 participants with T2D were followed up from entry (1993-1996) to death/end-2017. Mortality rates (MRs) and mortality rate ratios (MRRs) were calculated. Cox regression models identified independent determinants of death.


Of 121 participants with T1D and 484 age/sex/postcode-matched people without diabetes (pooled mean±SD age 43.1±15.3 years, 59.2% men), 55 (45.5%, MR 25.7 (95% CI 19.4 to 33.5)/1000 person-years) and 88 (18.2%, MR 8.5 (95% CI 6.8 to 10.4)/1000 person-years), respectively, died during 12 541 person-years of follow-up (MRR 3.04 (95% CI 2.13 to 4.31), p<0.001). Among participants with T1D, diagnosis at age 18-27 years and baseline HbA 1c, urinary albumin:creatinine ratio, and retinopathy were independent predictors of death (p≤0.011). Twenty-five FDS1 participants died from cardiovascular disease (MR 11.7 (95% CI 7.6 to 17.3)/1000 person-years) vs 28 residents without diabetes (MR 2.7 (95% CI 1.8 to 3.9)/1000 person-years; MRR (95% CI) 4.34 (2.43, 7.73) (p<0.001). There were 93 FDS1 participants with T1D who were age/sex matched with an FDS1 participant with T2D and 53 (57.0%) and 37 (39.8%), respectively, died (p=0.027). In pooled Cox regression analysis, T1D was not a determinant of mortality (HR 1.18 (95% CI 0.71 to 1.97), p=0.523).


T1D substantially increases the risk of death, especially when diagnosed in late adolescence/young adulthood. Diabetes type does not influence mortality after adjustment for key confounding variables.

Original languageEnglish
Article numbere003501
Number of pages11
JournalBMJ Open Diabetes Research and Care
Issue number4
Publication statusPublished - 24 Jul 2023

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