Estimated life expectancy in a Scottish cohort with type 1 diabetes, 2008-2010.
Level 3 - non-randomized controlled study
Prospective nationwide registry cohort study comparing mortality and life expectancy to the general population
PubMed 25562264 · doi:10.1001/jama.2014.16425
What was done
A prospective nationwide cohort study analyzed all individuals aged 20 years or older with type 1 diabetes in Scotland between 2008 and 2010 using a national diabetes register (n = 24,691; contributing 67,712 person-years and 1,043 deaths). Life expectancy from age 20 was estimated and compared with the general Scottish population without type 1 diabetes. Cause-specific contributions to mortality and outcomes among patients with preserved renal function (estimated glomerular filtration rate ≥90 mL/min/1.73 m²) were also evaluated.
What was found
Remaining life expectancy at age 20 was 46.2 years for men with type 1 diabetes versus 57.3 years for men without, representing an estimated loss of 11.1 years (95% CI, 10.1 to 12.1). For women, life expectancy from age 20 was 48.1 years with type 1 diabetes versus 61.0 years without, representing a loss of 12.9 years (95% CI, 11.7 to 14.1). In individuals with preserved kidney function (eGFR ≥90 mL/min/1.73 m²), life expectancy remained reduced, with an estimated loss of 8.3 years (95% CI, 6.5 to 10.1) in men and 7.9 years (95% CI, 5.5 to 10.3) in women. Ischemic heart disease accounted for the largest overall proportion of life expectancy loss (36% in men, 31% in women), whereas diabetic ketoacidosis or coma accounted for the largest proportion of life lost before age 50 (29.4% in men, 21.7% in women).
Why it matters
Even with modern diabetes management, type 1 diabetes is associated with an 11- to 13-year reduction in life expectancy. This survival gap persists even among individuals without renal impairment, driven predominantly by cardiovascular disease overall and acute metabolic complications in younger adults.
Limits
The study is limited to a single geographical cohort in Scotland from 2008 to 2010, which may not generalize to populations with different healthcare systems or demographics. The analysis relies on period life-table assumptions, which treat contemporary age-specific mortality rates as static. Confounders such as longitudinal glycemic control, smoking status, and socioeconomic factors are not reported in the abstract.
Cited by
- supports Patients with type 1 diabetes have a life expectancy reduced by 10 to 20 years and have a tenfold higher risk of cardiovascular disease.