Type 1 diabetes still carries higher mortality, most of all in women

Design

Retrospective registry cohort, propensity-matched 1:4 on age and sex

Population

4,299 people with type 1 diabetes diagnosed before age 35 (2000 to 2022) and 17,196 matched controls

Primary outcome

All-cause mortality

Effect

HR 3.66 (95% CI 2.53 to 5.31); 131.0 vs 35.2 deaths per 100,000 person-years

This was a retrospective cohort from Maccabi Healthcare Services in Israel. It followed 4,299 people diagnosed with type 1 diabetes before age 35 between 2000 and 2022 against 17,196 matched people without diabetes. There were 112 deaths over about 204,000 person-years.

Mortality was 131.0 per 100,000 person-years with type 1 diabetes against 35.2 in controls, a hazard ratio of 3.66 (95% CI 2.53 to 5.31). Relative excess was larger in females (adjusted HR 8.40, 3.71 to 19.04) than in males (2.90, 1.78 to 4.72), although absolute death rates were higher in males. Those diagnosed in 2011 to 2022 had a lower relative excess than those diagnosed in 2000 to 2010 (2.94 against 4.36).

The gap has narrowed with newer care, but it has not closed. The sex difference is a relative one: a small baseline risk in women makes the ratio large. It is a reason to look harder at women with type 1 diabetes, not a reason to treat men less carefully.

• Type 1 diabetes was associated with about 3.7 times the mortality of matched peers in this Israeli cohort.
• The relative excess was larger in women (HR 8.40) than in men (HR 2.90), but men had the higher absolute death rate.
• People diagnosed from 2011 onward had a smaller relative excess than those diagnosed in 2000 to 2010.
• Consider reviewing cardiovascular risk, hypoglycaemia and mental health in women with type 1 diabetes at routine visits.
• Do not apply Israeli registry rates to Indian patients without local data.

Why it matters

Better technology has not removed the survival gap, and the usual assumption that men carry the worse outlook does not hold on the relative scale.

Don't overread it

This is observational data from one insurer and cannot explain why women fared worse, and only 112 deaths underlie the estimates.

The statistics, in plain English

A hazard ratio of 3.66 means that at any point in follow-up, people with type 1 diabetes died at about 3.7 times the rate of matched controls. The female-to-male difference in ratios (8.40 against 2.90) came with a significant interaction test (P = 0.02), but the confidence interval for women is wide (3.71 to 19.04) because there were few deaths. Relative and absolute risk point in different directions here, which is why both must be read.

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