Compared with men who have type 1 diabetes, women with the disease were nearly 40% more likely to experience all-cause mortality and twice as likely to experience a fatal or nonfatal vascular event.
“On average, women live longer than men. But, our findings show that in women with type 1 diabetes, this ‘female protection’ seems to be lost and excess deaths in women with type 1 diabetes are higher than in men with the disease,” Rachel R. Huxley, DPhil, lead study author with the University of Queensland in Australia, said in a press release.
For the study, Dr. Huxley and colleagues systematically searched PubMed for studies published from Jan. 1, 1966, to Nov. 26, 2014, that reported sex-specific estimates of standardized mortality ratios (SMRs) or hazard ratios (HRs) associated with all-cause mortality or cause-specific outcomes related to type 1 diabetes.
The meta-analysis included 26 studies, 214,114 participants and 15,273 events.
Researchers reported the pooled women-to-men ratio of SMR was as follows:
- All-cause mortality: 1.37 (95% CI, 1.21-1.56)
- Incident stroke: 1.37 (95% CI, 1.03-1.81)
- Fatal renal disease: 1.44 (95% CI, 1.02-2.05)
- Fatal cardiovascular diseases (CVDs): 1.86 (95% CI, 1.62-2.15)
When researchers examined incident coronary disease, the sex-related discrepancy was even greater, as the pooled women-to-men ratio of SMR was 2.54 (95% CI, 1.80-3.60).
There were no data indicating a sex difference in mortality from cancer or accident and suicide in patients with type 1 diabetes.
“The marked difference between the sexes for vascular-related disease is likely to have profound clinical implications for how women with type 1 diabetes are treated and managed throughout their lives,” Dr. Huxley said.
“A recent joint statement issued by the American Heart Association and the American Diabetes Association concluded that further research into racial and ethnic differences and improved cardiovascular risk-prediction methods in people with type 1 diabetes is needed. In light of our findings, we argue that this statement should be extended to include sex differences.”
In an accompanying editorial, David Simmons, MD, of the University of Western Sydney, Campbelltown, Australia, agreed with the researchers that the observed sex differences in mortality among patients with type 1 diabetes should stimulate action.
“However, this action should not be sex-based,” he wrote. “Health and funding systems should systematically support improvements in glycemic control, from diagnosis, for all patients with type 1 diabetes, through tailored therapy as implemented in the [Diabetes Control and Complications Trial], including mental health support and personalized strategies that help avoid hypoglycemia. Sex differences in management of cardiovascular disease and its risk factors also need to be rectified. A process for reporting rates of cardiovascular disease risk factor treatment, goal achievement and intervention by sex, as well as overall, would help to systematically introduce strategies to address under-treatment where it exists.”
Dr. Simmons added that achieving a reduction in type 1 diabetes mortality rates will necessitate additional expenditure on the care of patients with the disorder — many of the benefits of which might not be seen for up to 20 years. “The additional investment in the services and equipment to improve glycemic control must start now,” he concluded.