Type 1 diabetes mortality rates decreasing

Mortality rates for people with type 1 diabetes are decreasing, however, overall rates remain more than five times higher than those for the general population, a new study reported.

While researchers at the University of Pittsburgh found no significant differences in mortality rates between sexes, women with type 1 diabetes were 13 times more likely to die compared with women who did not have diabetes. The researchers also discovered differences between races: a much higher proportion of blacks with type 1 diabetes (50.6%) died compared with whites (24%).

“This study was designed to document mortality rates of childhood-onset type 1 diabetes over the years, including how rates have improved and how they vary by sex and race,” Trevor Orchard, MD, of the department of epidemiology, Graduate School of Public Health, University of Pittsburgh, told Endocrine Today. “The remarkable finding is the dramatic decline in mortality seen throughout follow-up for those in later diagnosed cohorts.”

Declines over time

Orchard and colleagues used the childhood-onset type 1 diabetes registry in Allegheny County, Pennsylvania, to study 1,075 people diagnosed with type 1 diabetes from 1965 to 1979. The cohort was divided into three groups: those diagnosed from 1965 to 1969; 1970 to 1974; and 1975 to 1979. As of Jan. 1, 2008, the researchers ascertained the vital status for 1,043 of the 1,075 people identified. There were 34,363 total person-years of follow-up.

During a median follow-up of 33 years, 279 patients with type 1 diabetes died.

According to other results, men with type 1 diabetes were five times more likely to die compared with men in the general population. There was no difference in mortality between black people with type 1 diabetes compared with black men in the general population.

"Surprisingly, although mortality rates were twice as high in blacks vs. whites with diabetes, compared with the general population the relative increase was similar, reflecting a similar black-white difference disparity in general," Orchard said.

Mortality rates were lowest for those diagnosed in the late 1970s and highest for those diagnosed in the late 1960s. The standard mortality ratios were 9.3 in those diagnosed from 1965 to 1969, 7.5 in those diagnosed from 1970 to 1974, and 5.6 in those diagnosed from 1975 to 1979. The mortality rate was lower in participants who were diagnosed when younger than 10 years vs. those diagnosed when aged 10 years or older.

The mean age of the participants was 42.8 years, and the mean duration of diabetes was 32 years.

Advances in past decades

The researchers also noted that the main improvement in patients who were most recently diagnosed with type 1 diabetes was related to dramatic reductions in mortality in the first 5 years of diagnosis. Additionally, they postulated that these improved rates reflect better management and awareness of diabetes control and acute complications during the 1980s and in the 1990s, blood glucose self-monitoring, HbA1c testing and use of blood pressure medications such as angiotensin-converting enzyme inhibitors were major players, Orchard said.

Aaron M. Secrest, PhD, summarized the findings: "Women appeared to do particularly poorly, but that is improving. Black people have a particularly poor prognosis, which we think is probably related to socioeconomic status," Orchard said. "Things are improving considerably, and I am sure mortality will get even better over time as those diagnosed most recently will be able to benefit more from advances in treatment since those diagnosed in the 1960s and 1970s."– by Emily Shafer

Secrest AM. Diabetes Care. 2010;33:2573-2579.

The latest that this group was diagnosed was 1979, which was before we had any of the current methods of treatment. Blood glucose monitoring was initiated in the late 1970s, replacing urine glucose testing. The development of the rapid-acting and basal insulin analogues in the 1980s allowed for the more physiologic basal bolus method of administering insulin. We also weren’t attuned to use of ACE inhibitors and lipid-lowering drugs in children, like we are today, for abnormal cardiovascular risk factors. So while the findings of this study may certainly be true for people diagnosed in this timeframe, it is anticipated that those people diagnosed in the 1990s and later will have even better long-term outcomes. It is important to note that these people were all diagnosed in childhood, making us even more aware that the complications of diabetes, especially the CV complications, begin early, and we need to be careful about monitoring for CV disease in our teens and young adults, especially.

– Janet H. Silverstein, MD
Endocrine Today Editorial Board member

Dr. Silverstein has no direct financial interest in any of the products mentioned in this article nor is she a paid consultant for any companies mentioned.

Follow EndocrineToday.com on Twitter.