Although the recommended standard of care, it has yet to be established whether intensive diabetes therapy affects mortality in type 1 diabetes patients. A new study, however, has found an association between intensive treatment and a modestly lower all-cause rate of death.
Researchers from the University of Pittsburgh, PA, followed type 1 diabetes patients for an average of 27 years. Among these patients, receiving intensive treatment with the aim of reducing blood sugar levels to a nondiabetic range was linked to a slight reduction in mortality compared with conventional treatment.
While the effect of intensive diabetes therapy on the mortality of people with type 1 diabetes had not been established, previous research has found that the reduction of blood sugar toward the nondiabetic range in type 2 diabetes patients does not consistently lead to a reduction in mortality.
Type 1 diabetes is a condition whereby the body does not produce the insulin required to convert sugars, starches and other foods into energy. With type 2 diabetes, the body does not utilize the insulin that is produced properly – also referred to as insulin resistance.
According to the American Diabetes Association (ADA), 29.1 million Americans – around 9.3% of the population – had diabetes in 2012. This figure had increased from 25.8 million (8.3%) in 2010. Diabetes is the 7th leading cause of death in the US.
Other research suggests that type 1 diabetes patients may have shorter life expectancies than the general population. A recent Scottish population study, published in JAMA, reports that men with type 1 diabetes have an average life expectancy 11 years lower than the general public. Women with type 1 diabetes at the same age have a life expectancy 13 years lower than the general average.
In the new study, also published in JAMA, the authors note that other research from Europe and the US has suggested the risk of early death has decreased among type 1 diabetes patients. Experts have suggested the reduction may be due to intensive blood sugar-lowering therapy also reducing renal and cardiovascular disease – leading causes of early mortality.
To investigate, Dr. Trevor Orchard and his colleagues compared the mortality rates of patients receiving intensive treatment and conventional treatment in the long-term follow-up of the Diabetes Control and Complications Trial (DCCT).
From 1983 to 1993, participants with type 1 diabetes in the DCCT were randomly assigned to receive either intensive diabetes therapy or conventional treatment. Participants were aged between 13 and 39 years and were otherwise healthy volunteers.
A total of 711 patients received intensive therapy – treatment with the aim of achieving control of blood sugar as close to the nondiabetic range as possible. Another 730 patients received conventional therapy with the aim of avoiding abnormally low and abnormally high blood sugar levels.
Following the completion of the DCCT, after an average of 6.5 years, participants were taught and recommended intensive therapy techniques before diabetes care returned to their personal physicians. They were then followed up as part of an observational study until the end of 2012.
The researchers were able to ascertain the vital status for 1,429 (99.2%) of the participants. Of these, 107 died during the follow-up period – 43 from the intensive treatment group (6% of this group) and 64 from the conventional treatment group (8.8% of this group).
Higher levels of glycated hemoglobin or excessive protein in the urine were associated with an increased risk of mortality. The most common causes of mortality were cardiovascular events (22.4%), cancer (19.6%), acute diabetes complications (17.8%) and accidents or suicide (16.8%).
“These results provide reassurance that adoption of 6.5 years of intensive therapy in type 1 diabetes does not incur increased risk of overall mortality,” write the authors.
The study is limited by a population sample that is unrepresentative of patients with type 1 diabetes, according to experts from the Joslin Diabetes Center in Boston, MA. A relatively low number of deaths among the participants also makes it difficult to fully associate mortality reduction with intensive treatment.
In an associated editorial, Dr. Michelle Katz and Dr. Lori Laffel of the Joslin Diabetes Center refer to the study as providing “strong evidence of improved survival in the 21st century.” However, they also state that more needs to be done to improve the life expectancy of patients with type 1 diabetes:
“The search for genetic factors and biomarkers related to risk of diabetes complications generally and risk of diabetic nephropathy specifically needs to accelerate. There continues to be inadequate access to advanced diabetes technologies, education and support from health care professionals, and, at times, even family encouragement, which all need to improve.”
Recently, Medical News Today reported on a novel treatment found previously to reverse type 1 diabetes in mice that also works on human cells transplanted into mice.