Microvascular complications increase with diabetes duration but not age



MELBOURNE – A diagnosis of type 2 diabetes before age 50 was associated with an increased risk of microvascular complications, based on a secondary analysis of data from the international ADVANCE trial.

In ADVANCE, the risk of microvascular complications, such as eye and kidney disease, increased with disease duration but not with patient age. The risk of macrovascular complications, such as myocardial infarction, stroke, and cardiovascular events, as well as all-cause mortality, increased with both patient age and disease duration, Dr. John Chalmers, principal investigator for ADVANCE, said at the World Diabetes Congress.

Dr. John Chalmers

"The findings tell you that if you get [type 2 diabetes] early, you’re in for a rougher time. If you’re younger at the time of diagnosis, then you may have a slightly more progressive, aggressive, resistant-to-treatment form of type 2 diabetes. It’s important to be aware of that, to control the glucose and to keep looking at the kidneys and eyes," said Dr. Chalmers, senior director of the George Institute, Sydney, and emeritus professor of medicine at the University of Sydney.

ADVANCE is a randomized trial across 20 countries of blood pressure lowering and intensive versus standard glucose control in 11,140 adults with type 2 diabetes who were followed up for 5 years. Mean age at study entry was 66 years, and average diabetes duration was 7.9 years. However when patients were stratified in 5-year increments of disease duration, researchers observed that the average age for each increment was roughly the same, around 66 years.

"You might guess a priori that people with the longest duration might be the oldest, but they’re not necessarily," Dr. Chalmers said in an interview.

In ADVANCE, 7.5% of patients with disease duration of less than 5 years had a history of major microvascular disease, as did 18.6% of those with disease duration of more than 15 years. The patients with the longest duration of disease – more than 15 years – started at a mean age of 47, and those with less than 5 years’ disease duration started at a mean age of 63.

The study also noted that those with the longest duration of disease had the highest mean hemoglobin A1c at baseline, 7.9%, compared with 7.2% in patients with less than 5 years’ disease duration.

"Major macrovascular events rise steeply as patients get older and as the duration of diabetes increases; they both have independent effects," he said. "The microvascular complications are more influenced by the glycemic burden, whereas the macrovascular events are probably more affected by the traditional risk factors of blood pressure, cholesterol, and smoking."

The ADVANCE study was partly funded by Servier, the maker of Preterax (perindopril arginine plus indapamide). Dr. Chalmers declared that he received research grants and honoraria from Servier as the principal investigator for the study.

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