Early HbA1c control, low variability reduce major adverse CV event risk in type 2 diabetes
Once diagnosed with type 2 diabetes, adults who are able to reduce their HbA1c within 12 months can also lower their long-term risk for a major adverse cardiovascular event, but frequent shifts in HbA1c increase CV risks, according to findings presented at the European Association for the Study of Diabetes annual meeting.
“Normalization of glucose values in the first year after diagnosis of type 2 diabetes is associated with reduced likelihood of major adverse CV events in subsequent years,” Martin Whyte, PhD, FRCP, a clinical senior lecturer in metabolic medicine at the University of Surrey in the U.K., told Endocrine Today. “In addition, less glucose variability — measured by HbA1c — over the subsequent years of type 2 diabetes is also associated with fewer major adverse CV events.”
Whyte and colleagues retrospectively analyzed data from 21,281 adults aged at least 25 years with type 2 diabetes from England’s Royal College of General Practitioners Research and Surveillance Centre sentinel network database, Whyte said during a presentation. The researchers recorded HbA1c at diagnosis and 12 months. In the following years, five or more additional HbA1c readings were recorded. The researchers used these data to evaluate changes in HbA1c for the 12 months following diagnosis and to calculate long-term glycemic variability. Based on how often an individual had a HbA1c change of at least 0.5%, glycemic variability was scored from zero to 100, with higher numbers equating to more variability.
The researchers identified 1,291 combined instances of myocardial infarction, coronary intervention, stroke, heart failure, amputation or limb revascularization, which were grouped together as major adverse CV events. Adults who had an HbA1c of 58 mmol/mol to 74 mmol/mol at diagnosis and a lower HbA1c of 48 mmol/mol to 57 mmol/mol 12 months later were less likely to experience a major adverse CV event than those who maintained that lower HbA1c over the year (HR = 0.755; 95% CI, 0.643-0.887). In addition, those who had an HbA1c of at least 75 mmol/mol when they were diagnosed and lowered their HbA1c to 48 mmol/mol to 57 mmol/mol 12 months later were less likely to experience a major adverse CV event than those who maintained an HbA1c of 48 mmol/mol to 57 mmol/mol (HR = 0.686; 95% CI, 0.566-0.832). Conversely, individuals who maintained an HbA1c of 75 mmol/mol or more between diagnosis and 12 months were more likely to experience a major adverse CV event than those who maintained HbA1c of 48 mmol/mol to 57 mmol/mol (HR = 1.56; 95% CI, 1.12-2.19).
The researchers noted that major adverse CV event risk was higher for individuals with glycemic variability values between 81 and 100 compared with those with variability values between zero and 20 in the years following the initial 12 months (HR = 1.656; 95% CI, 1.23-2.229).
“The average HbA1c over follow-up time had no effect on subsequent major adverse CV events — it was the variability that was important,” Whyte told Endocrine Today. “[This research] provides further evidence, after trials such as UKPDS, ADVANCE and ACCORD, that early normalization of glycemic control is important; but that later in the disease course, swings in glycemia may be disadvantageous. Clinicians and services need to be proactive in the first few months after diagnosis of type 2 diabetes and avoid clinical inertia.” – by Phil Neuffer
Whyte MB, et al. OP 122. Presented at: European Association for the Study of Diabetes Annual Meeting; Sept. 16-20, 2019; Barcelona, Spain.
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Martin Whyte, PhD, FRCP, can be reached at email@example.com.
Disclosure: Whyte reports he has received grant support from Eli Lilly.