Minimum A1C needed

A study of patients with type 2 diabetes has found that the lowest and highest HbA1c levels are associated with increased all-cause mortality and cardiac events, prompting researchers to suggest guidelines may need revising to include a minimum HbA1c value. Using data from the U.K. General Practice Research Database British researchers identified two cohorts of patients aged 50 years or older with type 2 diabetes. Cohort one (n=27,965; mean baseline HbA1c, 9%) included patients whose treatment was intensified from oral monotherapy to combination therapy with sulfonylureas plus metformin. Cohort two (n=20,005; mean baseline HbA1c, 10%) included patients previously treated with oral agents who changed regimens to include insulin. Using the HbA1c level with the lowest mortality risk (7.5%) as a reference point, the researchers found a HR of 1.52 (95% CI, 1.32-1.76) for all-cause mortality among patients in the lowest HbA1c decile (6.4%) and 1.79 (95% CI, 1.56-2.06) among those in the highest HbA1c decile (10.5%). While results showed a similar U-shaped curve for both oral combination therapy and insulin therapy, all-cause mortality in people given insulin-based regimens was 50% higher than those give combination oral agents. The study authors said that this could be explained by the fact that insulin treated patients were older, had more comorbidities and a longer diabetes duration than those not on insulin. However, they said the data implied that for oral combination therapy “a wide HbA1c range is safe with respect to all-cause mortality and large-vessel events, but for insulin-based therapy, a more narrow range might be desirable”. Writing in the Lancet the researchers said their finding suggest that diabetes guidelines “might need revision to include a definition of an HbA1c minimum value.” In an accompanying editorial Drs Beverley Balkau (Université Paris Sud, Villejuif, France) and Dominique Simon (Groupe Hospitalier Pitié Salpetrière, Paris, France) said more research was needed to establish HbA1c thresholds and the combination of drugs to be recommended for intensive treatment, with perhaps differing recommendations according to the patient....