Patients newly diagnosed with clinical type 2 diabetes mellitus but presenting with HbA1c within normal range: 19-year mortality and clinical outcomes.

AIMS

To investigate whether long-term mortality or clinical outcomes differed between patients diagnosed with type 2 diabetes mellitus and presenting with HbA1c within or above normal range at time of diagnosis.

METHODS

Data were from a population-based sample of 1136 individuals with newly diagnosed type 2 diabetes mellitus. The diagnosis was confirmed with a single fasting whole blood/plasma glucose ≥7.0/8.0mmol/l. The median time from day of diagnosis until end of follow up was 18.8years. Patients were grouped according to normal HbA1c and elevated HbA1c at diagnosis. The effect of elevated HbA1c on a number of clinical outcomes and all-cause mortality was assessed in Cox regression models.

RESULTS

At diagnosis, 97 patients (8.5%) had an HbA1c level within normal range. Age (mean (SD)) at diagnosis was 64.5 (11.5) years. Both unadjusted and adjusted hazard ratios for the effect of HbA1c on mortality and other outcomes were not statistically significant.

CONCLUSIONS

Patients who are diagnosed with type 2 diabetes mellitus by means of elevated fasting whole blood/plasma glucose but have HbA1c within reference range at diagnosis do not seem to have a relatively benign long-term clinical course. Therefore new diagnostic procedures should preferably be able to identify these individuals.