Importance of Measuring Glycosylated Hemoglobin in Patients With Myocardial Infarction and Known Diabetes Mellitus

Although medical co-morbidities commonly affect clinical outcomes after acute myocardial infarction (AMI), current performance measures of AMI quality focus exclusively on the management of the AMI itself. However, patients with AMIs frequently present with other co-morbidities, such as diabetes mellitus (DM), that also warrant assessment and management. To date, the quality of DM evaluation in patients presenting with AMIs has not been described. From January 2003 to June 2004, the Prospective Registry Evaluating Myocardial Infarction Patients: Events and Recovery–Quality Improvement (PREMIER-QI) enrolled 3,953 patients with AMIs at 19 centers in the United States. The frequency of glycosylated hemoglobin (HbA_1c) assessment, either during the hospitalization or documented in the chart from the preceding 3 months, was prospectively evaluated. Among 1,168 patients with AMIs with preexisting DM, only 47% had recent HbA_1c levels available, with marked variability in HbA_1c assessment among hospitals (range 7% to 81%). Among those with available HbA_1c levels, 39% had good control (HbA_1c <7%), 36% had suboptimal control (HbA_1c 7% to 9%), and 25% had poor control (HbA_1c >9%). Patients with suboptimal and poor control were more likely to have their DM treatment intensified than those without HbA_1c assessment (for HbA_1c 7% to 9%, rate ratio 1.38, 95% confidence interval 1.03 to 1.85; for HbA_1c >9%, rate ratio 2.20, 95% confidence interval 1.68 to 2.88). Similarly, patients with DM who had HbA_1c measured were more likely to receive instructions on DM disease management before discharge. In conclusion, the assessment of chronic glycemic control is highly variable among patients with AMIs and DM. Because much of this variability occurs at the hospital level, the evaluation of DM control could represent an additional quality indicator and an opportunity to advance patient-centered AMI care.