Atypical chest pain in diabetic patients with suspected stable angina: impact on diagnosis and coronary outcomes

Aims
Silent myocardial ischaemia occurs commonly in diabetes. Whether altered perception of ischaemia also predisposes to atypical presentations with under-diagnosis of coronary disease is not known. To determine whether (i) patients with diabetes diagnosed with angina are more likely to report atypical symptoms compared with patients without diabetes, and (ii) atypical symptoms in patients with diabetes cause angina to go unrecognized, increasing the risk of coronary events.

Method and results
Prospective, multicentre cohort study of 8662 ambulatory patients with suspected angina, of whom 906 had diabetes. We recorded detailed chest pain descriptors and fatal and non-fatal coronary events over a median of 3.08 years of follow-up. Proportionately more patients with than without diabetes received a diagnosis of angina (42.7 vs. 25.1%). Among patients with diabetes diagnosed with angina, a greater proportion had atypical chest pain compared with patients without diabetes (21.0 vs. 11.3%), but the hazard of fatal and non-fatal coronary events was similar. However, among patients diagnosed with non-cardiac chest pain, those with diabetes—most of whom had atypical symptoms—remained at greater risk of coronary events [2.29 (95% CI 1.54, 3.41)] and all-cause mortality [1.67 (95% confidence interval, CI 1.04, 2.69)] compared with non-diabetic patients.

Conclusions
Patients with diabetes and atypical symptoms are nearly twice as likely to be diagnosed with angina compared with non-diabetic patients. Those diagnosed with non-cardiac pain are at increased risk of coronary events. Our study emphasizes the need for more intensive investigation of diabetic patients with chest pain, particularly those presenting with atypical symptoms.