Emergency department patient compliance with follow-up for outpatient exercise stress testing: a randomized controlled trial

INTRODUCTION: Numerous patients are assessed in the emergency department (ED) for chest pain suggestive of acute coronary syndrome (ACS) and subsequently discharged if found to be at low risk. Exercise stress testing is frequently advised as a follow-up investigation for low-risk patients; however, compliance with such recommendations is poorly understood. We sought to determine if compliance with follow-up for exercise stress testing is higher in patients for whom the investigation is ordered at the time of ED discharge, compared with patients who are advised to arrange testing through their family physician (FP). METHODS: Low-risk chest pain patients being discharged from the ED for outpatient exercise stress test and FP follow-up were randomized into 2 groups. ED staff ordered an exercise stress test for the intervention group, and the control group was advised to contact their FP to arrange testing. The primary outcome was completion of an exercise stress test at 30 days, confirmed through both patient contact and stress test results. Patients were unaware that our primary interest was their compliance with the exercise stress testing recommendations. RESULTS: Two-hundred and thirty-one patients were enrolled and baseline characteristics were similar between the 2 groups. Completion of an exercise stress test at 30 days occurred in 87 out of 120 (72.5%) patients in the intervention group and 60 out of 107 (56.1%) patients in the control group. The difference in compliance rates (16.4%) between the 2 groups was statistically significant (Chi(2) = 6.69, p < 0.001) with a relative risk of 1.29 (95% confidence interval 1.18-1.40), and the results remained significant after a "worst case" sensitivity analysis involving 4 control group cases lost to follow-up. When subjects were contacted by telephone 30 days after the ED visit, 60% of those who were noncompliant patients felt they did not have a heart problem and that further testing was unnecessary. CONCLUSION: When ED staff order an outpatient exercise stress test following investigation for potential ACS, patients are more likely to complete the test if it is booked for them before ED discharge. After discharge, many low-risk chest pain patients feel they are not at risk and do not return to their FP for further testing in a timely manner as advised. Changing to a strategy of ED booking of exercise stress testing may help earlier identification of patients with coronary heart disease.