This multicentre study has shown that among patients with undifferentiated chest pain assessed in RACPCs, those diagnosed with angina have a substantially higher risk of death due to coronary heart disease or non‐fatal acute coronary syndrome than patients diagnosed with non‐cardiac chest pain and the general population. The data confirm the prognostic validity of differential diagnosis within RACPCs. Our finding that 32.4% of all events during follow‐up occurred in patients diagnosed with non‐cardiac chest pain highlights the need to reduce misdiagnosis and identify all who might benefit from secondary prevention treatment.
This is the first large, multicentre consecutive series of ambulatory patients with new, undifferentiated chest pain, allowing estimates of prognosis in women and men. Angina was diagnosed in 27% of patients, and in this group cumulative rates of death due to coronary heart disease or acute coronary syndromes were high, estimated at 8.62% after 1 year and 16.52% after 3 years. Our finding of a poor prognosis for patients with incident angina, none of whom had a history of myocardial infarction, emphasises the importance of early diagnosis within RACPCs and contrasts with findings in recent trials of chronic stable angina, ACTION (A CHF Trial Investigating Outcomes of Exercise Training)15
and PEACE (Prevention of Events with Angiotensin‐converting Enzyme Inhibition)16
reporting annual mortalities of 1.5% (95% CI 1.4% to 1.7%) and 1.7% (95% CI 1.5% to 1.9%) compared with 3.1% (95% CI 2.6% to 3.5%) in our registry population. The trialists' conclusions that angina has a good prognosis,15
with risk reduced to normal levels with contemporary treatment,17
may partly reflect the selection bias in the patients they recruited, which comprised stable patients in secondary or tertiary care settings. Similarly, 75% of patients in the Euro Heart survey18
of stable angina had had symptoms for >6 months before their first cardiological assessment and are different from the patients in our study with incident angina, many of whom were within 4 weeks and most within 6 months of symptom onset, suggesting recent plaque instability and predisposition to ischaemic events.19,20
Underuse of secondary prevention drugs may also have contributed to the high event rates we observed, and although rates of aspirin and β‐blocker treatment in patients in our study diagnosed with angina were similar to those reported in the Euro Heart Survey, only 28% were prescribed statins at this first cardiological consultation. This is lower than the entry treatment rates for angina trial participants, many of whom had had prior myocardial infarction and full cardiological investigation over many visits, but exceeds the treatment rates reported for patients with ischaemic heart disease in primary care settings.21
More than 80% of our patients with angina did undergo further cardiological follow‐up and although most probably came to receive statins, it is a limitation of our study that we do not know what proportion remained untreated.
Patients diagnosed with non‐cardiac chest pain in our study had a lower event rate, but accounted for almost one third of all primary end points. This is a cause for concern, because these patients had been assessed for coronary disease in the RACPCs and might therefore be expected to exhibit a distinctly lower coronary mortality than the general population. We found evidence for this in older patients diagnosed with non‐cardiac chest pain, but not in patients aged <65 years for whom SMRs were not significantly different from the general population. Probably most of these patients, who were told they did not have angina, but then had a coronary event, were misdiagnosed at the initial assessment, perhaps because they were younger than patients diagnosed with angina, fewer had typical symptoms and most had normal resting ECGs. Among patients diagnosed with non‐cardiac chest pain, coronary event rates fell below current thresholds for secondary prevention treatment,10
but we identified subgroups in whom hazard ratios for the primary end point were increased by
50%. These included patients with diabetes, for whom secondary prevention treatment is already recommended,22
but also south Asians and patients with ECG abnormalities who might benefit from more aggressive preventive strategies in RACPCs. Although clinical factors signal a heightened risk among subgroups diagnosed with non‐cardiac chest pain, there is now a need for research to identify the methods for improving diagnostic precision. This may entail a better understanding of existing measures—for example, by development and validation of risk scores in this population, as well as consideration of the incremental prognostic or diagnostic value of serological testing23
and non‐invasive coronary imaging.24,25
Unlike myocardial infarction,26
there is no internationally agreed standard for defining the presence or absence of angina.
This is the first large multicentre study to evaluate the effectiveness of RACPCs by examining coronary outcomes in relationship to clinical diagnosis and mortality in the general population. There have been no previous outcome studies of other models of ambulatory chest pain assessment, particularly conventional cardiology outpatient clinics or chest pain assessment units. Our conclusions about the adverse prognosis of angina are consistent with those of a large population‐based outcome study from Finland,27
but are limited to those patients selected for referral by their primary care physicians, and generalisation to chest pain in the community requires caution. Additional limitations relate to ethical constraints that prohibited the documentation of ongoing secondary prevention treatment during follow‐up, and also the inevitable restriction imposed on baseline covariates by the data that was recorded. For example, a reliable history of hyperlipidaemia was unavailable, and we excluded from analysis family history of coronary disease as it was not clear whether it related to history of premature death in first‐degree relatives.
One‐stop cardiological assessment in RACPCs successfully identifies patients with incident angina who are at substantially higher coronary risk than those patients with non‐cardiac chest pain and the general population. However, >70% of patients attending these clinics were diagnosed with non‐cardiac chest pain, and our data have exposed misdiagnosis in a minority who were not appropriately treated. We need to improve the diagnosis and treatment of ambulatory patients when they first present with chest pain, to reduce coronary event rates.