Introduction

The primary indication for revascularization in stable coronary artery disease (CAD) is symptom relief. Therefore, the severity of symptoms is crucial in guiding treatment decisions and in evaluating treatment effect [1]. Canadian Cardiovascular Society (CCS) grading is the most used tool to describe the severity of angina pectoris symptoms [2]. However, CCS is usually assessed by the treating physician, not by the patient. This carries an inherent risk for bias, particularly if the effectiveness of treatment is addressed. To overcome this bias, patient-reported outcomes (PROMs) should be used for symptom evaluation [3, 4].

A recent study reported 36% agreement between physician- and patient-reported CCS scores in patients with multi-vessel CAD undergoing revascularization with CCS scores estimated after the coronary angiography [5]. We examined the agreement between physician- and patient-reported CCS scores among patients undergoing diagnostic coronary angiography and, thus, unaware of the result of the angiography.

Materials and methods

Altogether 650 patients scheduled for diagnostic coronary angiography (NOMESCO Classification of Surgical Procedures codes FN1AC, FN1BB, FN1BC, and FN1CC) at the Kuopio University Hospital, Finland between VI/2015 and VI/2017 filled in the CCS questionnaires (see S1 File) prior to angiography. Physicians performing the angiography evaluated patients’ CCS class before the procedure while being unaware of the patient-evaluated CCS score.

Patients were divided into those without significant CAD (stenosis diameter <50%) and those with CAD (stenosis diameter ≥50%). Those with CAD were further grouped according to the number of major coronary arteries with significant stenosis (single-, double- or triple-vessel disease).

The study was approved by the Research Ethics Committee of the Northern Savo Hospital District (numbers 3/2014, 221/2016, and 135/2017). Written informed consent was obtained from the patients as required by the Ethics Committee. The authors used only pseudonymized data.

Results

Coronary angiography revealed significant CAD in 205 of 650 (31.5%) patients (Table 1). Of them, 106 (51.7%) had single-vessel, 56 (27.3%) double-vessel and 43 (21.0%) triple-vessel diseases. Patients with CAD were older, more often men, and had a worse physician-reported mean CCS score than patients without CAD (Table 1, Fig 1). Mean physician-reported CCS score was worse in patients with triple-vessel disease compared to those with single-vessel disease. Patients with triple-vessel disease had on average worse mean self-reported CCS score than patients with single- or double-vessel disease or those without CAD.

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Fig 1. Patient- and physician-reported CCS scores.

Statistical significances: * p<0.05, ** p<0.01, and *** p<0.001 for patient- vs. physician-reported CCS.

https://doi.org/10.1371/journal.pone.0292058.g001

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Table 1. Characteristics of the study population.

https://doi.org/10.1371/journal.pone.0292058.t001

When comparing physician- and patient-reported mean CCS scores, the physician-reported CCS score was lower (less severe) than the patient-reported CCS score (Fig 1). This was true both for patients with or without CAD and for patients with single- or triple-vessel disease. The physician- and patient reported CCS scores agreed fully for only 51.8% (95% CI 44.5%–59.0%) of patients with CAD and for 51.9% (95% CI 47.0%–56.8%) of those without CAD (Table 2). For 33.9% (95% CI 27.6%–40.7%) of the patients with CAD and 36.2% (95% CI 31.8%–41.0%) of the patients without CAD, the physician reported at least one-point better CCS score than the patient. On the contrary, the physicians reported at least one-point worse CCS score than the patient in 14.4% (95% CI 10.1%–20.0%) of patients with CAD and 11.8% (95% CI 9.1%–15.3%) of those without CAD.

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Table 2. Agreement between patient- and physician-reported CCS scores.

https://doi.org/10.1371/journal.pone.0292058.t002

The correlation coefficients between physician- and patient-reported CCS scores were low, 0.22 (95% CI 0.09–0.35) and 0.24 (95% CI 0.15–0.33) in patients with and without CAD, respectively. The proportions of full or partial agreement between physician- and patient reported CCS scores were similar across the CAD severity categories (Table 2).

Discussion

We demonstrated a significant discrepancy in the severity of angina symptoms assessment between the physician and the patient. The physician- and patient-reported CCS grading agreed only in half of the cases. The physicians underestimated symptoms in one out of three patients scheduled for diagnostic coronary angiography. Similar discrepancies were observed among patients with and without CAD, and regardless of CAD severity.

The main purpose of stable CAD treatment is angina relief. Thus, the patient’s assessment of symptoms is crucial when considering the therapeutic options. However, the symptom severity is evaluated and interpreted by the physician. The agreement between physician- and patient-rated CCS (51.9%) in our study is in line with Kemp et al., who reported 36.3% agreement between the physician- and patient-reported CCS scores in patients with multi-vessel CAD and undergoing revascularization [5]. However, in that study the physicians overestimated the symptoms in 37.8% of patients, whereas in our study the physicians underestimated the symptoms in 35.4% of patients. Importantly, in that study [5], both the physician and the patients were aware of the presence of multivessel CAD, and the treatment decision had already been made. By contrast, in our study the CCS scores were evaluated before angiography when both the physician and the patient were unaware of the angiography result.

The awareness of the presence of CAD and the need for revascularization may influence the assessment of symptom severity, particularly by the physician. In a study comparing physician- and patient-estimated angina in patients undergoing percutaneous coronary intervention (PCI) 35% of patients undergoing elective PCI and 12% of those scheduled for urgent PCI reported no angina preoperatively [6]. However, the physician estimated that 20% of the symptom-free patients scheduled for elective PCI and 12% of those scheduled for urgent PCI had moderate to severe angina.

Our results agree also with the APPREAR study [7, 8]. It compared patient-reported severity of angina using the Seattle Angina Questionnaire (SAQ) and physician-assessed angina severity utilizing structured questions on, for example, angina frequency among CAD patients in cardiology outpatient clinics. The physician missed 42% of patients reporting angina during previous month [7], and of patients with daily or weekly angina, 26% were assessed as being free of angina by the physician [8]. However, these studies applied SAQ, typically used for research, not CCS which is the most used angina scoring tool in clinical practise.

The agreement between physician- and patient-estimated CCS score in our study (52%) is close to the agreement (54%) reported between two cardiologists assessing symptom severity among heart failure patients using the New York Heart Association (NYHA) grading [9]. The disagreement between the physicians was related to problems in distinguishing patients belonging to NYHA classes II and III. In our study, the disagreement between patient- and physician-reported symptom severity was evident in all CCS classes and most pronounced in the extremities of the disease severity scale (CCS classes I and IV). In our study, 18% of physicians, but 10% of patients classified symptom severity as mild (class I), whereas angina at rest (CCS class IV) was reported by 11% of the patients, but only by 1% of the physicians.

The differences between patient- and physician-evaluated CCS scores may partially arise from possible limitations of CCS related to inter- and intra-rater reproducibility, content validity and lack of sensitivity to differentiate between all levels of angina symptoms [10]. Still, our results demonstrate an important discrepancy between the two ratings and highlight that the symptoms should be evaluated by the patient herself/himself, not by the physician.

U.S. Food and Drug Administration has stated that assessment of patients’ health and symptoms should come directly from the patient without interpretation by a clinician or a healthcare provider [11]. The added value of PROMs is that they support patient-provider engagement by assessing the severity of symptoms, providing additional means for tracking the effect of treatments, informing treatment decisions, and monitoring general health and well-being. Further, the process of self-reporting per se can improve symptom management, quality of life, communication, and satisfaction with care [4, 12]. Therefore, patient-reported symptom severity should be more efficiently incorporated into practice.

A strength is that the CCS scores were recorded before angiography. Thus, the result of the invasive examination did not influence the assessment of symptom severity.

Selection bias is a potential limitation of our study. Only patients with both physician- and self-reported CCS scores were included. The response rate in an earlier study in patients scheduled for elective angiography and PCI in the Kuopio University Hospital was circa 40% [13]. Typically, the most comorbid and oldest patients are least prone to answer surveys [12]. However, this does not impact the conclusion of our study.

Conclusion

To conclude, our results show that physicians are prone to underestimate patients’ symptoms. When the primary aim of treatment is symptom relief, as it is in stable CAD, self-reported symptom assessment, rather than physician’s evaluation, should be the cornerstone of treatment decisions.

Supporting information