Patient-rated health status predicts prognosis following percutaneous coronary intervention with drug-eluting stenting

In the current study, health status as reported by the patient was shown to predict death or MI at follow-up in PCI patients treated with drug-eluting stenting and to add to the level of prediction of a model comprised of demographic and clinical characteristics. The impact of health status on death/MI was independent of disease severity and other demographic and clinical characteristics known to predict major adverse clinical events. The risk incurred by poor mobility, poor self-care, and poor self-rated health status as measured with the EQ-5D VAS was more than twofold, whereas the EQ-5D dimensions usual activities, pain/discomfort, and anxiety/depression were not related to clinical outcome.

Similar to the Euro Heart Survey on coronary revascularization conducted prior to the introduction of drug-eluting stenting [8], we found that of the five descriptive domains of the EQ-5D poor self-care was the most powerful predictor of mortality and non-fatal MI, with the adjusted risk being almost threefold. Self-care, comprising an important part of the management of chronic conditions, such as CAD, diabetes, and heart failure, refers to a set of daily behaviors, including the monitoring of symptoms and consulting a physician when necessary, performed by the patient to manage his or her condition and to promote health [21, 22]. Self-care and its impact on health outcomes have received most attention in patients with heart failure [21, 23]. This may be attributed to the chronicity of the condition and its associated functional impairments and poor prognosis, with poor self-care more likely to have an immediate impact on both functional status and quality of life and prognosis in heart failure compared to more benign conditions such as elective PCI due to stable CAD. However, the current results indicate that it is important also in PCI patients to tend to the issue of self-care.

In the current study, poor mobility was also an important and independent predictor of adverse clinical events at follow-up. This finding is consistent with previous studies showing that the extent of disability as perceived by the patient predicts poor prognosis and quality of life both in patients with CAD and heart failure, adjusting statistically for indicators of disease severity, such as left ventricular dysfunction and NYHA functional class [8, 11, 24‐26]. This was also confirmed in a recent systematic review on the impact of patient-rated health status on mortality and readmission in patients with CAD and heart failure [11].

The recent results of the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial, randomizing patients with stable CAD to either PCI with optimal medical therapy or optimal medical therapy alone, testify to the utility of incorporating a measure of health status in research and clinical practice [2, 8]. Patients enrolled in the COURAGE trial with more frequent anginal complaints, as assessed with the Seattle Angina Questionnaire, derived the most benefit from PCI in combination with optimal medical therapy. Patients with more severe anginal complaints would likely not be identified in clinical practice based on the clinician’s judgment alone, in particular since physicians seem to underestimate the disability of patients [6, 7]. Taken together with the results of the current study, this indicates that assessment of patients’ health status as part of routine clinical care may be helpful in clinical decision-making and risk stratification and be instrumental in identifying high-risk patients who may need more aggressive medical treatment and who might also benefit from adjunctive intervention to increase adherence with lifestyle changes, such as exercising and smoking cessation. Assessment of health status as part of routine clinical practice would thus enable treatment recommendations to be tailored to individual patients. The clinical utility of incorporating health status measures in the clinical care and management of cardiac patients is further elaborated upon in a seminal paper by Spertus [3] and in a recent review of the impact of poor health status on clinical outcomes in CAD and heart failure by Mommersteeg and colleagues [11].

An advantage of using the EQ-5D as a measure of health status in clinical practice is that it is brief and takes up little time for patients to complete compared to other more lengthy measures, such as the 36-item Short Form Health Survey (SF-36), which is often used in CAD patients. However, despite the prognostic value of the EQ-5D as shown here and in another study [8], the instrument may be less suitable to use as an outcome measure to tap treatment-related changes, as it is likely to be less sensitive compared to a disease-specific measure [11].

The results of the current study should be interpreted with some caution due to the following limitations. First, a selection bias may have occurred, since patients who died within the first 1 month post-PCI did not have the opportunity to participate in the study, in turn limiting the generalizability of the findings. Second, we used the EQ-5D, which is a generic rather than a disease-specific measure of health status, since standardized and validated disease-specific measures, such as the Seattle Angina Questionnaire (19 items) and the MacNew Quality of Life Questionnaire (27 items), tend to be longer. However, a disease-specific measure is likely to be more sensitive to tap symptoms that are important to patients. In addition, the EQ-5D contains only one question tapping into the five descriptive dimensions of mobility, self-care, usual activities, pain/discomfort, and anxiety/depression, which provides little room for variability in scores. Nevertheless, the EQ-5D health status domains poor mobility and poor self-care, and the EQ-5D VAS predicted adverse clinical events despite adjustment for standard, biomedical risk factors. Third, we had no information on renal failure, angina severity, NYHA functional class, heart failure, left ventricular ejection fraction, number of hospitalizations during follow-up, participation in cardiac rehabilitation, socio-economic status, and the use of psychotropic medication, which could serve as potential confounders. However, we did adjust for multi-vessel disease, as an indicator of somatic disease severity. Fourth, the multivariable models were not formally validated by means of the bootstrapping method nor in a different, independent population, but the results were consistent with the findings of Lenzen and colleagues [8], who also examined the predictive validity of the EQ-5D in patients treated with coronary revascularization, although prior to the drug-eluting stent era.

In conclusion, several health status dimensions as measured with the brief and validated EQ-5D predicted death or non-fatal MI at follow-up in PCI patients treated with drug-eluting stenting. The risk associated with poor health status was more than twofold and was independent of disease severity and other demographic and clinical characteristics. To our knowledge, this is only the second study to have examined the predictive validity of the EQ-5D as a measure of health status in patients with CAD and heart failure [11], and the first study to show that poor patient-rated health status predicts adverse clinical events in PCI patients despite optimal treatment with drug-eluting stenting. It may be timely to adopt standard assessment of health status in clinical practice, given evidence from this and other studies that patient-rated health status has unique prognostic value.