Mapping of the EQ-5D index from clinical outcome measures and demographic variables in patients with coronary heart disease.

BACKGROUND: The EuroQoL 5D (EQ-5D) is a questionnaire that provides a measure of utility for cost-effectiveness analysis. The EQ-5D has been widely used in many patient groups, including those with coronary heart disease. Studies often require patients to complete many questionnaires and the EQ-5D may not be gathered. This study aimed to assess whether demographic and clinical outcome variables, including scores from a disease specific measure, the Seattle Angina Questionnaire (SAQ), could be used to predict, or map, the EQ-5D index value where it is not available. METHODS: Patient-level data from 5 studies of cardiac interventions were used. The data were split into two groups - approximately 60% of the data were used as an estimation dataset for building models, and 40% were used as a validation dataset. Forward ordinary least squares linear regression methods and measures of prediction error were used to build a model to map to the EQ-5D index. Age, sex, a proxy measure of disease stage, Canadian Cardiovascular Society (CCS) angina severity class, treadmill exercise time (ETT) and scales of the SAQ were examined. RESULTS: The exertional capacity (ECS), disease perception (DPS) and anginal frequency scales (AFS) of the SAQ were the strongest predictors of the EQ-5D index and gave the smallest root mean square errors. A final model was chosen with age, gender, disease stage and the ECS, DPS and AFS scales of the SAQ. ETT and CCS did not improve prediction in the presence of the SAQ scales. Bland-Altman agreement between predicted and observed EQ-5D index values was reasonable for values greater than 0.4, but below this level predicted values were higher than observed. The 95% limits of agreement were wide (-0.34, 0.33). CONCLUSIONS: Mapping of the EQ-5D index in cardiac patients from demographics and commonly measured cardiac outcome variables is possible; however, prediction for values of the EQ-5D index below 0.4 was not accurate. The newly designed 5-level version of the EQ-5D with its increased ability to discriminate health states may improve prediction of EQ-5D index values.

Assessment of activity status and survival according to the Canadian Cardiovascular Society angina classification.

BACKGROUND: Despite its widespread use, limited data on the validity of the Canadian Cardiovascular Society angina (CCSA) classification relative to other measures of functional status have been reported. OBJECTIVE: To assess the validity of the CCSA classification by comparing it with the Duke Activity Status Index (DASI) and evaluate its prognostic significance with respect to long-term mortality. METHODS: The study population consisted of 1407 patients who underwent cardiac catheterization between 1992 and 1996. The median follow-up period was 9.7 years (interquartile range 6.1 to 11.1 years) and the mortality status as of December 31, 2004 was available for all patients. RESULTS: The first three CCSA classes were inversely related to the DASI. The mean (+/- SD) scores were as follows: class I, 31.4+/-16.7; class II, 22.5+/-15.4; class III, 14.7+/-14.3; and class IV, 15.5+/-14.9 (P<0.01). Increasing CCSA class was associated with increased long-term mortality, even after adjusting for baseline characteristics. Chest pain course was also an important modulator of mortality among class III and IV patients; one-year mortality rates were 8.1% among unstable patients compared with 4.8% among patients with stable or progressing course. CONCLUSION: CCSA classes I to III were inversely related to DASI scores and linearly associated with mortality. The similarity in outcomes among class III and IV patients is probably explained by the confounding effect of the stability of the patients' symptoms. The higher mortality risk among class III and IV patients with an unstable course provides impetus for a revised CCSA definition incorporating this information.

Diagnostic performance of coronary angiography by 64-row CT.

BACKGROUND: The accuracy of multidetector computed tomographic (CT) angiography involving 64 detectors has not been well established. METHODS: We conducted a multicenter study to examine the accuracy of 64-row, 0.5-mm multidetector CT angiography as compared with conventional coronary angiography in patients with suspected coronary artery disease. Nine centers enrolled patients who underwent calcium scoring and multidetector CT angiography before conventional coronary angiography. In 291 patients with calcium scores of 600 or less, segments 1.5 mm or more in diameter were analyzed by means of CT and conventional angiography at independent core laboratories. Stenoses of 50% or more were considered obstructive. The area under the receiver-operating-characteristic curve (AUC) was used to evaluate diagnostic accuracy relative to that of conventional angiography and subsequent revascularization status, whereas disease severity was assessed with the use of the modified Duke Coronary Artery Disease Index. RESULTS: A total of 56% of patients had obstructive coronary artery disease. The patient-based diagnostic accuracy of quantitative CT angiography for detecting or ruling out stenoses of 50% or more according to conventional angiography revealed an AUC of 0.93 (95% confidence interval [CI], 0.90 to 0.96), with a sensitivity of 85% (95% CI, 79 to 90), a specificity of 90% (95% CI, 83 to 94), a positive predictive value of 91% (95% CI, 86 to 95), and a negative predictive value of 83% (95% CI, 75 to 89). CT angiography was similar to conventional angiography in its ability to identify patients who subsequently underwent revascularization: the AUC was 0.84 (95% CI, 0.79 to 0.88) for multidetector CT angiography and 0.82 (95% CI, 0.77 to 0.86) for conventional angiography. A per-vessel analysis of 866 vessels yielded an AUC of 0.91 (95% CI, 0.88 to 0.93). Disease severity ascertained by CT and conventional angiography was well correlated (r=0.81; 95% CI, 0.76 to 0.84). Two patients had important reactions to contrast medium after CT angiography. CONCLUSIONS: Multidetector CT angiography accurately identifies the presence and severity of obstructive coronary artery disease and subsequent revascularization in symptomatic patients. The negative and positive predictive values indicate that multidetector CT angiography cannot replace conventional coronary angiography at present. (ClinicalTrials.gov number, NCT00738218.)

The burden of angina pectoris and its complications [corrected].

Between 10 to 30% of patients with coronary disease still suffer from symptoms of angina pectoris in contemporary clinical practice. This article summarizes analytic tools for measuring angina, as well as, its prevalence based on community based surveys, registries and in randomized controlled trials. Additionally, the impact of angina symptoms on patients' survival rates, functional status, quality of life and health-related costs is reviewed. The effectiveness of treatment, revascularization and medical therapies, on reducing angina symptoms is also reviewed.

Coronary artery bypass graft surgery in New Zealand's Auckland region: a comparison between the clinical priority assessment criteria score and the actual clinical priority assigned.

AIMS: To describe the cohort of patients waiting for Coronary Artery Bypass Graft (CABG) surgery in the Auckland region; compare the Clinical Priority Assessment Criteria (CPAC) score with the actual priority assigned; and to assess the impact of a patient's demographic characteristics on the CPAC score and the assigned priority. METHODS: An electronic register was developed to capture all patients who had a CPAC form completed for isolated CABG surgery during the period June 2002 to September 2004 in the Auckland region. CPAC scores and clinical priority assigned were collected from the CABG booking form. Demographic characteristics came from the booking form (age, gender) or linkage via the National Health Index (NHI) number (ethnicity, deprivation score). RESULTS: The cohort displayed severe coronary artery disease and symptoms: 70% had class 3 or class 4 angina; 89% had their ability to work, live independently, or care for dependents threatened; 65% had three-vessel coronary disease; and 26% had left-main coronary disease. The CPAC score correlated only modestly with the actual clinical priority assigned, with an extremely wide range of scores for any given clinical priority. The mean CPAC score varied by the age of the patient, level of deprivation, and ethnicity--with higher mean scores among male patients who were Maori, Pacific, or more socioeconomically deprived. Clinical priority varied less by demographic characteristics than did the CPAC score, except more women than men were assigned the 'emergency' category. Despite higher CPAC scores for Maori and Pacific men, these did not translate to greater urgency in clinical priority. CONCLUSIONS: The CPAC scoring system is used to limit access onto the CABG surgery waiting list in Auckland, but is not used to prioritise patients as to the urgency of surgery once on the list. The challenge is to determine why clinicians do not consider that the CPAC score is adequate to prioritise the urgency of surgery and to build in a process whereby any such score can be continuously evaluated and improved. We have demonstrated that the establishment of an electronic register of such patients can provide timely analysis of patterns of practice and could be used on a national scale to improve future CPAC scoring systems.

Cost of illness of chronic angina.

BACKGROUND: Angina pectoris is one of the principal manifestations of coronary artery disease (CAD). Chronic angina is a debilitating condition that affects millions of people in the United States. OBJECTIVE: The objective of the study is to estimate, from a societal perspective, the direct costs of chronic angina in the year 2000. METHODS: Data on medical utilization related to chronic angina were extracted from National Center for Health Statistics public-use databases and from IMS databases on medications (nitrates, beta-blockers, and calcium channel blockers). National average Medicare reimbursement rates were used to estimate costs. We identified medical utilization related to chronic angina based on International Classification of Diseases, Ninth Revision (ICD-9) codes. When ICD-9 codes that do not explicitly identify angina are used in medical databases, people with chronic angina may be coded as having CAD only. To address this, we developed upper- and lower-boundary estimates of the costs of chronic angina. The lower-boundary estimate is based on diagnoses that narrowly define the presence of chronic angina, and is termed "narrowly defined chronic angina." The upper-boundary estimate is based on diagnoses of CAD. RESULTS: The lower boundary on the cost of chronic angina is the estimated direct medical cost of narrowly defined chronic angina ($1.9 billion when it is the first-listed diagnosis and $8.9 billion when it is listed in any position). The upper boundary on the cost of chronic angina is the estimated total direct medical cost of CAD, which is $33 billion when it is the first-listed diagnosis and $75 billion when it is listed in any position. CONCLUSION: These analyses capture the range of direct costs that might be attributed to the care of chronic angina in the United States for the year 2000. Some components of care were not available, and estimated costs will be significantly higher if private payer reimbursement rates are used.

Factors predicting working status after aortocoronary bypass surgery.

The working status of 1165 patients aged 59 years or less (mean 49.8 years) was evaluated 7 to 77 months (mean 36 months) after aortocoronary bypass surgery. Although 76% of the patients eventually returned to work, only 56% were working 6 months after their operation. The proportion of patients working peaked at 2 years after the operation (at 66%) and decreased progressively to 56% at 4 years and 53% at 5 years without ever reaching the proportions that applied 12 and 6 months before the operation (84% and 69% respectively). Multivariate analysis identified three socioeconomic and three clinical variables as predicting the working status at 6 months and at yearly points during the first 4 years after the operation. Of the socioeconomic variables analysed, preoperative unemployment of long duration, a preoperative occupation that required strenuous physical effort and a low level of education were, in that order, the strongest predictors of postoperative unemployment. Among the clinical variables, associated noncardiovascular illness and the severity and duration of angina pectoris independently influenced the patients' post-operative working status. The authors conclude that modification of some of these variables should by attempted both before and after aortocoronary bypass surgery to see whether the rate of return to employment after the operation can be improved in selected patients.