A review of health utilities using the EQ-5D in studies of cardiovascular disease

Pan-Asian Resuscitation Outcomes Study (PAROS): rationale, methodology, and implementation

Disease-based registries can form the basis of comparative research to improve and inform policy for optimizing outcomes, for example, in out-of-hospital cardiac arrest (OHCA). Such registries are often lacking in resource-limited countries and settings. Anecdotally, survival rates for OHCA in Asia are low compared to those in North America or Europe, and a regional registry is needed. The Pan-Asian Resuscitation Outcomes Study (PAROS) network of hospitals was established in 2009 as an international, multicenter, prospective registry of OHCA across the Asia-Pacific region, to date representing a population base of 89 million in nine countries. The network's goal is to provide benchmarking against established registries and to generate best practice protocols for Asian emergency medical services (EMS) systems, to impact community awareness of prehospital emergency care, and ultimately to improve OHCA survival. Data are collected from emergency dispatch, ambulance providers, emergency departments, and in-hospital collaborators using standard protocols. To date (March 2011), there are a total of 9,302 patients in the database. The authors expect to achieve a sample size of 13,500 cases over the next 2 years of data collection. The PAROS network is an example of a low-cost, self-funded model of an Asia-Pacific collaborative research network with potential for international comparisons to inform OHCA policies and practices. The model can be applied across similar resource-limited settings.

Impaired physical quality of life in patients with diastolic dysfunction associates more strongly with neurohumoral activation than with echocardiographic parameters: quality of life in diastolic dysfunction

BACKGROUND

Quality of life (QoL) is impaired in diastolic heart failure. Little is known about QoL in diastolic dysfunction (DD) without heart failure.

METHODS

In the DIAST-CHF observational study, outpatients with risk factors for or a history of heart failure were included. In a cross-sectional analysis, we classified patients with preserved systolic function as having normal diastolic function (N, n = 264) or DD without (DD-, n = 957) or with (DD+, n = 321) elevated filling pressures according to echocardiography. Quality of life was evaluated by the Short Form 36 (SF-36) questionnaire.

RESULTS

Short Form 36 physical function (SF-36-PF) was worse in DD+ (mean ± SD 67.2 ± 25.6) than in DD- (76.2 ± 22.7, P < .05) than in N (mean ± SD 81.1 ± 23.5, P < .01). Other physical dimensions and the physical component score were also lower in DD, whereas the mental component score did not differ. The SF-36-PF correlated weakly with echocardiographic indicators of diastolic function. In multivariate linear regression controlling for age, sex, body mass index, depressiveness as assessed by Patient Health Questionnaire 9, N-terminal probrain-type natriuretic peptide, and midregional proadrenomedullin (MR-proADM), individual echocardiographic parameters or grade of DD was not independently associated with SF-36-PF, whereas the presence of DD+ was. Both N-terminal probrain-type natriuretic peptide and MR-proADM were independently associated with SF-36-PF, with MR-proADM showing the stronger association.

CONCLUSIONS

Physical dimensions of QoL are reduced in DD. Impaired SF-36-PF is only weakly associated with DD per se but rather seems to be contingent on the presence of elevated filling pressures. Biomarkers are more strongly and independently associated with SF-36-PF and may be more adequate surrogate markers of QoL in DD than echocardiographic measurements.

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.