Mapping SF-36 onto the EQ-5D index: how reliable is the relationship?

<p>Abstract</p> <p>Background</p> <p>Mapping from health status measures onto generic preference-based measures is becoming a common solution when health state utility values are not directly available for economic evaluation. However the accuracy and reliability of the models employed is largely untested, and there is little evidence of their suitability in patient datasets. This paper examines whether mapping approaches are reliable and accurate in terms of their predictions for a large and varied UK patient dataset.</p> <p>Methods</p> <p>SF-36 dimension scores are mapped onto the EQ-5D index using a number of different model specifications. The predicted EQ-5D scores for subsets of the sample are compared across inpatient and outpatient settings and medical conditions. This paper compares the results to those obtained from existing mapping functions.</p> <p>Results</p> <p>The model including SF-36 dimensions, squared and interaction terms estimated using random effects GLS has the most accurate predictions of all models estimated here and existing mapping functions as indicated by MAE (0.127) and MSE (0.030). Mean absolute error in predictions by EQ-5D utility range increases with severity for our models (0.085 to 0.34) and for existing mapping functions (0.123 to 0.272).</p> <p>Conclusion</p> <p>Our results suggest that models mapping the SF-36 onto the EQ-5D have similar predictions across inpatient and outpatient setting and medical conditions. However, the models overpredict for more severe EQ-5D states; this problem is also present in the existing mapping functions.</p

Reconsidering the use of rankings in the valuation of health states: a model for estimating cardinal values from ordinal data

BACKGROUND: In survey studies on health-state valuations, ordinal ranking exercises often are used as precursors to other elicitation methods such as the time trade-off (TTO) or standard gamble, but the ranking data have not been used in deriving cardinal valuations. This study reconsiders the role of ordinal ranks in valuing health and introduces a new approach to estimate interval-scaled valuations based on aggregate ranking data. METHODS: Analyses were undertaken on data from a previously published general population survey study in the United Kingdom that included rankings and TTO values for hypothetical states described using the EQ-5D classification system. The EQ-5D includes five domains (mobility, self-care, usual activities, pain/discomfort and anxiety/depression) with three possible levels on each. Rank data were analysed using a random utility model, operationalized through conditional logit regression. In the statistical model, probabilities of observed rankings were related to the latent utilities of different health states, modeled as a linear function of EQ-5D domain scores, as in previously reported EQ-5D valuation functions. Predicted valuations based on the conditional logit model were compared to observed TTO values for the 42 states in the study and to predictions based on a model estimated directly from the TTO values. Models were evaluated using the intraclass correlation coefficient (ICC) between predictions and mean observations, and the root mean squared error of predictions at the individual level. RESULTS: Agreement between predicted valuations from the rank model and observed TTO values was very high, with an ICC of 0.97, only marginally lower than for predictions based on the model estimated directly from TTO values (ICC = 0.99). Individual-level errors were also comparable in the two models, with root mean squared errors of 0.503 and 0.496 for the rank-based and TTO-based predictions, respectively. CONCLUSIONS: Modeling health-state valuations based on ordinal ranks can provide results that are similar to those obtained from more widely analyzed valuation techniques such as the TTO. The information content in aggregate ranking data is not currently exploited to full advantage. The possibility of estimating cardinal valuations from ordinal ranks could also simplify future data collection dramatically and facilitate wider empirical study of health-state valuations in diverse settings and population groups

A large age for the pulsar B1757-24 from an upper limit on its proper motion

The "characteristic age" of a pulsar usually is considered to approximate its true age, but this assumption has led to some puzzling results, including the fact that many pulsars with small characteristic ages have no associated supernova remnants. The pulsar B1757-24 is located just beyond the edge of a supernova remnant; the properties of the system indicate that the pulsar was born at the centre of the remnant, but that it has subsequently overtaken the expanding blast-wave. With a characteristic age of 16,000 yr, this implies an expected proper motion by the pulsar of 63-80 milliarcsec per year. Here we report observations of the nebula surrounding the pulsar which limit its proper motion to less than 25 mas/yr, implying a minimum age of 39,000 yr. A more detailed analysis argues for a true age as great as 170,000 yr, significantly larger than the characteristic age. From this result and other discrepancies associated with pulsars, we conclude that characteristic ages seriously underestimate the true ages of pulsars

Cost-effectiveness analysis of antimuscarinics in the treatment of patients with overactive bladder in Spain: A decision-tree model

<p>Abstract</p> <p>Background</p> <p>Fesoterodine, a new once daily antimuscarinic, has proven to be an effective, safe, and well-tolerated treatment in patients with overactive bladder (OAB). To date, no analysis has evaluated the economic costs and benefits associated with fesoterodine, compared to antimuscarinics in Spain. The purpose of this analysis was to assess the economic value of OAB treatment with fesoterodine relative to extended release tolterodine and solifenacin, from the societal perspective.</p> <p>Methods</p> <p>The economic model was based on data from two 12-week, randomized, double-blind, and multicenter trials comparing fesoterodine and tolterodine extended released (ER). Treatment response rates for solifenacin were extracted from the published literature. Discontinuation and efficacy were based on the results of a 12-week multinational randomized clinical trial extrapolated to 52 weeks. Changes in health related quality of life were assessed with the King's Health Questionnaire, which was transformed into preference-based utility values. Medical costs included (expressed in € 2010) were antimuscarinics, physician visits, laboratory tests, incontinence pads and the costs of OAB-related comorbidities, fractures, skin infections, urinary tract infections, depression, and nursing home admissions associated with incontinence. Time lost from work was also considered. Univariate sensitivity analyses were also performed.</p> <p>Results</p> <p>At week 12, continents accounted for 50.6%, 40.6% and 47.2% of patients in the fesoterodine, tolterodine, and solifenacin groups, respectively. By week 52, the projected proportions of patients remaining on therapy were 33.1%, 26.5% and 30.8%, respectively. The projected quality- adjusted life years (QALY) gain (compared to baseline) over the 52-week simulation period were 0.01014, 0.00846 and 0.00957, respectively. The overall treatment cost was estimated at €1,937, €2,089 and €1,960 for fesoterodine, tolterodine and solifenacin, respectively. Therefore, treatment with fesoterodine resulted in similar overall costs and greater QALY gain than treatment with either tolterodine or solifenacin. Sensitivity analysis showed that these results were robust to all changes performed.</p> <p>Conclusions</p> <p>The results of this economic analysis suggest that fesoterodine is a cost-effective alternative to tolterodine and solifenacin for the treatment of patients with OAB in Spain. Fesoterodine provides additional health benefits while maintain a similar level of costs being a cost-effective treatment strategy from a societal perspective.</p

Measuring health-related quality of life in population-based studies of coronary heart disease: comparing six generic indexes and a disease-specific proxy score

To compare HRQoL differences with CHD in generic indexes and a proxy CVD-specific score in a nationally representative sample of U.S. adults. The National Health Measurement Study, a cross-sectional random-digit-dialed telephone survey of adults aged 35–89, administered the EQ-5D, QWB-SA, HUI2, HUI3, SF-36v2™ (yielding PCS, MCS, and SF-6D), and HALex. Analyses compared 3,350 without CHD (group 1), 265 with CHD not taking chest pain medication (group 2), and 218 with CHD currently taking chest pain medication (group 3), with and without adjustment for demographic variables and comorbidities. Data on 154 patients from heart failure clinics were used to construct a proxy score utilizing generic items probing CVD symptoms. Mean scores differed between CHD groups for all indexes with and without adjustment (P &lt; 0.0001 for all except MCS P = 0.018). Unadjusted group 3 versus 1 differences were about three times larger than for group 2 versus 1. Standardized differences for the proxy score were similar to those for generic indexes, and were about 1.0 for all except MCS for group 3 versus 1. Generic indexes capture differences in HRQoL in population-based studies of CHD similarly to a score constructed from questions probing CVD-specific symptoms

Normative data and discriminative properties of short form 36 (SF-36) in Turkish urban population

BACKGROUND: SF-36 has been both translated into different languages and adapted to different cultures to obtain comparable data on health status internationally. However there have been only a limited number of studies focused on the discriminative ability of SF-36 regarding social and disease status in developing countries. The aim of this study was to obtain population norms of the short form 36 (SF-36) health survey and the association of SF-36 domains with demographic and socioeconomic variables in an urban population in Turkey. METHODS: A cross-sectional study. Face to face interviews were carried out with a sample of households. The sample was systematically selected from two urban Health Districts in Izmir, Turkey. The study group consisted of 1,279 people selected from a study population of 46,290 people aged 18 and over. RESULTS: Internal consistencies of the scales were high, with the exception of mental health and vitality. Physical health scales were associated with both age and gender. On the other hand, mental health scales were less strongly associated with age and gender. Women reported poorer health compared to men in general. Social risk factors (employment status, lower education and economic strain) were associated with worse health profiles. The SF-36 was found to be capable of discriminating disease status. CONCLUSION: Our findings, cautiously generalisable to urban population, suggest that the SF-36 can be a valuable tool for studies on health outcomes in Turkish population. SF-36 may also be a promising measure for research on health inequalities in Turkey and other developing countries

PACE - The first placebo controlled trial of paracetamol for acute low back pain: design of a randomised controlled trial

<p>Abstract</p> <p>Background</p> <p>Clinical practice guidelines recommend that the initial treatment of acute low back pain (LBP) should consist of advice to stay active and regular simple analgesics such as paracetamol 4 g daily. Despite this recommendation in all international LBP guidelines there are no placebo controlled trials assessing the efficacy of paracetamol for LBP at any dose or dose regimen. This study aims to determine whether 4 g of paracetamol daily (in divided doses) results in a more rapid recovery from acute LBP than placebo. A secondary aim is to determine if ingesting paracetamol in a time-contingent manner is more effective than paracetamol taken when required (PRN) for recovery from acute LBP.</p> <p>Methods/Design</p> <p>The study is a randomised double dummy placebo controlled trial. 1650 care seeking people with significant acute LBP will be recruited. All participants will receive advice to stay active and will be randomised to 1 of 3 treatment groups: time-contingent paracetamol dose regimen (plus placebo PRN paracetamol), PRN paracetamol (plus placebo time-contingent paracetamol) or a double placebo study arm. The primary outcome will be time (days) to recovery from pain recorded in a daily pain diary. Other outcomes will be pain intensity, disability, function, global perceived effect and sleep quality, captured at baseline and at weeks 1, 2, 4 and 12 by an assessor blind to treatment allocation. An economic analysis will be conducted to determine the cost-effectiveness of treatment from the health sector and societal perspectives.</p> <p>Discussion</p> <p>The successful completion of the trial will provide the first high quality evidence on the effectiveness of the use of paracetamol, a guideline endorsed treatment for acute LBP.</p> <p>Trail registration</p> <p>ACTRN12609000966291.</p

The impact of incident vertebral and non-vertebral fractures on health related quality of life in postmenopausal women

BACKGROUND: Little empirical research has examined the multiple consequences of osteoporosis on quality of life. METHODS: Health related quality of life (HRQL) was examined in relationship to incident fractures in 2009 postmenopausal women 50 years and older who were seen in consultation at our tertiary care, university teaching hospital-affiliated office and who were registered in the Canadian Database of Osteoporosis and Osteopenia (CANDOO) patients. Patients were divided into three study groups according to incident fracture status: vertebral fractures, non-vertebral fractures and no fractures. Baseline assessments of anthropometric data, medical history, therapeutic drug use, and prevalent fracture status were obtained from all participants. The disease-targeted mini-Osteoporosis Quality of Life Questionnaire (mini-OQLQ) was used to measure HRQL. RESULTS: Multiple regression analyses revealed that subjects who had experienced an incident vertebral fracture had lower HRQL difference scores as compared with non-fractured participants in total score (-0.86; 95% confidence intervals (CI): -1.30, -0.43) and the symptoms (-0.76; 95% CI: -1.23, -0.30), physical functioning (-1.12; 95% CI: -1.57, -0.67), emotional functioning (-1.06; 95% CI: -1.44, -0.68), activities of daily living (-1.47; 95% CI: -1.97, -0.96), and leisure (-0.92; 95% CI: -1.37, -0.47) domains of the mini-OQLQ. Patients who experienced an incident non-vertebral fracture had lower HRQL difference scores as compared with non-fractured participants in total score (-0.47; 95% CI: -0.70, -0.25), and the symptoms (-0.25; 95% CI: -0.49, -0.01), physical functioning (-0.39; 95% CI: -0.65, -0.14), emotional functioning (-0.97; 95% CI: -1.20, -0.75) and the activities of daily living (-0.47; 95% CI: -0.73, -0.21) domains. CONCLUSION: Quality of life decreased in patients who sustained incident vertebral and non-vertebral fractures