Claire Jenkinson

The relationship between body mass index and health-related quality of life: comparing the EQ-5D, EuroQol VAS and SF-6D

Background:No other studies have compared the relationship between body mass index (BMI) and health-related quality of life (HRQL) on more than one utility measure. Estimating the HRQL effects of obesity on a (common) utility scale enables the relative cost-effectiveness of interventions designed to alleviate obesity to be estimated.Objective:To examine the relationship between BMI and HRQL according to the EQ-5D, EuroQol visual analogue scale (EQ-VAS) and SF-6D.Methods:Patients aged ⩾45 years at one UK general practice were asked to complete the EQ-5D, EQ-VAS, SF-36 questionnaire (used to derive the SF-6D), and information on their characteristics and co-morbidity. Body mass index was categorized according to the World Health Organization (WHO) recommendations. Regression analysis was used to compare the HRQL of normal BMI patients to the HRQL of patients in other BMI categories, while controlling for patient characteristics and co-morbidity.Results:A total of 1865 patients responded (67%), mean BMI 26.0 kg/m2, 16% obese (BMI⩾30). Patients with back pain, hip pain, knee pain, asthma, diabetes or osteoarthritis were also significantly more likely to be obese. After controlling for other factors, compared to normal BMI patients, obese patients had a lower HRQL according to the EQ-5D (P<0.01), EQ-VAS (P<0.001) and SF-6D (P<0.001). Pre-obese patients were not estimated to have a significantly lower HRQL, and underweight patients were only estimated to have a significantly lower HRQL according to the SF-6D. These results arose because, on the EQ-5D, obese patients were found to have significantly more problems with mobility and pain, compared to physical functioning, social functioning and role limitations on the SF-6D. Whereas, according to the SF-6D, underweight patients had significantly more problems on the dimension of role limitation.Conclusion:The EQ-5D, EQ-VAS and SF-6D were in agreement that, relative to a normal BMI, obesity is associated with a lower HRQL, even after controlling for patient characteristics and co-morbidity. These three measures are thereby sensitive to the HRQL effects of obesity and can be used to estimate the cost-effectiveness of interventions designed to alleviate obesity.

Effects of dietary intervention and quadriceps strengthening exercises on pain and function in overweight people with knee pain: randomised controlled trial

Objective To determine whether dietary intervention or knee strengthening exercise, or both, can reduce knee pain and improve knee function in overweight and obese adults in the community. Design Pragmatic factorial randomised controlled trial. Setting Five general practices in Nottingham. Participants 389 men and women aged 45 and over with a body mass index (BMI) of ≥28.0 and self reported knee pain. Interventions Participants were randomised to dietary intervention plus quadriceps strengthening exercises; dietary intervention alone; quadriceps strengthening exercises alone; advice leaflet only (control group). Dietary intervention consisted of individualised healthy eating advice that would reduce normal intake by 2.5 MJ (600 kcal) a day. Interventions were delivered at home visits over a two year period. Main outcome measures The primary outcome was severity of knee pain scored with the Western Ontario McMaster (WOMAC) osteoarthritis index at 6, 12, and 24 months. Secondary outcomes (all at 24 months) included WOMAC knee physical function and stiffness scores and selected domains on the SF-36 and the hospital anxiety and depression index. Results 289 (74%) participants completed the trial. There was a significant reduction in knee pain in the knee exercise groups compared with those in the non-exercise groups at 24 months (percentage risk difference 11.61, 95% confidence interval 1.81% to 21.41%). The absolute effect size (0.25) was moderate. The number needed to treat to benefit from a ≥30% improvement in knee pain at 24 months was 9 (5 to 55). In those randomised to knee exercise improvement in function was evident at 24 months (mean difference −3.64, −6.01 to −1.27). The mean difference in weight loss at 24 months in the dietary intervention group compared with no dietary intervention was 2.95 kg (1.44 to 4.46); for exercise versus no exercise the difference was 0.43 kg (−0.82 to 1.68). This difference in weight loss was not associated with improvement in knee pain or function but was associated with a reduction in depression (absolute effect size 0.19). Conclusions A home based, self managed programme of simple knee strengthening exercises over a two year period can significantly reduce knee pain and improve knee function in overweight and obese people with knee pain. A moderate sustained weight loss is achievable with dietary intervention and is associated with reduced depression but is without apparent influence on pain or function. Trial registration Current Controlled Trials ISRCTN 93206785.

Do estimates of cost-utility based on the EQ-5D differ from those based on the mapping of utility scores?

BackgroundMapping has been used to convert scores from condition-specific measures into utility scores, and to produce estimates of cost-effectiveness. We sought to compare the QALY gains, and incremental cost per QALY estimates, predicted on the basis of mapping to those based on actual EQ-5D scores.MethodsIn order to compare 4 different interventions 389 individuals were asked to complete both the EQ-5D and the Western Ontartio and McMaster Universities Osteoarthritis Index (WOMAC) at baseline, 6, 12, and 24 months post-intervention. Using baseline data various mapping models were developed, where WOMAC scores were used to predict the EQ-5D scores. The performance of these models was tested by predicting the EQ-5D post-intervention scores. The preferred model (that with the lowest mean absolute error (MAE)) was used to predict the EQ-5D scores, at all time points, for individuals who had complete WOMAC and EQ-5D data. The mean QALY gain associated with each intervention was calculated, using both actual and predicted EQ-5D scores. These QALY gains, along with previously estimated changes in cost, were also used to estimate the actual and predicted incremental cost per QALY associated with each of the four interventions.ResultsThe EQ-5D and the WOMAC were completed at baseline by 348 individuals, and at all time points by 259 individuals. The MAE in the preferred model was 0.129, and the mean QALY gains for each of the four interventions was predicted to be 0.006, 0.058, 0.058, and 0.136 respectively, compared to the actual mean QALY gains of 0.087, 0.081, 0.120, and 0.149. The most effective intervention was estimated to be associated with an incremental cost per QALY of £6,068, according to our preferred model, compared to £13,154 when actual data was used.ConclusionWe found that actual QALY gains, and incremental cost per QALY estimates, differed from those predicted on the basis of mapping. This suggests that though mapping may be of value in predicting the cost-effectiveness of interventions which have not been evaluated using a utility measure, future studies should be encouraged to include a method of actual utility measurement.Trial registrationCurrent Controlled Trials ISRCTN93206785

Comparing Cost-Utility Estimates Does the Choice of EQ-5D or SF-6D Matter?

Background:A number of different measures can be used within cost-utility analyses, we compared results according to both the EQ-5D and SF-6D. Methods:A randomized trial was conducted to compare 4 options for people with knee pain. Over the 2 year trial period, the change in cost to health-service was estimated, and both the EQ-5D and SF-6D were used to estimate the change in quality-adjusted life years (QALYs). Using a complete case analysis, the cost-utility (incremental cost-effectiveness ratio [ICER]) of each option, according to both the EQ-5D and SF-6D, was calculated and assessed in relation to the cost-effectiveness threshold of £20,000 per QALY. Results:Of the 389 participants, 247 had complete cost, EQ-5D and SF-6D data. According to the EQ-5D, option 1 had an estimated ICER of £10,815 (compared with option 4), option 2 was dominated by option 1, and option 3 was subject to extended dominance. Conversely, according to the SF-6D, option 3 had an ICER of £9999 (compared with option 4), option 2 had an ICER of £36,883 (compared with option 3), and option 1 was subject to extended dominance. Conclusion:The EQ-5D and SF-6D estimated that different options (1 and 3, respectively) were cost-effective at the £20,000 per QALY threshold, demonstrating that the choice of measure does matter.

An assessment of the discriminative ability of the EQ-5D index , SF-6D, and EQ VAS, using sociodemographic factors and clinical conditions

ObjectiveTo assess whether three health-related quality-of-life (HRQL) measures (the EQ-5Dindex, SF-6D, and EQ VAS) can discriminate between the HRQL of different groups of individuals.MethodsIn one UK general practice a cross-sectional survey requested information on six sociodemographic factors, 10 clinical conditions, and the three HRQL measures. Regression analyses were used to assess whether there was a significant difference in HRQL between groups with different sociodemographic factors and those with and without clinical conditions.ResultsOne thousand eight hundred and sixty-five questionnaires were returned. There was a significant difference between the HRQL of the majority of different groups according to each HRQL measure. However, not all of the measures could discriminate between groups of different ethnicity, gender, or smoking status, or those with and without asthma, stroke, cancer or diabetes.ConclusionThe HRQL of the majority of different groups could be discriminated between by the EQ-5Dindex, SF-6D, and EQ VAS.

Comparing the performance of the EQ-5D and SF-6D when measuring the benefits of alleviating knee pain

ObjectiveTo assess the practicality, validity and responsiveness of using each of two utility measures (the EQ-5D and SF-6D) to measure the benefits of alleviating knee pain.MethodsParticipants in a randomised controlled trial, which was designed to compare four different interventions for people with self-reported knee pain, were asked to complete the EQ-5D, SF-6D, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at both pre- and post-intervention. For both utility measures, we assessed their practicality (completion rate), construct validity (ability to discriminate between baseline WOMAC severity levels), and responsiveness (ability to discriminate between three groups: those whose total WOMAC score, i) did not improve, ii) improved by <20%, and iii) improved by ≥20%).ResultsThe EQ-5D was completed by 97.7% of the 389 participants, compared to 93.3% for the SF-6D. Both the EQ-5D and SF-6D were able to discriminate between participants with different levels of WOMAC severity (p < 0.001). The mean EQ-5D change was -0.036 for group i), 0.091 for group ii), and 0.127 for group iii), compared to 0.021, 0.023 and 0.053 on the SF-6D. These change scores were significantly different according to the EQ-5D (p < 0.001), but not the SF-6D.ConclusionThe EQ-5D and SF-6D had largely comparable practicality and construct validity. However, in contrast to the EQ-5D, the SF-6D could not discriminate between those who improved post-intervention, and those who did not. This suggests that it is more appropriate to use the EQ-5D in future cost-effectiveness analyses of interventions which are designed to alleviate knee pain.Trial registrationCurrent Controlled Trials ISRCTN93206785

Lifestyle interventions for knee pain in overweight and obese adults aged ≥45: economic evaluation of randomised controlled trial.

Objective To estimate the cost effectiveness of four different lifestyle interventions for knee pain. Design Cost utility analysis of randomised controlled trial. Setting Five general practices in the United Kingdom. Participants 389 adults aged ≥45 with self reported knee pain and body mass index (BMI) ≥28. Interventions Dietary intervention plus quadriceps strengthening exercises, dietary intervention, quadriceps strengthening exercises, and leaflet provision. Participants received home visits over a two year period. Main outcome measure Incremental cost per quality adjusted life year (QALY) gained over two years from a health service perspective. Results Advice leaflet was associated with a mean change in cost of −£31, and a mean QALY gain of 0.085. Both strengthening exercises and dietary intervention were more effective (0.090 and 0.133 mean QALY gain, respectively) but were not cost effective. Dietary intervention plus strengthening exercises had a mean cost of £647 and a mean QALY gain of 0.147 and was estimated to have an incremental cost of £10 469 per QALY gain (relative to leaflet provision), and a 23.1% probability of being cost effective at a £20 000/QALY threshold. Conclusion Dietary intervention plus strengthening exercises was estimated to be cost effective for individuals with knee pain, but with a large level of uncertainty. Trial registration ISRCTN93206785.

An exploration of student experiences of using biology podcasts in nursing training.

BackgroundStudents regard biological science as one of the most difficult components of the nursing curriculum. However, a good understanding of this area is essential for effective nursing practice. The aim of this study was to explore nursing students’ perceptions of the usefulness of supplementary biology podcasts for their learning.MethodsBiological science podcasts (n = 9) were made available to first-year nursing students (n = 189) as supplementary learning tools. On completion of their first year, students were asked to complete a survey which investigated the frequency of their podcast use, reasons for use and their perception of the usefulness of podcasts as a learning tool. 153 of these students participated in the survey study (80.9%). Two focus groups were conducted with students (n = 6) to gain a detailed understanding of student experiences of the usefulness of the podcasts for their learning.ResultsSurvey data demonstrated that most students (71%) accessed at least one podcast. The majority of students who reported accessing podcasts agreed that they were useful as learning tools (83%), revision aids (83%) and that they helped promote understanding of course materials (72%). Focus group participants discussed how they found podcasts especially useful in terms of revision. Students valued being able to repeatedly access the lecture materials, and appreciated having access to podcasts from a range of lecturers. Focus group members discussed the benefits of live recordings, in terms of valuing the information gleaned from questions asked during the lecture sessions, although there were concerns about the level of background noise in live recordings. Lack of awareness of the availability of podcasts was an issue raised by participants in both the survey component and the focus groups and this negatively impacted on podcast use.ConclusionsNursing students found the availability of biology podcasts helpful for their learning. Successful implementation of these tools to support learning requires teaching staff to understand and promote the importance of these tools.