Comparison of the minimally important difference for two health state utility measures: EQ-5D and SF-6D.
ABSTRACT The SF-6D and EQ-5D are both preference-based measures of health. Empirical work is required to determine what the smallest change is in utility scores that can be regarded as important and whether this change in utility value is constant across measures and conditions.
To use distribution and anchor-based methods to determine and compare the minimally important difference (MID) for the SF-6D and EQ-5D for various datasets.
The SF-6D is scored on a 0.29-1.00 scale and the EQ-5D on a -0.59-1.00 scale, with a score of 1.00 on both, indicating 'full health'. Patients were followed for a period of time, then asked, using question 2 of the SF-36 as our anchor, if their general health is much better (5), somewhat better (4), stayed the same (3), somewhat worse (2) or much worse (1) compared to the last time they were assessed. We considered patients whose global rating score was 4 or 2 as having experienced some change equivalent to the MID. This paper describes and compares the MID and standardised response mean (SRM) for the SF-6D and EQ-5D from eight longitudinal studies in 11 patient groups that used both instruments.
From the 11 reviewed studies, the MID for the SF-6D ranged from 0.011 to 0.097, mean 0.041. The corresponding SRMs ranged from 0.12 to 0.87, mean 0.39 and were mainly in the 'small to moderate' range using Cohen's criteria, supporting the MID results. The mean MID for the EQ-5D was 0.074 (range -0.011-0.140) and the SRMs ranged from -0.05 to 0.43, mean 0.24. The mean MID for the EQ-SD was almost double that of the mean MID for the SF-6D.
There is evidence that the MID for these two utility measures are not equal and differ in absolute values. The EQ-5D scale has approximately twice the range of the SF-6D scale. Therefore, the estimates of the MID for each scale appear to be proportionally equivalent in the context of the range of utility scores for each scale. Further empirical work is required to see whether or not this holds true for other utility measures, patient groups and populations.
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ABSTRACT: The aim of the present study was to estimate minimally important differences (MIDs) in EQ-5D and SF-6D indices and to explore the responsiveness of EQ-5D and SF-6D indices in stroke. We used observational longitudinal survey data of EQ-5D and SF-36 that were administered to stroke patients at baseline and at 10 months. A range of MIDs for both indexes was estimated using anchor-based approaches. The modified Rankin scale and the Barthel index were used as an anchor. The MID estimates for EQ-5D ranged from 0.08 to 0.12 and those for SF-6D ranged from 0.04 to 0.14 in stroke patients. The MID values for these two utility measures differed in absolute magnitude, as the SF-6D index has wider range that that of the EQ-5D index. The MID values for these two utility measures differed in absolute magnitude, as the SF-6D index has wider range that that of the EQ-5D index. These MID estimates may assist the interpretation of health related quality of life assessments related to health care intervention in stroke patients.Health and Quality of Life Outcomes 12/2015; 13(1):227. DOI:10.1186/s12955-015-0227-3 · 2.10 Impact Factor
Health technology assessment (Winchester, England) 01/2015; 19(10):1-668. DOI:10.3310/hta19100 · 5.12 Impact Factor
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ABSTRACT: Objective: To study functional status (FS) and quality of life (QoL) after discharge from intensive care unit (ICU) in patients who had > 24 hours of mechanical ventilation (MV) and to compare them with reference Argentine population. Design: Prospective cohort study. Setting: ICU at Sanatorio Anchorena, Buenos Aires, Argentina. Patients: All patients admitted to the ICU between September 2008 and April 2009 with more than 24 hours of MV. Procedures: QoL was assessed by EQ-5D and FS was evaluated through Barthel index [evaluation of daily life activities (DLA)] by telephone at 4 months and 1 year after discharge from ICU. Results: 77 patients required MV, 41 females (53%), median age 65 years (IQR 55-77), SAPSII 41 (28-52), days of MV 4 (2-8). 47 patients survived after hospitalization, 40 (85.1%) at 4 months and 34 (72.3%) one year later. The EQ-5D at 4 months (median 0.693 IQR0.182-0.982) and at 1 year (median 0.841 IQR0.493-1) of follow up were significantly lower compared with general Argentine population (p = 0.0004 and 0.024 respectively). At 4 months, half of the patients had problems in all dimensions of the Euroqol and 57% were dependent on DLA. At 1 year, 54% could not return to their previous activities, suffered from anxiety/depression and 45% were dependent on DLA. Conclusions: Effects of critical illness and ICU stay are present at 4 months and 1 year after discharge. Survivors suffer a lower quality of life and functional status than general population.