Author/Authors :
Biglu Mohammad Hossein نويسنده Cardiovascular Research Center, Tabriz University of Medical Sciences, Tabriz, Iran , Mahboub-Ahari Alireza نويسنده Department of Health Management and Economics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran , Barouni Mohsen نويسنده Health Services Management Research Center, Institute of Future Health Studies, Kerman University of Medical Sciences, Kerman, Iran , Ghaffari Shahram نويسنده Iranian Social Security Organization, Tehran, IR Iran , Yousefi Mahmood نويسنده Iranian Center of Excellence in Health Management, School of Management and Medical Informatics, Tabriz University of Medical Sciences, Tabriz, IR Iran , Najafi Safa نويسنده Iranian Center for Breast Cancer (ICBC), Tehran, IR Iran , Behzadi Sheikhrobat Yousef نويسنده Research Committee of Farsan Hospital, Shahrekord
University of Medical Sciences, Shahrekord, IR Iran , Ghaderi Hossein نويسنده Health Management and Economics Research Center, Iran
University of Medical Sciences, Tehran, IR Iran , Memarzadeh Seyed Ezatollah نويسنده Ophthalmology Department, School of Medicine, Shahrekord
University of Medical Sciences, Shahrekord, IR Iran
Abstract :
Background Mapping from non-performance-based measures onto
generic performance-based measures provides an appropriate solution to
derive utilities to be used in economic evaluations. Objectives This
study aimed to create a model through which EQ-5D utilities for
cataracts can be obtained from scores on the disease-specific Catquest
measure. Patients and Methods One hundred ninety-nine observations from
103 patients who self-administered the EQ-5D, the Catquest and questions
on demographic and clinical characteristics were included in the
analysis. Data was divided into estimation and validation datasets. To
predict EQ-5D utilities, multiple regression analysis, using the
Ordinary Least Square (OLS) and the censored least absolute deviation
(CLAD), was performed. Catquest scores, age, gender, and performing
surgery were included as explanatory variables. An estimation dataset
was used to derive the coefficients, and these coefficients were then
validated using a validation dataset. Based on the explanatory power,
the consistency, the simplicity, the mean absolute error (MAE) and the
correlations between observed and fitted utilities, the most appropriate
model was selected. Results The mean EQ-5D and Catquest scores of the
total sample were 0.631 and 15.8, respectively. Age and surgery showed
no significant effect for either method. Removing age and surgery, model
II was built and given an R2 of 0.697, an MAE of
0.1176 for the OLS and an R2 of 0.614, and an MAE
of 0.1153 for the CLAD method. In the validation stage, the CLAD
revealed better prediction ability, with an MAE of 0.198 versus an MAE
of 0.209 for the OLS. ICC and Bland-Altman analysis put the CLAD as a
preferred method with the following equation: Utilities (EQ-5D) = 0.988
- 0.0281 × Catquest (PD) + 0.102 × gender (male = 1). Conclusions Based
on these results, a mapping function was obtained which appears to be
valuable in predicting EQ-5D utilities from Catquest scores. This
function gives an appropriate solution to estimate utilities when
primary EQ-5D data is not available. Although the model represents good
consistency and predictive ability, further examination of obtained
function is required with large samples.
