Development and validation of a questionnaire to assess quality of life related to health of patients with visual impairment: self and proxy versions

• Grant number: 12/07073-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2012
• End date: June 30, 2013
• Field of knowledge: Health Sciences - Medicine
• Principal Investigator: Paulo Schor
• Grantee: Andressa Martins Giorjao
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

There are several tools for assessing the quality of life of patients with visual disturbances. Some tools are targeted to specific symptoms, such as low vision. Others are directed to diseases with color deficiency/ movement. And several are related to changes in central vision (blurring). Since they are polymorphic manifestations and subjective responses, the information collected may lack consistency in the long turn, as occurs in studies in which patients say they are satisfied after months of intervention, and dissatisfied after that, even with no structural modification of the optical system. This led to the need for the development of a specific tool, which is not completely dependent on the patient's subjective evaluation but is aided by the perception by the family caregiver (proxy) of the changes in the patient's attitude. Hypothesis: to measure well-being after therapeutic interventions, it becomes essential to define terms such as perceived health status(Perceived health status), quality of life (quality of life - QoL), and quality of life-related to health (health-related quality of life ¿HRQL). Primary objective: to develop and test the psychometric properties of an instrument to assess the quality of life-related to the health of patients with visual impairment: self and proxy versions. Secondary objective: to develop self and proxy versions of an instrument to assess the quality of life related to the health of patients with visual impairment; to evaluate the face validity and content of the two versions by a committee of judges; to evaluate the validity of convergent and divergent construct and the dimensionality of the two versions of the instrument; to evaluate the reliability of the two versions of the instrument under the internal consistency of items; to evaluate the reproducibility (stability) of the two versions of the instrument; to evaluate the sensitivity of the two versions of the instrument; to evaluate the responsiveness of the two versions of the instrument; to evaluate the presence of ceiling and floor effects in the two versions of the instrument. Primary outcome: The data will be processed and analyzed with the Statistical Package for Social Sciences (SPSS) version 18.0. Descriptive analyzes will be performed to evaluate all the clinical and sociodemographic variables. Scalar variables will be analyzed considering the measures of central tendency and dispersion. Pearson's correlation test or Spearman will be used depending on the distribution observed in the values obtained by the instruments. These tests will analyze the correlations between the measures of quality of life from the new instrument and related constructs (SF-36, Sub-scales of the NEI-VFQ-25 as the HADS-D). The principal component analysis will be conducted to analyze the dimensionality of the new instrument. The reliability of the final Portuguese version of the DASS by the internal consistency of the items will be analyzed by Cronbach's alpha. For this analysis, the equivalence of two versions of the new instrument correlation coefficients (ICC) will be calculated. Student's t-test for dependent samples or the Mann-Whitney test will be conducted to compare, respectively, the mean or median raw score of the instrument between patients and proxies throughout follow-up. Student tests for independent samples will be performed to compare measurements between groups of patients (different visual conditions). The level of significance for hypothesis tests of construct validity is 0.05.(AU)