Validación de un instrumento de calidad de vida específico para pacientes con discapacidad visuallow vision quality of life (lvqol)
- PÉREZ MAÑÀ, LUIS
- Genís Cardona Torradeflot Director
- A. Antón López Co-director
Defence university: Universitat Politècnica de Catalunya (UPC)
Fecha de defensa: 11 October 2019
- I. Jürgens Chair
- Fidel Vega Secretary
- Luis Enrique Martínez Martínez Committee member
Type: Thesis
Abstract
Introduction: There is a growing need in the western world to know the quality of life (QoL) of patients affected by ocular pathologies that cause visual impairment (VI). In this type of pathologies, objective data such as visual acuity (VA), or diagnostic tests such as retinography or optical coherence tomography (OCT), offer important information, but do not reflect the effect of visual limitation on the life of the patient. Thus, in numerous studies, the use of specific instruments to assess QoL that indirectly measure the actual consequences of visual disability is becoming more important. The quality of life questionnaire related to vision (CVRV) Low Vision Quality of Life (LVQOL, Wolffsohn JS, Cochrane AL, 2000) was one of the first instruments designed specifically to measure QoL in patients with Low Vision (LV). The LVQOL consists of 25 questions subdivided into four different categories and, in its original version, has proved to be a reliable tool in patients with LV, measuring the initial baseline QoL, and subsequently in the evolution of the pathology, or to assess the success of a visual rehabilitation. Due to the lack of a properly validated instrument in Spanish to assess QoL in patients with LV, the main objective of this study is to validate the Low Vision Quality of Life questionnaire in Spanish and to evaluate its psychometric properties. Methods: After a cross-cultural adaptation of the questionnaire, a quantitative, longitudinal, multicentre study (a public hospital and a private clinic in Barcelona), a prospective cohort and a psychometric study was carried out to evaluate the psychometric properties. A total of 170 patients with DV and 195 healthy patients participated in the study. Sociodemographic and clinical variables were collected, as well as the responses to the QoL instruments: LVQOL, NEI VFQ-25 and EQ 5D-5L. Reliability was assessed by internal consistency (Cronbach's alpha) of the total sample, and by assessing the test-retest reproducibility (Spearman’s correlation coefficient (¿)) in stable patients at the baseline measurement and after 15 days (n = 73) in the sample of the public H. The validity was studied in the baseline test (n = 257) by means of the correlations with clinical, psychosocial variables and with the subscales of the QoL instruments administered. Finally, a factorial analysis (n = 170) was carried out to assess the structure of the instrument. Likewise, the psychometric properties of the NEI VFQ-25 were evaluated and the relationship of the results of the LVQOL with various sociodemographic, clinical and psychosocial variables was analysed. Results: The psychometric properties of the new instrument presented a Cronbach's alpha of 0.981 (95% CI: 0.978-0.985) and a reproducibility of 0.864, p <0.001. The score of the instrument was correlated with the score of the NEI VFQ-25 (0.96) and its subscales (all with values> 0.78), except for Driving (0.58) and Ocular pain, which presented divergence (0.23). As compared to the EQ 5D-5L, it showed convergence with the items Self-care (-0.41) and Daily activities (-0.73), and divergence with the rest of the items and with the total score. The results of the factorial analysis did not confirm the structure proposed by the author in the original version. Correlations with age, income level and type of pathology causing DV were found. Conclusions: The Spanish version of the LVQOL is semantically and conceptually equivalent to the original version. The results of the psychometric properties suggest that it presents an excellent validity, internal consistency and reproducibility. The introduction of this instrument in daily clinical practice may be very useful to evaluate, and thus improve, the quality of life of patients with DV.