First Author: J.Ramu UK
Co Author(s): I. Chatziralli D. Menon P. Hykin S. Sivaprasad
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Several clinical trials have shown a good correlation between vision related quality of life questionnaire (NEI VFQ-25) and best corrected visual acuity (BCVA). This study examined this correlation in detail in refractory diabetic macular oedema (DMO) patients in a clinical trial setting.
OZDRY was a prospective, randomized (1:1), active-controlled, non-inferiority study conducted across 5 centres in the UK (UK). The study was approved by the UK Collaborative Research Ethics Committee (12/LO/1534). The principles of Good Clinical Practice were adhered throughout in accordance with the Declaration of Helsinki.
The NEI VFQ-25 is a 25 point questionnaire study which measures patient reported outcome of visual function and quality of life. It measures 10 subscales which are vision dependent and one of general health. Each response is coded using the NEI VFQ-25 scoring system (range 0 to 100, 0 – worst and 100 – best). 100 eligible patients with refractory DMO with central subfield thickness (CST) > 300 µm, and the Early Treatment Diabetic Retinopathy Study (ETDRS) BCVA between 34 and 73 were included in the OZDRY study. NEI VFQ-25 was administered at baseline and exit in the study. Composite VFQ score was compared at both time points for various baseline characteristics using the paired t tests. Factors predicting a change in VFQ 25 was analysed as binary outcome, above and below the median using logistic regression analysis. We also looked at the correlation of each of the subscales of NEI VFQ-25 by stratifying BCVA into 3 groups (70 to 73, 55 to 69 and 34 to 54). P value of < 0.05 was considered significant. All analyses were carried out using the SPSS 22.0 statistics package.
Of the 100 patients enrolled in the study, 95 completed the study. 82 of these 95 patients completed the questionnaire for all sub scales at both baseline and exit and were included in the analysis. The mean composite score at baseline was 74.1 ± 19.9 and the change in score at exit was 3.39 ± 14.2 and was found to be not significant. Mean composite score at baseline and exit were compared between different age-groups, gender, ethnicity, treatment of diabetes and HbA1c. Of these, only the age group ≤ 64 years (N = 41, P = 0.0496) and White ethnic group (N = 56, P = 0.0333) were established to be significant. Mean composite score decreased with decreasing visual acuity but it was not significant. Logistic regression analysis for factors predicting NEI VFQ-25 score at exit showed that BCVA ≥ 55 letters, central subfield thickness (CST) < 300µm and macular volume < 9.2 mm3 on optical coherence tomography (OCT) predicted higher change in NEI VFQ-25 (p = 0.021, 0.043 and 0.043 respectively). Similar analysis for baseline showed higher change only for CST ≥ 400. Pearson’s correlation of the different NEI VFQ-25 subscales and the stratified VA didn’t show any correlation.
Our study did not show any significant change in the quality of life using NEI VFQ-25. Factors predicting the change in NEI VFQ-25 are the BCVA and OCT at exit. This study shows that individual subscale change may be additional outcome measures that can be used in clinical trials.