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Abstract #46882 Published in IGR 13-3
Glaucoma disease progression states: Establishing a direct, quantitative link between visual field defects and utility loss
Gerlier L; Lamotte M; Verboven YValue in Health 2010; 13: 248
OBJECTIVES: Treatments of ocular hypertension (OHT) and glaucoma aim mainly at maintaining the patient's visual function and related quality of life (QoL). However, it is not known to what extent the disease progression impacts the health-related QoL. Using recent publications, the objectives were to 1) derive a range of EQ-5D utility scores in OHT/glaucoma patients; (2) establish a direct, quantitative link between the mean defect in perimetry (MD) measured in decibels (db) and the utility loss; and (3) estimate the utility level of patients reaching a glaucoma stage. METHODS: The glaucoma stages were characterized using MD thresholds of 0 db (OHT), 0-6 db (early glaucoma), 6-12 db (moderate), 12-22 db (advanced), and >22 db (legal blindness), as per the Hodapp classification. An algorithm allowing to derive EQ-5D utility scores from the eight mean subscale scores to the SF-36 (Ara and Brazier 2008) was applied to the range of SF-36 scores published in a systematic review of QoL in glaucoma (Mills 2009). Besides, the same algorithm was used to estimate the utility loss corresponding to a MD of 1 db, based on a regression model assessing the correlation between visual function and QoL in glaucoma patients (Lin and Yang 2010). RESULTS: Over eight studies in OHT/glaucoma patients, utility scores ranged from 0.65 to 0.89. Based on a significant regression coefficient for the SF-36 Role Physical subscale, a utility loss of 0.0295/db was calculated. Applying this utility loss/db to the predefined thresholds, the ranges of unadjusted utility scores expected per glaucoma stage equal: 0.72-0.90 (early), 0.55-72 (moderate), 0.25-0.55 (advanced), and <0.25 (blindness), assuming a baseline utility of 0.90 for OHT. CONCLUSIONS: These utility scores per disease stage are consistent with published direct measures of HUI3. The estimated utility loss per db is sizeable and could be implemented in cost-utility models where disease progression is tracked.
L. Gerlier. IMS Health Consulting, Brussels, Belgium.
Classification:
14 Costing studies; pharmacoeconomics
6.6.2 Automated (Part of: 6 Clinical examination methods > 6.6 Visual field examination and other visual function tests)
