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Abstract #47734 Published in IGR 13-4
Defining glaucomatous optic neuropathy from a continuous measure of optic nerve damage the optimal cut-off point for risk-factor analysis in population-based epidemiology
Ramdas WD; Rizopoulos D; Wolfs RCW; Hofman A; de Jong PTVM; Vingerling JR; Jansonius NMOphthalmic Epidemiology 2011; 18: 211-216
Purpose: Diseases characterized by a continuous trait can be defined by setting a cut-off point for the disease measure in question, accepting some misclassification. The 97.5th percentile is commonly used as a cut-off point. However, it is unclear whether this percentile is the optimal cut-off point from the point of view of risk-factor analysis. The optimal cut-off point for risk-factor analysis can be found with a statistical method that minimizes the effect of misclassification. We applied this method to glaucomatous optic neuropathy. Here, the continuous trait is the cup-disc ratio. The aim of this study was to determine the optimal cup-disc ratio cut-off point for risk-factor analysis in population-based epidemiology. Methods: All participants in the population-based Rotterdam Study underwent intraocular pressure (IOP) measurements, assessment of the cup-disc ratio with the Heidelberg Retina Tomograph (HRT) and visual field testing. In the statistical method, the cup-disc ratio (the continuous trait) and the IOP (a major risk factor) were independent variables and glaucomatous visual field loss (the true glaucoma endpoint) the dependent variable in a logistic regression model. The optimal cup-disc ratio cut-off point was found by minimizing the influence of IOP in this model. Variability of the approach was assessed by using a bootstrap resampling technique. Results: Of 2444 included participants, 93 had glaucomatous visual field loss. The median optimal cup-disc ratio cut-off point was the 97.0th percentile with a 95% central range from 95.5 to 98.5. Conclusion: The optimal cup-disc ratio cut-off point for risk-factor analysis is close to the commonly used 97.5th percentile. (copyright) 2011 Informa Healthcare USA, Inc.
J.R. Vingerling. Department of Ophthalmology, Epidemiology and Biostatistics, Erasmus Medical Center Rotterdam, PO Box 2040, 3000 CA Rotterdam, Netherlands. Email: j.vingerling@erasmusmc.nl
Classification:
1.1 Epidemiology (Part of: 1 General aspects)
6.9.1.1 Confocal Scanning Laser Ophthalmoscopy (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis > 6.9.1 Laser scanning)
