External Validation of a Formula to Predict the Development of Proliferative Vitreoretinopathy (PVR) After Retinal Detachment (RD) Surgery. Retina 1 Project

Abstract

Purpose: : An objective method to establish the risk of PVR is a necessary tool for adequate planification of clinical trials to prevent this complication. An external sample of patients is being recruited to validate a recently published formula to predict the risk of PVR development (Curr Eye Res 2005; 30: 147–153). This paper shows an initial validation with a small sample

Methods: : A multicentric prospective study to improve predictive performance of the mentioned formula is being held in 13 hospitals of Spain and Portugal (Retina 1 Project). The first 93 patients who finished the follow up (3 months) coming from 7 different hospitals have been selected to validate that formula. Hosmer–Lemeshow test was used to validate the calibration of the model, and area under the ROC curve, sensitivity and specificity values to validate the discrimination of the model

Results: : 11 out of 93 patients developed PVR. The external validation showed lower values of area under the ROC curve (62.3%; CI 95%: 36.4–88.9%), sensitivity (62.5%; CI 95%: 30.6 – 86.3%) and specificity (80.7%; CI 95%: 68.7 – 88.9%) than the previous results published with the internal validation (Area under the ROC curve: 82%; Sensitivity: 67%; Specificity: 81%). These differences were not statistically significant. Nonetheless, preoperative characteristics of the new sample were slightly different than the previous one (a higher incidence of preoperative grade A or B PVR, pseudophakia<font face="symbol">¼</font>) and the management of patients showed an increase trend towards vitrectomy in the new sample

Conclusions: : This preliminary external validation of the published formula showing similar results than the internal one, warrants further recruitment of patients

Keywords: proliferative vitreoretinopathy • retinal detachment • clinical (human) or epidemiologic studies: risk factor assessment