Gordon Mae O, Torri Valter, Miglior Stefano, Beiser Julia A, Floriani Irene, Miller J Philip, Gao Feng, Adamsons Ingrid, Poli Davide, D'Agostino Ralph B, Kass Michael A
OHTS Coordinating Center, Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Box 8203, 660 South Euclid, St. Louis, MO 63110, USA.
Ophthalmology. 2007 Jan;114(1):10-9. doi: 10.1016/j.ophtha.2006.08.031. Epub 2006 Nov 7.
To test the validity and generalizability of the Ocular Hypertension Treatment Study (OHTS) prediction model for the development of primary open-angle glaucoma (POAG) in a large independent sample of untreated ocular hypertensive individuals and to develop a quantitative calculator to estimate the 5-year risk that an individual with ocular hypertension will develop POAG.
A prediction model was developed from the observation group of the OHTS and then tested on the placebo group of the European Glaucoma Prevention Study (EGPS) using a z statistic to compare hazard ratios, a c statistic for discrimination, and a calibration chi2 for systematic overestimation/underestimation of predicted risk. The 2 study samples were pooled to increase precision and generalizability of a 5-year predictive model for developing POAG.
The OHTS observation group (n = 819; 6.6 years' median follow-up) and EGPS placebo group (n = 500; 4.8 years' median follow-up).
Data were collected on demographic characteristics, medical history, ocular examination visual fields (VFs), and optic disc photographs.
Development of reproducible VF abnormality or optic disc progression as determined by masked readers and attributed to POAG by a masked end point committee.
The same predictors for the development of POAG were identified independently in both the OHTS observation group and the EGPS placebo group-baseline age, intraocular pressure, central corneal thickness, vertical cup-to-disc ratio, and Humphrey VF pattern standard deviation. The pooled multivariate model for the development of POAG had good discrimination (c statistic, 0.74) and accurate estimation of POAG risk (calibration chi2, 7.05).
The OHTS prediction model was validated in the EGPS placebo group. A calculator to estimate the 5-year risk of developing POAG, based on the pooled OHTS-EGPS predictive model, has high precision and will be useful for clinicians and patients in deciding the frequency of tests and examinations during follow-up and advisability of initiating preventive treatment.
在大量未经治疗的高眼压个体的独立样本中，检验眼压升高治疗研究（OHTS）预测模型对原发性开角型青光眼（POAG）发病的有效性和可推广性，并开发一种定量计算器，以估计高眼压个体发生POAG的5年风险。
从OHTS的观察组开发一个预测模型，然后使用z统计量比较风险比、用于区分的c统计量以及用于系统高估/低估预测风险的校准卡方，在欧洲青光眼预防研究（EGPS）的安慰剂组上进行测试。将这两个研究样本合并，以提高POAG发病5年预测模型的精度和可推广性。
OHTS观察组（n = 819；中位随访6.6年）和EGPS安慰剂组（n = 500；中位随访4.8年）。
收集有关人口统计学特征、病史、眼部检查视野（VF）和视盘照片的数据。
由盲法阅片者确定的可重复VF异常或视盘进展的发生，并由盲法终点委员会归因于POAG。
在OHTS观察组和EGPS安慰剂组中均独立确定了POAG发病的相同预测因素——基线年龄、眼压、中央角膜厚度、垂直杯盘比和Humphrey VF模式标准差。POAG发病的合并多变量模型具有良好的区分度（c统计量，0.74）和对POAG风险的准确估计（校准卡方，7.05）。
OHTS预测模型在EGPS安慰剂组中得到验证。基于合并的OHTS-EGPS预测模型估计POAG发病5年风险的计算器具有很高的精度，将有助于临床医生和患者决定随访期间检查的频率以及启动预防性治疗的可取性。
