Department of Ophthalmology and Vision Science, University of California, Davis, CA, USA.
Ophthalmology. 2012 Mar;119(3):437-42. doi: 10.1016/j.ophtha.2011.03.018. Epub 2011 Jun 25.
To determine if the accuracy of the baseline prediction model for the development of primary open-angle glaucoma (POAG) in patients with ocular hypertension can be improved by correcting intraocular pressure (IOP) for central corneal thickness (CCT).
Reanalysis of the baseline prediction model for the development of POAG from the Ocular Hypertension Treatment Study (OHTS) substituting IOP adjusted for CCT using 5 different correction formulae for unadjusted IOP.
A total of 1433 of 1636 participants randomized to OHTS who had complete baseline data for factors in the prediction model: age, IOP, CCT, vertical cup-to-disc ratio (VCDR), and pattern standard deviation (PSD).
Reanalysis of the prediction model for the risk of developing POAG using the same baseline variables (age, IOP, CCT, VCDR, and PSD) except that IOP was adjusted for CCT using correction formulae. A separate Cox proportional hazards model was run using IOP adjusted for CCT by each of the 5 formulae published to date. Models were run including and excluding CCT.
Predictive accuracy of each Cox proportional hazards model was assessed using the c-statistic and calibration chi-square.
C-statistics for prediction models that used IOP adjusted for CCT by various formulas ranged from 0.75 to 0.77, no better than the original prediction model (0.77) that did not adjust IOP for CCT. Calibration chi-square was acceptable for all models. Baseline IOP, whether adjusted for CCT or not, was statistically significant in all models including those with CCT in the same model. The CCT was statistically significant in all models including those with IOP adjusted for CCT in the same model.
The calculation of individual risk for developing POAG in ocular hypertensive individuals is simpler and equally accurate using IOP and CCT as measured, rather than applying an adjustment formula to correct IOP for CCT.
确定通过校正中央角膜厚度（CCT）来校正眼压（IOP）是否可以提高原发性开角型青光眼（POAG）患者眼压升高的发展基线预测模型的准确性。
重新分析来自眼高血压治疗研究（OHTS）的 POAG 发展基线预测模型，使用 5 种不同的校正公式校正未校正 IOP 时的 CCT。
共有 1636 名随机分配至 OHTS 的参与者中的 1433 名完成了预测模型的基线数据：年龄、IOP、CCT、垂直杯盘比（VCDR）和模式标准偏差（PSD）。
使用相同的基线变量（年龄、IOP、CCT、VCDR 和 PSD）重新分析预测模型，除了使用校正公式校正 CCT 外，IOP 也被校正。使用迄今为止发表的 5 种校正公式中的每一种，分别使用校正后的 CCT 对 Cox 比例风险模型进行单独的运行。模型包括和不包括 CCT。
使用 c 统计量和校准卡方评估每个 Cox 比例风险模型的预测准确性。
使用各种公式校正 CCT 后的 IOP 的预测模型的 C 统计量范围为 0.75 至 0.77，不如未校正 CCT 的原始预测模型（0.77）好。所有模型的校准卡方都可以接受。所有模型都包括基线 IOP，无论是否校正 CCT，IOP 在所有模型中都是统计学显著的，包括那些在同一模型中包含 CCT 的模型。在包括那些在同一模型中校正 IOP 以校正 CCT 的模型中，CCT 也是统计学显著的。
在眼高血压个体中，计算发展为 POAG 的个体风险，使用测量的 IOP 和 CCT 更简单，并且准确性相同，而不是应用校正公式来校正 CCT 中的 IOP。
