目的：分析术前糖化血红蛋白(HbA1c)水平对糖尿病患者白内障超声乳化术后后囊膜混浊(PCO)的预测价值及阈值效应。

方法：回顾性研究。收集2018-09/2020-09于本院就诊的糖尿病合并白内障患者106例106眼，根据患者术后36 mo是否发生PCO分为PCO组52例52眼和非PCO组54例54眼。分析患者术后发生PCO的影响因素。对患者术前HbA1c水平与患者术后发生PCO的发生情况进行阈值效应分析。采用受试工作者特征(ROC)曲线评估术前HbA1c水平对患者术后发生PCO的预测价值。构建预测模型，采用Bootstrap重采样对预测模型进行验证，并对模型的区分度和准确度进行评价。

结果：两组患者糖尿病病程、有无糖尿病视网膜病变、空腹血糖、餐后2 h血糖、术前HbA1c、眼轴长度、核硬度分级均有差异(P<0.05)。糖尿病病程≥12 a、有DR、空腹血糖≥8 mmol/L、餐后2 h血糖≥12 mmol/L、术前HbA1c≥7%、眼轴长度≥30 mm、核硬度分级Ⅲ级及以上均为影响患者术后发生PCO的因素(P<0.05)。曲线拟合发现随着HbA1c水平的升高，糖尿病患者白内障超声乳化术后发生PCO的概率呈现上升趋势。阈值效应分析发现，当HbA1c≥7%时，术后PCO的发生率随着HbA1c水平的增加而升高。敏感性分析显示E值=2.129。术前HbA1c与糖尿病患者白内障超声乳化术后发生PCO程度的关联效应分析结果显示，调整后术前HbA1c水平是糖尿病患者术后发生PCO不同程度混浊的影响因素，存在独立相关性(OR=1.65，95% CI：1.42-1.76，P=0.021)。当预测模型P=0.6时，模型预测准确度为88.51%，敏感度和特异度分别为86.33%和86.82%，表示糖尿病白内障患者出现PCO的结局。

结论：糖尿病病程、有DR、空腹血糖、餐后2 h血糖、术前HbA1c、眼轴长度、核硬度分级是影响糖尿病患者白内障超声乳化术后发生PCO的因素，且术前HbA1c可作为评估患者术后发生PCO的敏感指标。

METHODS:Retrospective study. A total of 106 diabetic patients(106 eyes)with cataract treated in our hospital from September 2018 to September 2020 were collected. The patients were divided into PCO group(52 cases, 52 eyes)and non-PCO group(54 cases, 54 eyes)according to whether PCO occurred at 36 mo after surgery. The risk factors affecting postoperative PCO were analyzed. The threshold effect of HbA1c level on the occurrence of postoperative PCO was analyzed. The predictive value of preoperative HbA1c level in postoperative PCO was evaluated using the receiver operating characteristic(ROC)curve. The prediction model was constructed, and Bootstrap resampling was used to verify the prediction model, and the differentiation and accuracy of the model were evaluated.

RESULTS: There were significant differences in diabetes course, diabetic retinopathy, fasting blood glucose, 2 h postprandial blood glucose, preoperative HbA1c, axial length and nuclear grade between PCO and non-PCO groups(P<0.05). Duration of diabetes ≥12 a, presence of DR, fasting blood glucose ≥8 mmol/L, 2 h postprandial blood glucose ≥12 mmol/L, preoperative HbA1c ≥7%, axial length ≥30 mm, and nuclear grade Ⅲ or above were all influencing factors for postoperative PCO(P<0.05). Curve fitting found that the probability of postoperative PCO showed an increasing trend with the increase of HbA1c level. Threshold effect analysis found that the incidence of postoperative PCO increased with the increase of HbA1c level when HbA1c≥7%. Sensitivity analysis showed that E value=2.129. The analysis of the correlation effect between preoperative HbA1c and the degree of PCO after phacoemulsification showed that the adjusted preoperative HbA1c level was an independent factor affecting the degree of PCO in diabetic patients(OR=1.65, 95% CI: 1.42-1.76, P=0.021). PCO outcome in diabetic cataract patients was indicated when the predictive model P=0.6, and the prediction accuracy of the model was 88.51%. Sensitivity and specificity were 86.33% and 86.82%, respectively.

CONCLUSION:Duration of diabetes, presence of DR, fasting blood glucose, 2 h postprandial blood glucose, preoperative HbA1c, axial length, and nuclear grade were independent risk factors for postoperative PCO in diabetic patients, and preoperative HbA1c could be used as a sensitive index to evaluate postoperative PCO.