A Nested Case-control Study Of Postoperative Vitreous Hemorrhage After Pars Plana Vitrectomy For Proliferative Diabetic Retinopathy

Purpose: To explore the risk factors for post-vitrectomy diabetic vitreous hemorrhage(PDVH)in patients with proliferative diabetic retinopathy(PDR)undergoing vitrectomy.Methods: We performed a retrospective nested case-control study(NCCS)based on a cohort of patients with unilateral PDR who underwent primary pars plana vitrectomy(PPV)and completed 12-month follow-up at the Central Theater General Hospital of the People’s Liberation Army of China from January 1,2020 to January 1,2023.Among them,63 cases with 63 eyes who developed rebleeding after surgery were set as the case group,and 25 cases with 252 eyes who did not develop PDVH were set as the control group,according to a ratio of 1:4 matching,thus establishing a research cohort.Clinical data from both groups were compared,factors included in the statistical analysis consist of systemic factors such as diabetes duration,fasting blood glucose levels,glycated hemoglobin levels,and the presence of hypertension or diabetic nephropathy;ocular factors mainly include visual acuity,intraocular pressure,lens status,PDR staging,preoperative pan-retinal photocoagulation treatment,and preoperative intravitreal injection of anti-vascular endothelial growth factor drugs;surgical factors involve concomitant cataract phacoemulsification,intraoperative dexamethasone use,intraoperative photocoagulation,and electrocoagulation hemostasis.Surgical factors included whether combined cataract phacoemulsification,intraoperative use of triamcinolone acetonide,intraoperative photocoagulation,electrocoagulation hemostasis,intraoperative vitreous cavity filler type,etc.The data with statistical differences were subjected to conditional logistic regression analysis for risk factors for PDVH after PPV in PDR patients.Results: Statistical differences in BMI(Body Mass Index),duration of diabetes,fasting glucose,glycated hemoglobin,hypertension,diabetic nephropathy,preoperative lens status,preoperative anti-VEGF therapy,incision suturing,and intraoperative combined cataract surgery were observed between the two groups.The statistical results of the final Logistic regression equation indicate that the following factors have a statistically significant impact on PDVH: the duration of diabetes(OR=1.098,95%CI: 1.035-1.165,P=0.002),preoperative glycated hemoglobin(OR=1.153,95%CI: 1.024-1.178,P=0.002),systemic combined diabetic nephropathy(OR=3.352,95%CI: 1.185-8.546,P=0.041),systemic combined hypertension(OR=2.855,95%CI: 1.202-6.782,P=0.017),preoperative crystalline lens status(OR=0.345,95%CI: 0.163-0.729,P=0.005),combined cataract surgery during the operation(OR=0.222,95%CI: 0.091-0.541,P=0.004),and preoperative anti-VEGF treatment(OR=0.317,95%CI: 0.146-0.685,P=0.001).Conclusions: Long diabetes duration,high preoperative Hb A1 c level,systemic hypertension,and diabetic nephropathy are risk factors for PDVH occurrence(OR value >1);preoperative artificial lens eye status Intraoperative combined cataract surgery and preoperative anti-VEGF treatment are protective factors for PDVH occurrence(OR value <1).