RCOphth NOD, Report 10: Risk factors for post-cataract surgery endophthalmitis

Endophthalmitis was recorded in 308 (0.02%) eyes (1 351 415 operations performed on 920 286 patients) between April 2010-March 2021. Identified risk factors were posterior capsular rupture, uveitis/synechiae, glaucoma, corneal pathology, diabetes mellitus, previous vitrectomy surgery and anti-VEGF therapy. Endophthalmitis was recorded in 308 (0.02%) eyes (1 351 415 operations performed on 920 286 patients) between April 2010-March 2021. Identified risk factors were posterior capsular rupture, uveitis/synechiae, glaucoma, corneal pathology, diabetes mellitus, previous vitrectomy surgery and anti-VEGF therapy. One of the most feared complications following cataract surgery is endophthalmitis, with sight-threatening intraocular inflammation(1Relhan N, Forster RK, Flynn HW. Endophthalmitis: Then and Now. American Journal of Ophthalmology: Elsevier Inc.; 2018. p. xx-xxvii.Google Scholar). Given the rarity of endophthalmitis, it is difficult for individual eye centres to conduct meaningful audit of cataract surgical infection rates, unless they are operating at very high volume or experienced a massive outbreak. Therefore, there is a great need for collaborative registries to study real-world post-operative infection rates. The Royal College of Ophthalmologists’ National Ophthalmology Database (RCOphth NOD) is well positioned to enable large-scale analysis of the incidence of, and risk factors for, post-cataract surgery endophthalmitis within the United Kingdom. National audit registries of this nature are exempt from ethical committee approvals, and the study adhered to the Declaration of Helsinki. The aim of this study is to identify the risk factors for endophthalmitis following phacoemulsification surgery. This will aid ophthalmic surgeons discussing risks with patients, allow surgeons to consider strategies to reduce these risks, and serve as a baseline for benchmarking. Included in this study were eligible patients who underwent cataract surgery in traditional National Health Service (NHS) centres submitting data to the RCOphth NOD between 1st April 2010 and 31st March 2021. Endophthalmitis was defined if any of the following occurred within 42 days of cataract surgery: post-operative complication record of endophthalmitis, post-operative diagnosis of endophthalmitis, post-cataract vitreous biopsy or anterior chamber tap. Fixed effects logistic regression was used to identify potential risk factors (full methods in online supplemental material available at www.aaojournal.org). Within the study period, 1 351 415 eligible operations were performed on 920 286 patients from 76 centres by 3 570 surgeons. Endophthalmitis was recorded in 308 (0.02%) eyes, with no cases from any of the 2 315 immediate sequential bilateral cataract surgery patients. There was no statistically significant difference in the rate of endophthalmitis based on the grade of operating surgeon. The post-cataract surgery endophthalmitis rate ranges from 0.015 to 0.035% from year 2010 to 2020, Figure 1, Panel A. Of the 308 patients who developed endophthalmitis, 171 (55.5%) were female and the median age was 76.9 years (IQR: 68.8 to 84.0 years). Identified risk factors were posterior capsular rupture (OR: 7.111; 95% CI: 4.890 to 10.341), uveitis / posterior synechiae (OR: 4.315; 95% CI: 2.467 to 7.549), previous vitrectomy surgery (OR: 2.879; 95% CI: 1.802 to 4.600), previous anti-vascular endothelial growth factor (VEGF) therapy (OR: 2.230; 95% CI: 1.411 to 3.523), glaucoma (OR: 2.114; 95% CI: 1.591 to 2.810), corneal pathology (OR: 2.113; 95% CI: 1.307 to 3.417) and diabetes mellitus (OR: 1.450; 95% CI: 1.114 to 1.886). Figure 1, Panel B. Using the risk factor model, the lowest probability of post-cataract surgery endophthalmitis is 0.015% for a patient without diabetes mellitus who has not had anti-VEGF therapy with none of the ocular conditions and where PCR is avoided during surgery. This risk increases to 0.108% if PCR occurs. The highest risk eyes are from patients with diabetes mellitus, previous anti-VEGF therapy, uveitis/posterior synechiae, previous vitrectomy, glaucoma, or corneal pathology, where the probability of endophthalmitis is 2.645% when PCR is avoided and 16.139% when PCR occurs. Previous published incidence rates for post-cataract endophthalmitis from recent series range from 0.1 to 0.5 per 1 000 cases2Pershing S, Lum F, Hsu S, Kelly S, Chiang MF, Rich WL, et al. Endophthalmitis after Cataract Surgery in the United States: A Report from the Intelligent Research in Sight Registry, 2013–2017. Ophthalmology: Elsevier Inc.; 2020. p. 151-158.Google Scholar,3Yannuzzi N.A. Si N. Relhan N. Kuriyan A.E. Albini T.A. Berrocal A.M. et al.Endophthalmitis After Clear Corneal Cataract Surgery: Outcomes Over Two Decades.American Journal of Ophthalmology: Elsevier Inc. 2017; : 155-159Abstract Full Text Full Text PDF Scopus (45) Google Scholar,4Moussa G. Bhatt H. Reekie I. Butt G. Ng A. Blanch R. et al.Using the West Midlands CONCERT to characterise regional incidence of acute-onset post cataract surgery endophthalmitis.Eye. 2021; 35: 1730-1740Crossref PubMed Scopus (1) Google Scholar. Previous small scale studies identified potential risk factors for developing post-procedural endophthalmitis which include history of ocular surface disease, diabetes mellitus, immunocompromised status and older age(1Relhan N, Forster RK, Flynn HW. Endophthalmitis: Then and Now. American Journal of Ophthalmology: Elsevier Inc.; 2018. p. xx-xxvii.Google Scholar). One of the main sources of contamination in cataract surgery is thought to be the commensal microbiota on the periocular skin and lid margin. The microbiology spectrum predominantly implicated in post-operative endophthalmitis cases is similar to those found on those sites. The microbial load on the ocular surface is influenced by age, chronic use of topical medications, such as anti-glaucoma medications or steroids, systemic disease (i.e. diabetes mellitus) and ocular surface disease. Dysregulation of the host immune responses and increased susceptibility to microbial invasion either as a direct consequence of the pre-existing ocular pathology or a result of treatment with long-term topical medication use may predispose patients to increased risk of post-cataract endophthalmitis. Posterior capsular rupture during cataract surgery is a significant risk factor for endophthalmitis. Once there is a breach to the posterior capsule, extra procedures and instrumentation (such as anterior vitrectomy) would be required, along with increased surgical time, which could increase the risk of introducing micro-organisms into the eye. It has also been suggested that incomplete or less efficient elimination of bacteria in the vitreous cavity following posterior capsular rupture could be a contributing factor(5Rahmani S. Eliott D. Postoperative Endophthalmitis: A Review of Risk Factors, Prophylaxis, Incidence, Microbiology, Treatment, and Outcomes.Seminars in Ophthalmology. 2018; 33: 95-101Crossref PubMed Scopus (41) Google Scholar). This study is limited by the potentially heavy influence of the small event and outcome rates in a large sample. Additionally, the use of electronic medical records (EMR) is not standardized across NHS sites, hence, data such as the use of prophylactic antibiotics intraoperatively or indication for AC tap (i.e. for treatment of high IOP in the absence of endophthalmitis) is not fully captured on the EMR systems. We are unable to link microbiology data to distinguish between non-infectious (toxic anterior segment syndrome/uveitis) and infectious cause. The general consensus is that patients who undergo cataract surgery in the private sector are less complex than ones undertaken in the NHS setting. Although the RCOphth NOD database does not have the same rigour as data validation in prospective clinical trials, the very large sample size required to evaluate rare outcomes, such as endophthalmitis, will be prohibitively costly to undertake in future clinical trial settings(6Gower E.W. Lindsley K. Tulenko S.E. Nanji A.A. Leyngold I. Mcdonnell P.J. Perioperative antibiotics for prevention of acute endophthalmitis after cataract surgery.Cochrane Database of Systematic Reviews: John Wiley and Sons Ltd. 2017; Crossref PubMed Scopus (16) Google Scholar). Thus, observational data such as that provided by the RCOphth NOD database will be depended upon to guide future policy and practice. In summary, our study demonstrates the utility of large-scale clinical databases for risk factor analysis of rare but highly important, sight-threatening surgical complications. Given the rarity of post-cataract surgery endophthalmitis, national benchmarks of incidence and risk-stratified surveillance of endophthalmitis outbreaks are warranted. Further development of national prospective surveillance networks to actively monitor post-cataract endophthalmitis cases in real-time, along with their microbiology and anti-microbial resistance data, would facilitate minimization of the infection rate, enable prompt identification of potential outbreaks and guide response measures. Download .pdf (.63 MB) Help with pdf files Download .pdf (.59 MB) Help with pdf files Download .pdf (.22 MB) Help with pdf files