Abstract
Purpose: :
Endophthalmitis is a serious complication following cataract surgery. Despite the relatively low incidence, the frequency of cataract surgery and the severity of the condition make it an important public health problem. Rates of endophthalmitis following cataract surgery in the U.S. are estimated to be approximately 1.5 per thousand surgeries. In Sweden, the rate of endophthalmitis is roughly half of that, suggesting that modifications to current surgical practice in the US could result in a reduction in the incidence of endophthalmitis. The aim of this study was to examine potential risk factors that could be easily modified.
Methods: :
We conducted a case-control study of a nationally representative sample of Medicare beneficiaries. Cases of post-cataract surgery endophthalmitis during the period 2003-2004 were identified using Medicare claims data. Five controls were matched to each case. Physicians were requested to complete a brief questionnaire regarding the surgery, patient characteristics, surgical volume and setting, and anti-infective measures used. The treating retinal specialist was also contacted and asked to provide information regarding the diagnosis and treatment of endophthalmitis. Conditional logistic analysis was used to evaluate the relationship between risk factors and case status.
Results: :
Data were analyzed for 327 endophthalmitis cases and 1488 controls. 8% of controls were aged >85 years compared to 11% of cases; males were 30% more likely than females to be cases (p=0.04). 55% of the study population had surgery performed with clear corneal incisions. 94% of surgeries were performed with phacoemulsification. However, fewer cases than controls had surgery performed with this technique (91% vs 95%, p =0.03.) Pre-operative topical antibiotic use was comparable between cases and controls. Controls were 1.4 times more likely to have received an intracameral antibiotic injection than cases (95% CI: 0.9, 2.3). Similarly, antibiotic use in the irrigating solution was 2 times more common among controls compared to cases (95% CI: 1.5, 2.9). No difference was seen between cases and controls with regard to post-operative topical antibiotic drops. Cases were 7 times more likely to have an intra-operative complication reported, with broken capsule and vitreous loss being the most common complications reported.
Conclusions: :
Some of the risk factors identified in this study can be addressed to reduce post-cataract surgery endophthalmitis in the U.S..
Keywords: cataract • endophthalmitis • treatment outcomes of cataract surgery