CALIFORNIAN ENDOPHTAHALMITIS STUDY SHOWS DRAMATIC RESULTS

While some American surgeons remain skeptical of the landmark ESCRS study demonstrating that intracameral (IC) cefuroxime reduces post-cataract surgery endophthalmitis risk, one large California surgery centre is convinced. Over a five-year period during which 14 surgeons increased their use of IC antibiotics from 11 per cent to 100 per cent of cataract cases, their endophthalmitis rate dropped 22-fold, according to a recent study (J Cataract Refract Surg 2013; 39:8–14).

The ecological time-trend study strongly suggests that IC antibiotics reduce endophthalmitis risk, and may be particularly effective in cases involving posterior capsule rupture. Previously, no Us centre has demonstrated such an association. The study also suggests that IC antibiotics may be more effective than topical fourth-generation fluoroquinolones, and there may be little or no additional benefit from adding drops to IC antibiotics, though additional research is needed. If confirmed, the financial impact could be substantial. substituting IC cefuroxime, or even moxifloxacin, for topical gatifloxacin saves about €55 per case, which could amount to more than €100m in savings annually for the Us Medicare public insurance program, the study estimated.

[caption id='attachment_4827' align='alignright' width='300'] On a recent trip to Tibet, Dr Shorstein demonstrated some phacoemulsification
techniques to Dr Yong in the operating theatre at the Shangri-La People’s Hospital[/caption]

Lead investigator Neal h shorstein MD acknowledged that the study cannot conclusively rule out that factors beyond the centre’s changes in antibiotic prophylaxis practices may have helped reduce endophthalmitis rates. however, he pointed out that the drop in endophthalmitis associated with using iC antibiotics was an order of magnitude greater than that associated with switching from topical tobramycin to topical gatifloxacin, and was statistically significant whereas the drop associated with increasing use of the topical fluoroquinolone was not. From a clinical perspective, Dr shorstein has no doubt that IC antibiotics are the way to go. “in the end the results were quite stark. in 2010 and 2011 we had one case of endophthalmitis out of more than 7,000 cataract surgeries. Not only did intracameral antibiotics work better, they seemed to work a whole lot better.â€

The study involved 16,264 consecutive phacoemulsification procedures at Kaiser Permanente Diablo service Area from 2007 through 2011. Patient data were collected through Kaiser Permanente’s electronic medical records system, with followup obtained for all but one of the cataract patients operated, Dr shorstein said. in total, 19 cases of endophthalmitis were observed. Rates per 1,000 cases were calculated for three time periods during which surgeons operated under three different prophylactic antibiotic protocols.

Dr shorstein initiated the study in 2007 after observing that his department’s endophthalmitis rate rose to nine cases in 2,878 patients, or 3.13 cases per 1,000, from about one per 1,000 in the early 2000s. At that time, surgeons chose their own antibiotic regimen. in 2007, most patients received postoperative antibiotic drops only, though 11 per cent received iC antibiotics. Finding no association by surgeon or change in procedures to explain the increase, Dr shorstein looked for new methods to reduce infection risk. The ESCRS study caught his attention. “This was the first large randomised clinical trial that tried to answer what could be done to reduce endophthalmitis. it was an opportunity to put evidence-based medicine to work.â€

Working with Kaiser Permanente’s in-house compounding pharmacy, the department changed its protocol beginning in 2008 to inject intracameral cefuroxime for all cataract patients without penicillin/cephalosporin allergies or posterior capsule ruptures. As a result, in 2008 and 2009, about 80 per cent of patients received iC antibiotics plus each surgeon’s usual post-op drops. Of 6,278 cases, nine developed endophthalmitis, dropping the rate by more than half to 1.43 per 1,000. however, the decline was not statistically significant (p=0.09), Dr shorstein noted. Further confounding the results was a shift from topical tobramycin to gatifloxacin, which nearly doubled from 42 per cent of cases in 2007 to 75 per cent in 2008, and 80 per cent in 2009.

Seeking more improvement, Dr shorstein and colleagues added iC antibiotics in PCR cases, which he noted have about a five-to 10-fold higher risk of endophthalmitis than uncomplicated cases. For penicillin-allergic patients, moxifloxacin and vancomycin were added as second- and third-line IC antibiotics. Beginning in 2010, all cataract patients received IC injections, plus surgeons’ preferred post-op drops. The results were dramatic. in 2010 and 2011, just one of 7,108 cataract patients developed endophthalmitis, resulting in a significant drop in rate to 0.14 per 1,000 (p<0.01). Dr shorstein pointed out that this sharp drop occurred while topical gatifloxacin use remained stable, suggesting that iC antibiotics may be the key change that reduced endophthalmitis risk.

[caption id='attachment_4828' align='alignright' width='300'] Dr Shorstein (right) and Dr Yong with the Shangri-La Tibetan monastery in the background[/caption]

Overall, infection rates were much lower in iC injected cases for the entire five years. Of 12,609 cases, just four developed endophthalmitis for a rate of 0.32 per 1,000. By contrast, of the 3,655 cases not receiving IC antibiotics, 15 developed endophthalmitis for a rate of 4.20 per 1,000, or more than 13 times the IC antibiotic rate. in addition, of 2,038 cases that received iC antibiotics but no drops, one case of endophthalmitis developed for a rate of 0.49 per 1,000. This is close to the swedish registry rate of 0.45, Dr shorstein noted. “I am convinced that the benefits of intracameral injections are indisputable and remarkable.â€

IC antibiotics are now standard of practice at Dr shorstein’s centre and are being considered throughout the Kaiser Permanente system, which serves nearly nine million members. he noted, however, that his centre’s on-site compounding pharmacy makes it easy and safe to dilute cefuroxime for IC injection. For surgeons without such access, moxifloxacin may be a better choice since it can be drawn up without dilution, and can be nearly as economical as cefuroxime when used for multiple doses prepared under appropriate sterile conditions, he said.