Purpose
1) To determine the overall risk of endophthalmitis in a large national U.S. population 2) To describe how the risk of endophthalmitis after intravitreal injection has changed over time
Methods
Administrative medical claims data from a large, national U.S. insurer was reviewed. All intravitreal injections (CPT code 67028) performed between 1/1/2003 to 12/31/2012 were identified. The index date was considered the date of the intravitreal injection. Cases of endophthalmitis were defined as having a claim for both an endophthalmitis diagnosis code (360.0x) and a “tap and inject” procedure code (CPT 67015 or 67025) on the same day and which also had to be 1-14 days after the index date. Exclusion from analysis occurred if the patient had a previous diagnosis of endophthalmitis, the patient had <6 months of data prior to index date, the patient had <1 month of time in dataset after the index date, or if intraocular surgery occurred between the index date and diagnosis of endophthalmitis. Counts of total patients, injections and cases were aggregated by year. Rates of endophthalmitis and risk ratios were calculated on a per injection basis.
Results
From 2003 to 2012 (Table 1) 126,740 patients (11,603 from 2003-2006/115,137 from 2007-2012) had 450,708 injections (21,930/428778) with 168 (47/121) cases of endophthalmitis occurring post procedure for an overall rate of 0.037% (1/2702 injections). From 2003 to 2006, endophthalmitis rate varied from 0.120-0.728% and averaged 0.214%. From 2007 to 2012 the endophthalmitis rate was less variable and ranged from 0.0186-0.0480%. The average rate during this time was significantly lower 0.028% (chi square=193.91, p<0.0001) compared to the 2003-2006 average rate. The risk ratio for endophthalmitis after an injection was 7.59 times higher (95% CI: 5.42,10.63) for an injection given from 2003-2006 compared to one given 2007-2012.
Conclusions
The overall rate of endophthalmitis post intravitreal injection from 2003-2012 was 0.037% (1/2702). The current (post 2006) rate is even lower, at 1 in 3,543 injections and has dropped dramatically compared to rates prior to 2007.