Review question
We reviewed the available information regarding the added effect of corticosteroid eye drops in people with bacterial keratitis (corneal ulcers) who were also being treated with antibiotics.
Background
Bacterial keratitis, or corneal inflammation due to bacterial infection, is a sight-threatening condition. Contact lens wear, ocular surface disease, corneal trauma, and previous ocular or eyelid surgery have been linked to bacterial keratitis. Antibiotic eye drops are the standard treatment for eyes with bacterial keratitis. Corticosteroid eye drops also may be used to control the inflammation from infection. Eye doctors disagree about whether corticosteroid eye drops should be used with antibiotics to treat this condition due to potential side effects of using steroids in the eye.
Study characteristics
We found four studies in which antibiotics alone had been compared with antibiotics plus corticosteroids for the treatment of bacterial keratitis. These studies were conducted in the USA, Canada, India, and South Africa, and included a total of 612 eyes of 611 participants. The largest study included 500 participants followed for one year. The three smaller studies followed participants for two to three months. The evidence is current to July 2014.
Key results
None of the four studies reported an important difference between topical corticosteroid therapy and placebo or control treatment for reduction in ulcer size, change in visual acuity, adverse events, or quality of life. One study reported that healing or cure time in the steroid group was slower than the placebo group (for every 100 people cured in the control group, only 47 were cured in the steroid group during the same time period), but the largest study did not report any difference (for every 100 people cured in the control group, 92 were cured in the steroid group during the same time interval). For adverse events, none of the studies found a difference between the two groups, except that one study reported that more eyes in the control group developed intraocular pressure (IOP) elevation. We did not find any information on economic outcomes.
Quality of the evidence
Generally, the quality of the evidence based on the four studies we identified was moderate due to the proportions of participants who were not included in the final study analyses and the inconsistency of outcomes assessed across the four studies. In addition, three studies enrolled too few participants (30 to 42) to reach scientifically valid conclusions.
There is inadequate evidence as to the effectiveness and safety of adjunctive topical corticosteroids compared with no topical corticosteroids in improving visual acuity, infiltrate/scar size, or adverse events among participants with bacterial keratitis. Current evidence does not support a strong effect of corticosteroid, but may be due to insufficient power to detect a treatment effect.
Bacterial keratitis is a serious ocular infectious disease that can lead to severe visual disability. Risk factors for bacterial corneal infection include contact lens wear, ocular surface disease, corneal trauma, and previous ocular or eyelid surgery. Topical antibiotics constitute the mainstay of treatment in cases of bacterial keratitis, whereas the use of topical corticosteroids as an adjunctive therapy to antibiotics remains controversial. Topical corticosteroids are usually used to control inflammation using the smallest amount of the drug. Their use requires optimal timing, concomitant antibiotics, and careful follow-up.
The objective of the review was to assess the effectiveness and safety of corticosteroids as adjunctive therapy for bacterial keratitis. Secondary objectives included evaluation of health economic outcomes and quality of life outcomes.
We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2014, Issue 6), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to July 2014), EMBASE (January 1980 to July 2014), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to July 2014), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 14 July 2014. We also searched the Science Citation Index to identify additional studies that had cited the only trial included in the original version of this review, reference lists of included trials, earlier reviews, and the American Academy of Ophthalmology guidelines. We also contacted experts to identify any unpublished and ongoing randomized trials.
We included randomized controlled trials (RCTs) that had evaluated adjunctive therapy with topical corticosteroids in people with bacterial keratitis who were being treated with antibiotics.
We used the standard methodological procedures expected by The Cochrane Collaboration.
We found four RCTs that met the inclusion criteria of this review. The total number of included participants was 611 (612 eyes), ranging from 30 to 500 participants per trial. One trial was included in the previous version of the review, and we identified three additional trials through the updated searches in July 2014. One of the three smaller trials was a pilot study of the largest study: the Steroids for Corneal Ulcers Trial (SCUT). All trials compared the treatment of bacterial keratitis with topical corticosteroid and without topical corticosteroid and had follow-up periods ranging from two months to one year. These trials were conducted in the USA, Canada, India, and South Africa.
All trials reported data on visual acuity ranging from three weeks to one year, and none of them found any important difference between the corticosteroid group and the control group. The pilot study of the SCUT reported that time to re-epithelialization in the steroid group was 53% slower than the placebo group after adjusting for baseline epithelial defect size (hazard ratio (HR) 0.47; 95% confidence interval (CI) 0.23 to 0.94). However, the SCUT did not find any important difference in time to re-epithelialization (HR 0.92; 95% CI 0.76 to 1.11). For adverse events, none of the three small trials found any important difference between the two treatment groups. The investigators of the largest trial reported that more patients in the control group developed intraocular pressure (IOP) elevation (risk ratio (RR) 0.20; 95% CI 0.04 to 0.90). One trial reported quality of life and concluded that there was no difference between the two groups (data not available). We did not find any reports regarding economic outcomes.
Although the four trials were generally of good methodological design, all trials had considerable losses to follow-up (10% or more) in the final analyses. Further, three of the four trials were underpowered to detect treatment effect differences between groups and inconsistency in outcome measurements precluded meta-analyses for most outcomes relevant to this review.