Antibiotics versus placebo for acute bacterial conjunctivitis: findings from a Cochrane Systematic Review

PURPOSE: To summarize key findings from a Cochrane Review of the benefits and safety of antibiotic therapy compared with placebo (or vehicle) for acute bacterial conjunctivitis. DESIGN: Systematic review and meta-analysis. METHODS: We included placebo-controlled randomized controlled trials (RCTs) that compared topical antibiotics with placebo. We followed Cochrane methods for trial selection, data extraction, risk of bias assessment, and evidence synthesis. RESULTS: Twenty-one RCTs involving 8805 participants with acute bacterial conjunctivitis were included. Fifteen (71%) RCTs examined fluoroquinolone (FQ) drops, three tested macrolides, alone or in combination with steroids, and another three compared other non-FQ antibiotics. Intention-to-treat (ITT) estimates suggested that compared with placebo, antibiotics may increase clinical recovery by 26% (risk ratio [RR] 1.26 [95% confidence interval (CI) 1.09 - 1.46] at the end of therapy (5 RCTs, 1474 participants). Modified ITT estimates, in which only participants with laboratory-confirmed bacterial conjunctivitis were analyzed, indicated that antibiotics were associated with 53% higher likelihood of microbiological cure as compared with placebo (RR 1.53 [95% CI 1.34 - 1.74]; 10 RCTs, 2827 participants). Non-FQs (RR 4.05 [95% CI 1.36 - 12.00]), but not FQs (RR 0.70 [95%CI 0.54 - 0.90]), were likely to increase treatment-associated ocular complications such as eye pain, discomfort, and allergic reactions; the certainty of level of evidence was very low. CONCLUSIONS: Moderate level certainty of evidence suggested that antibiotics may increase the likelihood of clinical recovery and microbiological clearance compared with placebo. Very low-level certainty of evidence suggested that antibiotics may be associated with potential harm in patients with acute bacterial conjunctivitis, but the potential risk of bias from study design, inconsistency in outcome measurement and reporting limit the evidence to very low certainty.