Abstract: Five RCTs with a total of 1193 adult participants met our inclusion criteria. We judged methodological quality to be moderate in four trials and high in one trial. Acute sinusitis was defined clinically in all trials. However, the three trials performed in ear, nose and throat (ENT) outpatient clinics also used radiological assessment as part of their inclusion criteria. All participants were assigned to either oral corticosteroids (prednisone 24 mg to 80 mg daily or betamethasone 1 mg daily) or the control treatment (placebo in four trials and non-steroidal anti-inflammatory drugs (NSAIDs) in one trial). In four trials antibiotics were prescribed in addition to oral corticosteroids or control treatment, while one trial investigated the effects of oral corticosteroids as a monotherapy. When combining data from the five trials, participants treated with oral corticosteroids were more likely to have short-term resolution or improvement of symptoms than those receiving the control treatment: at days three to seven (risk ratio (RR) 1.3, 95% confidence interval (CI) 1.1 to 1.6; risk difference (RD) 17%, 95% CI 6% to 29%) and at days four to 14 (RR 1.2, 95% CI 1.0 to 1.5; RD 14%, 95% CI 1% to 27%). A sensitivity analysis including the four trials with placebo as a control treatment showed similar results but with a lesser effect size: at days three to seven (RR 1.2, 95% CI 1.1 to 1.3; RD 11%, 95% CI 4% to 17%) and days four to 14 (RR 1.1, 95% CI 1.0 to 1.2; RD 8%, 95% CI 2% to 13%). Statistical heterogeneity was high for many analyses. Subgroup analyses revealed that corticosteroid monotherapy had no beneficial effects. Furthermore, scenario analysis showed that outcomes missing from the trial reports might have introduced attrition bias (a worst-case scenario showed no statistically significant beneficial effect of oral corticosteroids). No trial reported effects on relapse or recurrence rates. Reported side effects in patients treated with oral corticosteroids were mild (nausea, vomiting, gastric complaints) and did not significantly differ from those receiving placebo. Oral corticosteroids as a monotherapy appear to be ineffective for adult patients with clinically diagnosed acute sinusitis. Current data on the use of oral corticosteroids as an adjunctive therapy to oral antibiotics are limited: almost all trials are performed in secondary care settings and there is a significant risk of bias. This limited evidence suggests that oral corticosteroids in combination with antibiotics may be modestly beneficial for short-term relief of symptoms in acute sinusitis, with a number needed to treat to benefit of seven for resolution or symptom improvement. A large primary care factorial trial is needed to establish whether oral corticosteroids offer additional benefits over antibiotics in acute sinusitis.

Plain-language summary: This review included evidence up to 19 February 2014. Five trials involving 1193 participants aged 15 years and older with acute sinusitis were included. In four trials participants received either antibiotics plus oral corticosteroids or antibiotics plus control treatment, while one trial assessed the effects of corticosteroids alone. Information on symptom relief was only available for the short term (two weeks or less) and no trial reported on relapse rates. No data for children were available. After combining trial findings, the results suggest that adults treated with oral corticosteroids plus antibiotics are more likely to have short-term symptom relief than those receiving a placebo or non-steroidal anti-inflammatory drug plus antibiotics. To benefit a single person, seven would need to receive treatment (number needed to treat to benefit). The trial assessing the effects of oral corticosteroids without antibiotics found no beneficial effects compared to placebo. Reported side effects in patients treated with oral corticosteroids were mild (nausea, vomiting, gastric complaints) and did not significantly differ from those receiving placebo. We judged the quality of the evidence for oral corticosteroids plus antibiotics to be low (further research is very likely to have an important impact on our confidence in the effect estimate and is likely to change the estimate) as the evidence is derived from four trials, including a relatively low number of participants, with a substantial risk of bias. Evidence of the effect of oral corticosteroids without antibiotics is derived from only one high-quality trial and we therefore judged the quality to be moderate (further research is likely to have an important impact on our confidence in the effect estimate and may change the estimate).