Abstract: Two trials with a total of 78 participants met the inclusion criteria. Both the populations and the 'standard' treatments differed in the two studies. Oral steroids as an adjunct to intranasal corticosteroids One trial in adults with nasal polyps included 30 participants. All participants used intranasal corticosteroids and were randomised to either short-course oral steroids (oral methylprednisolone, 1 mg/kg and reduced progressively over a 21-day treatment course) or no additional treatment. None of the primary outcome measures of interest in this review were reported by the study. There may have been an important reduction in the size of the polyps (measured by the nasal polyps score, a secondary outcome measure) in patients receiving oral steroids and intranasal corticosteroids, compared to intranasal corticosteroids alone (mean difference (MD) -0.46, 95% confidence interval (CI) -0.87 to -0.05; 30 participants; scale 1 to 4) at the end of treatment (21 days). This corresponds to a large effect size, but we are very uncertain about this estimate as we judged the study to be at high risk of bias. Moreover, longer-term data were not available and the other outcomes of interest were not reported. Oral steroids as an adjunct to antibiotics One trial in children (mean age of eight years) without nasal polyps included 48 participants. The trial compared oral corticosteroids (oral methylprednisolone, 1 mg/kg and reduced progressively over a 15-day treatment course) with placebo in participants who also received a 30-day course of antibiotics. This study addressed one of the primary outcome measures (disease severity) and one secondary outcome (CT score). For disease severity  the four key symptoms used to define chronic rhinosinusitis in children (nasal blockage, nasal discharge, facial pressure, cough) were combined into one score. There was a greater improvement in symptom severity 30 days after the start of treatment in patients who received oral steroids and antibiotics compared with placebo and antibiotics (MD -7.10, 95% CI -9.59 to -4.61; 45 participants; scale 0 to 40). The observed mean difference corresponds to a large effect size. At the same time point there was a difference in CT scan score (MD -2.90, 95% CI -4.91 to -0.89; 45 participants; scale 0 to 24). We assessed the quality of the evidence to be low. There were no data available for the longer term (three months). There might be an improvement in symptom severity, polyps size and condition of the sinuses when assessed using CT scans in patients taking oral corticosteroids when these are used as an adjunct therapy to antibiotics or intranasal corticosteroids, but the quality of the evidence supporting this is low orvery low (we are uncertain about the effect estimate; the true effect may be substantially different from the estimate of the effect). It is unclear whether the benefits of oral corticosteroids as an adjunct therapy are sustained beyond the short follow-up period reported (up to 30 days), as no longer-term data were available. There were no data in this review about the adverse effects associated with short courses of oral corticosteroids as an adjunct therapy. More research in this area, particularly research evaluating longer-term outcomes and adverse effects, is required.

Plain-language summary: This review includes evidence up to 11 August 2015. We included two randomised controlled trials with a total of 78 participants. One trial involved 30 adults with nasal polyps. Participants received either intranasal corticosteroids and oral corticosteroids or only intranasal corticosteroids. The only result reported of interest to this review was whether the size of the nasal polyps was reduced, when these treatments were completed (three weeks). One trial involved 48 children (mean age of eight years) with chronic rhinosinusitis but no nasal polyps. Participants received either antibiotics and oral corticosteroids or only antibiotics and a placebo (sugar pill). The oral corticosteroids and placebo were given for 15 days and the antibiotics were given for 30 days. The trial reported findings when the antibiotic treatment was completed (at one month). At the end of a three-week treatment course, people who took both intranasal corticosteroids and oral steroids may have had smaller nasal polyps than people who just received intranasal corticosteroids. The trial did not follow up people to determine whether the polyp size increased after the end of the trial. The trial did not provide information on adverse events or other outcomes important to patients, such as symptom severity or quality of life. Children who received both antibiotics and oral corticosteroids seemed to have a lower total symptom score and better computerised tomography (CT) scan score after treatment compared with children who received antibiotics and control treatment. The reporting of adverse effects in this trial was not very clear and so is difficult to tell if any participant experienced gastrointestinal disturbances, mood changes or difficulty in sleeping. We judged the quality of the evidence for oral steroids plus intranasal steroids for adults with nasal polyps to be very low (we are very uncertain about the estimate) as the evidence comes from one trial that has a low number of participants. The trial had a high risk of bias due to the way it was conducted. The trial did not report adverse events and did not report results after the end of treatment. We judged the quality of the evidence for oral steroids plus antibiotics for children 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 comes from one small trial. The trial did not have a high risk of bias, but it only included children without nasal polyps, who might not have the same results as adults with nasal polyps. The trial did not report results after the end of treatment and the adverse effects of treatment were not well reported.