Abstract: We included eight RCTs (474 randomised participants), which compared oral corticosteroids with placebo or no intervention. All trials only recruited adults with chronic rhinosinusitis with nasal polyps. All trials reported outcomes at two to three weeks, at the end of the short-course oral steroid treatment period. Three trials additionally reported outcomes at three to six months. Two of these studies prescribed intranasal steroids to patients in both arms of the trial at the end of the oral steroid treatment period. Oral steroids versus placebo or no intervention Disease-specific health-related quality of life  was reported by one study. This study reported improved quality of life after treatment (two to three weeks) in the group receiving oral steroids compared with the group who received placebo (standardised mean difference (SMD) -1.24, 95% confidence interval (CI) -1.92 to -0.56, 40 participants, modified RSOM-31), which corresponds to a large effect size. We assessed the evidence to be low quality (we are uncertain about the effect estimate; the true effect may be substantially different from the estimate of the effect). Disease severity  as measured by patient-reported symptom scores was reported by two studies, which allowed the four key symptoms used to define chronic rhinosinusitis (nasal blockage, nasal discharge, facial pressure, hyposmia) to be combined into one score. The results at the end of treatment (two to three weeks) showed an improvement in patients receiving oral steroids compared to placebo, both when presented as a mean final value (SMD -2.84, 95% CI -4.09 to -1.59, 22 participants) and as a change from baseline (SMD -2.28, 95% CI -2.76 to -1.80, 114 participants). These correspond to large effect sizes but we assessed the evidence to be low quality. One study (114 participants) followed patients for 10 weeks after the two-week treatment period. All patients in both arms received intranasal steroids at the end of the oral steroid treatment period. The results showed that the initial results after treatment were not sustained (SMD -0.22, 95% CI -0.59 to 0.15, 114 participants, percentage improvement from baseline). This corresponds to a small effect size and we assessed the evidence to be low quality. There was an increase in adverse events  in people receiving orals steroids compared with placebo for gastrointestinal disturbances (risk ratio (RR) 3.45, 95% CI 1.11 to 10.78; 187 participants; three studies) and insomnia (RR 3.63, 95% CI 1.10 to 11.95; 187 participants; three studies). There was no significant impact of oral steroids on mood disturbances at the dosage used in the included study (risk ratio (RR) 2.50, 95% CI 0.55 to 11.41; 40 participants; one study). We assessed the evidence to be low quality due to the lack of definitions of the adverse events and the small number of events or sample size, or both). Other comparisons No studies that compared short-course oral steroids with other treatment for chronic rhinosinusitis met the inclusion criteria. At the end of the treatment course (two to three weeks) there is an improvement in health-related quality of life and symptom severity in patients with chronic rhinosinusitis with nasal polyps taking oral corticosteroids compared with placebo or no treatment. The quality of the evidence supporting this finding is low. At three to six months after the end of the oral steroid treatment period, there is little or no improvement in health-related quality of life or symptom severity for patients taking an initial course of oral steroids compared with placebo or no treatment. The data on the adverse effects associated with short courses of oral corticosteroids indicate that there may be an increase in insomnia and gastrointestinal disturbances but it is not clear whether there is an increase in mood disturbances. All of the adverse events results are based on low quality evidence. More research in this area, particularly research evaluating patients with chronic rhinosinusitis without nasal polyps, longer-term outcomes and adverse effects, is required. There is no evidence for oral steroids compared with other treatments.

Plain-language summary: This review includes evidence up to 11 August 2015. We included eight randomised controlled trials with a total of 474 participants. All of the patients were adults who had chronic rhinosinusitis with nasal polyps. All of the studies followed patients until the end of treatment (two to three weeks) and three studies (210 participants) followed up people for three to six months after the initial treatment had ended. Five of the eight reports mentioned how the trial was funded. None of the funding sources were pharmaceutical companies. At the end of a two- or three-week treatment course, people who took oral steroids may have had a better quality of life, less severe symptoms and smaller nasal polyps than people who had placebo or did not receive any treatment. After three to six months, there was little or no difference in quality of life, symptom severity or nasal polyps between the people who had oral steroids and the people who had placebo or no intervention. The people who took oral steroids may have had more gastrointestinal disturbances and insomnia than the people who had placebo or no intervention. It is not clear if the people who took oral steroids had more mood disturbances than the people who had placebo or no intervention. We judged the quality of the evidence for oral steroids plus intranasal steroids for adults with nasal polyps 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 some of the results are only from one or two studies, which do not have a lot of participants. Most of the trials do not have a high risk of bias, but only people with nasal polyps were included in the review.