Fig. 8

Meta-analysis by category of clinical condition for: a all N = 54 trials with analysable data; b N = 26 ‘A’- and ‘B’-rated trials. p values for pooled effect estimates: a Allergy and asthma: p = 0.001; Cardiovascular: p = 0.046; Dermatology: p = 0.047; Ear, nose and throat: p = 0.014; Gastroenterology: p = 0.009; Mental disorder: p = 0.865; Musculoskeletal: p = 0.488; Obstetrics and gynaecology: p = 0.088; Respiratory infection: p = 0.092; Surgery and anaesthesiology: p = 0.448; Toxicology: p = 0.406. b Allergy and asthma: p = 0.041; Dermatology: p = 0.047; Ear, nose and throat: p < 0.001; Mental disorder: p = 0.165; Musculoskeletal: p = 0.762; Obstetrics and gynaecology: p = 0.486; Respiratory infection: p = 0.092; Surgery and anaesthesiology: p = 0.576; Toxicology: p = 0.896