Comment: The quality of evidence is downgraded by indirectness (differences between the population of interest and those studied: participants had largely mild to moderate asthma and may have been at less risk of serious adverse events).
A Cochrane review [Abstract] 1 included 66 studies with a total of 7 944 subjects. Most participants had mild or intermittent asthma, often with co-morbid allergic rhinitis. Twenty-three studies recruited adults and teenagers, 31 recruited only children, 3 recruited both, and 9 did not specify. The aim of the review was too assess the efficacy and safety of sublingual immunotherapy (SLIT) compared with placebo or standard care for adults and children with asthma.
Only 2 studies (n=108) reported the primary outcome of exacerbations requiring an emergency department (ED) or hospital visit (OR 0.35, 95% CI 0.10 to 1.20; SLIT compared with placebo or usual care). Nine studies reported quality of life outcomes numerically, but the data were not suitable for meta-analysis. Whilst the direction of effect favoured SLIT in most studies reporting quality of life, the effect was often uncertain and of small magnitude. SLIT did not increase serious adverse events (SAEs) compared with placebo or usual care, and analysis by risk difference suggested no more than 1 in 100 people taking SLIT will have a serious adverse event (RD −0.0004, 95% CI −0.0072 to 0.0064; 29 studies, n=4 810).More people taking SLIT had adverse events of any kind compared with control (OR 1.99, 95% CI 1.49 to 2.67; 27 studies, n=4 251), but events were usually reported to be transient and mild.Asthma symptom and medication scores were mostly measured with non-validated scales, which precluded meaningful meta-analysis or interpretation, but there was a general trend of SLIT benefit over placebo.
Date of latest search: 25 March 2015
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