We identified 19 eligible studies (3459 individuals), all observational; 13 studies (1917 individuals) were suitable for inclusion in the meta-analysis of mortality . Of these, 12 studied patients infected with 2009 influenza A H1N1 virus (H1N1pdm09). Risk of bias was greatest in the 'comparability domain' of the Newcastle-Ottawa scale, consistent with potential confounding by indication. Data specific to mortality were of very low quality. Reported doses of corticosteroids used were high and indications for their use were not well reported. On meta-analysis , corticosteroid therapy was associated with increased mortality ( odds ratio ( OR ) , 95% confidence interval ( CI ) to ). Pooled subgroup analysis of adjusted estimates of mortality from four studies found a similar association ( OR , 95% CI to ). Three studies reported greater odds of hospital-acquired infection related to corticosteroid therapy ; all were unadjusted estimates and we graded the data as very low quality.
Epidural injections are often used to treat radicular pain, also called sciatica , which is pain that radiates from the site of a pinched nerve in the low back to the area of the body aligned with that nerve, such as the back of the leg or into the foot. Inflammatory chemicals (. substance P, PLA2, arachidonic acid, TNF-α, IL-1, and prostaglandin E2) and immunologic mediators can generate pain and are associated with common back problems such as lumbar disc herniation or facet joint arthritis . These conditions, as well as many others, provoke inflammation that in turn can cause significant nerve root irritation and swelling.