Results of r and omized controlled trials performed to date provide evidence that antibiotic prophylaxis reduces subsequent infection and that courses as short as one day are as effective as courses of three to five days , although the evidence warrants only low to moderate confidence .
BACKGROUND The purpose of the present study was to perform a systematic review and meta- analysis of the use of alternative antibiotic regimens-including ( A ) antibiotic prophylaxis versus no prophylaxis , ( B ) longer versus shorter duration of antibiotic prophylaxis , and ( C ) alternative drugs-for  patients with open fracture of the extremities .
GRADE guidelines: 4. Rating the quality of evidence--study limitations (risk of bias).
In the GRADE approach , r and omized trials start as high- quality evidence and observational studies as low- quality evidence , but both can be rated down if most of the relevant evidence comes from studies that suffer from a high risk of bias . Well-established limitations of r and omized trials include failure to conceal allocation , failure to blind , loss to follow-up , and failure to appropriately consider the intention-to-treat principle . More recently recognized limitations include stopping early for apparent benefit and selective reporting of outcomes according to the results . Key limitations of observational studies include use of inappropriate controls and failure to adequately adjust for prognostic imbalance . Risk of bias may vary across outcomes ( e.g. , loss to follow-up may be far less for all-cause mortality than for quality of life ) , a consideration that many systematic review s ignore . In deciding whether to rate down for risk of bias -- whether for r and omized trials or observational studies -- authors should not take an approach that averages across studies . Rather , for any individual outcome , when there are some studies with a high risk , and some with a low risk of bias , they should consider including only the studies with a lower risk of bias
Results of r and omized controlled trials performed to date provide evidence that antibiotic prophylaxis reduces subsequent infection and that courses as short as one day are as effective as courses of three to five days , although the evidence warrants only low to moderate confidence .
BACKGROUND The purpose of the present study was to perform a systematic review and meta- analysis of the use of alternative antibiotic regimens-including ( A ) antibiotic prophylaxis versus no prophylaxis , ( B ) longer versus shorter duration of antibiotic prophylaxis , and ( C ) alternative drugs-for  patients with open fracture of the extremities .