We searched the The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded regardless of study language. This was augmented by a manual search. The last date of search was November, 2011.
SELECTION CRITERIA: Included trials were systematically abstracted, as were excluded studies for the purposes of assessing harms. Analyses were conducted in accordance with The Cochrane Handbook and practices of The Cochrane Hepato-Biliary Group.
MAIN RESULTS: Seven randomised trials were included. Four trials with 403 patients compared an
antibiotic with placebo or no intervention. Three trials compared at least one
antibiotic regimen with another
antibiotic regimen. The trials all had high risk of bias. The trials varied in the severity of
leptospirosis among trial patients. The ability to group data for meta-analysis was limited. While all four trials that compared
antibiotics with placebo reported mortality and used parenteral
penicillin, there were no deaths in two of them. Since odds ratio calculations cannot employ zero-event trials, only two trials contributed to this estimate. The number of deaths were 16/200 (8.0%) in the
antibiotic arm versus 11/203 (5.4%) in the placebo arm giving a fixed-effect OR 1.56 (95% CI 0.70 to 3.46). The random-effects OR is 1.16 (95% CI 0.23 to 5.95). The heterogeneity among these four trials for the mortality outcome was moderate (I(2)= 50%). Only one trial (253 patients) reported days of hospitalisation. It compared parenteral
penicillin to placebo without significant effect of
therapy (8.9 versus 8.8 days; mean difference (MD) 0.10 days, 95% CI -0.83 to 1.03). The difference in days of clinical illness was reported in two of these trials (71 patients). While parenteral
penicillin therapy conferred 4.7 to 5.6 days of clinical illness in contrast to 7.7 to 11.6 days in the placebo arm, the size of the estimate of effect increased but statistical significance was lost under the random-effect model (fixed-effect: MD -2.13 days, 95% CI -2.46 to -1.80; random-effects: MD -4.04, 95% CI -8.66 to 0.58). I(2) for this outcome was high (81%). When duration of
fever alone was assessed between
antibiotics and placebo in a single trial (79 patients), no significant difference existed (6.9 versus 6.6 days; MD 0.30, 95% CI -1.26 to 1.86). Two trials with 332 patients in relatively severe and possibly late
leptospirosis, resulted in trends towards increased dialysis when
penicillin was used rather than placebo, but the estimate of effect was small and did not reach statistical significance (42/163 (25.8%) versus 31/169 (18.4%); OR 1.54, 95% CI 0.91 to 2.60). When one
antibiotic was assessed against another
antibiotic, there were no statistically significant results. For mortality in particular, these comparisons included
cephalosporin versus
penicillin (2 trials, 6/176 (3.4%) versus 9/175 (5.2%); fixed-effect: OR 0.65, 95% CI 0.23 to 1.87, I(2)= 16%),
doxycycline versus
penicillin (1 trial, 2/81 (2.5%) versus 4/89 (4.5); OR 0.54, 95% CI 0.10 to 3.02),
cephalosporin versus
doxycycline (1 trial, 1/88 (1.1%) versus 2/81 (2.5%); OR 0.45, 95% CI 0.04 to 5.10). There were no adverse events of
therapy which reached statistical significance.
AUTHORS' CONCLUSIONS: