Meta-analysis investigating the use of low-dose dopamine to prevent or treat renal dysfunction . Endpoint: mortality (total of 109 events in 1523 patients in the intervention group and 105 events in 1454 patients in the control group). The first three horizontal bar charts show the proportion of trials, patients, and outcome events in the meta-analysis of all "Trials with No Zeros" (trials with at least one event in both the intervention and control arms), "Trials with One Zero" (trials with no events in either the intervention or the control arm), and "Trials with Two Zeros" (trials with no events in both the intervention and control arms). The next three pairs of bar charts show the total weighting of all trials with no zeros, one zero, and two zeros, respectively, in the final pooled RD, OR, and RR. The first bar in each pair refers to a meta-analysis that includes only trials with at least one event in either the intervention or the control arm ("Event trials"). The second bar includes both trials with and without events ("All trials"). For each effect measure, a corresponding plot indicates the pooled treatment effect estimate with its 95% confidence interval (white circles when event trials only are included and black circles when all trials are included), and the I2 heterogeneity measure. The RD is plotted on a linear scale, and OR and RR are plotted on the same logarithmic scale. Abbreviations: RD = risk difference, OR = odds ratio, RR = relative risk.
Friedrich et al. BMC Medical Research Methodology 2007 7:5 doi:10.1186/1471-2288-7-5