Fig 1.
Flowchart for study selection and data acquisition.
Table 1.
MeSH search terms utilised in the search strategy.
Table 2.
Study characteristics included in the systematic review and meta-analysis.
Fig 2.
Forest plot for survival outcome of miRNAs in NPC patients.
The pooled hazard ratios of HR values for NPC prognostic data were calculated and analysed using CMA software (version 3.3.070, USA). The red square represents the pooled effect estimate of survival for NPC patients randomly assigned to miRNA evaluation. The black diamond with line indicates the effect size of miRNA of the included studies with 95% confidence interval. The risk ratio of 1 suggests no difference in risk of NPC patients survival. A risk ratio > 1 indicates an increased risk of patients survival whereas a risk ratio < 1 suggests a reduced risk of patients survival. Favours A refers to better survival and B indicates worse survival.
Fig 3.
Funnel plot of studies correlating the overall patient survival and miRNA expression.
The funnel plot measures the study size standard error and precision on the vertical axis as a function of effect size on the horizontal axis. Dots represent the individual study and most of this area contains regions of high significance, which reveals that publication bias would be represented in the form of asymmetry. This would reflect the fact that smaller studies (which appear toward the bottom) are more likely to be published if they have larger than average effects, which makes them more likely to meet the criterion for statistical significance.
Fig 4.
Funnel plot with observed and imputed studies.
Large studies appear outside the funnel and tend to cluster on one side of the funnel plot. Smaller studies appear toward the bottom of the graph, and (since there is more sampling variation in effect size estimates in the smaller studies) will be dispersed across a range of values.
Table 3.
Quality assessment of the selected studies.