Journal List > J Rheum Dis > v.22(1) > 1064235

Lee: Meta-analysis


Meta-analysis is a statistical tool for combining the results of different studies on the same topic, providing a precise estimate of the effect size and increasing statistical strength, which is particularly important when the strength of the primary study is limited because of a small sample size. Properly conducted meta-analysis provides an invaluable link between past and future studies by quantitatively synthesizing evidence while minimizing bias. Recently, because studies on meta-analysis have been published increasingly, there is a need for rheumatologists to understand meta-analysis. In order to help rheumatologists in use of a meta-analysis, the author describes the basic steps in statistical analysis of a meta-analysis: 1) search for presence of between-study heterogeneity, 2) performing statistical analysis of meta-analysis, 3) checking publication bias, 4) search for causes of heterogeneity, and 5) interpreting and presenting meta-analysis results.


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Figure 1.
Forrest plot of odds ratios (ORs) and 95% confidence interval (CIs) of individual studies and pooled data for the association between the C allele of the Fc receptor-like 3-169 C/T polymorphism and rheumatoid arthritis (RA) in each ethnic group. NAN: North American Native.
Figure 2.
Funnel plot of studies regarding the association between the Fc receptor-like 3-169 C allele and rheumatoid arthritis showed no evidence of asymmetry and Egger's regression test showed no significant p-value (Egger's regression test p-value=0.863), indicating no evidence of publication bias in the meta-analysis.
Table 1.
Process of statistical analysis of meta-analysis
1. Search for presence of between-study heterogeneity: Cochran Q test, I2
2. Performing meta-analysis: fixed or random effect model, forrest plot
3. Checking publication bias: funnel plot, Egger's regression test
4. Search for causes of heterogeneity: subgroup analysis, sensitivity analysis, meta-regression
5. Interpreting and presenting meta-analysis result
Table 2.
Meta-analysis of the associations between the FCRL3-169 C/T polymorphism and rheumatoid arthritis
Polymorphism Population No. of studies Test of association
Test of heterogeneity
OR 95% CI p-value Model p-value I2
FCRL3 Overall 17 1.046 0.997∼1.098 0.068 R 0.084 34.1
C vs. T European 9 1.012 0.962∼1.065 0.643 F 0.128 36.2
  Asian 7 1.101 1.035∼1.171 0.002 F 0.314 15.1
  Japanese 3 1.124 1.029∼1.227 0.009 F 0.266 24.5
  Non-Japanese 4 1.080 0.990∼1.177 0.082 F 0.260 25.2
CC vs. CT+TT (recessive) Overall 17 1.069 0.977∼1.170 0.146 R 0.052 38.8
European 9 1.004 0.883∼1.141 0.955 R 0.040 50.5
  Asian 7 1.138 1.014∼1.277 0.028 F 0.418 0.75
  Japanese 3 1.216 1.027∼1.438 0.023 F 0.469 0
  Non-Japanese 4 1.074 0.917∼1.258 0.375 F 0.330 12.4
CC+CT vs. TT (dominant) Overall 17 1.056 0.996∼1.119 0.066 F 0.328 10.7
European 9 1.019 0.941∼1.102 0.647 F 0.641 0
Asian 7 1.134 1.037∼1.241 0.006 F 0.449 0
  Japanese 3 1.144 1.006∼1.300 0.040 F 0.264 24.8
  Non-Japanese 4 1.125 0.992∼1.276 0.067 F 0.379 2.68
CC vs. TT Overall 17 1.100 1.017∼1.190 0.018 F 0.105 31.4
  European 9 1.032 0.931∼1.144 0.549 F 0.129 36.1
  Asian 7 1.208 1.063∼1.373 0.004 F 0.300 16.9
  Japanese 3 1.282 1.064∼1.544 0.009 F 0.274 22.7
  Non-Japanese 4 1.146 0.961∼1.366 0.129 F 0.272 23.1
CC vs. CT Overall 17 1.052 0.960∼1.154 0.275 R 0.084 34.0
  European 9 1.008 0.918∼1.106 0.872 R 0.064 45.7
  Asian 7 1.092 0.967∼1.234 0.157 F 0.575 0
  Japanese 3 1.174 0.983∼1.401 0.077 F 0.666 0
  Non-Japanese 4 1.024 0.865∼1.211 0.785 F 0.472 0

CI: confidence interval, F: fixed effect model, FCRL3: Fc receptor-like 3, OR: odds ratio, R: random effect model.

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