Safety, quality & education

Estimating sample means and standard deviations from the log-normal distribution using medians and quartiles: evaluating reporting requirements for primary and secondary endpoints of meta-analyses in anesthesiology

Can J AnaesthPublished Simulation study

Authors' conclusion

All evaluated methods of estimating means and standard deviations from quartiles of log-normal distributed data result in confidence interval coverages below the expected 95%.

Study context

Population
Simulated log-normal data with zero log-scale means (n = 15, 27, 51; CV = 0.15, 0.3, 0.5), representative of anesthesiology studiessimulated samples
Comparison
Methods estimating means and standard deviations (SDs) from medians and quartiles: Luo/Wan vs McGrath quantile estimation vs McGrath Box-Cox vs Cai maximum likelihood
Outcome
Coverage of 95% generalized CIs for the ratio of means and ratio of SDs
Methodological detailslog-normal data simulation
  • Log-normal data simulation

Main finding

As reported in the abstract

95% CI coverage for ratio of means and of SDs
GroupMean ratio coverageSD coverage
Luo et al. and Wan et al.92.4% to 93.6%79.2 to 89.6
McGrath quantile estimation88.5% and 91.5%78.0 and 82.7
McGrath Box-Cox86.6% to 94.4%67.1 to 83.1
Cai maximum likelihood78.9% to 86.4%67.6 to 78.0

Mean ratio coverage

Luo et al. and Wan et al.92.4% to 93.6%
McGrath quantile estimation88.5% and 91.5%
McGrath Box-Cox86.6% to 94.4%
Cai maximum likelihood78.9% to 86.4%

SD coverage

Luo et al. and Wan et al.79.2 to 89.6
McGrath quantile estimation78.0 and 82.7
McGrath Box-Cox67.1 to 83.1
Cai maximum likelihood67.6 to 78.0

Original publication

Estimating sample means and standard deviations from the log-normal distribution using medians and quartiles: evaluating reporting requirements for primary and secondary endpoints of meta-analyses in anesthesiology. Can J Anaesth. Published 11 April 2025. doi:10.1007/s12630-025-02922-6

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