2-AIN-505, 2-AIN-251: Seminár z bioinformatiky (1) a (3)
Zima 2018
Abstrakt

Chirag J. Patel, Belinda Burford, John P. A. Ioannidis. Assessment of vibration of effects due to model specification can demonstrate theinstability of observational associations. Journal of clinical epidemiology, 68(9):1046-1048. 2015.

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Abstract:

OBJECTIVES: Model specification-what adjusting variables are analytically
modeled-may influence results of observational associations. We present a
standardized approach to quantify the variability of results obtained with
choices of adjustments called the \"vibration of effects\" (VoE). STUDY DESIGN AND 
SETTING: We estimated the VoE for 417 clinical, environmental, and physiological 
variables in association with all-cause mortality using National Health and
Nutrition Examination Survey data. We selected 13 variables as adjustment
covariates and computed 8,192 Cox models for each of 417 variables' associations 
with all-cause mortality. RESULTS: We present the VoE by assessing the variance
of the effect size and in the -log10(P-value) obtained by different combinations 
of adjustments. We present whether there are multimodality patterns in effect
sizes and P-values and the trajectory of results with increasing adjustments. For
31% of the 417 variables, we observed a Janus effect, with the effect being in
opposite direction in the 99th versus the 1st percentile of analyses. For
example, the vitamin E variant alpha-tocopherol had a VoE that indicated higher
and lower risk for mortality. CONCLUSION: Estimating VoE offers empirical
estimates of associations are under different model specifications. When VoE is
large, claims for observational associations should be very cautious.