In multivariant regression model to predict RHI level by different variables (age, gender, TOA, origin, and steroid therapy), the variable were chosen based on correlation between TOA and gender in the univariable analysis combined with basic demographic data. The final model included gender (female higher) (β = 0.58 P = 0.034), and the TOA that had a positive effect on RHI (β = 0.091, P = 0.025).\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \mathrm{R}\mathrm{H}\mathrm{I} = 2.112 + 0.091*\mathrm{T}\mathrm{O}\mathrm{A} + 0.584*\mathrm{female}. $$\end{document}RHI=2.112+0.091*TOA+0.584*female.