Fig. 4.
Joint hazard ratios between frail surgical volume quintile and total surgical volume quintile. This figure demonstrates the joint hazard ratios between frailty volume quintile and total surgical volume quintile. Joint hazard ratios were generated by multiplying the multilevel, multivariable adjusted regression parameters for each frailty volume quintile with those from each total surgical volume quintile. Red colors represent decreased survival (darker shades = worse survival), while blue colors represent improved survival (darker shades = improved survival).