The prednisone-treated group showed an adjusted mean 6.4-point ( 95 % CI , 1.9-10 .9 ; P = .006 ) greater improvement in ODI scores at 3 weeks than the placebo group and a mean 7.4-point ( 95 % CI , 2.2-12 .5 ; P = .005 ) greater improvement at 52 weeks .