The intervention group had significantly greater increases in mean symptom-free days per 2 weeks ( 2.02 [ 95 % CI , 0.94-3 .09 ] ; P < .001 ) and quality of life ( 0.50 [ 95 % CI , 0.28-0 .71 ] points ; P < .001 ) relative to the control group , adjusted for age , sex , race/ethnicity , and education level .