RESULTS	In these 4 groups , the median numbers of work disability days per patient-year from 6 months through 60 months of followup were 0 ( interquartile range [ IQR ] 0-3 ) , 4 ( IQR 0-131 ) , 16 ( IQR 0-170 ) , and 352 ( 16-365 ) , respectively ( P < 0.001 ) .\