Table 4

Minimum clinically important difference.

Patient-Reported Outcome MeasuresLOS ≥45 h,
% (n)
LOS <45 h,
% (n)
P Valuea
ODI
 6 wk28.6% (2)71.4% (5)0.703
 12 wk10.0% (1)90.0% (9)0.375
 6 mo37.5% (3)62.5% (5)0.561
 1 y14.3% (1)85.7% (6)0.515
 2 y0.0% (0)0.0% (0)-
 Overall17.7% (3)82.4% (14) 0.004
PROMIS-PF
 6 wk9.1% (1)90.9% (10)0.747
 12 wk22.2% (2)77.8% (7)0.964
 6 mo16.7% (2)83.3% (10)0.137
 1 y22.2% (2)77.8% (7)0.480
 2 y33.3% (1)66.7% (2)1.000
 Overall18.2% (4)81.8% (18) 0.001
SF-12 PCS
 6 wk25.0% (3)75.0% (9)0.527
 12 wk14.3% (2)85.7% (12)0.490
 6 mo32.3% (6)64.7% (11)0.394
 1 y11.1% (1)88.9% (8)0.522
 2 y25.0% (1)75.0% (3)0.809
 Overall24.1% (7)75.9% (22) 0.001
VAS back
 6 wk44.0% (22)56.0% (28)0.201
 12 wk47.1% (24)52.9% (27)0.566
 6 mo51.1% (23)48.9% (22)0.222
 1 y22.2% (2)77.8% (7)0.913
 2 y0.0% (0)100.0% (1)0.505
 Overall43.7% (31)56.3% (40)0.058
VAS leg
 6 wk31.3% (5)68.8% (11)0.312
 12 wk18.8% (3)81.3% (13)0.925
 6 mo33.3% (5)66.7% (10)0.637
 1 y25.0% (2)75.0% (6)0.707
 2 y100.0% (1)100.0% (1)-
 Overall27.6% (8)72.4% (21) 0.004
  • Abbreviations: LOS, length of stay; ODI, Oswestry Disability Index; PROMIS-PF, patient-reported outcome measurement information system physical function; SF-12 PCS, 12-item short form physical composite score; VAS, visual analog scale.

  • Note: Boldface indicates statistical significance.

  • a P values calculated using χ 2 analysis.