text: Full multivariate model performance 
  Overall performance for each full multivariate model is 
  listed in Table 5. Block 1 (Demographic, clinical and co- 
  morbidity) consistently contributed to prediction of 
  healthcare utilization and accounted for the greatest 
  amount of variation in utilization outcome for all 
  models. Block 4 (change scores for pain, disability, and 
  OSPRO-YF) provided statistically significant contribu- 
  tions in all models except prediction of injection. Blocks 
  including baseline OSPRO-YF and OSPRO-ROS, both 
  short and long forms, did not predict utilization out- 
  comes. Weighted models consistently outperformed 
  their complete case analysis model counterparts with 
  overall model pseudo-R2 values ranging from .337 (Any 
  care) to .611 (Emergency room).  Results 
  Four hundred and forty subjects were recruited at initial 
  evaluation. Follow-up at 4 weeks was 75.0% (n = 330), at 
  6 months was 69.0% (n = 304) and at 12 months was 
  65.2% (n = 287). Baseline demographics and health-related 
  characteristics for the full cohort, as well as those who did 
  and did not complete all 
  follow-up are presented in 
  Tables 1, 2 and 3. Those who did not complete follow-up 
  were younger, more likely to be non-white, had less than a 
  college degree, were more likely to have had sudden 
  symptom onset, had higher baseline pain intensity, and 
  had higher baseline pain-related psychological distress 
  measured by the OSPRO-YF. Only those with complete 