Adding 3-month patient data improves prognostic models of 12-month disability, pain, and satisfaction after specific lumbar spine surgical procedures: development and validation of a prediction model

Prognostic models including early postoperative variables may provide optimal estimates of long-term outcomes and help direct postoperative care. To develop and validate prognostic models for 12-month disability, back pain, leg pain, and satisfaction among patients undergoing microdiscectomy, laminectomy, and laminectomy with fusion for degenerative lumbar conditions. Retrospective cohort study using the Quality Outcomes Database. Patients receiving elective lumbar spine surgery due to degenerative spine conditions. Oswestry Disability Index, pain numerical rating scale, and NASS Patient Satisfaction Index. Prognostic models were developed using proportional odds ordinal logistic regression using patient characteristics and baseline and 3-month patient-reported outcome scores. Models were fit for each outcome stratified by type of surgical procedure. Adjusted odds ratio and 95% confidence intervals were reported for all predictors by procedure. Models were internally validated using bootstrap resampling. Discrimination was reported as the c-index and calibration was presented using the calibration slope. We compared the performance of models with and without 3-month patient-reported variables. This research was supported by the Foundation for Physical Therapy's Center of Excellence in Physical Therapy Health Services, and Health Policy Research and Training grant. The sample consisted of 5,840 patients receiving a microdiscectomy (n=2,085), laminectomy (n=1,837), or laminectomy with fusion (n=1,918). The 3-month Oswestry score was the strongest and most consistent predictor associated with 12-month outcomes. All prognostic models performed well with overfitting-corrected c-index values ranging from 0.718 to 0.795 and all optimism corrected calibration slopes over 0.92. The increase in c-index values ranged from 0.09 to 0.21 when adding 3-month patient-reported outcome scores. Models had good discrimination and were well calibrated for estimating 12-month disability, back pain, leg pain, and satisfaction. Patient-reported outcomes at 3 months after surgery, especially 3-month Oswestry scores, improved the 12-month performance of all prognostic models beyond using only baseline variables.