Do Patient Demographics and Patient-Reported Outcomes Predict 12-Month Loss to Follow-Up After Spine Surgery?

Study Design. Analysis of patients in a prospective registry. Objective. To determine the association between patient demographics, outcomes, and loss to follow-up 12 months after spine surgery. Summary of Background Data. Obtaining outcomes 12 months after spine surgery remains a challenge. Loss to follow-up is believed to introduce biases and portend poor outcomes. Associations between follow-up, patient demographics, and outcomes in the degenerative spine population have not been studied. Methods. Patients undergoing surgery for degenerative spine disease at a single institution over a 2-year period were enrolled in a prospective registry. Patient demographics, comorbidities, treatment variables, readmissions/reoperations, and all 90-day surgical morbidity were collected. Patient-reported outcomes were recorded at baseline, 3-months, and 12-months after surgery. Multivariate logistic regression analysis was done to identify predictors of loss to follow-up. Results. A total of 1484 patients with baseline and 3-month outcomes were included. Two hundred thirty-three (15.7%) patients were lost to follow-up at 12 months. There was no difference in the baseline demographics (Sex: P = 0.46) and comorbidities (American Society of Anesthesiologists Grade: P = 0.06) of patients who had follow-up at 12-months versus those who did not, except age and employment status. Patients lost to follow-up at 12 months were younger (51.0 vs. 57.1 years; P<0.001) and a higher proportion were employed preoperatively (45.9% vs. 41.7%, P = 0.24). Preoperative pain, disability, and quality of life was similar between the two groups (P>0.05). There was no difference in 90-day morbidity (17.2% vs. 16.2%; P = 0.70) and 3-month pain, disability, quality of life, and patient satisfaction (85.0% vs. 88.3%; P = 0.63) (P>0.05). In multivariate model, only younger age (P<0.001) was an independent predictor of loss to follow-up at 12 months. Conclusion. In our prospective spine registry the 12-month loss to follow-up rate is approximately 15%. The only independent predictor of loss to follow-up is younger age and preoperative employment.