Physical function computer adaptive test outcomes in diabetic lumbar spine surgical patients.

Background Context: Diabetes is a highly prevalent comorbid condition among patients undergoing spine surgery. Several studies have used legacy patient-reported outcome measures to implicate diabetes as a predictor of increased disability, pain, and decreased physical function and quality of life following spine surgery. The effect of diabetes on postoperative physical function has not yet been studied using the PROMIS Physical Function Computer Adaptive Test (PF CAT).

Purpose: To understand the effect of diabetes on physical function outcomes among patients undergoing lumbar spine surgery, as reported by the PF CAT.

Study Design/setting: A retrospective cohort study was performed at a single university-based spine clinic.

Patient Sample: Patients who underwent lumbar spine surgery between October 1, 2013 and April 26, 2018 with both PF CAT and Oswestry Disability Index (ODI) scores available for review.

Outcome Measures: PROMIS PF CAT. Secondary measures of disability included the ODI.

Methods: PF CAT and ODI questionnaires were administered to patients via electronic tablets. Data from these questionnaires were collected prospectively, and retrieved from a university database. Wilcox tests, Exact Wilcox tests, linear regression models, and descriptive analytics were applied.

Results: Patients meeting inclusion criteria included 233 nondiabetic patients and 65 diabetic patients. Mean PF CAT scores among diabetics were lower than those of nondiabetics at all time-points from preoperative through 12 months postoperative, with significance found at both 6 months (p=.035) and 12 months (p=.039) postoperative. Mean ODI scores among diabetics were significantly higher than those of nondiabetics at 3 months (p=.018) and 12 months (p=.027) postoperative. By 12 months postoperative, a smaller proportion of diabetics reached PF CAT and ODI minimum clinically important difference thresholds when compared to nondiabetics.

Conclusions: Diabetes is associated with lower PF CAT scores up to one year following lumbar spine surgery. However, many of these patients achieve meaningful improvement in physical function during this time. The PF CAT is consistent with legacy outcome measures in assessing outcomes in diabetic patients undergoing lumbar spine surgery, with an added benefit of decreased patient burden.