The 9-Item Patient Health Questionnaire (PHQ-9): an aid to assessment of patient-reported functional outcomes after spinal surgery

Preoperative depression is increasingly understood as an important predictor of patient outcomes after spinal surgery. In this study, we examine the relationship between depression and patient-reported functional outcomes (PRFOs), including disability and pain, at various time points postoperatively.

The objective of this study was to analyze the use of depression, as measured by the 9-Item Patient Health Questionnaire (PHQ-9), as a means of assessing postoperative patient-reported disability and pain.

This study includes an analysis of prospective non-randomized spine registry compiled through an academic multispecialty group practice model.

A total of 1,000 spinal surgery patients from an affiliated surgical registry, enrolled from January 2010 onward, were included in this study.

Pain was assessed via the visual analog scale (VAS) for leg or back pain. Disability was measured by the Oswestry Disability Index (ODI). Depression was measured by the PHQ-9.

Patient data were collected preoperatively and at 1, 4, 10, and 24 months postoperatively. Data were analyzed via analysis of variance and Pearson correlation coefficient.

All patient stratifications analyzed experienced improvements in pain and ability postoperatively, as measured by the VAS and the ODI, respectively. Moderately and severely depressed patients (as measured by preoperative PHQ-9) experienced decreases in the mean PHQ-9 score of -6.00 and -7.96 24 months after surgery, respectively.

In all groups, spinal surgery was followed by relief of pain and improved PRFO. Preoperative depression, as measured by the PHQ-9, predicted postoperative PRFO. Patients with moderate to severe depression as measured by the PHQ-9 experienced large mean decreases in the PHQ-9 score postoperatively. As a psychosocial metric, the PHQ-9 is a useful method of assessing value-added service of a spinal surgery.