Depression as a predictor of worse quality of life outcomes following nonoperative treatment for lumbar stenosis.

Abstract

The goal of this study was to determine whether pretreatment depression is predictive of quality of life (QOL) improvement for patients with lumbar spinal stenosis (LSS) who are treated conservatively. This retrospective cohort study included patients with LSS and concordant neurogenic claudication who were treated nonoperatively at a single institution between September 2010 and March 2013. Patient QOL measures were recorded pretreatment and then 4 months after treatment. Pretreatment depression was assessed using the Patient Health Questionnaire-9 (PHQ-9). Successful outcome was defined as posttreatment improvement in EuroQol-5D (EQ-5D) index or in Pain and Disability Questionnaire (PDQ) scores. Regression analysis was performed to identify independent predictors of outcome while controlling for confounding variables. A total of 502 patients were included in the study. The average age for these patients was 66.1 years, with 51% female and 90.6% white. After adjusting for baseline demographic and clinical variables, there was a statistically significant association between baseline PHQ-9 score and posttreatment change in EQ-5D index (β = -0.007, p = 0.0002). All other things being equal, a patient with a baseline PHQ-9 score of 0 (no depression) would be expected to improve in the EQ-5D index by 0.14 points (greater than the minimum clinically important difference) more than would a patient with a baseline PHQ-9 score of 20 (major depression). There was no significant association between baseline PHQ-9 score and change in Pain and Disability Questionnaire scores. When controlling for other baseline characteristics, severely depressed patients with LSS who are treated nonoperatively have significantly less improvement in their QOL compared with those with little or no depression. These data are similar to the negative predictive effects of depression on posttreatment QOL following lumbar fusion surgery.