Patient-reported outcomes after lumbar epidural steroid injection for degenerative spine disease in depressed versus non-depressed patients

Background Context

Medical interventional modalities such as lumbar epidural steroid injections (LESIs) are often used in the setting of lumbar spine disorders where other conservative measures have failed. Concomitant depression can lead to worse outcomes in lumbar spine pathology. A number of studies have demonstrated an association between preoperative depression and poor outcomes following surgery, but the effect of depression on outcomes following medical interventional modalities is poorly understood.

Purpose

To evaluate the differences in patient-reported outcomes (PROs) between depressed and non-depressed patients undergoing LESI.

Study Design/Setting

This study is an analysis of a prospective longitudinal registry database at a single academic institution.

Patient Sample

All patients undergoing LESI from 2012 to 2014 were eligible for enrollment into a prospective, web-based registry. Eligible patients had radicular pain, correlative imaging findings of degenerative pathology, and failed 6 weeks of conservative care.

Outcome Measures

The PROs measured included the (1) numeric rating scale for back pain (NRS-BP), (2) numeric rating scale for leg pain (NRS-LP), (3) disease-specific physical disability—Oswestry Disability Index (ODI), and (4) preference-based health status—EuroQol-5D (EQ-5D).

Materials and Methods

Patients who met the inclusion criteria underwent LESI. Patient-reported outcomes were collected at baseline and at 12 months following treatment. Based on previously validated values for the Zung Depression Scale (ZDS) as a screening tool for depression, patients were dichotomized into non-depressed (ZDS score ≤33) and depressed (ZDS score >33). The PRO change scores from baseline to 12 months were calculated. The mean absolute and change scores between the groups were compared using Student t test. Multivariable linear regression analysis for ODI, EQ-5D, NRS-LP, and NRS-BP was performed.

Results

A total of 161 patients with complete 12-month follow-up were included. Seventy-one patients (44%) were classified as depressed and 90 patients (56%) were classified as non-depressed. The mean baseline PRO scores were significantly worse in depressed patients compared with non-depressed patients: ODI (p<.001), NRS-BP (p=.013), NRS-LP (p<.001), and EQ-5D (p=.001). The mean absolute scores at 12 months were significantly lower in the depressed versus non-depressed patients: ODI (p<.001), NRS-BP (p=.001), NRS-LP (p=.05), and EQ-5D (p=.003). However, there was no difference in mean change scores observed at 12 months between the depressed and non-depressed cohorts: ODI (p=.42), NRS-BP (p=.31), NRS-LP (p=.25), EQ-5D (p=.14). Adjusting for pre-procedure variables, the higher ZDS score was associated with higher disability (ODI) at 12 months.

Conclusions

Depression led to worse absolute scores for PROs and is associated with higher disability following LESI. However, patients with depressive symptoms can expect similar improvement in PROs at 12 months.