# Impact of diabetes mellitus on spinal injection two-week outcomes in patients with predominant lower extremity pain

## TL;DR

This study found that diabetes does not generally affect spinal injection outcomes for lower back pain, but effects are reduced in patients with chronic pain or mild pre-injection pain.

## Contribution

The study identifies specific subgroups of diabetic patients where spinal injections may be less effective.

## Key findings

- Diabetes mellitus did not significantly impact overall spinal injection effectiveness two weeks post-procedure.
- Patients with diabetes and chronic pain or mild preprocedural pain showed reduced treatment effects.
- Adverse event rates were not significantly different between diabetic and non-diabetic patients.

## Abstract

To evaluate the effect of diabetes mellitus (DM) on the effectiveness of spinal injections in patients with predominant lower extremity pain.

This retrospective study included 218 patients (109 with DM and 109 without DM, matched by propensity scores; mean age 68.4 ± 9.6 years; 111 men) who underwent lumbar spinal injections in 2017. Treatment effectiveness was assessed by calculating the relative reduction in numerical rating scale (NRS) scores 2 weeks post-injection. A generalized estimating equation analysis was conducted to determine whether DM influenced overall treatment outcomes and to perform subgroup analyses based on age (< 50 years, ≥ 50 years), sex, pain onset (acute/subacute [≤ 6 months] vs. chronic [> 6 months]), preprocedural pain severity (mild [NRS 0‒3], moderate [NRS 4‒6], severe [NRS 7‒10]), and pain symmetry (symmetric vs. asymmetric). Fisher’s exact test was used to compare adverse event rates between patients with and without DM.

DM did not significantly impact the overall effectiveness of spinal injections 2 weeks after the injection (relative NRS reduction difference [95% confidence interval], –5.5% [–13.3% to 2.2%]; P = 0.163). However, patients with DM and chronic pain (–16.7% [–25.6% to –7.9%], P < 0.001) or mild preprocedural pain (–20.2% [–37.1% to –3.2%], P = 0.019) exhibited reduced treatment effects 2 weeks after the injection. Adverse event rates did not significantly differ between groups (P > 0.99).

There was no difference in the spinal injection effectiveness between patients with and without DM 2 weeks after the injection. However, their therapeutic effect may be diminished in patients with chronic or mild preprocedural pain, warranting consideration of a potential diagnostic overlap with diabetic neuropathy.