Background and aims The SubQStim study showed subcutaneous nerve stimulation (SQS) plus optimized medical management (OMM) was more effective in reducing back pain than OMM alone in patients with failed back surgery syndrome.¹ We explore the use of pain medications by the study participants.

Methods Ethics committee approval was obtained for each site. Analysis of prescribed pain medications between the SQS+OMM (n=38) and OMM (n=36) arms from baseline through 9-months post-randomization was performed using descriptive statistics and complete cases approach. Total daily dose was calculated by multiplying the prescribed dose by quantity and then by daily frequency. Morphine Milligram Equivalent (MME) dose was calculated by multiplying the total daily dose of each applicable opioid by the MME conversion factor.²

Results From baseline to 9 months, the SQS+OMM arm showed a decrease in the proportion of subjects on NSAIDs (-7.9%) and opioids (-10.5%), whereas the OMM arm showed a slight reduction in antidepressants (-2.8%) and other category (-2.8%) (figure 1).

Most subjects (64%) were taking opioids at baseline. From baseline to 9 months, mean MME dose increased by 8.8 mg in the OMM arm (42.5±92.1 to 51.2±107.2); whereas the SQS+OMM arm decreased by 8.9 mg (29.8±42.3 to 20.9±37.3)(figure 2–3). At 9 months, 31.6% of SQS+OMM subjects reduced MME compared to 8.3% of OMM subjects. Only 13.2% of SQS+OMM subjects had an increase in MME opioids compared to 27.8% of OMM subjects.

Conclusions There is a positive trend that pain medication and morphine intake as assessed by MME may be reduced in patients receiving SQS.

References

1. Eldabe SS, et al. Neuromodulation 2018; DOI:10.1111/ner.12784.

2. https://www.cms.gov/Medicare/Prescription-Drug-Coverage/PrescriptionDrugCovContra/Downloads/Opioid-Morphine-EQ-Conversion-Factors-vFeb-2018.pdf