Factors That Might Impact Intrathecal Drug Delivery (IDD) Dose Escalation: A Longitudinal Study

Background Intrathecal drug delivery (IDD) system with implantable pumps has been used to treat cancer-related pain as well as noncancer-related chronic pain. Opioids, including morphine and hydromorphone, are the most commonly used intrathecal (IT) agents. Although technology, techniques, and knowledge of IDD have improved, dose escalation occurs relatively rapidly in noncancer pain. Methods Retrospective chart review of IDD pump patients, implanted for a minimum of 2years, was designed to investigate possible existing predictors that might impact IDD dose escalation, such as patient's demographic risk factors, duration of the treatment, and diagnosis of the patient's pain correlates with increase in medication requirement. Primary outcome was defined as the annual percent escalation in daily opioid dosage, and secondary outcome was the average annual percent reduction in VRS pain scores. Results Median dosage escalation was 17% per year for patients with neuropathic pain compared with 12% per year for patients with other pain modalities. Mean opioid dosage increased 30.4% more rapidly for patients with neuropathic pain than for other pain modalities. The adjusted difference in means was 28.8% (P=0.001). None of the secondary exposures were statistically significant after the Bonferroni adjustment. No association was found between pain modality and annual percent change in VRS pain score. Conclusion Annual increases in daily opioid dosage were higher among patients with neuropathic pain than among patients with other modalities; we also found no evidence of difference in annual pain reduction.