Occurrence of adverse events in long-term intrathecal baclofen infusion: a 1-year follow-up study of 158 adults

Abstract

Objective: To assess the frequency and types of adverse events (AEs) related to intrathecal baclofen (ITB) therapy in adults, and associated risk factors.

Design: A prospective, observational cohort study of adults followed up from January 1 to December 31, 2010.

Setting: A neurologic rehabilitation department in a university hospital.

Participants: All consecutive adult subjects (N=158) receiving ITB via a pump, either implanted or followed up during the study period.

Intervention: Not applicable.

Main outcome measures: Frequency and type of AEs.

Results: In 2010, 158 subjects were followed up for ITB therapy, of whom 128 were implanted before 2010 (nonsurgical subjects), and 30 underwent implantation in 2010 (surgical subjects). Of these 30 subjects, 20 were "newly implanted" and 10 were "replacements." The most frequent pathologic disorders were spinal cord injury (42%) and multiple sclerosis (28%). Twenty-eight subjects (18%) experienced a total of 38 AEs. The rate of AEs was .023 per month of ITB treatment. AEs were related to the surgical procedure in 53% of cases, to the device in 29% (predominantly catheter dysfunctions), and to adverse effects of baclofen in 18%. AEs related to the surgical incision (scar complications and collections) were more frequent in replacement than newly implanted subjects (P=.009). No significant association between occurrence of an AE and subject characteristics (age, gait capacity, spinal vs cerebral spasticity, duration of ITB therapy follow-up) was found. Nearly half of the AEs were serious, extending admission time by a mean of 16 days. No AE induced long-term morbidity or death.

Conclusions: The AE rate was relatively low in this cohort. This has to be balanced against the clinical, functional, and quality-of-life improvements, which are expected from ITB therapy.

Keywords: Adverse drug event; Baclofen; Infusion pumps, implantable; Muscle spasticity; Rehabilitation.