(P) Inpatient Constipation Among Migraine Patients Treated with Preventive Medications in a United States Electronic Health Record Database

Publication Number: 306

Background: Erenumab, an anti-calcitonin gene-related peptide (CGRP) pathway monoclonal antibody (mAb), was approved for migraine prevention by the US Food and Drug Administration in May 2018. Approval of other mAbs (galcanezumab, fremanezumab, eptinezumab) in the class followed thereafter.

Objectives: To estimate the risk of inpatient constipation among migraine patients prescribed anti-CGRP pathway mAbs and standard of care anti-epileptic drugs (AEDs).

Methods: Within the Optum Electronic Health Record Research Database, patients with migraine who initiated erenumab, other anti-CGRP pathway mAbs, and AEDs (carbamazepine, gabapentin, topiramate, valproate sodium/valproic acid/divalproex sodium, zonisamide) were identified from May 2018 through March 2020. Erenumab initiators were propensity score-matched separately to initiators of other mAbs and AEDs. Inpatient constipation was defined as constipation (ICD-10-CM code K59.0-) recorded during an emergency department or inpatient visit. Incident inpatient constipation events within 90 days following treatment initiation were identified among patients who initiated treatment by 31 December 2019 (to ensure patients had the requisite follow-up time). Odds ratios (ORs) were calculated comparing risk of inpatient constipation among propensity-score matched erenumab initiators relative to propensity-score matched comparators.

Results: We identified 15,983 erenumab, 11,345 other mAb, and 43,810 AED initiators who met study criteria and initiated treatment between 17 May 2018 and 31 December 2019. Among matched initiators, inpatient constipation risk was 0.46% (95% confidence interval (CI): 0.35-0.60) for erenumab and 0.44% (95%CI: 0.33-0.58) for other mAbs, with a corresponding OR of 1.06 (95%CI: 0.72-1.55). Among matched erenumab and AED initiators, inpatient constipation risk was 0.53% (95%CI: 0.42-0.66) and 0.76% (95%CI: 0.62-0.92), respectively, and the OR was 0.69 (95%CI: 0.51-0.94).

Conclusions: The risk of inpatient constipation within 90 days of treatment initiation was similar among patients prescribed erenumab and patients prescribed other anti-CGRP pathway mAbs, and slightly higher among patients prescribed AEDs.