The Impact of a Prolonged Multivitamin Shortage on Home Parenteral Nutrition Patients: A Single-Center Retrospective Cohort Study with Case Reports of Wernicke’s Encephalopathy

<b>Background/Objectives</b>: Shortages in parenteral nutrition (PN) micronutrient components can lead to deficiencies in patients heavily relying on home PN (HPN) to meet nutritional requirements. Despite monitoring, this can cause severe and even life-threatening conditions if intravenous (IV) micronutrients are not available for a prolonged period. <b>Methods</b>: We conducted a retrospective study to evaluate the effect of an IV multivitamin shortage that occurred between December 2022 and July 2023. The study included patients at high risk for multivitamin deficiencies who received HPN for at least 5 days. Patients were classified into two groups: those compliant with instructions to take additional oral multivitamin supplements to compensate for the shortage and those who were not compliant. Monitoring included tracking symptoms and routine bloodwork, which measured certain vitamins, excluding thiamine. <b>Results</b>: A total of 25 HPN patients were identified. Among them, 56% (<i>n</i> = 14) were compliant with daily oral multivitamin supplementation. No significant differences in pre- and post-shortage bloodwork were observed, but there was a significant difference in bicarbonate changes between the compliant and non-compliant groups (0 (-0.9, 1) vs. -2 (-8, -1), <i>p</i> = 0.04, respectively). Approximately 68% of all patients reported new symptoms during the shortage, but no significant difference was observed between groups. Three patients known to have increased gastrointestinal losses (two compliant and one non-compliant) required hospitalization: two had Wernicke's encephalopathy reversed with thiamine infusion. <b>Conclusions</b>: When IV multivitamins are unavailable for an extended period, at-risk patients need to be closely monitored by the HPN team, particularly for compliance to oral supplementation and for symptoms of thiamine deficiency when blood level monitoring is not feasible.