Objective: Assess response to intravenous immunoglobulin (IVIG) in presumed autoimmune postural orthostatic tachycardia syndrome (POTS)
Background: POTS predominantly affects young women and may be associated with systemic autoimmune disorders, serum autoantibodies or recent infection. Uncontrolled case studies suggest that IVIG is beneficial for treating autoimmune POTS. However, no previous randomized controlled trials have been conducted.
Methods: This single site randomized controlled clinical trial compared IVIG to intravenous albumin infusions. Albumin comparator ensured blinding and control for effects of volume expansion. Eligible POTS patients had COMPASS-31 score ≥ 40 and met pre-determined criteria suggesting autoimmunity. Over 12 weeks, participants received 8 infusions (0.4gm/kg each). Four infusions were given weekly followed by four infusions every other week. Primary outcome measure was improvement in COMPASS-31 two weeks after final infusion.
Results: 50 participants consented; 30 met inclusion criteria and received study drug (16 IVIG and 14 albumin; 29 female). Group baseline characteristics were well matched. 27 participants completed treatment protocol. Change in COMPASS-31 did not differ between groups (median change [IQR]; IVIG: -5.5 [-23.3, 2.5] vs. Albumin: -10.6 [-14.1, -4.7]; p-value = 0.629). Response rate was also not different between groups. Adverse events were common but usually mild and did not differ between treatment groups.
Conclusions: This first randomized controlled trial of IVIG in POTS found no difference in symptom response compared to albumin infusion. Both groups showed improvement possibly related to volume expansion obscuring other benefits. Future clinical trials may benefit from the use of POTS-specific clinical outcome measures sensitive to symptoms other than orthostatic intolerance.