Low incidence of pericardial effusion in alopecia patients taking oral minoxidil: A single center retrospective cohort study

Summary: Abstract Body: Oral minoxidil (OM) is commonly used off-label for alopecia, but the risk of pericardial effusion (PEff) is poorly documented. We evaluated the prevalence of PEff in patients prescribed OM for alopecia. We identified patients without pericardial disease who were prescribed OM between January 1, 1979 and June 1, 2024, along with age, sex, race, and ethnicity-matched controls. PEff cases were identified using ICD-9/10 codes. Retrospective chart review confirmed indication, demographics, medical history, and disease course. Statistical analysis used Fisher’s exact test and linear regression. Median age was 53 years, with 46% (2054/4501) women and 54% (2445/4501) men. 94% (4238/4501) were initially prescribed 2.5mg. PEff occurred more frequently in patients on OM (2.5%, 110/4501) than controls (0.5%, 41/8841, p<0.001). Of those on OM who developed PEff, 0.2% (10/4501) were prescribed OM for alopecia. Patients on LDOM for alopecia had lower odds of PEff than controls (OR 0.52, 95% CI: 0.23-1.06, p=0.08) and patients taking OM for other indications (p=0.005). A linear relationship was found between PEff incidence and LDOM dosage up to 10mg (R-squared=0.56, p=0.03). All effusions among alopecia patients were small-to-moderate or less (10/10), with 60% (6/10) being incidental and asymptomatic. The remaining 40% (4/10) were symptomatic but attributable to other causes. The odds of PEff on LDOM for alopecia are low and not significantly higher than the general population. Effusions are typically small and incidental. Clinicians should be aware of potential PEff development, especially in patients with comorbidities. Janaya Nelson¹, Victor L. Quan¹, Edward B. Li¹, Maria Colavincenzo¹ 1. Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States. Clinical Research: Epidemiology and Observational Research