Elderly versus younger patients with microscopic polyangiitis vasculitis (MPA): a single-center retrospective study.

Microscopic polyangiitis (MPA) is a form of necrotizing vasculitis affecting the small vessels. Our study is the first study with the objective of describing the difference in clinical presentation of MPA and response to treatment at 6 months based on the age of disease onset. All patients seen at a tertiary vasculitis clinic between 2015 and 2023 with a diagnosis of MPA were included. Patients were divided into an elderly group (age >  = 65 years) and a younger group (age < 65). Comparative analysis was conducted to characterize differences amongst the elderly and younger patients, including differences in organ involvement and clinical presentation, Birmingham Vasculitis Activity Score (BVAS) scores, Vasculitis Damage Index( VDI) scores, and response to treatment at 6 months. Thirty-one patients were included in our study. Younger MPA patients (n = 18) with mean age at diagnosis of 53.17 years were compared with older MPA patients(n = 13) with mean age at diagnosis of 76.08 years. The younger patients had statistically significant higher BVAS scores (p = 0.009), along with higher incidence of renal (p = 0.028), pulmonary (p = 0.0069), and cutaneous (p = 0.026) manifestations at disease onset. Furthermore, amongst the younger population, there was noted statistically significant clinical improvement at 6 months following treatment induction, particularly in the domains of general symptoms (p = 0.011), MSK (p = 0.019), cutaneous (p = 0.011), and pulmonary symptoms (p = 0.04). In contrast, the elderly population presented with a predominant of non-specific constitutional symptoms, with statistically significant improvement in the domain of non-specific general symptoms at 6 months (p = 0.00008). All MPA patients responded well to treatment, with statistically significant improvement amongst younger patients (p = 0.0032), but no statistically significant improvement amongst elderly patients (p = 0.67). Our study findings concluded that MPA's clinical presentation differed by age group. Younger patients had more aggressive vasculitis disease presentation with better response to treatments, whereas, elderly patients had less severe disease presentation with predominant of general symptoms at disease onset. Key Points • MPA clinical presentation differed by age at disease onset. Younger patients presented with more aggressive and classic vasculitis-like presentations, with multi-system organ involvement and statistically significant higher incidence of renal, pulmonary, and cutaneous manifestations. In contrast, elderly patients had a predominant of constitutional and non-specific symptoms with often delayed diagnosis. • All MPA patients responded well to treatment. Amongst the younger population, there was statistically significant improvement in BVAS scores after treatment induction at 6 months; however, there was no statistically significant improvement of BVAS scores in the elderly population. • Future studies are required to further understand the difference in the clinical presentation of MPA based on the age at disease onset, and the implication on disease diagnosis and management.