Association between follistatin-related protein 1 and the functional status of patients with anti-neutrophil cytoplasmic antibody-associated vasculitis

Abstract

Abstract Background: Follistatin-like 1 (FSTL1) plays both pro-inflammatory and anti-inflammatory roles in the inflammatory processes. We investigated whether serum FSTL1 could predict the current anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV)-specific indices. Methods: We randomly selected 74 patients with AAV from a prospective and observational cohort of Korean patients with AAV. Clinical and laboratory data and AAV-specific indices were recorded. FSTL1 concentration was determined using the stored sera. The lowest tertile of the short-form 36-item health survey (SF-36) was defined as the current low SF-36. The cutoffs of serum FSTL1 for the current low SF-36 physical component summary (PCS) and SF-36 mental component summary (MCS) were extrapolated by the receiver operator characteristic curve. Results: The median age was 62.5 years (55.4% were women). Serum FSTL1 was significantly correlated with SF-36 PCS (r\u200a=\u200a\u200a−\u200a0.374), SF-36 MCS (r\u200a=\u200a−0.377), and C-reactive protein (CRP) (r\u200a=\u200a0.307), but not with Birmingham vasculitis activity score (BVAS). In the multivariable linear regression analyses, BVAS, CRP, and serum FSTL1 were independently associated with the current SF-36 PCS (β\u200a=\u200a−0.255, β\u200a=\u200a−0.430, and β\u200a=\u200a−0.266, respectively) and the current SF-36 MCS (β\u200a=\u200a−0.234, β\u200a=−0.229, and β\u200a=\u200a−0.296, respectively). Patients with serum FSTL1 ≥779.8 pg/mL and those with serum FSTL1 ≥841.6 pg/mL exhibited a significantly higher risk of having the current low SF-36 PCS and SF-36 MCS than those without (relative risk 7.583 and 6.200, respectively). Conclusion: Serum FSTL1 could predict the current functional status in AAV patients.