Blood pressure variability associates with mortality risk of patients with ANCA-associated vasculitis

Objectives: Antineutrophil cytoplasmic antibody-associated vasculitis (AAV) is associated with increased cardiovascular risk, related to persistent inflammation and endothelial dysfunction. Long-term systolic blood pressure variability (SBPV), reflecting vascular damage, may predict outcomes better than mean blood pressure (BP). We investigated the impact of BP control and visit-to-visit BP variability (VVV), on all-cause mortality in AAV patients during maintenance therapy. Methods: We retrospectively studied 95 AAV patients followed at three Italian nephrology centers. SBPV was defined as the standard deviation of ≥4 systolic BP measurements within 12 months from the first SBPV assessment. Patients were stratified by SBPV tertiles. The primary outcome was all-cause mortality. Results: Over a median follow-up of 78 months, 14 patients (14.7%) died. Deceased patients were older and had higher pulse pressure (PP) and VVV. Hypertension prevalence increased across SBPV tertiles (35%, 62%, 69%; P = .02). Mortality rose from 6% in the lowest to 34.5% in the highest SBPV tertile (Fisher's exact, P = .001). Time-averaged systolic BP was not associated with mortality. Conversely, each 5-mmHg increase in SBPV was associated with a two-fold higher risk of death [hazard ratio (HR) 2.03, 95% confidence interval (CI) 1.29-3.20; P = .002]. SBPV remained significantly associated with outcome after full multi-variable adjustment, including age, sex, myeloperoxidase positivity, estimated glomerular filtration rate, PP, and proteinuria (adjusted HR 8.06 per 1 mmHg, 95% CI 1.42-45.54; P = .02). Conclusion: In AAV patients, increased VVV was associated with all-cause mortality outperforming mean systolic BP. Further research is needed to confirm the impact of variable blood pressure on patient outcomes in AAV.