Background Although lung involvement in ANCA-associated vasculitis (AASV) is frequent, few studies1 exist regarding assessment of lung function.
Objectives To describe lung function in inactive AASV patients, relate them to previous lung damage as measured by respiratory items in the Vascular Index Damage (VDI) and explore cardiopulmonary exercise capacity.
Methods Patients with AASV were prospectively studied with lung function tests (LFT), plethysmography, diffusing capacity for carbon monoxide (DLCO), six-minute walk (6MW), cardiopulmonary exercise test (CPX) and Saint George respiratory questionnaire (SGRQ) which evaluates patients in a 0 (minimal) to 100 (maximal impairment) scale. Normal values (corrected for Mexico City altitude): FEV1, FVC, corrected DLCO, VO2 >80% of predicted values, pO2 decrease during exercise <4 mmHg, 6MW >300 meters. Inclusion criteria: age ≥18 years old, diagnosis of AASV according to ACR criteria and/or Chapel Hill Consensus nomenclature and signed informed consent. Exclusion criteria: active disease (BVAS >0), concurrent infections. comorbidity which limited lung function evaluation.
Results Out of 46 patients, 20 consented participation, 10 males, 10 females, all but one under maintenance treatment. Mean age: 53±15.6 years, median: 57 (20-72). 14 had granulomatosis with polyangiitis (GPA), 4 microscopic polyangiitis (MPA) and 2 Churg-Strauss syndrome (CSS). Overall results (mean ± SD): FEV1 91.3±27.2%, FVC 101.3±21.6, corrected DLCO 91±21.5%, VO2% 78.2±18.5, 6MW 449.5±78.4 meters, SGRQ 24.8±14.4, total VDI 2.6±2.08 (median 2, range 0-7), pulmonary VDI 0.7±0.97 (median 0, range 0-3). Only 5 patients had all tested parameters within normal (3 GPA, 2 MPA). Fourteeen patients had normal LFT; five patients had an obstructive pattern (3 GPA, 2 CSS), in 2 being severe, and one patient had an spirometric restrictive pattern, although plethysmography was normal. Seven had low DLCO, abnormal CPX was seen in 10 and in 4, decrease in pO2 during exercise occurred. These changes did not relate with pulmonary VDI parameters, initial presentation or time since disease onset. In spite of this, only one patient had an abnormal 6MW (296 mts) and only two patients reported a SGRQ over 40 points, interpreted as inadequate quality of life perception.
Conclusions As in a previous report1, lung impairment and diminished exercise capacity occurs in AASV, irrespective of adequate disease control, previous lung involvement and/or damage, concurrent treatment and total disease time. However, in our population, overall health status does not seem to be as affected as in that report. Intervention leading to early recognition of these phenomenae is needed, with the purpose to avoid permanent lung impairment.
Newall C et al. Rheumatology 2005;44:623-8.
Disclosure of Interest None Declared