Utility of the Brief Illness Perception Questionnaire to Monitor Patient Beliefs in Systemic Vasculitis.

OBJECTIVE: To assess the validity and clinical utility of the Brief Illness Perception Questionnaire (BIPQ) to measure illness perceptions in multiple forms of vasculitis. METHODS: Patients with giant cell arteritis (GCA), Takayasu arteritis (TA), antineutrophil cytoplasmic antibody-associated vasculitis (AAV), and relapsing polychondritis (RP) were recruited into a prospective, observational cohort. Patients independently completed the BIPQ, Multidimensional Fatigue Inventory (MFI), Medical Outcomes Study 36-item Short Form survey (SF-36), and a patient global assessment (PtGA) at successive study visits. Physicians concurrently completed a physician global assessment (PGA) form. Illness perceptions, as assessed by the BIPQ, were compared to responses from the full-length Revised Illness Perception Questionnaire (IPQ-R) and to other clinical outcome measures. RESULTS: There were 196 patients (GCA = 47, TA = 47, RP = 56, AAV = 46) evaluated over 454 visits. Illness perception scores in each domain were comparable between the BIPQ and IPQ-R (3.28 vs 3.47, P = 0.22). Illness perceptions differed by type of vasculitis, with the highest perceived psychological burden of disease in RP. The BIPQ was significantly associated with all other patient-reported outcome measures (rho = |0.50-0.70|, P < 0.0001), but did not correlate with PGA (rho = 0.13, P = 0.13). A change in the BIPQ composite score of ≥ 7 over successive visits was associated with concomitant change in the PtGA. Change in the MFI and BIPQ scores significantly correlated over time (rho = 0.38, P = 0.0008). CONCLUSION: The BIPQ is an accurate and valid assessment tool to measure and monitor illness perceptions in patients with vasculitis. Use of the BIPQ as an outcome measure in clinical trials may provide complementary information to physician-based assessments.

Outcome Measures in Large Vessel Vasculitis: Relationship Between Patient-, Physician-, Imaging-, and Laboratory-Based Assessments.

OBJECTIVE: To assess the relationship between measures of disease assessment in patients with large vessel vasculitis. METHODS: Patients with giant cell arteritis (GCA) or Takayasu arteritis (TAK) were recruited into a prospective, observational cohort. Assessments within the following outcomes were independently recorded: 1) patient-reported outcomes (Multidimensional Fatigue Inventory, patient global assessment of disease activity [PtGA], Short Form 36 health survey [SF-36], Brief Illness Perception Questionnaire), 2) physician global assessment of disease activity (PhGA), 3) laboratory outcomes (C-reactive protein [CRP] level, erythrocyte sedimentation rate [ESR]), and 4) imaging outcomes (PETVAS, a qualitative score of vascular 18 F-fluorodeoxyglucose-positron emission tomography activity). RESULTS: Analyses were performed on 112 patients (GCA = 56, TAK = 56), over 296 visits, with a median follow-up of 6 months. Correlation network analysis revealed assessment measures clustered independently by type of outcome. PhGA was centrally linked to all other outcome types, but correlations were modest (ρ = 0.12-0.32; P < 0.05). PETVAS, CRP level, and PtGA were independently associated with clinically active disease. All 4 patient-reported outcomes strongly correlated with each other (ρ = 0.35-0.60; P < 0.0001). Patient-reported outcomes were not correlated with PETVAS, and only PtGA correlated with CRP level (ρ = 0.16; P < 0.01). Patients whose clinical assessment changed from active disease to remission (n = 29) had a corresponding significant decrease in ESR, CRP level, and PETVAS at the remission visit. Patients whose clinical assessment changed from remission to active disease (n = 11) had a corresponding significant increase in CRP level and PtGA at the active visit. CONCLUSION: Measures of disease assessment in large vessel vasculitis consist of independent, yet complementary, outcomes, supporting the need to develop composite outcome measures or a standard set of measures covering multiple types of outcomes.