Background: The enhancement of quality of life (QOL) is a principal health care objective. Surprisingly, few studies have investigated this outcome in ANCA associated vasculitis (AAV), a complex chronic disease. Existing studies have, however, identified fatigue as a specific problem amongst this population. Although its aetiology is unknown, there is evidence, from other populations, to support a neural basis for this symptom. Aims: This study aimed to characterise QOL and its determinants amongst patients with AAV. A secondary study examined the association of AAV related fatigue with alterations of the brain. Methods: An AAV case-control study was conducted, incorporating a comparison and within-case analysis, using two groups of population and chronic disease controls. All participants completed a questionnaire comprising measures of QOL and putative determinants of QOL impairment. Concurrently, putative clinical determinants were collected from cases. The secondary study recruited AAV cases based on fatigue status. A further group with idiopathic fatigue was recruited from the general population. All subjects underwent magnetic resonance (MR) brain scanning incorporating structural and physiological imaging. Results: Compared to population controls, cases were substantially more likely to report low QOL and levels were equable to disease controls. Potentially modifiable biological and psycho-social factors were independently associated with poor QOL, of which fatigue was found to be of principal importance. In the secondary study, structural and physiological differences were observed between AAV patients with and without fatigue, as well as fatigued population subjects. Conclusions: AAV patients experienced significant QOL impairment. A bio-psychosocial approach to AAV health care is likely to improve QOL outcomes, although a better understanding of specific mechanisms is necessary to fully manage these problems. MR techniques have suggested a neural basis for AAV related fatigue. In the future they may help delineate the mechanisms of fatigue and consequently improve QOL in AAV.

Background: The International Classification of Function, Disability and Health (ICF) describes health using 1424 categories from 4 components: body functions (BF), body structures (BS), activities and participation (AP) and contextual factors (environmental (EF) and personal (PF)). In this study the ICF was used to describe and compare aspects of ANCA-Associated Vasculitis (AAV) measured in clinical trials and those important to clinicians and patients. Methods: Individual interviews and focus groups were used to capture the perspective of AAV patients. Clinicians’ perspective was obtained with an email-based questionnaire. Outcomes used in AAV randomized trials were extracted from results of a systematic review of literature. Identified concepts were mapped to the ICF according to previously published ICF linking rules, and the resulting lists of relevant AAV outcomes were compared descriptively. Results: Twelve individual interviews and 2 focus groups represented the patient perspective while responses from 27 clinicians yielded the clinicians’ perspective. Systematic literature review identified 67 clinical trials and 28 abstracts from which measured outcomes were extracted. All three perspectives demonstrated detailed coverage of ICF components BF and BS. In the component AP patients and clinicians identified similar ICF categories, a number of which were under-sampled by AAV trials. Contextual factors appear to be significantly more relevant to patients than clinicians and researchers. Conclusion: Patients and clinicians have different views of the relevance of various AAV outcomes, and these views differ from what is measured in clinical trials of AAV. This highlights the need for a broad and standardized approach to developing and selecting outcomes for complex medical conditions such as AAV.

L’acide mycophénolique (MPA) est un immunosuppresseur très prometteur dans le traitement des maladies auto-immunes (MAI) telles que le lupus érythémateux disséminé (LED) et les vascularites à ANCA, et disponible sous deux formes pharmaceutiques : le mycophénolate mofétil (MMF) et le mycophénolate sodique (EC-MPS). Les études menées chez les patients transplantés recommandent le dosage plasmatique et le suivi pharmacocinétique (PK) du MPA, dans un objectif d’optimisation thérapeutique. A ce jour, ce suivi est encore inexistant dans les MAI, et les données de corrélation concentrations-efficacité thérapeutique, sur lesquelles se base l’optimisation, demeurent toujours rares dans ce domaine. Les travaux présentés dans cette thèse s’inscrivent dans l’étude des corrélations PK/pharmacodynamie (PD) du MPA dans les MAI. Ces travaux ont permis de proposer des schémas et des outils d’optimisation des traitements à base de MPA pour ces patients. Pour cela, les concentrations plasmatiques du MPA et de son métabolite 7-O-glucuronide (MPAG) ont été déterminées pour 53 patients présentant de manifestations extra-rénales de MAI à l’aide d’une méthode de chromatographie couplée à la spectrométrie de masse. Les paramètres PK ont été estimés pour MMF et EC-MPS dans les deux groupes de MAI. D’après ces travaux, l’optimisation du MMF chez les patients atteints de MAI peut reposer sur le suivi de la concentration à 12 h (C12) en MPA. Un seuil de 3 mg/L est proposé afin de maintenir la rémission dans le LED, mais reste à définir dans les vascularites. Pour EC-MPS, une stratégie de prélèvements limités basée sur la mesure de la concentration maximale et la C12 est nécessaire pour estimer l’aire sous la courbe des concentrations entre 0 et 12 h du MPA. / Mycophenolic acid (MPA), the active form of both mycophenolate mofetil (MMF) and enteric-coated mycophenolate sodium (EC-MPS), is an immunosuppressant increasingly used in the treatment of autoimmune diseases such as systemic lupus erythematosus (SLE) and ANCA-associated vasculitis. In transplant recipients, therapeutic drug monitoring (TDM) of MPA is widely used to prevent acute organ rejection. However, MPA TDM is currently not available in autoimmune diseases, as data on the pharmacokinetic (PK)/pharmacodynamic (PD) relationships are very sparse in this indication. Our aim was to study the possible PK/PD relationships of MPA in patients with non-renal manifestations of SLE or ANCA-associated vasculitis. An assay based on liquid chromatography coupled with mass spectrometry was applied to the PK study of MPA and its major glucuronide metabolite (MPAG) in 53 SLE and vasculitis patients receiving either MMF or EC-MPS. According to our results, in SLE patients with non-renal manifestations, TDM based on the measurement of MPA 12-h trough concentration (C12) would allow optimizing therapies with MMF. A 3-mg/L efficacy threshold could be proposed to prevent clinical flares under MMF maintenance therapy. For EC-MPS, a limited sampling strategy including MPA maximum concentration and C12 is necessary to estimate the area under the curve between 0 and 12-h of MPA.