Características relacionadas ao prognóstico da sarcoidose e identificação de atividade da doença através de biomarcadores e PET CT

Abstract

Sarcoidosis is a granulomatous, multisystemic disease, with variable clinical and radiological presentation, as well as its course and response to treatment. It is a great challenge to identify the activity of the disease and to predict the evolution of each patient to outline the individualized therapeutic plan. This thesis has the proposal of presenting tools for the monitoring and therapeutic management of sarcoidosis, used in a way not previously presented in the literature. Three studies were developed, with 105 sarcoidosis patients, composed of activity, remission and control groups, in the period of 4 years (2015-2019), at the interstitial diseases center in the Polyclinic Piquet Carneiro / UERJ. Chitotriosidase (CHITO), angiotensin-converting enzyme (ACE) and ultra-sensitive C-reactive protein (us CRP) were measured and positron emission computed tomography (PET CT) scans were performed. First: biomarkers (CHITO, ACE and us CRP) to assess disease activity and remission; second: score of prognostic indicators for sarcoidosis; third: PET CT and CHITO in assessing the patient’s evolution. In the first study, cutoff points were defined for each biomarker: CHITO = 120 U / mL, ACE = 270 ng / mL, us CRP = 0.4 mg / dl with sensitivity and specificity to define disease activity, respectively, 55 %, 88%, 66% and 100%, 47% and 68%. An algorithm was also performed combining the 3 markers, obtaining an accuracy of 82%, sensitivity of 78% and specificity of 89%, to differentiate the activity of sarcoidosis remission. In the second study, after a minimum follow-up period of 24 months, patients were classified according to their clinical evolution. Forty-eight percent of patients progressed to chronic sarcoidosis. The absence of rheumatological markers, forced vital capacity (%) and the presence of early respiratory symptoms (chest pain, cough, dyspnoea and wheezing) were related to a better prognosis. In the third study, PET CT and CHITO had accuracy greater than 60% for monitoring sarcoidosis, helping in selected cases. There was no statistical difference in accuracy, sensitivity and specificity between the two methods (overlapping confidence intervals). Thus, this thesis aims to contribute to the management of patients diagnosed with sarcoidosis since the beginning of the disease by predicting the clinical evolution and identifying its activity throughout the treatment.