Avaliação do manejo da gota, com foco especial no contexto da doença renal crônica

Abstract

Gout is one of the most prevalent inflammatory arthritis among adults less common than osteoarthritis and calcium pyrophosphate deposition disease only. It is characterized by recurrent flares of very painful acute arthritis and may present macroscopic deposits of uric acid (tophi). Although it was first described over 4,000 years ago, has defined etiology, relatively easy diagnosis and available treatment, gout is still inadequately treated and it is associated with high morbimortality and negative effect on quality of life. This thesis aimed to investigate the management of gout, stressing the context of chronic kidney disease. Specific objectives were: (i) to describe and analyze current practices of gout management among Brazilian rheumatologists (study 1); (ii) to review the management of gout and hyperuricemia in the context of chronic kidney disease (study 2), (iii) to review the relation between hyperuricemia and urate-lowering therapy and renal outcomes (study 2), and (iv) to evaluate the effect of allopurinol on kidney function of individuals with gout (study 3). Study 1 was a survey on the treatment of gout in a random sample of 309 Brazilian rheumatologists. Study 2 was a narrative review on the management of gout in the context of chronic kidney disease and the effects of hyperuricemia and urate-lowering therapy on kidney function. In study 3, we investigated a cohort of 9520 adults residents in the United Kingdom with recently-diagnosed gout, stratified by time, matched by propensity score. We evaluated the effects of the incident use of ≥300 mg/day of allopurinol on the kidney function of patients without chronic kidney disease. Study 1 revealed that the Brazilian rheumatologists had unsatisfactory knowledge, especially the non-recognition of gouty tophi as an indication for urate-lowering therapy, the withdrawal of the urate-lowering therapy during a gout flare, the initial prescription of allopurinol in high doses and the non-recognition that urate-lowering therapy should be maintained indefinitely. In study 2, we synthesized the most updated recommendations on the management of urate-lowering therapy, anti-inflammatory prophylaxis and the treatment of gout flares. We also showed the deleterious effects of hyperuricemia and the potential benefits of urate-lowering therapy on kidney function. The results of the papers included in this review varied from a protective effect of the urate-lowering therapy to the non-identification of a significant association, with no article pointing out deleterious effect of the urate-lowering therapy on the kidneys. We identified large heterogeneity in the inclusion criteria of the participants, with few papers evaluating gout patients exclusively, and some methodological issues that could lead to biased findings. In Study 3 we identified a renoprotective effect of allopurinol, with a 13% reduction in the risk of developing chronic kidney disease stage ≥3. Considering the lack of knowledge about gout management, especially in patients with compromised kidney function, and in light of the body of evidence of the broad benefits of urate-lowering therapy, it is of great importance that continuing education programs about gout management are proposed to guarantee that patients receive a more adequate and complete treatment.