Potential Association between Kaposi Sarcoma and Gout: An Exploratory Observational Study.

Background: Kaposi sarcoma is a rare vascular mesenchymal neoplasm, associated with Human Herpes Virus 8 (HHV8). Gout is a condition clinically characterized by recurrent flares of arthritis and hyperuricemia. Following our clinical impression that patients with classical Kaposi sarcoma (CKS) have a high rate of gout, we explored this in a retrospective manner.

Methods: All consecutive patients diagnosed with sarcoma or carcinosarcoma within a single tertiary center between 1/2012-12/2017 were identified through the pathology department database. A cohort of CKS patients was compared with the non-Kaposi sarcoma and carcinosarcoma cohort. Data were extracted from patients' electronic medical records. Patients younger than 18 and patients without clinical data available were excluded. Association between diagnosis of gout and CKS was assessed and adjusted for risk factors.

Results: Three hundred and sixty-one patients were eligible for this analysis, 61 were diagnosed with CKS and 300 with other types of sarcoma. We found a higher incidence of gout in CKS patients, 11/61 (18%) patients, compared with 8/300 (2.6%) with other types of sarcoma, odds ratio (OR) 8.0 (P < 0.00001). This association persisted when adjusted for age >39 years (OR = 6.7, P < 0.00001), age and male sex (OR = 4.97, P < 0.0001), and when adjusting for multiple confounding factors and medical comorbidities.

Conclusions: We have demonstrated a statistically significant association between gout and CKS. As risk factors for gout were accounted for, this association may be explained by HHV8 immune-related effects. This should be further explored in vitro and in population-based studies.