Background/Purpose:

Increased cardiovascular (CV) risk in gout relates to crystal-driven inflammation. In a preliminary, cross-sectional study we found that silent deposits of monosodium urate (MSU) crystals in asymptomatic hyperuricemia (AH) associated with a more severe coronary calcification, in comparison to AH alone and normouricemia (NU) [1]. Whether this silent deposit also leads to a poor CV prognosis of AH patients has not been assessed so far. We aimed to compare the incidence of CV events between the study groups in the follow-up period after the admission.

Methods:

Prospective follow up of patients from the previous study [1]; consecutive patients admitted due to an acute coronary event  were classified at baseline as NU, AH alone, and AH with crystals after serum uric acid levels, joint ultrasound and polarized microscopy of synovial fluid samples. The date of admission was considered as the index date. Electronic clinical records were reviewed in order to register the occurrence of all-cause death, CV-related death, new ST-elevation (STE) acute coronary event, new non-STE acute coronary event, and need for coronary revascularization during follow-up. Kaplan-Meier curves were plotted for each outcome for between-group comparisons, and a multivariate Cox regression model was built to adjust for CV risk factors.

Results:

140 patients were enrolled, and classified as 66 NU, 61 AH alone, and 13 AH with MSU crystals. Only one patient (from the AH alone group) was lost in the follow-up. Median (p25-75) follow-up was 12.0 (8.3-16.0) months. No new STE acute coronary event was registered. No significant differences were found in all-cause or CV-related death. The AH with crystals group showed higher need for new coronary revascularization and higher incidence of new non-STE acute coronary event [Figures A and B, respectively). After adjustment for CV risk factors, a non-sigficant but evident trend towards a higher need for new coronary revascularization was found in the AH with crystals group (aHR 4.5; 95%CI 0.8-24.1, p=0.08); no significant differences in non-STE acute event were found.

Conclusion:

Silent deposits of MSU crystals in AH appear to lead to a higher need for new coronary revascularization. Low patient numbers likely account for the lack of significance. This finding adds more evidence to the detrimental role of MSU crystals on the arteriosclerotic disease of these subjects.

References:

[1] 2014 ACR Annual Meeting (abstract #829).

Figure:

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/silent-monosodium-urate-crystals-deposits-in-asymptomatic-hyperuricemia-lead-to-a-higher-need-for-coronary-revascularization/