Where should we set the start of gout?

J-shaped association of serum uric acid concentrations with all-cause mortality in individuals with osteoarthritis: A prospective cohort study

OBJECTIVE

The purpose of this study was to explore the relationship between serum uric acid (SUA) concentrations and all-cause mortality in individuals with osteoarthritis (OA).

METHODS

All participant data were retrieved from the National Health and Nutrition Examination Survey database. A total of 4671 participants (age range: 20 to 85 years old), including 2988 females and 1683 males, were included in this study. The determination of death outcome was based on the National Death Index (up to December 31, 2019). We explored the nonlinear relationship between SUA concentrations and all-cause mortality in OA patients by establishing a Cox proportional risk model and a two-segment Cox proportional risk model and ran an interaction test to identify the high-risk population for all-cause mortality.

RESULTS

During 30,645 person-years of follow-up, the number of all-cause deaths for females and males was 736 and 516, respectively. After multivariate adjustment, we found a nonlinear relationship between SUA concentrations and all-cause mortality in both females and males with OA. In addition, we found a J-shaped relationship between SUA concentrations and all-cause mortality. The SUA concentration thresholds for all-cause mortality of females and males were stable at 5.6mg/dl and 6.2mg/dl, respectively. Compared with SUA concentrations below the inflection point, the all-cause mortality risk at higher SUA concentrations in females and males with OA increased by 20% (hazard ratio [HR]: 1.2, 95% confidence interval [CI]: 1.1 to 1.2) and 25% (HR: 1.2, 95% CI: 1.12 to 1.39), respectively.

CONCLUSIONS

There is a nonlinear relationship between SUA concentrations and all-cause mortality in the American OA population (J-shaped association). The all-cause mortality thresholds for SUA concentrations in females and males are 5.6mg/dl and 6.2mg/dl, respectively.

Emerging Urate-Lowering Drugs and Pharmacologic Treatment Strategies for Gout: A Narrative Review

Hyperuricemia with consequent monosodium urate crystal deposition leads to gout, characterized by painful, incapacitating inflammatory arthritis flares that are also associated with increased cardiovascular event and related mortality risk. This narrative review focuses on emerging pharmacologic urate-lowering treatment (ULT) and management strategies in gout. Undertreated, gout can progress to palpable tophi and joint damage. In oral ULT clinical trials, target serum urate of < 6.0 mg/dL can be achieved in ~ 80-90% of subjects, with flare burden reduction by 1-2 years. However, real-world ULT results are far less successful, due to both singular patient nonadherence and prescriber undertreatment, particularly in primary care, where most patients are managed. Multiple dose titrations commonly needed to optimize first-line allopurinol ULT monotherapy, and substantial potential toxicities and other limitations of approved, marketed oral monotherapy ULT drugs, promote hyperuricemia undertreatment. Common gout comorbidities with associated increased mortality (e.g., moderate-severe chronic kidney disease [CKD], type 2 diabetes, hypertension, atherosclerosis, heart failure) heighten ULT treatment complexity and emphasize unmet needs for better and more rapid clinically significant outcomes, including attenuated gout flare burden. The gout drug armamentarium will be expanded by integrating sodium-glucose cotransporter-2 (SGLT2) inhibitors with uricosuric and anti-inflammatory properties as well as clinically indicated antidiabetic, nephroprotective, and/or cardioprotective effects. The broad ULT developmental pipeline is loaded with multiple uricosurics that selectively target uric acid transporter 1 (URAT1). Evolving ULT approaches include administering selected gut anaerobic purine degrading bacteria (PDB), modulating intestinal urate transport, and employing liver-targeted xanthine oxidoreductase mRNA knockdown. Last, emerging measures to decrease the immunogenicity of systemically administered recombinant uricases should simplify treatment regimens and further improve outcomes in managing the most severe gout phenotypes.