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HYPERURICEMIA AND ITS IMPLICATIONS
Benjamin Wang, M.D., FRCPC
Division of Rheumatology
Mayo Clinic
Jacksonville, FL
Disclosures
• None
Topics
• Hyperuricemia defined
• Consequences of hyperuricemia
• New data in gout
• Hypertension, cardiovascular disease, and renal failure
• Interventions and outcomes
Hyperuricemia • Uric acid concentrations in serum
• in people consuming traditional non-Western diets, is 2 to 4
mg/dL (120-240 μM).
• in industrialized populations, is 3-8 mg/dL (180-480 μM)
• diets richer in purines and fructose (both of which generate
urate)
• greater alcohol intake
• Higher prevalence of factors that reduce kidney urate
excretion (eg, insulin resistance, renal vasoconstriction
associated with hypertension, and decreased kidney function)
• interpopulation genetic differences
• in most non-primate mammals, serum urate concentrations are
low (1-3 mg/dL [60-180 μM]) due to the enzyme uricase
• humans lack uricase
Hyperuricemia
• Sustained hyperuricemia (≥7 mg/dL in men, ≥6 mg/dL in
women) is associated with tissue deposition of uric acid
and metabolic effects
• Hyperuricemia is most often familial, involving
polymorphisms is renal urate transport proteins
Complications of Hyperuricemia
• Confirmed
• Gout
• Nephrolithiasis
• Emerging Data
• Hypertension
• Cardiovascular disease
• Metabolic syndrome
• Still Controversial: Dementia
Case
• 70 year old Caucasian male – Consultation for sustained hyperuricemia
• First STEMI at age 54; three subsequent MIs; 3-vessel CABG at age 57
• Since then 15 coronary stenting procedures
• Currently asymptomatic, exercising
• Serum urate over last two years 8.2, 9.0, 8.8 mg/dL
• Recalls having 2 attacks of gout, last one15 years ago, classic podagra and instep of right foot; none since then
• BP 136/84; no tophi
• Labs: CBC and diff normal; Cr 1.3; Chol (total) 223, LDL 130, HDL 38, TG 230; hsCRP 22; HbA1c 6.3%; ESR 8 mm/h; RF, ANA negative
• Is there a reason to treat his elevated uric acid level?
Gout
• A disease of chronic urate accumulation; hence treatment
should result in gradual urate elimination
• Gout prevalence increasing worldwide
• Diagnostic modalities
• Treat-to-Target guidelines (American College of
Rheumatology) vs. don’t treat to target (ACP)
• Linisurad in combination with allopurinol
• Biologic therapy in gout
Dual-energy CT (DECT) for urate deposition
Gout is a disease of urate accumulation
• Uric acid will begin to precipitate
at a concentration of 6 mg/dL in
water at 37°C and pH 7.4
• Lowering concentration leads to
dissolution of crystals and
decreased tissue burden of
urate
• This is the basis of the treat-to-
target goal of serum urate
concentration [sUA] of 6.0
mg/dL, or ≤5.0 mg/dL in
tophaceous disease (Neogi 2015;
Richette 2016; Becker MA 2008)
Chronic urate-lowering treatment
• Allopurinol
• Begin at 100 mg/d in order to minimize chance of “initiation flare”
• Titrate upwards in 100 mg increments q6wk to reach target [sUA]
• Maximum daily dose 800 mg/d – frequently underdosed
• Hypersensitivity reactions very rare, but inform patient
• Higher risk of sensitivity reactions in CKD not confirmed
• Febuxostat (Uloric®)
• Start at 40 mg/d, increase to 80 mg/d
• Some increased CV risk? (White 2018)
• Probenecid – weak uricosuric; cannot use in GFR < 35
• Lesinurad (Zurampic®) – new uricosuric drug
Lesinurad inhibits URAT1 transporter
Reginato AM. Nat Rev Rheum 2012; 8(10):610-21.
Lesinurad in allopurinol nonresponders
Saag K et al. Arthritis Rheum 2017: 69(1):203–212.
n=603
Biologic therapy in gout
• Treating acute inflammation: IL-1 inhibitors (not FDA
approved)
• Anakinra
• Canakinumab
• Treating urate accumulation (severe tophaceous disease)
• pegloticase (Krystexxa®)
• rasburicase (Elitek®)
Hyperuricemia and hypertension: physiologic
mechanisms
Johnson RJ et al. Am J Kidney Dis. 2018:1-15. Published online.
Meta-analysis
demonstrates the
association of
hyperuricemia and
hypertension in
men and women
Random-effects analysis
of sex-specific adjusted
risk ratios of
hyperuricemia
associated with incident
hypertension.
95% CI =95%
confidence interval.
Grayson PC, Kim SY, LaValley M, Choi HK. Arthritis Care Res (Hoboken). 2011;63(1):102-110.
Epidemiologic data support an independent effect of
hyperuricemia on hypertension
Feig DI, et al. J Pediatr. 2013;162(5):896-902.
Effect of allopurinol treatment on BP in hypertensive
adolescents (crossover RCT)
Feig DI, Soletsky B, Johnson RJ.JAMA. 2008;300(8):924-932.
Allopurinol decreases SBP and carotid intimal
thickness in post-stroke prehypertensive patients
Higgins P et al. Heart 2014;100(14):1085-1092.
Hyperuricemia and Cardiovascular Outcomes – Select
Observations
• Coronary heart disease is more severe in hyperuricemic patients with
asymptomatic urate crystal deposition than normouricemic or hyperuricemic
patients without crystal deposits, which suggests a vascular deleterious effect of
monosodium urate crystals (Andres M et al. Arthritis Rheumatol 2016;68:1531-9)
• High-dose allopurinol (600 mg/day) led to regression of left ventricular mass in 66
patients with ischaemic heart disease (Rekhraj Set al. J Am Coll Cardiol 2013;61:926) and
enhanced exercise capacity in patients with chronic stable angina (Norman A. Lancet
2010;375:2161).
• Reduced risk of myocardial infarction in those receiving allopurinol (Larsen KS. Am J
Med 2016;129:299; de Abajo FJ. Heart 2015;101:679)
• Large epidemiological studies found that allopurinol decreased morbidity and
mortality rates in patients with congestive heart failure and a history of gout (Higgins
P. Cardiovasc Ther 2012;30:217)
• In one RCT, patients (n = 253) with symptomatic HF and hyperuricaemia [serum
uric acid (sUA) level 59.5 mg/dl] were randomized to receive allopurinol (600
mg/day) or a placebo (Givertz MM et al. Circulation 2015;131:1763).
• The primary composite endpoint at 24 weeks was based on survival, worsening
HF and patient global assessment. At 24 weeks, clinical status did not differ
between the allopurinol- and placebo-treated patients
Elevated serum urate contributes to conventional cardiac risk
factors to develop moderate coronary calcification
J.E. Jun, et al. Atherosclerosis (2018), https://doi.org/10.1016/j.atherosclerosis.2018.02.014
• CARES (Cardiovascular Safety of Febuxostat or
Allopurinol in Patients with Gout and Cardiovascular
Disease)
• Prospective, double-blind, 320-center North American
clinical trial
• 6,190 patients were randomized to febuxostat (Uloric) at
40-80 mg once daily or 200-600 mg of allopurinol once
daily.
• Primary endpoint : composite of cardiovascular death, MI,
stroke, and unstable angina resulting in urgent
revascularization
Febuxostat and increased cardiovascular mortality: the
CARES Study
White W et al. N Engl J Med. 2018 Mar 12. doi: 10.1056/NEJMoa1710895
Febuxostat and increased cardiovascular mortality: the
CARES Study
White W et al. N Engl J Med. 2018 Mar 12. doi: 10.1056/NEJMoa1710895
Febuxostat and increased cardiovascular mortality: the
CARES Study
White W et al. N Engl J Med. 2018 Mar 12. doi: 10.1056/NEJMoa1710895
• Because of the high lost-to-follow-up rate, a private
investigator was hired to look for missed deaths among
study subjects. An extra 199 deaths were found. When
those were added to the total, all-cause mortality in the
febuxostat group was no longer significantly higher than
allopurinol.
• Nonfatal MI, nonfatal stroke, and urgent revascularization
due to unstable angina – were neutral or were less
common with febuxostat.
Febuxostat and increased cardiovascular mortality: the
CARES Study
White W et al. N Engl J Med. 2018 Mar 12. doi: 10.1056/NEJMoa1710895
Lowering Uric Acid With Allopurinol Improves Insulin Resistance and
Systemic Inflammation in Asymptomatic Hyperuricemia
• Allopurinol 300 mg/d for three
months (n=43) vs. placebo (n=33)
• Allopurinol-treated subjects showed
• reduction in serum uric acid
• Improved fasting glucose
• Improved fasting insulin
• Improved HOMA-IR index
• Reduction in high-sensitivity
C-reactive protein
• The number of subjects with
impaired fasting glucose
significantly decreased in the
allopurinol group at 3 months
compared with baseline (n=8 [20%]
vs n=30 [75%], 3 months vs
baseline, P < 0.001).
Takir M, Kostek O, Ozkok A, et al. J Investig Med.
2015;63(8):924-929.
Allopurinol stabilzes metabolic syndrome: a 3-year
controlled trial in patients with T2DM (n=176)
• Intervention: allopurinol adjusted
to maintain [sUA] below 6.0
mg/dL vs. placebo
• Usual antihypertensives (except
losartan) and oral hypoglycemics
maintained
• The allopurinol-treated
group
• Lower SBP and DBP
• Less worsening of
HOMA-IR and serum
triglyceride concentration
• Lower albuminuria
• Higher eGFR
• Less new-onset diabetic
nephropathy (defined as urine
albumin excretion >
200μg/min (4.9% vs 10%)
Liu P et al. Clinical Endo 2015; 83:475-482
Summary
• Hyperuricemia has wide ranging inflammatory and
metabolic effects, with implications in arthritic,
cardiovascular, and metabolic disease
• Available evidence suggests that intervention with urate-
lowering drugs has positive benefits in the above domains
• Larger clinical trials and observational studies will be
needed to confirm these benefits
• Febuxostat may have an independent, increased risk of
cardiovascular disease compared to allopurinol
Conclusion of the case
• What would you do?
• My considerations
• High risk for adverse cardiovascular outcomes
• He’s had gout in the remote past, indicating some urate deposition
• I’m pretty comfortable managing urate-lowering drugs
• If he has a gout attack, he gets urate lowering drugs immediately
• My leanings
• I would probably treat his elevated uric acid level
• I would probably stay away from febuxostat
wang.benjamin@mayo.edu
Thank you
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