Clinical manifestations of gout and their management

Hyperuricemia and Progression of Chronic Kidney Disease: A Review from Physiology and Pathogenesis to the Role of Urate-Lowering Therapy

The relationship between hyperuricemia, gout, and renal disease has been investigated for several years. From the beginning, kidney disease has been considered a complication of gout; however, the viewpoints changed, claiming that hypertension and elevated uric acid (UA) levels are caused by decreased urate excretion in patients with renal impairment. To date, several examples of evidence support the role of hyperuricemia in cardiovascular or renal diseases. Several mechanisms have been identified that explain the relationship between hyperuricemia and chronic kidney disease, including the crystal effect, renin-angiotensin-aldosterone system activation, nitric oxide synthesis inhibition, and intracellular oxidative stress stimulation, and urate-lowering therapy (ULT) has been proven to reduce renal disease progression in the past few years. In this comprehensive review, the source and physiology of UA are introduced, and the mechanisms that explain the reciprocal relationship between hyperuricemia and kidney disease are reviewed. Lastly, current evidence supporting the use of ULT to postpone renal disease progression in patients with hyperuricemia and gout are summarized.

Febuxostat: A Novel, Non-Purine Xanthine Oxidase Inhibitor

Objective:

To review the pharmacology and clinical data for febuxostat in the treatment of gout and hyperuricemia.

Data Sources:

Articles on febuxostat published in English between 1966 and November 2006 were identified through a MEDLINE search using the key words febuxostat, TEI-6720, TMX-67, gout, and hyperuricemia. Additional articles were identified through search of the publications' reference lists. Abstracts from the 2005 proceedings of the American College of Rheumatology, American College of Clinical Pharmacology, and American Society for Clinical Pharmacology and Therapeutics were also searched for febuxostat studies.

Study Selection and Data Extraction:

All published febuxostat trials in humans were selected for this review. Clinical, pharmacokinetic, and pharmacodynamic data were evaluated.

Data Synthesis:

Febuxostat is a non-purine, selective inhibitor of xanthine oxidase that has demonstrated efficacy in lowering serum uric acid levels in patients with hyperuricemia associated with gout. Compared with allopurinol 300 mg/day, febuxostat 80 or 120 mg/day was more effective in lowering serum uric acid levels to less than 6 mg/dL. Febuxostat appears to be safe, with the majority of treatment-related adverse events reported being transient and mild-to-moderate in severity. However, abnormal elevation of liver enzyme levels has been reported with its use. There have been no documented major drug interactions with febuxostat.

Conclusions:

Febuxostat is a novel, non-purine xanthine oxidase inhibitor undergoing review by the FDA. It represents a potential advancement in the treatment of hyperuricemia associated with gout.

Frequency, risk, and cost of gout-related episodes among the elderly: does serum uric acid level matter?

OBJECTIVE

We examined the association between serum uric acid (SUA) level and the frequency, risk, and cost of gout flares among the elderly.

METHODS

Data were extracted from the Integrated Healthcare Information Services claims database (1999-2005). Patients were included if they had gout, were aged 65 years and older and had both medical and pharmacy benefits, and electronic laboratory data. Patients with gout and gouty episodes were identified using algorithms based on ICD-9-CM codes and medications. Logistic regression and negative binomial regressions were used to study the relationship between SUA concentration and the annual frequency and one-year risk of gout episodes. Generalized linear models were used to examine the direct healthcare costs associated with gout episodes in the 30 days following each episode.

RESULTS

Elderly patients with gout (n = 2237) with high (6-8.99 mg/dl) and very high (> 9 mg/dl) SUA concentrations were more likely to develop a flare within 12 months compared to patients with normal (< 6 mg/dl) SUA levels (OR 2.1, 95% CI 1.7-2.6; OR 3.4, 95% CI 2.6-4.4, respectively). In multivariate regressions, the average annual number of flares increased by 11.9% (p < 0.001) with each unit-increase in SUA level above 6 mg/dl (p < 0.001). Among patients with very high SUA levels, average adjusted total healthcare and gout-related costs per episode were $2,555 and $356 higher, respectively, than those of patients with normal SUA levels (both p < 0.001).

CONCLUSION

Higher SUA levels are associated with increased frequency and risk of gout episode, and with higher total and gout-related direct healthcare costs per episode.

Candida albicans induces cyclo-oxygenase 2 expression and prostaglandin E2 production in synovial fibroblasts through an extracellular-regulated kinase 1/2 dependent pathway

Introduction

Synovial cells are potential sources of inflammatory mediators in bacterial-induced arthritis but their involvement in the inflammatory response to Candida albicans-induced septic arthritis is largely unknown.

Methods

Primary cultures of rat synovial fibroblasts were infected with C. albicans (ATCC90028). Immunocytochemistry, western blotting, and RT-PCR were performed to assess cyclo-oxygenase 2 induction. Phosphorylation of extracellular-regulated kinase (ERK1/2) following infection in the absence or presence of U0126 was assessed by western blotting whilst prostaglandin E2 production was measured by ELISA. Nuclear factor κB (NFκB) translocation was evaluated by an electrophoretic mobility shift assay.

Results

Infection of synovial fibroblasts with C. albicans resulted in cyclo-oxygenase 2 expression and prostaglandin E2 production. Cyclo-oxygenase 2 expression and prostaglandin E2 production was dependent upon extracellular-regulated kinase 1/2 phosphorylation, associated with activation of NFκB and significantly elevated in the presence of laminarin, an inhibitor of dectin-1 activity. Synovial fibroblasts adjacent to C. albicans hyphae aggregates appeared to be the major contributors to the increased levels of cyclo-oxygenase 2 and phosphorylated extracellular-regulated kinase 1/2.

Conclusions

C. albicans infection of synovial fibroblasts in vitro results in upregulation of cyclo-oxygenase 2 and prostaglandin E2 by mechanisms that may involve activation of extracellular-regulated kinase 1/2 and are associated with NFκB activation.

Inhibition of cyclooxygenase 2 expression by diallyl sulfide on joint inflammation induced by urate crystal and IL-1beta

OBJECTIVE

Investigation of the effects of diallyl sulfide (DAS), a garlic sulfur compound, on joint tissue inflammatory responses induced by monosodium urate (MSU) crystals and interleukin-1beta (IL-1beta).

DESIGN

The HIG-82 synovial cell line was used to establish the experimental model and DAS regime. Primary cultures of articular chondrocytes and synovial fibroblasts obtained from patients undergoing joint replacement for osteoarthritis were used in experimental studies. Cyclooxygenase (COX) expression following MSU crystal and IL-1beta stimulation with/without DAS co-incubation was assessed by reverse transcription-polymerase chain reaction (RT-PCR), western blotting, and immunocytochemistry and nuclear factor-kappa B (NF-kappaB) activation determined by electrophoretic mobility shift assay. Prostaglandin E2 (PGE(2)) production was measured by enzyme-linked immunosorbent assay (ELISA). DAS effects on COX gene expression in an MSU crystal-induced acute arthritis in rats were assessed by RT-PCR.

RESULTS

MSU crystals upregulated COX-2 expression in HIG-82 cells and this was inhibited by co-incubation with DAS. DAS inhibited MSU crystal and IL-1beta induced elevation of COX-2 expression in primary synovial cells and chondrocytes. Production of PGE(2) induced by crystals was suppressed by DAS and celecoxib. MSU crystals had no effect on expression of COX-1 in synovial cells. NF-kappaB was activated by MSU crystals and this was blocked by DAS. Increased expression of COX-2 in synovium following intraarticular injection of MSU crystals in a rat model was inhibited by co-administration of DAS.

CONCLUSIONS

DAS prevents IL-1beta and MSU crystal induced COX-2 upregulation in synovial cells and chondrocytes and ameliorates crystal induced synovitis potentially through a mechanism involving NF-kappaB. Anti-inflammatory actions of DAS may be of value in treatment of joint inflammation.

Miliarial gout (a new entity)

BACKGROUND

Tophaceous gout typically presents as a subcutaneous, nodular collection of monosodium urate crystals sharply circumscribed from surrounding tissues. Although intradermal cutaneous manifestations of gout have been described, no reported cases of miliarial gout remain.

OBJECTIVE

We describe the first known presentation of miliarial gout and list other uncommon cutaneous manifestations of gouty tophi. The treatment of miliarial gout is discussed, as well as risk factors predisposing an individual to the development of intradermal tophi.

RESULTS

Miliarial gout is an intradermal phenomenon consisting of multiple tiny papules containing material of a white to cream color scattered on an erythematous base that responds to allopurinol administration. Risk factors predisposing an individual to the development of intradermal gout include renal insufficiency, hypertension, chronic diuretic therapy, long duration of disease, and lack of consistent use of urate-lowering therapy.

CONCLUSION

Miliarial gout is a unique intradermal manifestation of tophaceous gout.

Impact of selective cyclooxygenase-2 inhibitors on anti-ulcer medication and non-steroidal anti-inflammatory drug use in patients with rheumatic disease

BACKGROUND

Anti-inflammatory medications are the most common treatment for rheumatic disease in Australia. Recent years have seen large increases in the use of selective cyclooxygenase-2 (COX-2) inhibitors. Predictors of use, costs and benefits of the new medications have not been evaluated.

AIMS

To determine trends in selective COX-2 inhibitor, non-steroidal anti-inflammatory drug (NSAID) and anti-ulcer medication (AUM) prescription following the introduction of selective COX-2 inhibitors; to determine predictors of selective COX-2 inhibitor, NSAID and AUM prescribing and to perform a limited evaluation of the costs and benefits associated with the introduction of selective COX-2 inhibitors.

METHODS

Groups of consecutive patients attending a hospital rheumatology clinic, private rooms of consulting rheumatologists and a dermatology outpatient clinic were surveyed by investigator-administered questionnaire on three separate occasions. Information was sought about AUM, NSAID and selective COX-2 use and about factors likely to influence selective COX-2 prescribing. Sampling was carried out at 3, 10 and 16 months after the release of COX-2 selective inhibitors in Australia. The final survey was 3 months after Pharmaceutical Benefits Scheme (PBS) listing of celecoxib in Australia. Costs of treatment were calculated from survey findings of frequency of drug use as well as published drug prices and hospitalisation costs.

RESULTS

Four-hundred and fifty-eight patients were surveyed. From the 3 months post-release to the 3 months post-PBS listing, a period of 13 months, COX-2 use in rheumatology patients increased from 18 to 57%. De novo prescription of selective COX-2 inhibitors increased from 42 to 61%. During the same period there was a fall in both NSAID (43-20%) and AUM use (41-27%). Neither selective COX-2 inhibitor nor NSAID prescription was related to risk factors for gastro-intestinal (GI) complications, but AUM use was found to correlate strongly to histories of gastroscopy, GI ulceration or GI bleed. The calculated increase in the cost of treatment was $1 033 002/10 000 patients per year. The net cost per serious GI event prevented was $71 736, compared with the normal cost of treatment of $2004.

CONCLUSIONS

Among rheumatology patients, selective COX-2 inhibitors have largely replaced NSAIDs and have resulted in a reduction in AUM consumption, but prescribing patterns for selective COX-2 inhibitors have not been related clearly to risk factors for GI complications. The introduction of selective COX-2 inhibitors has been associated with a significant increase in expenditure.

Gout: a clinical and radiologic review

Gout is a group of diseases characterized by arthritis and results from a disturbance of urate metabolism with the deposition of monosodium urate crystals in the joints and soft tissues. Often, but not invariably, the serum urate levels are elevated as a result of overproduction or underexcretion of uric acid. Clinical manifestations include acute and chronic arthritis, tophaceous deposits, interstitial renal disease, and uric acid nephrolithiasis. The diagnosis is based on the identification of uric acid crystals in joints, tissues, or body fluids. Acute episodes are treated with colchicine, NSAIDs, or steroids. Long-term management includes treatment with uricosuric agents or xanthine oxidase inhibitors.

Efficacy and safety profile of treatment with etoricoxib 120 mg once daily compared with indomethacin 50 mg three times daily in acute gout: a randomized controlled trial

OBJECTIVE

To evaluate the efficacy and safety of etoricoxib and indomethacin in the treatment of patients with acute gout.

METHODS

A randomized, double-blind, active-comparator study was conducted at 42 sites. A total of 189 men and women (> or =18 years of age) who were experiencing an acute attack (< or =48 hours) of clinically diagnosed gout were treated for 8 days with etoricoxib, 120 mg/day (n = 103), or indomethacin, 50 mg 3 times a day (n = 86). The primary efficacy end point was the patient's assessment of pain in the study joint (0-4-point Likert scale) over days 2-5. Safety was assessed by adverse experiences (AEs) occurring during the trial.

RESULTS

Etoricoxib demonstrated clinical efficacy comparable to that of indomethacin in terms of the patient's assessment of pain in the study joint. The difference in the mean change from baseline over days 2-5 was -0.08 (95% confidence interval -0.29, 0.13) (P = 0.46), which fell within the prespecified comparability bounds of -0.5 to 0.5. Secondary end points over the 8-day study, including the onset of efficacy, reduction in signs of inflammation, and patient's and investigator's global assessments of response to therapy, confirmed the comparable efficacy of the two treatments. The etoricoxib-treated patients had a numerically lower incidence of AEs (43.7%) than did the indomethacin-treated patients (57.0%) and a significantly lower incidence of drug-related AEs (16.5% versus 37.2%; P < 0.05).

CONCLUSION

Etoricoxib at a dosage of 120 mg once daily was confirmed to be an effective treatment for acute gout. Etoricoxib was comparable in efficacy to indomethacin at a dosage of 50 mg 3 times daily, and it was generally safe and well tolerated.

A literature review of the epidemiology and treatment of acute gout

BACKGROUND

Gout is the most common cause of inflammatory arthritis in men aged >40 years and is frequently encountered in clinical practice.

OBJECTIVE

The goal of this article was to review the published literature on the epidemiology, treatment, and estimated burden of illness of acute gout.

METHODS

Articles on gout published in English between 1980 and June 2002 were identified through a MEDLINE search. Relevant clinical studies and review articles were found using the text- and keyword-search term gout alone and in combination with epidemiology, prevalence, incidence, complications, outcome, quality of life, economics, cost, prevention or drug therapy. The reference lists of identified articles, especially review articles, were checked for any additional studies that might have been missed in the original MEDLINE search.

RESULTS

The epidemiology of gout in various geographic regions has been well documented. Data suggest that environmental, racial, and hereditary factors may influence the development of gout, and that the prevalence of gout appears to be on the rise worldwide. Evidence from well-designed clinical studies evaluating drug therapies for gout is limited. Therapies for acute gout include corticotropin, corticosteroids, colchicine or, more often, nonsteroidal anti-inflammatory drugs (NSAIDs), which have shown comparable efficacy. A recent study suggests that etoricoxib, a new cyclooxygenase-2-selective inhibitor, may be as effective as and better tolerated than traditional NSAIDs in the treatment of gout. Urate-lowering therapy, prophylactic colchicine, and low-dose NSAIDs are used for the long-term prophylaxis of gout. However, all acute and prophylactic therapies are associated with adverse events. Using an economic model for gout, the annual direct burden of illness for new cases of acute gout can be estimated at 27,378,494 US dollars in the United States.

CONCLUSIONS

Gout is an increasingly prevalent condition worldwide and creates a heavy economic burden. Available treatments are generally effective; however, they are not devoid of adverse events. Well-designed, long-term, controlled clinical trials evaluating the comparative efficacy and tolerability of treatments for gout are needed.