The optimal use of allopurinol: an audit of allopurinol use in South Auckland

Frequency of Serum Creatinine Monitoring During Allopurinol Therapy in Ambulatory Patients

Background:

Allopurinol dosage reduction is recommended in patients with renal dysfunction because drug toxicity risk is increased. Little information is available about serum creatinine (SCr) monitoring in ambulatory patients taking allopurinol.

Objective:

To evaluate SCr monitoring among patients prescribed allopurinol, identify associated factors, and evaluate administrative data in assessing monitoring.

Methods:

Information for this retrospective cohort study was drawn from a dataset of 2 020 037 individuals; approximately 200 000 members from each of 10 organizations. Study patients had received at least one year of ongoing allopurinol prescription dispensings. Patient variables analyzed included age, gender, chronic diseases, outpatient visits, hospitalizations, gout diagnosis, and SCr monitoring. A random sample of medical records was reviewed to assess the accuracy of the automated data. Statistical analysis included descriptive and logistic regression techniques.

Results:

Overall, 1139 (26%) of 4357 patients did not have SCr monitoring. For individuals without recent hospitalization, factors protective against lack of monitoring were increasing age (OR 0.77 per 10 y; 95% CI 0.74 to 0.79), more chronic diseases (OR 0.81; 95% CI 0.78 to 0.83), more outpatient visits (OR 0.87 per 5 visits; 95% CI 0.83 to 0.91), and gout diagnosis (OR 0.74; 95% CI 0.65 to 0.85). The sensitivity and specificity of administrative data compared with medical records for SCr monitoring were 92% and 65%, respectively.

Conclusions:

More than one-fourth of patients dispensed allopurinol did not have SCr monitoring during one year of therapy. Lack of monitoring and lack of subsequent possible dosage adjustment put patients at increased risk of allopurinol toxicity.

Predicting allopurinol response in patients with gout

AIMS

The primary aim of this research was to predict the allopurinol maintenance doses required to achieve the target plasma urate of ≤0.36 mmol l(-1) .

METHODS

A population analysis was conducted in nonmem using oxypurinol and urate plasma concentrations from 133 gout patients. Maintenance dose predictions to achieve the recommended plasma urate target were generated.

RESULTS

The urate response was best described by a direct effects model. Renal function, diuretic use and body size were found to be significant covariates. Dose requirements increased approximately 2-fold over a 3-fold range of total body weight and were 1.25-2 fold higher in those taking diuretics. Renal function had only a modest impact on dose requirements.

CONCLUSIONS

Contrary to current guidelines, the model predicted that allopurinol dose requirements were determined primarily by differences in body size and diuretic use. A revised guide to the likely allopurinol doses to achieve the target plasma urate concentration is proposed.

The prescription of allopurinol in a tertiary care centre: appropriate indications and dose adjustment

Objective

To determine the appropriateness (both indications and adequate dosage regimen via creatinine clearance estimation) of allopurinol by physicians of different specialties in a tertiary care centre.

Patients and methods

In this cross sectional study computerized clinical records of 156 adult patients who were prescribed allopurinol from 12th November to 11th December, 2011 were retrieved from Al Hada Hospital Taif Saudi Arabia. Main outcome variables were approprsiate indications of allopurinol, prescribing physician’s specialty, and dosage of allopurinol. The prescribed dosages were categorized into correct and incorrect dose adjustments based on creatinine clearance estimation. The SPSS version 16 was utilized for data analyses.

Results

The mean (±SD) age was 58.15 (±14.99) years. There were 105 (67.3%) males and 51 (32.7%) females with male to female ratio being 2:1. Allopurinol was frequently prescribed by nephrologists and family physicians in this study. Out of 156 patients, 46 (29.5%) patients received allopurinol with appropriate indications. Eighty-five (54.5%) patients were received allopurinol without dose adjustment based on their creatinine clearance estimation; among them, 21 (13.5%) received allopurinol with appropriate indications.

Conclusion

The inappropriate use of allopurinol (both the indication and prescribed dosage) is still a major problem in a large tertiary care centre. Furthermore, the specialty of physicians is also a contributory factor in this inappropriateness.

A cohort study comparing cardiovascular risk factors in rural Maori, urban Maori and non-Maori communities in New Zealand

OBJECTIVES

To understand health disparities in cardiovascular disease (CVD) in the indigenous Māori of New Zealand, diagnosed and undiagnosed CVD risk factors were compared in rural Māori in an area remote from health services with urban Māori and non-Māori in a city well served with health services.

DESIGN

Prospective cohort study.

SETTING

Hauora Manawa is a cohort study of diagnosed and previously undiagnosed CVD, diabetes and risk factors, based on random selection from electoral rolls of the rural Wairoa District and Christchurch City, New Zealand.

PARTICIPANTS

Screening clinics were attended by 252 rural Māori, 243 urban Māori and 256 urban non-Māori, aged 20-64 years.

MAIN OUTCOME MEASURES

The study documented personal and family medical history, blood pressure, anthropometrics, fasting lipids, insulin, glucose, HbA1c and urate to identify risk factors in common and those that differ among the three communities.

RESULTS

Mean age (SD) was 45.7 (11.5) versus 42.6 (11.2) versus 43.6 (11.5) years in rural Māori, urban Māori and non-Māori, respectively. Age-adjusted rates of diagnosed cardiac disease were not significantly different across the cohorts (7.5% vs 5.8% vs 2.8%, p=0.073). However, rural Māori had significantly higher levels of type-2 diabetes (10.7% vs 3.7% vs 2.4%, p<0.001), diagnosed hypertension (25.0% vs 14.9% vs 10.7%, p<0.001), treated dyslipidaemia (15.7% vs 7.1% vs 2.8%, p<0.001), current smoking (42.8% vs 30.5% vs 15.2%, p<0.001) and age-adjusted body mass index (30.7 (7.3) vs 29.1 (6.4) vs 26.1 (4.5) kg/m(2), p<0.001). Similarly high rates of previously undocumented elevated blood pressure (22.2% vs 23.5% vs 17.6%, p=0.235) and high cholesterol (42.1% vs 54.3% vs 42.2%, p=0.008) were observed across all cohorts.

CONCLUSIONS

Supporting integrated rural healthcare to provide screening and management of CVD risk factors would reduce health disparities in this indigenous population.

Quality of care in patients with gout: why is management suboptimal and what can be done about it?

Gout is a common inflammatory arthritis. We know a great deal about its etiopathogenesis and have relatively safe and effective therapies for it. Gout, however, remains a poorly managed disease with mistakes made in securing an accurate diagnosis and in using appropriate therapies for acute and chronic stages of the disease. Synovial fluid analysis with polarizing microscopy is the "gold standard" for confirming the diagnosis of gout but has been used in fewer than 10% of all patients diagnosed with gout. The newly adopted European clinical guidelines offer a practical alternative to synovial fluid analysis, but primary care physicians are not well-versed in their use. Other serious errors in the management of gout are related to the use of medications to treat acute and chronic gout. Frequently, the anti-inflammatory drugs used to treat acute symptoms and urate-lowering drugs used to prevent long-term destruction are improperly dosed, leading to dissatisfaction on the part of patients and physicians. Widespread education about evidence-based diagnostic and treatment guidelines is desperately needed.

Chronic kidney disease in gout in a managed care setting

Background

To study the prevalence of chronic kidney disease (CKD) and its impact on allopurinol dosing and uric acid control among patients with gout.

Methods

This was a retrospective study using data from a large US health plan. Claims and laboratory data were analyzed for enrollees from the health plan database from January 2002 through December 2005. Patients with gout were identified from pharmacy and medical claims data based on the presence of codes for gout medication or gout diagnosis. Severity of CKD was determined using the estimated glomerular filtration rate (eGFR). Allopurinol titration was defined as a change in average daily dose from first prescription to last prescription of ≥ 50 mg.

Results

A total of 3,929 patients were identified for inclusion in this study, 39% of whom had CKD (based on having an eGFR < 90 mL/min/1.73 m²). Subjects with CKD were older (p < 0.01) and more likely to be women (p < 0.01), had a greater number of comorbid conditions (p < 0.01), and were more likely to be prescribed allopurinol (p < 0.01) compared to those with no CKD. The average starting dose of allopurinol was lower among those with CKD, and it decreased with worsening kidney function. Among the 3,122 gout patients who used allopurinol, only 25.6% without CKD and 22.2% with CKD achieved a serum uric acid concentration of < 6.0 mg/dL (p = 0.0409). Also, only 15% of allopurinol users had an upward dose titration (by ≥50 mg), but the average increase in dose did not differ significantly between those with and without CKD.

Conclusions

About two out of every five patients with gout in this population had CKD. Allopurinol doses were not adjusted in the majority of CKD patients. Serum uric acid control in gout was poor among patients without CKD and even worse among those with CKD.

Gout therapeutics: new drugs for an old disease

The approval of febuxostat, a non-purine-analogue inhibitor of xanthine oxidase, by the European Medicines Agency and the US Food and Drug Administration heralds a new era in the treatment of gout. The use of modified uricases to rapidly reduce serum urate concentrations in patients with otherwise untreatable gout is progressing. Additionally, advances in our understanding of the transport of uric acid in the renal proximal tubule and the inflammatory response to monosodium urate crystals are translating into potential new treatments. In this Review, we focus on the clinical trials of febuxostat. We also review results from studies of pegloticase, a pegylated uricase in development, and we summarise data for several other pipeline drugs for gout, such as the selective uricosuric drug RDEA594 and various interleukin-1 inhibitors. Finally, we issue a word of caution about the proper use of the new drugs and the already available drugs for gout. At a time of important advances, we need to recommit ourselves to a rational approach to the treatment of gout.

Necrotizing fasciitis: review of 82 cases in South Auckland

BACKGROUND

Early recognition of necrotizing fasciitis (NF) can be difficult, but is important as infections progress rapidly and have significant mortality. The aim of this study of patients with NF was to determine the clinical characteristics at presentation, causative pathogens and subsequent clinical outcome.

METHODS

We retrospectively reviewed consecutive patients with NF presenting to Middlemore Hospital from January 2000 to June 2006.

RESULTS

Eighty-two patients were evaluated: 56% male, mean age 54.9 years (standard deviation 18.5), 40% Pacific Islanders. The site of infection was the lower limb in 46 (56%) patients, upper limb in 12 (15%) patients and perineum in 13 (16%) patients. Twenty-two (27%) patients were taking non-steroidal anti-inflammatory drugs, 29 (35%) had diabetes mellitus, 25 (30%) had gout and 17 (21%) had congestive heart failure. Forty-nine (60%) patients had a surgical procedure within 24 h of admission. Streptococcus pyogenes was isolated from tissue or blood cultures in 33 (40%) patients and 26 (32%) patients had polymicrobial infection. Twenty-five (30%) patients died, 17 (68%) within 72 h of admission. Independent predictors of mortality include congestive heart failure (P = 0.033) and a history of gout (P = 0.037).

CONCLUSION

NF remains an important disease in our community with significant morbidity and mortality. Pacific Islanders were disproportionately represented. Early diagnosis of NF can be difficult and requires a high index of suspicion in all patients presenting with cellulitis or unexplained sepsis. Congestive heart failure and gout are independent predictors of mortality and patients with these conditions and sepsis need early assessment with more aggressive hospital triaging.

Advances in the management of gout and hyperuricaemia

An acute attack of gouty arthritis is one of the most painful experiences reported throughout medical history. Therefore it is paramount to initiate appropriate therapy quickly in order to terminate the acute phase. This goal can be achieved with non-steroidal anti-inflammatory agents, colchicine, or corticosteroid-based therapies. Rarely, because of contraindications to these agents, only symptomatic treatment can be given until the attack subsides. The next step is to lower the serum urate level below the limit of solubility (i.e., below 40.8 mmol/L, or 6.8mg/dL) which reduces recurrences and begins to return the total body urate pool to normal. This equally important goal can be achieved by uricosuric agents or xanthine oxidase inhibitors, although the latter is generally favored. Allopurinol is the agent most commonly preferred because of its safety profile and ease of use, but there are known serious allergic reactions and untoward side effects that occasionally require discontinuation. Febuxostat, a xanthine oxidase inhibitor, and pegylated uricase are new agents under development and may be beneficial in these situations or when other comorbid conditions prevent the use of conventional treatments. Alcohol and dietary consumption are also related to hyperuricemia and acute gout. Recently beer, wine, and liquor were studied and the risk of gout varied according to the alcohol ingested. Furthermore, recent data sheds light on important dietary modifications that may help in the treatment of gout, and dispels certain beliefs about protein ingestion and the occurrence of acute gout. As we learn more about the associated conditions of hypertriglyceridemia, hypertension, and the metabolic syndrome, it may allow the tailoring of medical regimens that directly prevent or reduce recurrent attacks of gouty arthritis. There are specific approved treatments for these common comorbidities that have parallel effects of lowering serum urate levels. These recent findings may be especially important for treating refractory cases. While patient education remains a cornerstone to ensure compliance, other quality indicators for the management of this disease have been reported and should guide the clinician in the treatment of gout and result in improved care.

Impact of a rheumatology consultation service on the diagnostic accuracy and management of gout in hospitalized patients

OBJECTIVE

To determine if a hospital rheumatology consultation service improves diagnostic accuracy and adherence to treatment recommendations for gout.

METHODS

This was a retrospective, single-center, case-control study of consecutive hospitalized patients with gout. Demographic, diagnostic, and treatment variables were compared in patients with and without a rheumatology consultation (controls). American College of Rheumatology (ACR) preliminary criteria for the classification of acute gout and the European League Against Rheumatism (EULAR) recommendations were used to determine diagnostic accuracy. Adherence to EULAR drug management recommendations and Quality Indicators for treatment were compared between groups.

RESULTS

In total, 138 patients were studied. The mean (SD) age was 71.3 (13.4) years and 70% were men. Forty-eight (35%) patients had gout on admission, 90 (65%) during their hospital stay, and 8 (6%) had multiple attacks. A total of 79 (57%) patients had a rheumatology consultation. These patients had more joints involved (p < 0.001), more frequent synovial fluid analysis (p < 0.001), and fulfilled ACR classification criteria more frequently than those who did not have a rheumatology consultation (65% vs 37%; p = 0.002). Intraarticular corticosteroid use was more common (44% vs 12%; p < 0.001) in patients who were seen by rheumatology. In contrast, colchicine was used more frequently in controls (63% vs 40%; p = 0.006). Patients seen by rheumatology were more likely to use nonsteroidal antiinflammatory drugs or colchicine for gout prophylaxis while titrating allopurinol to target (p = 0.033).

CONCLUSION

A rheumatology consultation service for hospitalized patients with gout significantly improved the diagnostic accuracy and adherence to established guidelines for short and longterm treatment.

Optimizing therapy with allopurinol: factors limiting hypouricemic efficacy

The aim of this review is to examine clinical aspects of the use of the hypouricemic drug allopurinol. Allopurinol is a moderately active hypouricemic drug. Its activity is largely the result of the inhibition of xanthine oxidoreductase by oxypurinol, the active metabolite of allopurinol. The activity of allopurinol may be limited by oxypurinol, reducing the renal clearance of urate. Optimal use of allopurinol involves individualization of dose to attain a sufficient decrease in plasma urate concentrations. This may require a dose greater than recommended based on creatinine clearance. The initial use of an anti-inflammatory drug or low-dose colchicine decreases but does not eliminate the development of acute attacks of gout during the initiation of therapy with allopurinol. Monitoring of oxypurinol concentrations has shed some light on the efficacy of allopurinol but more data are required particularly in patients with renal impairment. Probenecid increases the hypouricemic effect of allopurinol but the favorable interaction may be significant only in patients with glomerular filtration rates greater than about 50 mL/min.

We can make gout management more successful now

PURPOSE OF REVIEW

The purpose of this editorial review is to identify and comment on factors contributing to the current less-than-optimal state of gout management and to emphasize immediate opportunities to improve management practices affecting many patients with gout.

RECENT FINDINGS

Numerous publications document deficits in the current management and clinical outcomes of gout despite detailed understanding of the pathogenesis and pathophysiology of the disorder, the ability to establish the diagnosis with certainty, and the likely effectiveness, for most patients, of available lifestyle and pharmacological interventions. Among impediments to successful gout management are diagnostic inaccuracy; a paucity of validated management recommendations to guide care providers; incomplete patient education about gout and the aims and modalities of management; suboptimal patient adherence, even to demonstrably effective therapeutic recommendations; comorbidities and drug interferences that complicate treatment of gout; patient groups at special risk for progression to chronic tophaceous gout; and limited urate-lowering alternatives.

SUMMARY

Recent publication of evidence-based recommendations for the diagnosis and management of gout and the impending availability of new urate-lowering agents suggest that this is an opportune time to initiate professional and patient education efforts toward improved management of this increasingly common disorder.

Allopurinol dosing in renal impairment: walking the tightrope between adequate urate lowering and adverse events

Allopurinol is the mainstay of urate-lowering therapy for patients with gout and impaired renal function. Although rare, a life-threatening hypersensitivity syndrome may occur with this drug. The risk of this allopurinol hypersensitivity syndrome (AHS) is increased in renal impairment. The recognition that AHS may be because of delayed-type hypersensitivity to oxypurinol, the main metabolite of allopurinol, and that oxypurinol concentrations are frequently elevated in patients with renal impairment prescribed standard doses of allopurinol has led to the widespread adoption of allopurinol-dosing guidelines. These guidelines advocate allopurinol dose reduction according to creatinine clearance in patients with renal impairment. However, recent studies have challenged the role of these guidelines, suggesting that AHS may occur even at low doses of allopurinol, and that these guidelines lead to under-treatment of hyperuricemia, a key therapeutic target in gout. Based on current data, we advocate gradual introduction of allopurinol according to current treatment guidelines, with close monitoring of serum uric acid concentrations. In patients with severe disease and persistent hyperuricemia, allopurinol dose escalation above those recommended by the guidelines should be considered, with careful evaluation of the benefits and risks of therapy. Further work is needed to clarify the safety and efficacy of allopurinol dose escalation, particularly in patients with renal impairment.

Allopurinol is the most common cause of Stevens-Johnson syndrome and toxic epidermal necrolysis in Europe and Israel

BACKGROUND

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare severe cutaneous adverse reactions.

OBJECTIVES

We sought to update knowledge on the causes of SJS or TEN with a focus on the rate of allopurinol-associated cases and to identify risk factors for allopurinol-associated SJS or TEN.

METHODS

We conducted a multinational case-control study.

RESULTS

In all, 379 patients with severe cutaneous adverse reactions validated as SJS or TEN and 1505 matched hospitalized control subjects were enrolled. Allopurinol was the drug most frequently associated with SJS or TEN, with 66 exposed patients (17.4%) and 28 exposed control subjects (1.9%) (adjusted odds ratio = 18, 95% confidence interval: 11-32). Allopurinol use was greater than in a previous case-control European study. Daily doses equal to or greater than 200 mg were associated with a higher risk (adjusted odds ratio = 36, 95% confidence interval: 17-76) than lower doses (adjusted odds ratio = 3.0, 95% confidence interval: 1.1-8.4). The risk was restricted to short-term use (<or=8 weeks). The use of comedications did not increase the risk.

LIMITATIONS

Nonsystematic recording of the indications for allopurinol use was a limitation.

CONCLUSIONS

Results of this multinational study (EuroSCAR) revealed that allopurinol is the drug most commonly associated with SJS or TEN. The incidence of allopurinol-associated SJS or TEN has increased possibly because of increased use and dosages of this drug.

A simple method for quantification of allopurinol and oxipurinol in human serum by high-performance liquid chromatography with UV-detection

OBJECTIVES

Allopurinol is a uric acid lowering drug used in the treatment of gout and the prevention of tumor lysis syndrome. Allopurinol and its active metabolite oxipurinol inhibit xanthine oxidase, which forms uric acid from xanthine and hypoxanthine. Therapeutic drug monitoring is an important option for evaluation and optimization of allopurinol treatment in case of renal impairment, interaction with uricosuric drugs or to verify patient adherence. In this study we developed and validated a simple quantitative assay using reverse phased high-performance liquid chromatography (HPLC) with UV-detection as a method for quantification of allopurinol and oxipurinol in human serum in the presence of different frequently used drugs.

METHODS

The HPLC-UV method uses a mobile phase consisting of sodium acetate (0.02 M; pH 4.5), at a flow rate of 1.0 mL/min. Allopurinol and oxipurinol are detected by UV-absorption at 254 nm with a retention time of 9.9 min for oxipurinol and 12.3 min for allopurinol. Aciclovir is used as internal standard.

RESULTS

Validation showed for allopurinol lower and upper limits of quantification of 0.5 and 10mg/L and for oxipurinol 1 and 40 mg/L, respectively. The assay was linear over the concentration range of 0.5-10mg/L (allopurinol) and 1-40 mg/L (oxipurinol). Intra- and inter-day precision showed coefficients of variation <15% over the complete concentration range; accuracy was within 5% for allopurinol and oxipurinol. Endogenous purine-like compounds were separated from allopurinol, oxipurinol and aciclovir with a resolution factor >1.5. Exogenous purine-like compounds and co-medication frequently used by gout patients did not hinder the analysis due to the dichloromethane washing step or to low UV-absorpion at 253 nm. Serum levels of 66 patients prescribed allopurinol 300 mg/day were determined using this HPLC-UV method. Measured serum allopurinol and oxipurinol concentrations in clinical practice showed large variability with a range of <0.5-4.3 mg/L for allopurinol and <1.0-39.2 mg/L for oxipurinol, respectively.

CONCLUSION

We developed an easy-to-operate and validated HPLC-UV method for the quantification of allopurinol and oxipurinol in human serum. This method was proven to be valid for samples of gout patients frequently using concomitant medications.

Emerging therapies in the long-term management of hyperuricaemia and gout

Gout is a common chronic arthritis that can lead to significant disability. Gout is one of the few rheumatological conditions that can be diagnosed with certainty, has a known cause and can be cured with appropriate therapy. Hypouricaemic agents reduce uric acid concentrations through inhibiting uric acid production (allopurinol) or enhancing uric acid excretion (probenecid, benzbromarone). Allopurinol is the most commonly used hypouricaemic agent but at recommended doses often fails to reduce adequately uric acid concentrations and prevent acute attacks of gout. The use of probenecid is limited by lack of efficacy in renal impairment. In the last few years, new agents in the management of hyperuricaemia and gout have become available. Febuxostat, a new xanthine oxidase inhibitor, is an effective hypouricaemic agent although further data are required for patients with renal impairment and other significant medical conditions. Rasburicase, a recombinant uricase (which catalyses the conversion of uric acid to the more readily excreted allantoin) is available for prevention of tumour lysis syndrome. However, its repeated use, as would be required in chronic gout, is limited by antigenicity. A less antigenic PEGylated uricase can rapidly reduce serum uric acid concentrations and promote resorption of tophi. However, further information with regard to the long-term risks and benefits of these agents is required. These agents may ultimately be used in the short term to rapidly deplete urate stores (induction therapy) followed by long-term therapy with an alternative hypouricaemic agent to prevent subsequent accumulation of uric acid (maintenance therapy).

Management of gout in older adults: barriers to optimal control

Gout, a common inflammatory arthritis, can be diagnosed with absolute certainty. Gout results from the body's reaction to urate crystals deposited in tissues, and this pathophysiology is well understood. If used appropriately, available therapies can be entirely effective in not only treating the symptoms of gout, but also in eliminating the excess urate from the body, thereby eradicating the disease. Because of these facts, management of patients with gout should be successful. However, management of gout is particularly challenging in the elderly, even though the principles of management are the same for all age groups. The purpose of this article is to review these principles and discuss them as they pertain to the elderly. The classic gout attack is acute in onset, extremely painful and associated with marked swelling, warmth, erythema and tenderness of a single joint. However, the diagnosis of gout may be challenging in the elderly because atypical presentations are more common in this group. Treatment of acute gout involves the use of NSAIDs, colchicine, corticosteroids or corticotropin (adrenocorticotropic hormone). Unfortunately, co-morbid conditions such as chronic kidney disease, peptic ulcer disease and congestive heart failure may make the use of these agents dangerous or contraindicated. Thus, it is important to try to treat an acute flare of gout at the earliest sign, because the sooner treatment is initiated, the faster the inflammation will resolve. Urate-lowering agents include allopurinol and uricosuric agents. These also must be used judiciously in the elderly. However, if used at the lowest dose that maintains the serum urate level below 5.0-6.0 mg/dL, the excess urate in the body will be eliminated, acute flares will no longer occur and tophi will resolve. Gout is often seen in association with hypertension, excessive alcohol consumption, obesity and hypertriglyceridaemia. These conditions and the medications used to treat them may contribute to the hyperuricaemia. Treating these conditions and using medications that do not promote hyperuricaemia will aid in the management of gout. Despite the challenges that often complicate the management of gout in the elderly, an understanding of the pathophysiology of the disease and both the indications and limitations of the medications used should allow successful treatment.

Gout in solid organ transplantation: a challenging clinical problem

Hyperuricaemia occurs in 5-84% and gout in 1.7-28% of recipients of solid organ transplants. Gout may be severe and crippling, and may hinder the improved quality of life gained through organ transplantation. Risk factors for gout in the general population include hyperuricaemia, obesity, weight gain, hypertension and diuretic use. In transplant recipients, therapy with ciclosporin (cyclosporin) is an additional risk factor. Hyperuricaemia is recognised as an independent risk factor for cardiovascular disease; however, whether anti-hyperuricaemic therapy reduces cardiovascular events remains to be determined. Dietary advice is important in the management of gout and patients should be educated to partake in a low-calorie diet with moderate carbohydrate restriction and increased proportional intake of protein and unsaturated fat. While gout is curable, its pharmacological management in transplant recipients is complicated by the risk of adverse effects and potentially severe interactions between immunosuppressive and hypouricaemic drugs. NSAIDs, colchicine and corticosteroids may be used to treat acute gouty attacks. NSAIDs have effects on renal haemodynamics, and must be used with caution and with close monitoring of renal function. Colchicine myotoxicty is of particular concern in transplant recipients with renal impairment or when used in combination with ciclosporin. Long-term urate-lowering therapy is required to promote dissolution of uric acid crystals, thereby preventing recurrent attacks of gout. Allopurinol should be used with caution because of its interaction with azathioprine, which results in bone marrow suppression. Substitution of mycophenylate mofetil for azathioprine avoids this interaction. Uricosuric agents, such as probenecid, are ineffective in patients with renal impairment. The exception is benzbromarone, which is effective in those with a creatinine clearance >25 mL/min. Benzbromarone is indicated in allopurinol-intolerant patients with renal failure, solid organ transplant or tophaceous/polyarticular gout. Monitoring for hepatotoxicty is essential for patients taking benzbromarone. Physicians should carefully consider therapeutic options for the management of hypertension and hyperlipidaemia, which are common in transplant recipients. While loop and thiazide diuretics increase serum urate, amlodipine and losartan have the same antihypertensive effect with the additional benefit of lowering serum urate. Atorvastatin, but not simvastatin, may lower uric acid, and while fenofibrate may reduce serum urate it has been associated with a decline in renal function. Gout in solid organ transplantation is an increasing and challenging clinical problem; it impacts adversely on patients' quality of life. Recognition and, if possible, alleviation of risk factors, prompt treatment of acute attacks and early introduction of hypouricaemic therapy with careful monitoring are the keys to successful management.

Correction of allopurinol dosing should be based on clearance of creatinine, but not plasma creatinine levels: another insight to allopurinol-related toxicity

BACKGROUND

Dosing of allopurinol should be corrected depending on renal function, but corrections based on either plasma creatinine (Pcr) or creatinine clearance (CrCl) have been suggested to be minimal standards of care.

METHODS

Data from a cohort database of 484 gouty patients were used to calculate estimated allopurinol doses using CrCl and estimation of the clearance of creatinine using the equation of Cockroft and Gault (CrCl-CG) if, as a hypothesis, a dosage of 300 mg/d would be prescribed in any patient with Pcr <2.0 mg/dL. Also, allopurinol-related toxicity previous to rheumatologic consultation, during previous allopurinol therapy, and the relationship between both and estimated allopurinol doses were reviewed.

RESULTS

The cutoff point of plasma creatinine <2 showed 13% sensitivity and 100% specificity to detect CrCl <50 mL/min. Correlation and agreement between CrCl and CrCl-CG were good, as was the correlation between corrected doses using CrCl and CrCl-CG. One third of patients with Pcr 1.0-1.5 mg/dL and 90% of those with Pcr 1.5-2.0 mg/dL would receive estimated doses over 400 mg/dL/d CrCl. Also, 10% and 34% would receive estimated doses over 600 mg/dL/d CrCl, respectively. Allopurinol-related toxicity previous to consultation (11%) was associated with estimated doses over 400 mg/dL/d CrCl and severe toxicity with estimated doses over 600 mg/dL/d CrCl. When patients were given doses corrected on CrCl, few side effects were observed during follow up (6.7%), and the only severe one was associated with corrected dose over 600 mg/d.

CONCLUSIONS

Dosage adjustment of allopurinol should be based on clearance of creatinine or estimation of glomerular filtration using the Cockcroft-Gault equation. Pcr is insensitive enough to detect renal function impairment so that patients may be placed at risk for overdosing side effects. Corrected doses over 600 mg/dL/d CrCl may be associated with increased risk of severe toxicity.

Gout treatment: What is evidence-based and how do we determine and promote optimized clinical care?

Gout, a common form of inflammatory arthritis, has been markedly understudied relative to other rheumatologic conditions. As a result, evidence guiding clinical management in gout has traditionally been lacking. Burgeoning data suggests that quality of gout care in gout is frequently suboptimal. In this paper, we examine the evidence supporting gout management strategies in clinical practice. In addition, we examine consensus building efforts that have culminated in the recent publication of gout management quality indicators. We also discuss the need for future initiatives aimed at improving patient safety and quality of care in gout.

Febuxostat, a novel nonpurine selective inhibitor of xanthine oxidase: a twenty-eight-day, multicenter, phase II, randomized, double-blind, placebo-controlled, dose-response clinical trial examining safety and efficacy in patients with gout

OBJECTIVE

Gout affects approximately 1-2% of the American population. Current options for treating hyperuricemia in chronic gout are limited. The purpose of this study was to assess the safety and efficacy of febuxostat, a nonpurine selective inhibitor of xanthine oxidase, in establishing normal serum urate (sUA) concentrations in gout patients with hyperuricemia (>or=8.0 mg/dl).

METHODS

We conducted a phase II, randomized, double-blind, placebo-controlled trial in 153 patients (ages 23-80 years). Subjects received febuxostat (40 mg, 80 mg, 120 mg) or placebo once daily for 28 days and colchicine prophylaxis for 14 days prior to and 14 days after randomization. The primary end point was the proportion of subjects with sUA levels <6.0 mg/dl on day 28.

RESULTS

Greater proportions of febuxostat-treated patients than placebo-treated patients achieved an sUA level <6.0 mg/dl at each visit (P < 0.001 for each comparison). The targeted sUA level was attained on day 28 in 0% of those taking placebo and in 56% of those taking 40 mg, 76% taking 80 mg, and 94% taking 120 mg of febuxostat. The mean sUA reduction from baseline to day 28 was 2% in the placebo group and 37% in the 40-mg, 44% in the 80-mg, and 59% in the 120-mg febuxostat groups. Gout flares occurred with similar frequency in the placebo (37%) and 40-mg febuxostat (35%) groups and with increased frequency in the higher dosage febuxostat groups (43% taking 80 mg; 55% taking 120 mg). During colchicine prophylaxis, gout flares occurred less frequently (8-13%). Incidences of treatment-related adverse events were similar in the febuxostat and placebo groups.

CONCLUSION

Treatment with febuxostat resulted in a significant reduction of sUA levels at all dosages. Febuxostat therapy was safe and well tolerated.

Suboptimal physician adherence to quality indicators for the management of gout and asymptomatic hyperuricaemia: results from the UK General Practice Research Database (GPRD)

OBJECTIVES

: To examine adherence to validated quality indicators assessing the quality of allopurinol use in the treatment of gout and asymptomatic hyperuricaemia.

METHODS

We determined physician adherence in the UK General Practice Research Database (GPRD) to three validated quality indicators developed to assess the quality of allopurinol prescribing practices. These indicators were developed to assess: (i) dosing in renal impairment; (ii) concomitant use with azathioprine or 6-mercaptopurine; and (iii) use in the treatment of asymptomatic hyperuricaemia. We also examined the association of patient-level factors (sociodemographics, comorbidity, follow-up duration and concomitant medicine use) with the treatment of asymptomatic hyperuricaemia using multivariable logistic regression.

RESULTS

Of the 63 105 gout patients, 185 (0.3%) were eligible for Quality Indicator 1 and 52 (0.1%) were eligible for Quality Indicator 2. There were an additional 471 patients with asymptomatic hyperuricaemia eligible for Quality Indicator 3. Rates of practice deviation for the three individual quality indicators ranged from 25 to 57%. Male sex, older age, a history of chronic renal failure, and a greater number of concomitant medications were significantly associated with increased odds of inappropriate treatment for asymptomatic hyperuricaemia. Hypertension and diuretic use were associated with lower odds of this practice.

CONCLUSIONS

One-quarter to one-half of all patients eligible for at least one of the validated quality of care indicators were subject to possible allopurinol prescribing error, suggesting that inappropriate prescribing practices are widespread with this agent. Future interventions aimed at reducing inappropriate allopurinol use are needed and should be targeted towards high-risk groups, including older men and those receiving multiple concomitant medications.

Gout and hyperuricemia

Gout continues to be a health problem around the world despite the availability of effective therapies. Although the prevalence is influenced by genetic factors, the associations of alcohol consumption, obesity, and hypertension appear to be partially responsible for the increased prevalence of gout and hyperuricemia in African and Oriental countries. The association between hyperuricemia and cardiovascular disease seems linked to insulin resistance. This relation, in part, explains the common coexistence of hyperlipidemia and glucose intolerance in patients with gout. Accordingly, it is recommended that one pay more attention to dietary manipulation in patients with gout in addition to managing hypertension, obesity, and other medical problems. Although acute gout attacks can be treated, eliminating gout requires effective removal of urate from the body. Allopurinol remains a dominant urate-lowering agent, however its use may be limited by allergic reactions. Uricosuric agents are also effective urate-lowering agents and provide an alternative to allopurinol. Strategies to treat patients who are sensitive to allopurinol continue to evolve.