Clinical and health care use characteristics of patients newly starting allopurinol, febuxostat, and colchicine for the treatment of gout

Febuxostat dose requirement according to renal function in patients who achieve target serum urate levels: A retrospective cohort study

OBJECTIVES

To determine the febuxostat dose requirement according to renal function in patients who achieve target serum urate (SU) levels.

METHODS

Of 3153 gout patients who underwent febuxostat treatment, 873 patients with an initial SU level>6mg/dL were included and categorized by the estimated glomerular filtration rate: normal, chronic kidney disease (CKD) stage 3, and stages 4-5. Ninety-five patients with insufficient follow-up were further excluded. The dose of febuxostat in patients who achieved the SU target (< 6mg/dL) was defined as the average daily dosage at the time of SU target achievement.

RESULTS

The cohort of 778 gout patients had a median age of 52.0 years (IQR, 41.0-63.0) and comprised 711 (91.4%) men. The mean SU at febuxostat initiation was higher in the CKD 4-5 (9.6 [± 3.1] mg/dL) than in the other groups (CKD 3, 8.7 [± 1.7]; normal, 8.4 [± 1.7]; P<0.001). Patients achieved target SU at a median of 4.0 (1.9-9.6) months and in those who achieved target SU, the dose of febuxostat at the time of SU target achievement was significantly lower in the CKD 4-5 group (50.0 [± 16.5] mg) than in the other groups (vs. CKD stage 3, 60.0 [± 19.5] mg; P<0.01, vs. normal, 60.0 [± 19.8] mg; P<0.01). Furthermore, CKD stage 4-5 had a negative correlation with the febuxostat dose requirement (Beta: -2.334, P<0.05).

CONCLUSION

Among patients who achieved SU target, those with severely decreased renal function (CKD 4-5) required a lower febuxostat dose to achieve the target SU level compared to patients with normal or mild renal impairment.

Colchicine linked with risk reduction for myocardial infarction in gout patients: systematic review and meta-analysis

INTRODUCTION

This meta-analysis aimed to identify the effect of colchicine on myocardial infarction (MI) in patients with gout.

METHODS

In February 2021, a systematic computer-based search was conducted in PubMed, EMBASE, and Cochrane Database of Systematic Reviews. Data on patients with gout that compared colchicine versus others (no use of colchicine) were retrieved. The endpoints were the incidence rate for MI. After testing for heterogeneity between studies, data were aggregated for fixed-effects models when necessary.

RESULTS

Three clinical studies with 3012 patients (colchicine group = 1523, control group = 1489) were finally included in the meta-analysis. Colchicine was associated with a decreased risk for myocardial infarction (pooled odds ratio 0.35, 95% confidence interval 0.23-0.55, p < 0.00001).

CONCLUSIONS

Colchicine was effective in reducing the incidence of MI in patients with gout.

Cardiovascular risk and mortality in patients with hyperuricemia treated with febuxostat or allopurinol: a retrospective nation-wide cohort study in Austria 2014-2017

Patients with hyperuricemia and gout are at an increased risk for cardiovascular (CV) disease. Inhibition of the xanthine oxidase with allopurinol or febuxostat have become the mainstay for urate lowering therapy. However, it has been suggested that febuxostat increases the risk for CV mortality as compared to allopurinol. The aim of this retrospective cohort study was to assess the CV risk among patients with febuxostat or allopurinol therapy. Patients who initiated urate lowering therapy with febuxostat or allopurinol between 2014 and 2017 were selected from the drug reimbursement database of the Austrian health insurances funds. The primary CV endpoint was a composite of angina pectoris, nonfatal myocardial infarction, nonfatal subarachnoid or cerebral hemorrhage, nonfatal ischemic stroke, or death from any cause. In total, 28.068 patients (62.1% male) with a mean age of 71 years were included. 7.767 initiated febuxostat treatment and 20.301 received allopurinol. The incidence rate per 100 patient-years of the composite primary endpoint was 448 (febuxostat) and 356 (allopurinol) with a corresponding adjusted hazard ratio (HR) of 0.58 (95% CI 0.53–0.63) for allopurinol vs. febuxostat initiators. Similar HR were found for secondary endpoints including all-cause mortality [0.61 (95% CI 0.55–0.68)] and separate analyses of cardiac events [0.48 (95% CI 0.38–0.61)] and ischemic stroke [0.47 (95% CI 0.36–0.61)]. Data from this Austrian population-based study suggests that febuxostat initiators are at an increased risk for nonfatal CV events or death from any cause as compared to those with allopurinol. This is consistent with CV concerns of other trials, which limited the broad therapeutic use of febuxostat.

Design, synthesis and bioactive evaluation of geniposide derivatives for antihyperuricemic and nephroprotective effects

Hyperuricemia is a principal factor mediating gout and kidney damage, and xanthine oxidase (XOD) is a key enzyme in the pathogenesis of hyperuricemia. In this context, a series of geniposide derivatives were designed and synthesized, and antihyperuricemic and nephroprotective effects of all derivatives was evaluated in vitro and in vivo. Compound 2e emerged as the most potent XOD inhibitor, with an IC₅₀ value of 6.67 ± 0.46 µM. Simultaneously, cell viability, ROS generation, and SOD levels assay showed that compound 2e could repair the damage of HKC cells by inhibiting the oxidative stress response. The results of the study indicated compound 2e significantly decreased uric acid levels by inhibiting the XOD activity, and repaired kidney damage by inhibiting the expression of TLR4/TLR2/MyD88/NF-κB and NALP3/ASC/caspase-1 signaling pathways. Enzyme inhibition kinetics suggested that compound 2e functioned via reversible mixed competitive inhibition. Moreover, a molecular docking study was performed to gain insight into the binding mode of compound 2e with XOD. These results suggest that geniposide derivatives were potential to be developed into a novel medicine to reveal healthy benefits in natural prevention and reduction risk of hyperuricemia and kidney damage.

Assessment of Cardiovascular Risk in Older Patients With Gout Initiating Febuxostat Versus Allopurinol: Population-Based Cohort Study

BACKGROUND

Hyperuricemia and gout are associated with an increased risk of cardiovascular disease. Xanthine oxidase inhibitors, allopurinol and febuxostat, are the mainstay of urate-lowering treatment for gout and may have different effects on cardiovascular risk in patients with gout.

METHODS

Using US Medicare claims data (2008-2013), we conducted a cohort study for comparative cardiovascular safety of initiating febuxostat versus allopurinol among patients with gout ≥65 years of age. The primary outcome was a composite end point of hospitalization for myocardial infarction or stroke. Secondary outcomes were individual end points of hospitalization for myocardial infarction, stroke, coronary revascularization, new and recurrent heart failure, and all-cause mortality. We used propensity score matching with a ratio of 1:3 to control for confounding. We estimated incidence rates and hazard ratios for primary and secondary outcomes in the propensity score-matched cohorts of febuxostat and allopurinol initiators.

RESULTS

We included 24 936 febuxostat initiators propensity score-matched to 74 808 allopurinol initiators. The median age was 76 years, 52% were male, and 12% had cardiovascular disease at baseline. The incidence rate per 100 person-years for the primary outcome was 3.43 in febuxostat and 3.36 in allopurinol initiators. The hazard ratio for the primary outcome was 1.01 (95% CI, 0.94-1.08) in the febuxostat group compared with the allopurinol group. Risk of secondary outcomes including all-cause mortality was similar in both groups, except for a modestly decreased risk of heart failure exacerbation (hazard ratio, 0.94; 95% CI, 0.91-0.99) in febuxostat initiators. The hazard ratio for all-cause mortality associated with long-term use of febuxostat (>3 years) was 1.25 (95% CI, 0.56-2.80) versus allopurinol. Subgroup and sensitivity analyses consistently showed similar cardiovascular risk in both groups.

CONCLUSIONS

Among a cohort of 99 744 older Medicare patients with gout, overall there was no difference in the risk of myocardial infarction, stroke, new-onset heart failure, coronary revascularization, or all-cause mortality between patients initiating febuxostat compared with allopurinol. However, there seemed to be a trend toward an increased, albeit not statistically significant, risk for all-cause mortality in patients who used febuxostat for >3 years versus allopurinol for >3 years. The risk of heart failure exacerbation was slightly lower in febuxostat initiators.

The impact of adoption of a new urate-lowering agent on trends in utilization and cost in practice

OBJECTIVES

Changes in treatment choice of therapy and size of treated population that can lead to under- or overestimate of payer's budget are less likely to be reassured after reimbursement adoption of a new drug. The aim of this study was to evaluate the effects of febuxostat introduction and the modifications in its insurance coverage on the utilization and expenditure of urate-lowering therapy (ULT).

METHODS

Electronic medical records for adults patients prescribed any ULT during 2010-2015 was derived from the largest medical organization in Taiwan. Aggregated estimates of ULT use and costs were assessed per 3-month and per patient per month (PPPM). Factors associated with total ULT expenditure were assessed using a time series design with factored Autoregressive Integrated Moving Average (ARIMA) models.

RESULTS

ULT prevalent users increased 34.1% from 2010 to 2015 and a 123% increase in total ULT expenditure. Numbers on allopurinol and sulfinpyrazone both declined 31%, and on benzbromarone and febuxostat gradually increased to 38.21% and 22.89% of all users in 2015. Insurance payments PPPM ($4.44 to $9.22) and total monthly ULT cost ($32,946 to $ 85,732) growth more than doubled in 6 years, trend changes generated mostly by individuals switching to febuxostat.

CONCLUSIONS

ULT use moved to favor benzbromarone and febuxostat; greater expensive uptake for febuxostat led to a rapid rise in ULT cost. Marginal values of increasing access to febuxostat for asymptomatic hyperuricemia should be focus on future studies to facilitate drug prices negotiation and ensure appropriate ULT use.

Effects of Discontinuation of Urate-Lowering Therapy: A Systematic Review

BACKGROUND

Urate-lowering therapy (ULT) is associated with low rates of adherence, leading to a potential risk of relapse of gouty arthritis, tophi, or urolithiasis. Our main aim was to identify the recurrence of gouty arthritis, tophi, or urolithiasis after discontinuation of ULT. Secondary aims included an assessment of ULT reintroduction rates and factors associated with relapse.

METHODS

We conducted a systematic literature review of clinical studies investigating the effect of discontinuing any ULT (allopurinol, febuxostat, probenecid, sulfinpyrazone, benzbromarone) in adults on long-term therapy. We searched The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Science Citation Index, and ClinicalTrials.gov from inception to March 2016. Conference abstracts of the ACR/ARHP and EULAR annual conferences were hand-searched. Study quality was assessed using the first eight items of the methodological index for non-randomized studies (MINORS) tool. The review protocol is registered with PROSPERO (CRD42016042048).

RESULTS

A total of 4640 articles were identified, eight of which were ultimately included. Most of these studies predated 2000. MINORS scores ranged from 5 to 10 out of a possible 16. Mean follow-up duration after discontinuation ranged from 12 to 96 months. Five studies focused on discontinuation of ULT in gouty arthritis and tophi, two in urolithiasis, and one in asymptomatic hyperuricemia. Relapse rates were high in gout (36-81%) and lower in urolithiasis (15%). Relapses occurred 1-4.5 years after ULT discontinuation. In one study, a low serum urate level before and after ULT discontinuation was associated with lower gout recurrence.

DISCUSSION

Relapse of gout is common although delayed after discontinuation of ULT. Short-term prognosis after ULT discontinuation appears favorable if the serum urate level was low before ULT discontinuation. The results of this review are limited by the paucity of existing studies and their low quality. Further comparative studies should consider larger primary care populations and discontinuation of febuxostat.

Major Cardiovascular Events in Patients with Gout and Associated Cardiovascular Disease or Heart Failure and Chronic Kidney Disease Initiating a Xanthine Oxidase Inhibitor

BACKGROUND

Several observational studies and meta-analyses have suggested that treating hyperuricemia in patients with gout and moderate or severe chronic kidney disease (CKD) may improve renal and cardiovascular (CV) outcomes.

OBJECTIVE

To evaluate the impact of initiating allopurinol or febuxostat treatment on major CV events in patients with gout, preexisting CV disease (CVD) or heart failure (HF), and stage 3 or 4 CKD in a real-world setting.

METHODS

Patients with gout (aged >18 years) who initiated allopurinol or febuxostat treatment between 2009 and 2013 after a diagnosis of stage 3 or 4 CKD and CVD-including coronary artery disease (CAD), cerebrovascular disease, and peripheral vascular disease (PVD)-or HF were selected from the MarketScan databases. The major CV events included CAD-specific, cerebrovascular disease-specific, and PVD-specific events. Cox proportional hazards modeling identified the predictors of major CV events in aggregate, and of CAD, cerebrovascular disease, and PVD events, individually.

RESULTS

During follow-up, 2426 patients (370 receiving febuxostat and 2056 receiving allopurinol; 63% male; mean age, 73 years) had 162 major CV events (3.8% in those receiving febuxostat vs 7.2% in those receiving allopurinol; P = .015). The rates of major CV events per 1000 person-years were 51.8 (95% confidence interval [CI], 28-87) in patients initiating febuxostat and 99.3 (95% CI, 84-117) among those initiating allopurinol. Overall, 49.4% of patients had a CAD event, 32.5% had a PVD event, and 23.5% had a cerebrovascular disease-specific event. Febuxostat initiation was associated with a significantly lower risk for a major CV event versus patients who initiated allopurinol (hazard ratio, 0.52; P = .02), driven in large part by lower PVD-specific events (P = .026).

CONCLUSION

Patients with moderate-to-severe CKD and CVD or HF who initiated febuxostat treatment had a significantly lower rate of major CV events than patients who initiated allopurinol.

Predictors of reaching a serum uric acid goal in patients with gout and treated with febuxostat

Purpose

Clinical guidelines recommend febuxostat as first-line pharmacologic urate-lowering therapy for patients with gout to achieve a goal serum uric acid (sUA) <6 mg/dL; however, little is known about other contributing factors. This study identified clinical characteristics of patients treated with febuxostat to develop and validate a predictive model for achieving a goal sUA.

Patients and methods

Patients with Humana Medicare or commercial insurance, diagnosed with gout and newly initiated on febuxostat (index date February 1, 2009 – December 31, 2013), were identified for a retrospective cohort study. Patients were followed for 365 days and the first valid sUA test result ≥120 days after index was retained. A stepwise logistic regression with backward elimination was estimated to model sUA goal attainment, and a linear model was estimated to model the impact of predictor variables on sUA level.

Results

The study sample (n=678) was divided into a development (training) dataset (n=453) and a validation (holdout) dataset (n=225). In the training sample, patients in the sUA <6 mg/dL group were on febuxostat for a longer time, were more adherent, and had a lower average base-line sUA level (all p<0.0001) vs patients in the sUA ≥6 mg/dL group. In the logistic model, febuxostat adherence (odds ratio [OR]=1.03, p<0.0001) and baseline sUA level (OR=0.84, p<0.0001) increased the odds of attaining sUA <6 mg/dL. In the linear regression model, increase in febuxostat adherence (p<0.0001), baseline sUA level (p<0.0001), advanced age (p=0.0021), and not having congestive heart failure (p<0.05) were associated with a reduction of sUA level. Pre-index allopurinol use was a marginally significant predictor of sUA level reduction (p=0.06).

Conclusions

Among febuxostat users diagnosed with gout in a real-world setting, adherence to febuxostat and lower baseline sUA level were the strongest predictors of attaining sUA goal. These findings may help clinicians to identify appropriate patients most likely to benefit from febuxostat treatment, and underscore the importance of medication adherence in this challenging patient population.

Xanthine oxidoreductase and its inhibitors: relevance for gout

Xanthine oxidoreductase (XOR) is the rate-limiting enzyme in purine catabolism and converts hypoxanthine to xanthine, and xanthine into uric acid. When concentrations of uric acid exceed its biochemical saturation point, crystals of uric acid, in the form of monosodium urate, emerge and can predispose an individual to gout, the commonest form of inflammatory arthritis in men aged over 40 years. XOR inhibitors are primarily used in the treatment of gout, reducing the formation of uric acid and thereby, preventing the formation of monosodium urate crystals. Allopurinol is established as first-line therapy for gout; a newer alternative, febuxostat, is used in patients unable to tolerate allopurinol. This review provides an overview of gout, a detailed analysis of the structure and function of XOR, discussion on the pharmacokinetics and pharmacodynamics of XOR inhibitors-allopurinol and febuxostat, and the relevance of XOR in common comorbidities of gout.

Dual-energy computed tomography has limited diagnostic sensitivity for short-term gout

The aim of this study was to discuss the diagnostic value of dual-energy computed tomography (DECT) in patients with gout during different disease phases. Two hundred twenty-one patients (136 with gout and 85 with other arthritic diseases) were recruited to the study. Arthrosis pain was evaluated in all patients by DECT scans. We calculated the sensitivity and specificity of DECT for the diagnosis of gout, including the first onset period, less than 24 months period, and more than 24 months period. We then investigated the related risk factors of urate crystals volume in the foot. The diagnostic sensitivity of DECT in the first onset, less than 24 months, and more than 24 months groups was 35.71, 61.54, and 92.86%, respectively. The overall sensitivity and specificity values were 80.88 and 88.24%, respectively. The multilinear regression analysis showed that longer disease duration (P = 0.001) and higher serum uric acid (SUA) (P = 0.001) were the two important predictive factors of the monosodium urate (MSU) crystal volume in the foot. DECT provides good diagnostic accuracy for detection of MSU crystal deposits in gout patients. However, DECT has limited diagnostic sensitivity for short-term gout patients, especially for the first onset patients. Longer disease duration and higher SUA were predictive factors of MSU crystal volume.

Cost Comparison of Urate-Lowering Therapies in Patients with Gout and Moderate-to-Severe Chronic Kidney Disease

BACKGROUND

Patients with chronic kidney disease (CKD) are at increased risk for developing gout and having refractory disease. Gout flare prevention relies heavily on urate-lowering therapies such as allopurinol and febuxostat, but clinical decision making in patients with moderate-to-severe CKD is complicated by significant comorbidity and the scarcity of real-world cost-effectiveness studies.

OBJECTIVE

To compare total and disease-specific health care expenditures by line of therapy in allopurinol and febuxostat initiators after diagnosis with gout and moderate-to-severe CKD.

METHODS

A retrospective observational cohort study was conducted to compare mean monthly health care cost (in 2012 U.S. dollars) among gout patients with CKD (stage 3 or 4) who initiated allopurinol or febuxostat. The primary outcome was total mean monthly health care expenditures, and the secondary outcome was disease-specific (gout, diabetes, renal, and cardiovascular disease [CVD]) expenditures. Gout patients (ICD-9-CM 274.xx) aged ≥ 18 years with concurrent CKD (stage 3 or 4) were selected from the MarketScan databases (January 2009-June 2012) upon allopurinol or febuxostat initiation. Patients were followed until disenrollment, discontinuation of the qualifying study agent, or use of the alternate study agent. Patients initiating allopurinol were subsequently propensity score-matched (1:1) to patients initiating febuxostat. Five generalized linear models (GLMs) were developed, each controlling for propensity score, to identify the incremental costs (vs. allopurinol) associated with febuxostat initiation in first-line (without prior allopurinol exposure) and second-line (with prior allopurinol exposure) settings.

RESULTS

Propensity score matching yielded 2 cohorts, each with 1,486 patients (64.6% male, mean [SD] age 67.4 [12.8] years). Post-match, 74.6% of patients had stage 3 CKD; 82.9% had CVD; and 42.1% had diabetes. The post-match sample was well balanced on numerous comorbidities and medication exposures with the following exception: 50.0% of febuxostat initiators were treated in the second-line setting; that is, they had baseline exposure to allopurinol, whereas only 4.2% of allopurinol initiators had baseline exposure to febuxostat. Unadjusted mean monthly cost was $1,490 allopurinol and $1,525 febuxostat (P = 0.809). GLM results suggest that first-line febuxostat users incurred significantly (P = 0.009) lower cost than allopurinol users ($1,299 vs. $1,487), whereas second-line febuxostat initiators incurred significantly (P = 0.001) higher cost ($1,751 vs. $1,487). Febuxostat initiators in both settings had significantly (P < 0.001) higher gout-specific cost, due to higher febuxostat acquisition cost. Increased gout-specific cost in the first-line febuxostat cohort was offset by significantly (P < 0.001) lower CVD ($288 vs. $459) and renal-related cost ($86 vs. $216). There were no significant differences in either renal or CVD costs (adjusted) between allopurinol initiators treated almost exclusively in the first-line setting and second-line febuxostat patients.

CONCLUSIONS

Gout patients with concurrent CKD, initiating treatment with febuxostat in a first-line setting, incurred significantly less total cost than patients initiating allopurinol during the first exposure to each agent. Conversely, patients treated with second-line febuxostat following allopurinol incurred significantly higher total cost than patients initiating allopurinol. There was no significant difference in total cost between the agents across line of therapy. Although study findings suggest the potential for CVD and renal-related savings to offset febuxostat's higher acquisition cost in gout patients with moderate-to-severe CKD, this is the first such retrospective evaluation. Future research is warranted to both demonstrate the durability of study findings and to better elucidate the mechanism by which associated cost offsets occur.

DISCLOSURES

No outside funding supported this study. Turpin is an employee of Takeda Pharmaceuticals U.S.A. Mitri and Wittbrodt were employees of Takeda Pharmaceuticals U.S.A. at the time of this study. Tidwell and Schulman are employees of Outcomes Research Solutions, consultants to Takeda Pharmaceuticals U.S.A. All authors contributed to the design of the study and to the writing and review of the manuscript. All authors read and approved the final manuscript. Tidwell and Schulman collected the data, and all authors participated in data interpretation.

A Real-World Study of Switching From Allopurinol to Febuxostat in a Health Plan Database

OBJECTIVE

The objective of this study was to assess the real-world comparative effectiveness of continuing on allopurinol versus switching to febuxostat.

METHODS

In a retrospective claims data study of enrollees in health plans affiliated with Optum, we evaluated patients from February 1, 2009, to May 31, 2012, with a gout diagnosis, a pharmacy claim for allopurinol or febuxostat, and at least 1 serum uric acid (SUA) result available during the follow-up period. Univariate and multivariable-adjusted analyses (controlling for patient demographics and clinical factors) assessed the likelihood of SUA lowering and achievement of target SUA of less than 6.0 mg/dL or less than 5.0 mg/dL in allopurinol continuers versus febuxostat switchers.

RESULTS

The final study population included 748 subjects who switched to febuxostat from allopurinol and 4795 continuing users of allopurinol. The most common doses of allopurinol were 300 mg/d or less in 95% of allopurinol continuers and 93% of febuxostat switchers (prior to switching); the most common dose of febuxostat was 40 mg/d, in 77% of febuxostat switchers (after switching). Compared with allopurinol continuers, febuxostat switchers had greater (1) mean preindex SUA, 8.0 mg/dL versus 6.6 mg/dL (P < 0.001); (2) likelihood of postindex SUA of less than 6.0 mg/dL, 62.2% versus 58.7% (P = 0.072); (3) likelihood of postindex SUA of less than 5.0 mg/dL, 38.9% versus 29.6% (P < 0.001); and (4) decrease in SUA, 1.8 (SD, 2.2) mg/dL versus 0.4 (SD, 1.7) mg/dL (P < 0.001). In multivariable-adjusted analyses, compared with allopurinol continuers, febuxostat switchers had significantly higher likelihood of achieving SUA of less than 6.0 mg/dL (40% higher) and SUA of less than 5.0 mg/dL (83% higher).

CONCLUSIONS

In this "real-world" setting, many patients with gout not surprisingly were not treated with maximum permitted doses of allopurinol. Patients switched to febuxostat were more likely to achieve target SUA levels than those who continued on generally stable doses of allopurinol.

Risk of incident atrial fibrillation in gout: a cohort study

OBJECTIVE

Atrial fibrillation (AF) is the most common arrhythmia associated with cardiovascular disease and mortality. Recent studies suggest an association between inflammation, hyperuricaemia and AF, but little is known whether gout is associated with AF risk.

METHODS

Using data from a US commercial insurance plan (2004-2013), we conducted a cohort study to evaluate the risk of incident AF in patients with gout versus osteoarthritis. Patients with gout or osteoarthritis were identified with ≥2 diagnoses and ≥1 dispensing for gout or osteoarthritis medications. Incident AF was defined as a new AF diagnosis and a new dispensing for anticoagulants or antiarrhythmics. The risk of incident AF in gout was also compared with the non-gout group.

RESULTS

We identified 70 015 patients with gout and 210 045 with osteoarthritis, matched on age, sex and index date. The mean age was 57 years, and 81% were men. Over the mean 2-year follow-up, the incidence rate of AF per 1000 person-years was 7.19 in gout and 5.87 in osteoarthritis. The age, sex and index date-matched HR of AF was 1.23 (95% CI 1.14 to 1.32) in gout versus osteoarthritis. In a multivariable Cox regression, adjusting for age, sex, comorbidities, medications and healthcare usage, the HR of AF in gout was 1.13 (95% CI 1.04 to 1.23). When compared with non-gout, the multivariable HR of AF in gout was also increased (HR 1.21, 95% CI 1.11 to 1.33).

CONCLUSIONS

In this large population-based cohort study, gout was associated with a modestly increased risk of incident AF compared with osteoarthritis and non-gout after adjusting for other risk factors.

Comorbidity Burden in Trial-Aligned Patients with Established Gout in Germany, UK, US, and France: a Retrospective Analysis

Introduction

Patients with gout have numerous comorbidities. We aimed to estimate the prevalence and incidence rates of renal and cardiovascular morbidities in trial-aligned patients with established gout in Germany (DE), the United Kingdom (UK), the United States (US), and France (FR).

Methods

This longitudinal cohort study used retrospective data from IMS Disease Analyzer™ (DE, FR), Clinical Practice Research Datalink–Hospital Episode Statistics (UK), and IMS’ PharMetrics Plus database linked with outpatient laboratory results (US). Included patients were ≥18 years at index date (January 1, 2010; all dates +1 year for FR), with continuous enrollment during the pre-index year, had “prevalent established gout” determined by data in the pre-index year, and ≥1 documented visit after index date; additional inclusion/exclusion criteria were aligned with recent gout clinical trials. Look-back for comorbidity prevalence extended to January 1, 2003 (US: January 1, 2009). Follow-up for incidence extended from index date to at most March 26, 2013 (FR: May 31, 2014). Events of interest were identified by diagnostic codes and/or laboratory data.

Results

The trial-aligned cohorts included 35,118 (DE), 24,607 (UK), 121,591 (US), and 17,338 (FR) patients. Among renal conditions, baseline diagnosis of chronic kidney disease/renal failure was most prevalent in the UK followed by DE; abnormal serum creatinine was most prevalent in the UK. Hypertension was the most prevalent cardiovascular diagnosis in all countries, followed by ischemic heart disease (IHD) and myocardial infarction. Incidence rates (per 100 patient-years) for new/worsening renal impairment ranged from 1.67 (DE) to 4.34 (US) and for nephrolithiasis diagnosis from 0.31 (FR) to 3.79 (US). The incidence rates for hypertension diagnosis were highest among cardiovascular-related events, ranging from 3.23 (UK) to 20.27 (US), followed by IHD.

Conclusions

Patients with established gout such as those included in gout trials have a high burden of established morbidity and new diagnoses of morbid events. Consideration of comorbidities, which greatly exacerbate disease burden, is important in gout management.

Funding

AstraZeneca.

Electronic supplementary material

The online version of this article (doi:10.1007/s12325-016-0346-1) contains supplementary material, which is available to authorized users.

Dual-energy computed tomography for monitoring the effect of urate-lowering therapy in gouty arthritis

OBJECTIVE

To investigate the relationships between changes in serum urate levels and dual-energy computed tomography (DE-CT) results during urate-lowering therapy (ULT) and to investigate the effects of treatment duration and drugs on changes in DE-CT results.

METHODS

Forty-four patients diagnosed with gout were enrolled in this investigation. DE-CT was conducted on the foot at baseline and the end of follow-up (6-24 months). Crystals were classified as: (i) L, number of large crystals with diameter ≥ 3 mm; (ii) S, number of small crystals with diameter < 3 mm; (iii) T, total number of crystals; and (iv) Vmax, volume of the maximal crystal.

RESULTS

Number of urate crystals (L, S as well as T) and Vmax decreased significantly through ULT. Significant decrease of urate crystal numbers and/or Vmax was observed in different follow-up groups, and the decrease in serum urate levels was positively related to the decrease of T (r = 0.43, P = 0.04) and Vmax (r = 0.63, P = 0.04). Moreover, analysis of covariance results demonstrated significant effects of treatment duration and serum urate levels on results of DE-CT.

CONCLUSION

Both urate crystal numbers and Vmax decreased significantly during ULT. Additionally, ULT duration and serum urate levels had significant effects on the decrease of Vmax and number of large crystals measured by DE-CT.

Effects of xanthine oxidase inhibitors on cardiovascular disease in patients with gout: a cohort study

BACKGROUND

Hyperuricemia and gout are associated with an increased risk of cardiovascular disease (CVD). It is unknown whether treating hyperuricemia with xanthine oxidase inhibitors (XOIs), including allopurinol and febuxostat, modifies cardiovascular risks.

METHODS

We used US insurance claims data to conduct a cohort study among gout patients, comparing XOI initiators with non-users with hyperuricemia defined as serum uric acid level ≥6.8 mg/dL. We calculated incidence rates of a composite nonfatal cardiovascular outcome that included myocardial infarction, coronary revascularization, stroke, and heart failure. Propensity score (PS)-matched Cox proportional hazards regression compared the risk of composite cardiovascular endpoint in XOI initiators vs those with untreated hyperuricemia, controlling for baseline confounders. In a subgroup of patients with uric acid levels available, PS-matched Cox regression further adjusted for baseline uric acid levels.

RESULTS

There were 24,108 PS-matched pairs with a mean age of 51 years and 88% male. The incidence rate per 1000 person-years for composite CVD was 24.1 (95% confidence interval [CI] 22.6-26.0) in XOI initiators and 21.4 (95% CI, 19.8-23.2) in the untreated hyperuricemia group. The PS-matched hazard ratio for composite CVD was 1.16 (95% CI, 0.99-1.34) in XOI initiators vs those with untreated hyperuricemia. In subgroup analyses, the PS-matched hazard ratio for composite CVD adjusted for serum uric acid levels was 1.10 (95% CI, 0.74-1.64) among XOI initiators.

CONCLUSIONS

Among patients with gout, initiation of XOI was not associated with an increased or decreased cardiovascular risk compared with those with untreated hyperuricemia. Subgroup analyses adjusting for baseline uric acid levels also showed no association between XOI and cardiovascular risk.

Comparative effectiveness of urate lowering with febuxostat versus allopurinol in gout: analyses from large U.S. managed care cohort

Introduction

To assess the comparative effectiveness of febuxostat and allopurinol in reducing serum urate (sUA) levels in a real-world U.S. managed care setting.

Methods

This retrospective study utilized 2009 to 2012 medical and pharmacy claims and laboratory data from a large U.S. commercial and Medicare Advantage health plan. Study patients had at least one medical claim with a diagnosis of gout, at least one filled prescription for febuxostat or allopurinol and at least one sUA measurement post-index prescription. Reduction in sUA was examined using propensity score-matched cohorts, matched on patient demographics (gender, age), baseline sUA, comorbidities, geographic region and insurance type.

Results

The study sample included 2,015 patients taking febuxostat and 14,025 taking allopurinol. At baseline, febuxostat users had a higher Quan-Charlson comorbidity score (0.78 vs. 0.53; P <0.001), but similar age and gender distribution. Mean (standard deviation (SD)) sUA level following propensity score matching among treatment-naïve febuxostat vs. allopurinol users (n = 873 each) were: pre-index sUA, 8.86 (SD, 1.79) vs. 8.72 (SD, 1.63; P = 0.20); and post-index sUA, 6.53 (SD, 2.01) vs. 6.71 (SD, 1.70; P = 0.04), respectively. A higher proportion of febuxostat users attained sUA goals of <6.0 mg/dl (56.9% vs. 44.8%; P <0.001) and <5.0 mg/dl (35.5% vs. 19.2%; P <0.001), respectively. Time to achieve sUA goals of <6.0 mg/dl (346 vs. 397 days; P <0.001) and <5.0 mg/dl was shorter in febuxostat vs. allopurinol users (431 vs. 478 days; P <0.001), respectively. Similar observations were made for overall propensity score-matched cohorts that included both treatment-naïve and current users (n = 1,932 each).

Conclusions

Febuxostat was more effective than allopurinol at the currently used doses (40 mg/day for febuxostat in 83% users and 300 mg/day or lower for allopurinol in 97% users) in lowering sUA in gout patients as demonstrated by post-index mean sUA level, the likelihood of and the time to achieving sUA goals.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0624-3) contains supplementary material, which is available to authorized users.

Comparison of new-onset gout in adults prescribed chlorthalidone vs. hydrochlorothiazide for hypertension

This study assessed the risk of new-onset gout following prescribing of hydrochlorothiazide (HCTZ) compared with chlorthalidone (CTD). This retrospective cohort analysis used administrative claims from 2000 to 2012 to identify patients aged 18 to 89 years with hypertension who were prescribed CTD or HCTZ. Patients were excluded if they had a prior diagnosis of gout, conditions or prescription claims for medications that alter risk of gout, or if they switched between these two diuretics. A total of 1011 patients prescribed CTD were matched with 2022 patients prescribed HCTZ based on age, sex, and Chronic Condition Indicator. New-onset gout occurred in 17 of 1011 (1.68%) patients in the CTD group and in 26 of 2022 (1.29%) patients in the HCTZ group (P=.27). The number of days to first occurrence of gout was 183.6 days and 152.7 days in the CTD and HCTZ groups, respectively (P=.39). The mean daily dose was 22.7 mg for CTD and 24.3 mg for HCTZ, and the median dose of both CTD and HCTZ was 25 mg at the time of new-onset gout. Patients prescribed CTD for hypertension have a similar risk of developing new-onset gout compared with patients prescribed similar doses of HCTZ.