A lifetime economic research of universal HLA-B*58:01 genotyping or febuxostat initiation therapy in Chinese gout patients with mild to moderate chronic kidney disease.

OBJECTIVE: To evaluate Chinese long-term economic impact of universal human leukocyte antigen B (HLA-B)*58:01 genotyping-guided urate-lowering therapy or febuxostat initiation therapy for gout patients with mild to moderate chronic kidney disease (CKD) from perspective of healthcare system. METHODS: A Markov model embedded in a decision tree was structured including four mutually exclusive health states (uncontrolled-on-therapy, controlled-on-therapy, uncontrolled-off-therapy, and death). Mainly based on Chinese real-world data, the incremental costs per quality-adjusted life years (QALYs) gained were evaluated from three groups (universal HLA-B*58:01 testing strategy, and no genotyping prior to allopurinol or febuxostat initiation therapy) at 25-year time horizon. All costs were adjusted to 2021 levels based on Chinese Consumer Price Index and were discounted by 5% annually. One-way and probability sensitivity analysis were performed. RESULTS: Among these three groups, universal HLA-B*58:01 genotyping was the most cost-effective strategy in base-case analysis according to Chinese average willingness-to-pay threshold of $37 654.50 per QALY. The based incremental cost-effectiveness ratio was $31784.55 per QALY, associated with 0.046 additional QALYs and $1463.81 increment costs per patient at a 25-year time horizon compared with no genotyping prior to allopurinol initiation strategy. Sensitivity analysis showed 64.3% robustness of these results. CONCLUSION: From Chinese perspective of healthcare system, HLA-B*58:01 genotyping strategy was cost-effective for gout patients with mild to moderate CKD in mainland China, especially in the most developed area, such as Beijing and Shanghai. Therefore, we suggest China's health authorities choose the genotyping strategy and make different recommendations according to the differences of local conditions.

Gout prevalence in the Hmong: a prime example of health disparity and the role of community-based genetic research.

Individuals of distinct Asian backgrounds are commonly aggregated as Asian, which could mask the differences in the etiology and prevalence of health conditions in the different Asian subgroups. The Hmong are a growing Asian subgroup in the United States with a higher prevalence of gout and gout-related comorbidities than non-Hmong. Genetic explorations in the Hmong suggest a higher prevalence of genetic polymorphisms associated with an increased risk of hyperuricemia and gout. History of immigration, acculturation, lifestyle factors, including dietary and social behavioral patterns, and the use of traditional medicines in the Hmong community may also increase the risk of developing gout and lead to poor gout management outcomes. Engaging minorities such as the Hmong population in biomedical research is a needed step to reduce the burden of health disparities within their respective communities, increase diversity in genomic studies, and accelerate the adoption of precision medicine to clinical practice.

People of different Asian heritage are commonly grouped as Asian, which could mask the differences in the causes and rates of specific health conditions in the different Asian subgroups. The Hmong are a growing Asian group in the United States with higher gout rates and gout-related conditions than non-Hmong. Genetic research in the Hmong suggests higher rates of genetic changes associated with higher urate levels and increased gout risk. The immigration to the United States and adaptation to the Western lifestyle could also affect the Hmong's risk for developing elevated urate levels and gout. Some lifestyle factors, including dietary and social behavioral patterns, and the use of traditional medicines in the Hmong, may also increase their risk of developing gout and lead to poor gout management. Engaging minorities such as the Hmong population in clinical research is a needed step to reduce the burden of health disparities within their respective communities, increase diversity in genetic studies, and widen the application of precision medicine to clinical practice.

Cost-effectiveness of sequential urate lowering therapies for the management of gout in Singapore.

Aims: Allopurinol is the most common urate lowering therapy (ULT) used to treat gout but may cause life-threatening severe cutaneous adverse reactions (SCAR) in a small number of patients. Risk of SCAR is increased for patients with the HLA-B*58:01 genotype. When alternative ULT is required, febuxostat or probenecid are recommended. The aim of this study was to conduct a cost-utility analysis of sequential ULT treatment strategies for gout, including strategies with and without HLA-B*58:01 genotyping prior to treatment initiation, with a view to inform optimal gout management in Singapore.Materials and methods: A Markov model was developed from the Singapore healthcare payer perspective. Reflecting local practice, 12 different treatment strategies containing at least one ULT (allopurinol, febuxostat, probenecid) were evaluated in adults with gout. Response rates (SUA < 6mg/dL) were derived from an in-house network meta-analysis and from published literature. Incremental cost-effectiveness ratios (ICERs) were calculated over a 30-year time horizon, with costs and benefits discounted at 3% per annum. Sensitivity analyses were conducted to explore uncertainties.Results: Sequential treatment of allopurinol 300 mg/day-allopurinol 600 mg/day-probenecid ("standard of care") was cost-effective compared to no ULT, with an ICER of SGD1,584/QALY. Allopurinol300-allopurinol600-probenecid-febuxostat sequence compared to allopurinol300-allopurinol600-probenecid had an ICER of SGD11,400/QALY. All other treatment strategies were dominated by preceding strategies. Treatment strategies incorporating HLA-B*58:01 genotyping before ULT use were dominated by the corresponding non-genotyping strategy.Conclusions: Current standard of care (allopurinol300-allopurinol 600-probenecid) for gout is cost-effective compared with no ULT in the local context. Febuxostat is unlikely to be cost-effective in Singapore at current prices unless it is used last-line.

Is HLA-B*58:01 genotyping cost effective in guiding allopurinol use in gout patients with chronic kidney disease?

Aim: Concerns for fatal severe cutaneous adverse reactions (SCARs) hamper allopurinol use. Methods and material: We adopted a health system perspective to evaluate the cost-effectiveness of HLA-B*58:01 genotyping before allopurinol initiation. A decision tree compared three treatment strategies in gout patients with chronic kidney disease who have higher risk for SCAR. They were standard allopurinol treatment followed by febuxostat in nonresponders, test-positive patients receive febuxostat while test-negative receive allopurinol and universal use of febuxostat. Results: The first strategy was the most cost effective. Genotyping dominated universal febuxostat use. Time horizon and SCAR incidence were the most influential factors on the incremental cost-effectiveness ratio. Conclusion: HLA-B*58:01 genotyping compared with standard allopurinol-febuxostat sequential treatment does not provide good value for money in gout with chronic kidney disease.

A retrospective investigation of HLA-B*5801 in hyperuricemia patients in a Han population of China.

BACKGROUND: Hyperuricemia and gout have become increasingly prevalent in China. Allopurinol is an effective urate-lowering therapy, but it has severe side effects. HLA-B*5801 is highly associated with the allopurinol-induced toxic epidermal necrolysis and Stevens-Johnson syndrome. PATIENTS AND METHODS: In this retrospective report, we had genotyped HLA-B*5801 in 253 cases of hyperuricemia and gout patients in a Han population in Shenzhen and analyzed the clinical management of medications. RESULTS: We found 30 carriers of the HLA-B*5801 allele in 253 cases of hyperuricemia or gout patients in the population (11.9%). Allopurinol was prescribed in both HLA-B*5801-positive and HLA-B*5801-negative groups. The evaluation of four models with or without genetic screening and management of allopurinol or febuxostat indicated that the HLA-B*5801 screening had significant cost benefit for clinical management. CONCLUSION: For appropriate management and cost-effectiveness, the HLA-B*5801 allele should be screened in all patients with hyperuricemia and gout in the Chinese population.

Cost effectiveness analysis of HLA-B*58:01 genotyping prior to initiation of allopurinol for gout.

Objective: To determine whether prospective testing for HLA-B*58:01, as a strategy to prevent serious adverse reactions to allopurinol in patients with gout, is cost-effective from the perspective of the National Health Service in the UK. Methods: A systematic review and meta-analysis for the association of HLA-B*58:01 with cutaneous and hypersensitivity adverse drug reactions informed a decision analytic and Markov model to estimate lifetime costs and outcomes associated with testing vs standard care (with febuxostat prescribed for patients who test positive). Scenario analyses assessed alternative treatment assumptions and patient populations. Results: The number of patients needed to test to prevent one case of adverse drug reaction was 11 286 (95% central range (CR): 2573, 53 594). Cost and quality-adjusted life-year (QALY) gains were small, £103 (95% CR: £98, £106) and 0.0023 (95% CR: -0.0006, 0.0055), respectively, resulting in an incremental cost-effectiveness ratio (ICER) of £44 954 per QALY gained. The probability of testing being cost-effective at a threshold of £30 000 per QALY was 0.25. Reduced costs of testing or febuxostat resulted in an ICER below £30 000 per QALY gained. The ICER for patients with chronic renal insufficiency was £38 478 per QALY gained. Conclusion: Routine testing for HLA-B*58:01 in order to reduce the incidence of adverse drug reactions in patients being prescribed allopurinol for gout is unlikely to be cost-effective in the UK; however testing is expected to become cost-effective with reductions in the cost of genotyping, and with the future availability of cheaper, generic febuxostat.

Cost-effectiveness Analysis for Genotyping before Allopurinol Treatment to Prevent Severe Cutaneous Adverse Drug Reactions.

OBJECTIVE: Patients with an HLA-B*58:01 allele have an increased risk of developing severe cutaneous adverse drug reactions (SCAR) when treated with allopurinol. Although one-off pharmacogenetic testing may prevent life-threatening adverse drug reactions, testing prior to allopurinol initiation incurs additional costs. The study objective was to evaluate the cost-effectiveness of HLA-B*58:01 screening compared with using other available urate-lowering agents (ULA). METHODS: A decision-analytical model was used to compare direct medical costs and effectiveness [including lifetime saved, quality-adjusted life-yrs (QALY) gained] in treating new patients with the following options: (1) genetic screening followed by allopurinol prescribing for noncarriers of HLA-B*58:01, (2) prescribing benzbromarone without screening, (3) prescribing febuxostat without screening, and (4) prescribing allopurinol without screening. A 1-year time frame and third-party payer perspective were modeled for both the entire cohort (base-case) and for the subgroup of patients with chronic kidney disease (CKD). RESULTS: The incremental cost-effectiveness ratio of genetic screening prior to ULA therapy was estimated as New Taiwan (NT) $234,610 (US$7508) per QALY gained in the base-case cohort. For patients with CKD, it was estimated as NT$230,925 (US$7390) per QALY. The study results were sensitive to the probability of benzbromarone/febuxostat-related hypersensitivity, and a negative predicted value of genotyping. CONCLUSION: HLA-B*58:01 screening gave good value for money in preventing allopurinol-induced SCAR in patients indicated for ULA therapy. In addition to the costs of genotyping, it is important to monitor ULA safety closely in adopting HLA-B*58:01 screening in practice.

Cost-effectiveness analysis of genotyping for HLA-B*5801 and an enhanced safety program in gout patients starting allopurinol in Singapore.

AIMS: Allopurinol is an efficacious urate-lowering therapy (ULT), but is associated with rare serious adverse drug reactions of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), with higher risk among HLA-B*5801 carriers. We assessed the cost-effectiveness of HLA-B*5801 testing, an enhanced safety program or strategies with both components. METHODS: The analysis adopted a health systems perspective and considered Singaporean patients with chronic gout, over a lifetime horizon, using allopurinol or probenecid. The model incorporated SJS/TEN and gout treatment outcomes, allele frequencies, drug prices and other medical costs. RESULTS: Based on cost-effectiveness threshold of US$50,000 per quality-adjusted life year, HLA-B*5801-guided ULT selection or enhanced safety program was not cost effective. Avoidance of ULTs was the least preferred strategy as uncontrolled gout leads to lower quality-adjusted life years and higher costs. CONCLUSION: The analysis underscores the need for biomarkers with higher positive predictive value for SJS/TEN, less expensive genetic tests or safety programs, or more effective gout drugs. .

Cost-effectiveness analysis of HLA-B5801 genotyping in the treatment of gout patients with chronic renal insufficiency in Korea.

OBJECTIVE: Allopurinol-induced severe cutaneous adverse reactions (SCARs) are relatively rare but cause high rates of morbidity and mortality. Studies have shown that the HLA-B5801 allele and renal impairment are strongly associated with SCARs. Recent American College of Rheumatology guidelines recommend that, prior to treatment with allopurinol, the HLA-B5801 genotype of gout patients at high risk for SCARs, including Korean patients with chronic renal insufficiency, should be determined. However, whether such genotyping is cost-effective is unknown. This study evaluated the cost-effectiveness of HLA-B5801 genotyping for the treatment of gout in patients with chronic renal insufficiency in Korea. METHODS: A decision analytical model over a time period of 12 months was employed to compare the cost and outcomes of treatment informed by HLA-B5801 genotyping with that of a conventional treatment strategy using a hypothetical cohort of gout patients with chronic renal insufficiency. Direct medical costs were obtained from real patients with SCARs from 2 tertiary hospitals. Outcomes were measured as a total expected cost and an incremental cost-effectiveness ratio. RESULTS: In the base model, the total expected cost and probability of continuation of gout treatment without SCARs for the conventional and HLA-B5801 screening strategies were $1,193 and 97.8% and $1,055 and 100%, respectively. The results were robust according to sensitivity analyses. CONCLUSION: Our model suggests that gout treatment informed by HLA-B5801 genotyping is less costly and more effective than treatment without genotyping, and HLA-B5801 genotyping could considerably reduce the occurrence of allopurinol-induced SCARs and related deaths.

Racial and gender disparities among patients with gout.

Gout affects 8.3 million Americans according to NHANES 2007-2008, approximately 3.9 % of the US population. Gout has substantial effect on physical function, productivity, health-related quality of life (HRQOL), and health care costs. Uncontrolled gout is also associated with significant use of emergency care services. Women are less likely to have gout than men, but in the postmenopausal years the gender difference in disease incidence decreases. Compared with whites, racial and/or ethnic minorities, especially blacks, have higher prevalence of gout. Blacks are also less likely to receive quality gout care, leading to disproportionate morbidity. Women are less likely than men to receive allopurinol, and less likely to undergo joint aspirations for crystal analysis to establish diagnosis, but those on urate-lowering therapy are as likely as, or more likely than, men to undergo serum urate check within six months of initiation. Although a few studies provide the knowledge related to gender and race and/or ethnicity disparities for gout, several knowledge gaps exist in gout epidemiology and outcomes differences by gender and race and/or ethnicity. These should be investigated in future studies.

Analyze multivariate phenotypes in genetic association studies by combining univariate association tests.

Multivariate phenotypes are frequently encountered in genome-wide association studies (GWAS). Such phenotypes contain more information than univariate phenotypes, but how to best exploit the information to increase the chance of detecting genetic variant of pleiotropic effect is not always clear. Moreover, when multivariate phenotypes contain a mixture of quantitative and qualitative measures, limited methods are applicable. In this paper, we first evaluated the approach originally proposed by O'Brien and by Wei and Johnson that combines the univariate test statistics and then we proposed two extensions to that approach. The original and proposed approaches are applicable to a multivariate phenotype containing any type of components including continuous, categorical and survival phenotypes, and applicable to samples consisting of families or unrelated samples. Simulation results suggested that all methods had valid type I error rates. Our extensions had a better power than O'Brien's method with heterogeneous means among univariate test statistics, but were less powerful than O'Brien's with homogeneous means among individual test statistics. All approaches have shown considerable increase in power compared to testing each component of a multivariate phenotype individually in some cases. We apply all the methods to GWAS of serum uric acid levels and gout with 550,000 single nucleotide polymorphisms in the Framingham Heart Study.