The Direct Economic Burden of Gout in an Elderly Canadian Population

Adherence and Treat-to-Target Benchmarks in Older Adults With Gout Initiating Urate-Lowering Therapy in Ontario, Canada: A Population-Based Study

OBJECTIVE

We sought to evaluate urate-lowering therapy (ULT) adherence and treatment-to-target (T2T) serum uric acid (SUA) levels among older adults with gout starting ULT.

METHODS

We performed a population-based retrospective cohort study in Ontario, Canada in patients with gout aged ≥66 years newly dispensed ULT between 2010 and 2019. We defined successful T2T as patients having SUA levels <360 μmol/L (6 mg/dL) within 12 months after ULT dispensation. We also assessed adherence to ULT. Multilevel logistic regression clustered by ULT prescriber evaluated patient, physician, and prescription factors associated with reaching target SUA levels.

RESULTS

Among 44,438 patients (mean ± SD age 76.0 ± 7.3 years; 64.4% male), 30,057 (67.6%) patients had ≥1 SUA test completed. Overall, 52.3% patients reached SUA target within 12 months, improving from 45.2% in 2010 to 61.2% in 2019 (P < 0.0001). ULT adherence was 55.3% overall and improved annually. Key factors associated with achieving T2T included febuxostat treatment (odds ratio [OR] 11.40, 95% confidence interval [95% CI] 5.10-25.43) (was only dispensed in 88 patients), ULT adherence (OR 5.17, 95% CI 4.89-5.47), allopurinol starting doses >50 mg (OR 2.53, 95% CI 2.14-2.99), colchicine/oral glucocorticoids co-prescription (OR 1.24, 95% CI 1.14-1.34), and ULT prescription from a rheumatologist.

CONCLUSION

Only 52.3% of patients achieved an optimal SUA level within 1 year of ULT initiation. ULT adherence was suboptimal, although improving over time. ULT adherence and higher allopurinol starting doses had the strongest associations of achieving a target SUA level. This study highlights room for improvement in gout management and potential strategies to address care gaps.

Gout and Hospital Admission for Ambulatory Care-Sensitive Conditions: Risks and Trajectories

OBJECTIVE

To investigate the risks and trajectories of hospital admission for ambulatory care-sensitive conditions (ACSCs) in gout.

METHODS

Among individuals aged 35 years to 85 years residing in Skåne, Sweden, in 2005, those with no doctor-diagnosed gout during 1998 to 2005 (n = 576,659) were followed from January 1, 2006, until a hospital admission for an ACSC, death, relocation outside Skåne, or December 31, 2016. Treating a new gout diagnosis (International Classification of Diseases, 10th revision, code M10) as a time-varying exposure, we used Cox proportional and additive hazard models to estimate the effects of gout on hospital admissions for ACSCs. We investigated the trajectory of hospital admissions for ACSCs from 3 years before to 3 years after gout diagnosis using generalized estimating equations and group-based trajectory modeling in an age-and sex-matched cohort study.

RESULTS

Gout was associated with a 41% increased rate of hospital admission for ACSCs (hazard ratio 1.41, 95% CI 1.35-1.47), corresponding to 121 (95% CI 104-138) more hospital admissions for ACSCs per 10,000 person-years compared with those without gout. Our trajectory analysis showed that higher rates of hospital admission for ACSCs among persons with gout were observed from 3 years before to 3 years after diagnosis, with the highest prevalence rate ratio (2.22, 95% CI 1.92-2.53) at the 3-month period after diagnosis. We identified 3 classes with distinct trajectories of hospital admissions for ACSCs among patients with gout: almost none (88.5%), low-rising (9.7%), and moderate-sharply rising (1.8%). The Charlson Comorbidity Index was the most important predictor of trajectory class membership.

CONCLUSION

Increased risk of hospital admissions for ACSCs in gout highlights the need for better management of the disease through outpatient care, especially among foreign-born, older patients with comorbidities.

Genetic assessment of hyperuricemia and gout in Asian, Native Hawaiian, and Pacific Islander subgroups of pregnant women: biospecimens repository cross-sectional study

Background

Gout, an inflammatory condition, is characterized by the precipitation of monosodium urate crystals (MSU) in or around distal joints. The latter is caused by chronic hyperuricemia (HU)—high urate levels in the blood. Genetic variations in urate transporters play a significant role in determining urate levels within the human body, rendering some racial and ethnic groups more or less susceptible to developing either HU or gout. This study aims to estimate the frequencies of HU and gout risk alleles in Asian, Native Hawaiian, and Pacific Islander subgroups, using biorepository DNA samples.

Methods

The biospecimens repository at the University of Hawai’i provided DNA samples of consented post-partum women of Japanese, Filipino, Korean, Native Hawaiian, Samoan, and Marshallese descent. The DNA was previously extracted from maternal blood and genotyped at the Genomics and Bioinformatics Shared Resource, Cancer Center (Honolulu, HI). Nine urate genes: ABCG2, SLC2A9, SLC16A9, GCKR, SLC22A11, SLC22A12, LRR16A, PDZK1, and SLC17A1, were selected due to their significant association with HU and gout risk. Hardy–Weinberg Equilibrium (HWE) for genotype frequencies was assessed, using the Chi-Square test with p < 0.006 for statistical significance. Allele frequencies in our study were then compared to EUR from the 1000 Genomes Project Database Phase III, using Chi-square or Fisher's exact test, when appropriate. Bonferroni correction for multiple comparisons was used, with p < 0.006 for statistical significance.

Results

Our study involved 1059 post-partum women 18-year-old or older who self-reported their respective race and ethnicity, including Asian, Native Hawaiian, and Pacific Islander ancestry. The Asian subgroups included Japanese, Filipino, and Korean. The Pacific Islander subgroups included Marshallese and Samoan. None of the study participants had a history of gout. We excluded the PDZK1 gene from the final analysis due to its deviation from HWE (p < 0.006) across all the population subgroups, with eight loci remaining for cross-subgroup comparisons. Compared to EUR, the genetic polymorphism frequencies were significantly different-8/8 in Japanese, 6/8 in Korean, 6/8 in Filipino, 8/8 in Samoan, 6/8 in Native Hawaiian, and 6/8 in Marshallese. HU and gout risk alleles indices were 8, 6, 5, 5, 4, and 4 in Japanese, Filipino, Korean, Samoan, Marshallese, and Native Hawaiian, respectively. The percentage of cumulative risk alleles was 100% in both Japanese and Filipino, followed by 83.5% in Korean.

Conclusions

Compared to EUR, Asian subgroups, particularly Japanese, Filipino, and Korean, had the highest percentage of the cumulative uric acid risk alleles. These results could partly explain the increased risk of developing gout among some Asian ancestral subgroups compared to EUR.

The prevalence of gout and hyperuricaemia in Australia: An updated systematic review

BACKGROUND

Gout continues to increase in prevalence in developed countries with Oceanic countries particularly affected. Both gout and hyperuricaemia are associated with the metabolic syndrome and its sequelae. Recently, the Australian Institute for Health and Welfare (AIHW) reported a prevalence rate of 0.8% which appeared incongruous with other published research. Thus, an updated systematic review was undertaken to review the literature on the prevalence of gout and hyperuricaemia in Australia from data published after 2011.

METHODS

A comprehensive, systematic search was conducted in MEDLINE, Embase and Web of Science in addition to relevant websites to identify research reporting the prevalence of gout and/or hyperuricaemia in Australia from May 2011 until June 2020. Crude gout and hyperuricaemia prevalence data was obtained and presented alongside case ascertainment, time-period, age range and stratified by gender if available.

RESULTS

118 full text articles were screened. 12 articles were included for analysis of gout prevalence. 4 articles were identified for the hyperuricaemia analysis. Wide variation in prevalence figures exist largely due study design and sample age range. Studies using a case definition of self-reported diagnosis of gout reported prevalence rates between 4.5% and 6.8%. The remaining studies used either electronic coding data from general practitioners or wastewater estimation of allopurinol consumption and documented adult prevalence rates between 1.5% and 2.9%. Prevalence increases with age, male sex and over time in keeping with global data. Hyperuricaemia prevalence ranged between 10.5% and 16.6% in Caucasian or an Australian representative population. AIHW estimates applied a chronic condition status, defined as current and lasted or expected to last more than six months, to cases of gout in the Australian National Health Survey. This likely results in an under-estimation in reported Australian gout prevalence rates.

CONCLUSIONS

Gout is highly prevalent in Australia compared to global comparisons and continues to increase over time. Hyperuricaemia prevalence is also high although contemporary data is limited.

Patient Perspectives on Gout and Gout Treatments: A Patient Panel Discussion That Informed the 2020 American College of Rheumatology Treatment Guideline

OBJECTIVE

The objective of this study was to understand patient perspectives to inform the voting process for the 2020 American College of Rheumatology (ACR) gout treatment guideline.

METHODS

We conducted a panel meeting of eight patients with gout in Birmingham, Alabama. Patients were referred to the project by private and academic rheumatologists in the Birmingham area. All participants received orientation related to the guideline development process and evidence rating at the beginning of the meeting. With the help of a physician moderator, the patient panel reviewed nine key clinical scenarios and the supporting evidence and discussed their views and perspectives related to each. They also provided their preference for one of the two treatment options for each clinical scenario.

RESULTS

The patient panel included eight men with gout. Of these eight participants, seven received their gout care from a rheumatologist and one from a primary care physician. Patients favored more active urate-lowering therapy (ULT) management and interventional management of gout flares to achieve desired clinical outcomes, resulting in unanimous consensus on choices related to six clinical scenarios: ULT initiation in gout, treat-to-target management strategy, use of pegloticase for refractory gout, starting ULT during a gout flare, using injectable treatments (over oral) for acute gout flares, and use of febuxostat in people with cardiovascular disease.

CONCLUSION

Knowledge of patient preferences and values is valuable and was influential for the development of the 2020 ACR gout treatment guideline.

Global epidemiology of gout: prevalence, incidence, treatment patterns and risk factors

Gout is the most common inflammatory arthritis and occurs when hyperuricaemia, sustained elevation of serum urate levels resulting in supersaturation of body tissues with urate, leads to the formation and deposition of monosodium urate crystals in and around the joints. Recent reports of the prevalence and incidence of gout vary widely according to the population studied and methods employed but range from a prevalence of <1% to 6.8% and an incidence of 0.58-2.89 per 1,000 person-years. Gout is more prevalent in men than in women, with increasing age, and in some ethnic groups. Despite rising prevalence and incidence, suboptimal management of gout continues in many countries. Typically, only a third to half of patients with gout receive urate-lowering therapy, which is a definitive, curative treatment, and fewer than a half of patients adhere to treatment. Many gout risk factors exist, including obesity, dietary factors and comorbid conditions. As well as a firmly established increased risk of cardiovascular disease and chronic kidney disease in those with gout, novel associations of gout with other comorbidities have been reported, including erectile dysfunction, atrial fibrillation, obstructive sleep apnoea, osteoporosis and venous thromboembolism. Discrete patterns of comorbidity clustering in individuals with gout have been described. Increasing prevalence and incidence of obesity and comorbidities are likely to contribute substantially to the rising burden of gout.

Recent updates on worldwide gout epidemiology

To provide recent statistics on worldwide gout epidemiology. Current and prediction data on gout epidemiology were retrieved from the Global Health Data Exchange (GHDx) registry and from the World Health Organization (WHO) database on projected mortality. Overall, 7.44 million cases of gout have been estimated around the world in 2017 (incidence, 0.097%), with a prevalence of 41.22 million cases (0.54%), and causing 1.28 million DALYs (0.051% of all DALYs). Gout incidence, prevalence, and health loss considerably increased during the last 25 years and are all higher in men than in women. The burden of gout increases linearly with aging, until the age of 64 years, and is correlated with socio-demographic index (SDI), with incident risk of gout > 3-fold higher in high than in low SDI regions. Projections suggest that gout mortality may increase by 55% in 2060. The epidemiologic burden of gout remains high around the world, especially in men and in high SDI countries, with a trend that is unlikely to reverse soon.Key Points• A significant association can be found between gout and socioeconomic status.• Projections suggest that gout mortality may increase by 55% in 2060.• The epidemiologic burden of gout remains high around the world.

Improving adherence to gout therapy: an expert review

Gout is the most common form of inflammatory arthritis and is a considerable burden to patients and health care systems worldwide. Despite its clinical, economic, and social impact, patient persistence and adherence to prescribed urate-lowering therapies (ULT), ranging from 20% to 70%, is considered to be among the poorest of all chronic conditions. The majority of gout patients consequently receive suboptimal benefits of their prescribed pharmacotherapies. As gout is associated with several comorbidities along with an increased risk of premature mortality, achieving improved outcomes through adherence to ULT is crucial. Adherence to medication is complex and multidimensional and includes a combination of treatment-, patient-, and physician-related factors. This review explores the factors related to ULT adherence with the overall aim of helping health care providers better understand the barriers to adherence. Several interventions targeting pharmacists, nurses, and patients are being investigated to improve adherence. Furthermore, enhanced awareness and understanding of the need to treat-to-target in order to improve patient outcomes is needed among health care professionals. Greater understanding of the multidimensional nature of non-adherence can help physicians to treat gout more effectively and empower patients to improve self-management of this long-term disease.

Evaluation of healthcare costs and utilization for patients with gout: a population-based matched cohort study

OBJECTIVES

To better understand the economic burden of gout patients in Taiwan, a nationwide retrospective study was conducted to compare the healthcare costs and utilization between gout and gout-free patients.

METHODS

The Longitudinal Health Insurance Database (LHID) 2010 was used to identify gout cases and matched gout-free controls. Gout cases were defined as having (1) at least three instances of diagnoses of gout on medical claims, or (2) one diagnosis of gout with at least one gout-related pharmacy claim in 2011. A control cohort was matched with cases at a 3:1 ratio by age, gender, residential area, and the Charlson Comorbidity Index. All medical utilization and costs per patient within the 365 days following the index date were compared between cases and controls.

RESULTS

Out of 993,332 beneficiaries, a total of 21,376 matched gout patients met the gout inclusion criteria. Compared to controls, gout patients had more outpatient visits (mean = 31.2 vs 22.6), inpatient visits (mean = 1.7 vs 1.5), and ER visits (mean = 1.9 vs 1.7) (all p < .0001), as well as more outpatient costs (median = USD $634 vs $404), inpatient costs (median = USD $1330 vs $1254), and ER costs (median = USD $87 vs $89) (all p < .05).

CONCLUSION

Gout patients had higher medical utilization and costs than gout-free patients. In gout patients, all-cause and gout-related utilization were mostly outpatient visits, whereas most of the all-cause and gout-related costs were due to hospitalization. The study findings could be useful for future economic evaluations and healthcare resource allocation.