Chang-Fu Kuo

Rising burden of gout in the UK but continuing suboptimal management: a nationwide population study

Objectives To describe trends in the epidemiology of gout and patterns of urate-lowering treatment (ULT) in the UK general population from 1997 to 2012. Methods We used the Clinical Practice Research Datalink to estimate the prevalence and incidence of gout for each calendar year from 1997 to 2012. We also investigated the pattern of gout management for both prevalent and incident gout patients. Results In 2012, the prevalence of gout was 2.49% (95% CI 2.48% to 2.51%) and the incidence was 1.77 (95% CI 1.73 to 1.81) per 1000 person-years. Prevalence and incidence both were significantly higher in 2012 than in 1997, with a 63.9% increase in prevalence and 29.6% increase in incidence over this period. Regions with highest prevalence and incidence were the North East and Wales. Among prevalent gout patients in 2012, only 48.48% (95% CI 48.08% to 48.89%) were being consulted specifically for gout or treated with ULT and of these 37.63% (95% CI 37.28% to 38.99%) received ULT. In addition, only 18.6% (95% CI 17.6% to 19.6%) of incident gout patients received ULT within 6 months and 27.3% (95% CI 26.1% to 28.5%) within 12 months of diagnosis. The management of prevalent and incident gout patients remained essentially the same during the study period, although the percentage of adherent patients improved from 28.28% (95% CI 27.33% to 29.26%) in 1997 to 39.66% (95% CI 39.11% to 40.22%) in 2012. Conclusions In recent years, both the prevalence and incidence of gout have increased significantly in the UK. Suboptimal use of ULT has not changed between 1997 and 2012. Patient adherence has improved during the study period, but it remains poor.

Significance of serum uric acid levels on the risk of all-cause and cardiovascular mortality

OBJECTIVE To assess the associations between serum uric acid (SUA) level and mortality. METHODS The study included 354 110 subjects without a history of gout and whose SUA levels were tested at Chang Gung Memorial Hospital in Taiwan. Cox regression models were used to estimate hazard ratios and 95% CIs for mortality in six predefined SUA strata (≤0.17, 0.18-0.29, 0.30-0.41, 0.42-0.53, 0.54-0.65 and ≥0.66 mmol/l), after adjusting for age, sex, SUA stratum, estimated glomerular filtration rate, fasting glucose, total cholesterol and history of hypertension, diabetes mellitus, coronary heart disease, stroke, heart failure or chronic kidney disease. RESULTS There were 33 562 all-cause deaths during the study period. Crude all-cause mortality rates across the SUA strata were 52.5, 19.7, 17.4, 20.0, 28.0 and 41.1 deaths per 1000 person-years. Using the stratum 3 of SUA as a reference, the age- and sex-adjusted hazard ratios (95% CIs) across SUA strata were 2.79 (2.62, 2.96), 1.32 (1.28, 1.36), 1.00, 1.10 (1.07, 1.14), 1.42 (1.37, 1.48) and 2.12 (2.01, 2.23) for all-cause mortality; 2.24 (1.93, 2.59), 1.18 (1.10, 1.27), 1.00, 1.21 (1.14, 1.29), 1.74 (1.60, 1.88) and 2.53 (2.28, 2.81) for cardiovascular mortality and 3.41 (3.11, 3.73), 1.48 (1.42, 1.55), 1.00, 0.88 (0.84, 0.92), 0.91 (0.85, 0.98) and 1.23 (1.11, 1.36) for cancer-related mortality. CONCLUSION Individuals with SUA levels at either extremes are at higher risk for all-cause and cardiovascular mortality. SUA levels of 0.30-0.41 mmol/l were associated with the lowest mortality rate and should be regarded as optimal.

Comorbidities in patients with gout prior to and following diagnosis: case-control study

Objectives To determine the burden of comorbidities in patients with gout at diagnosis and the risk of developing new comorbidities post diagnosis. Methods There were 39 111 patients with incident gout and 39 111 matched controls identified from the UK Clinical Practice Research Data-link. The risk of comorbidity before (ORs) and after the diagnosis of gout (HRs) were estimated, adjusted for age, sex, diagnosis year, body mass index, smoking and alcohol consumption. Results Gout was associated with adjusted ORs (95% CIs) of 1.39 (1.34 to 1.45), 1.89 (1.76 to 2.03) and 2.51 (2.19 to 2.86) for the Charlson index of 1–2, 3–4 and ≥5, respectively. Cardiovascular and genitourinary diseases, in addition to hyperlipidaemia, hypothyroidism, anaemia, psoriasis, chronic pulmonary diseases, osteoarthritis and depression, were associated with a higher risk for gout. Gout was also associated with an adjusted HR (95% CI) of 1.41 (1.34 to 1.48) for having a Charlson index ≥1. Median time to first comorbidity was 43 months in cases and 111 months in controls. Risks for incident comorbidity were higher in cardiovascular, genitourinary, metabolic/endocrine and musculoskeletal diseases, in addition to liver diseases, hemiplegia, depression, anaemia and psoriasis in patients with gout. After additionally adjusting for all comorbidities at diagnosis, gout was associated with a HR (95% CI) for all-cause mortality of 1.13 (1.08 to 1.18; p<0.001). Conclusions The majority of patients with gout have worse pre-existing health status at diagnosis and the risk of incident comorbidity continues to rise following diagnosis. The range of associated comorbidities is broader than previously recognised and merits further evaluation.

Incidence, cancer risk and mortality of dermatomyositis and polymyositis in Taiwan: a nationwide population study

Background  Nationwide data on the epidemiology of dermatomyositis (DM) and polymyositis (PM) were limited.

Familial Aggregation of Systemic Lupus Erythematosus and Coaggregation of Autoimmune Diseases in Affected Families

IMPORTANCE Relatives of patients with systemic lupus erythematosus (SLE) appear to be at higher risk of SLE and other autoimmune diseases, but estimates of individual familial risks are largely unavailable or unreliable. Furthermore, relative contributions of genetic, shared, and unshared environmental factors to SLE susceptibility remain unclear. OBJECTIVE To examine familial aggregation and heritability of SLE and the relative risks (RRs) of other autoimmune diseases in relatives of patients with SLE. DESIGN, SETTING, AND PARTICIPANTS A population-based family study using the Taiwan National Health Insurance Research Database was conducted. Participants included all individuals (N = 23,658,577) registered with that database in 2010; of these, 18,283 had SLE. We identified 21,009,551 parent-child relationships, 17,168,340 full sibling pairs, and 342,066 twin pairs. Diagnoses of SLE were ascertained from March 1, 1995, to December 31, 2010, and analysis was conducted between March 1 and August 15, 2014. MAIN OUTCOMES AND MEASURES The prevalence and RRs of SLE and other autoimmune diseases in relatives and spouses of patients with SLE as well as the relative contributions of heritability, shared, and nonshared environmental factors to SLE susceptibility. RESULTS Among the more than 23 million participants, the RRs (95% CIs) for SLE were 315.94 (210.66-473.82) for twins of the patients, 23.68 (20.13-27.84) for siblings, 11.44 (9.74-13.43) for parents, 14.42 (12.45-16.70) for offspring, and 4.44 (2.38-8.30) for spouses without genetic similarity. The accountability for phenotypic variance of SLE was 43.9% for heritability, 25.8% for shared environmental factors, and 30.3% for nonshared environmental factors. The RRs (95% CIs) in individuals with a first-degree relative with SLE were 5.87 (4.89-7.05) for primary Sjögren syndrome, 5.40 (3.37-8.65) for systemic sclerosis, 2.95 (2.04-4.26) for myasthenia gravis, 2.77 (1.45-5.32) for idiopathic inflammatory myositis, 2.66 (2.28-3.11) for rheumatoid arthritis, 2.58 (1.16-5.72) for multiple sclerosis, 1.68 (1.22-2.32) for type 1 diabetes mellitus, 1.39 (0.66-2.91) for inflammatory bowel diseases, and 0.86 (0.43-1.71) for vasculitis. CONCLUSIONS AND RELEVANCE The individual risks of SLE and other autoimmune diseases were increased in families that included patients with SLE. The heritability of SLE was estimated to be 43.9%. These data should be considered when counseling families with affected members.

Epidemiology and management of gout in Taiwan: a nationwide population study

IntroductionGout is the most common inflammatory arthritis worldwide and is the only type of chronic arthritis that potentially can be ‘cured’. However, data on gout incidence, prevalence and management, assessed at multiple time points in the same population, are sparse, particularly in Asian populations. The aim of this study was to describe trends in the epidemiology of gout in the general population of Taiwan.MethodsThe National Health Insurance Research Database was used to identify patients with gout and to estimate the prevalence and incidence of gout for each calendar year from 2005 to 2010. The pattern of gout management was also examined.ResultsOf 23,371,362 beneficiaries in 2010, there were 1,458,569 prevalent and 56,595 incident cases of gout, giving a prevalence of 6.24% (95% confidence interval (CI), 6.23% to 6.25%) and an incidence of 2.74 (95% CI, 2.72 to 2.76) per 1,000 person-years. The annual percentage change (APC) of the standardised prevalence was −0.7% (95% CI, −1.7% to 0.3%; P = 0.14), suggesting that the prevalence of gout was essentially the same throughout the study period. However, The APC of incidence was −13.4 (95% CI, −16.1 to −10.6) between 2005 and 2007 and −2.1 (95% CI, −10.4 to 7.1) between 2007 and 2010. Regions with the highest prevalence and incidence were eastern coastal counties and offshore islets, where indigenous people are clustered. Among prevalent gout cases in 2010, only 22.93% (95% CI, 22.87% to 23.00%) were prescribed urate-lowering treatment (ULT), which remained unchanged between 2005 and 2010 at an APC of 0.0 (95% CI, −3.8 to 4.0). Uricosuric agents were more commonly prescribed than xanthine oxidase inhibitors in Taiwan.ConclusionsIn Taiwan, 1 in 16 people have gout. Whereas the incidence has decreased recently, the prevalence remains unchanged. Management of gout in Taiwan is poor, with only one in five affected people being treated with ULT.

Familial aggregation of gout and relative genetic and environmental contributions: a nationwide population study in Taiwan

Objective To examine familial aggregation of gout and to estimate the heritability and environmental contributions to gout susceptibility in the general population. Methods Using data from the National Health Insurance (NHI) Research Database in Taiwan, we conducted a nationwide cross-sectional study of data collected from 22 643 748 beneficiaries of the NHI in 2004; among them 1 045 059 individuals had physician-diagnosed gout. We estimated relative risks (RR) of gout in individuals with affected first-degree and second-degree relatives and relative contributions of genes (heritability), common environment shared by family members and non-shared environment to gout susceptibility. Results RRs for gout were significantly higher in individuals with affected first-degree relatives (men, 1.91 (95% CI 1.90 to 1.93); women, 1.97 (95% CI 1.94 to 1.99)) and also in those with affected second-degree relatives (men, 1.27 (95% CI 1.23 to 1.31); women, 1.40 (95% CI 1.35 to 1.46)). RRs (95% CIs) for individuals with an affected twin, sibling, offspring, parent, grandchild, nephew/niece, uncle/aunt and grandparent were 8.02 (6.95 to 9.26), 2.59 (2.54 to 2.63), 1.96 (1.95 to 1.97), 1.93 (1.91 to 1.94), 1.48 (1.43 to 1.53), 1.40 (1.32 to 1.47), 1.31 (1.24 to 1.39), and 1.26 (1.21 to 1.30), respectively. The relative contributions of heritability, common and non-shared environmental factors to phenotypic variance of gout were 35.1, 28.1 and 36.8% in men and 17.0, 18.5 and 64.5% in women, respectively. Conclusions This population-based study confirms that gout aggregates within families. The risk of gout is higher in people with a family history. Genetic and environmental factors contribute to gout aetiology, and the relative contributions are sexually dimorphic.

Risk of end-stage renal disease associated with gout: a nationwide population study

IntroductionWe explored the risk of end-stage renal disease (ESRD) among gout patients in a representative cohort in Taiwan.MethodsThe primary database used was the Taiwan National Health Insurance Research Database. Subjects older than 20 years without ESRD, coronary heart disease, or stroke were included in the study. The case definition of gout in the present study was gout diagnosis and medical treatment for gout. An ESRD case was defined by the presence of chronic renal failure necessitating long-term renal replacement therapy. Multivariate Cox proportional hazards models were used to evaluate the risk of ESRD among gout patients.ResultsThe analysis included data of 656,108 patients who were followed up for a mean of 8.0 years. Among them, 19,963 (3.0%) patients had gout. At the end of 2008, 2,377 individuals (gout, n = 276; non-gout, n = 2,101) had ESRD, and 861 individuals (gout, n = 77, 27.9%; non-gout, n = 521, 24.8%) died due to ESRD. The rates of incidence of ESRD were 1.73 and 0.41 cases per 1,000 patient-years in the gout and non-gout groups. After adjustment for age, sex, and history of diabetes mellitus and/or hypertension, gout was associated with a hazard ratio (HR) of 1.57 for ESRD (95% confidence interval [CI], 1.38-1.79; P < 0.001). In patients with ESRD, the adjusted HR for death in patients with gout was 0.95 (0.74-1.23, P = 0.71), which was similar to the HR obtained in patients without gout.ConclusionsGout is associated with an increased hazard for development of ESRD.

Eligibility for and Prescription of Urate-Lowering Treatment in Patients With Incident Gout in England

Gout is caused by urate crystal deposition secondary to persistent hyperuricemia. Current guidelines recommend urate-lowering treatment to prevent crystal deposition and encourage crystal dissolution for patients with more severe gout or concomitant conditions.1,2 However, after the first diagnosis, it remains unclear when such treatment is appropriate. We investigated the timing of eligibility for and prescription of urate-lowering treatment following first gout diagnosis and factors associated with prescription.

Sex- and age-specific incidence of autoimmune rheumatic diseases in the Chinese population: A Taiwan population-based study

OBJECTIVES The purpose of this study was to estimate the sex- and age-specific incidence rates of major autoimmune rheumatic diseases (ARDs) in Taiwan using a population longitudinal database. METHODS A health insurance database containing the records of 1,000,000 beneficiaries of Taiwan National Health Insurance from 2005 to 2009 was used. RESULTS Between 2005 and 2009, the overall incidence rate of the major ARDs was 29.8 (95% CI = 28.3-31.3) per 100,000 person-years. Among the ARDs studied, the incidence of rheumatoid arthritis (RA; per 100,000 person-years) was highest (17.2, 95% CI = 16.1-18.4) and was followed by Sjögrens syndrome (11.8, 95% CI = 10.8-12.7), systemic lupus erythematosus (SLE; 7.2, 95% CI = 6.5-8.0), systemic sclerosis (SS; 1.1, 95% CI = 0.8-1.4), vasculitis (1.0, 95% CI = 0.7-1.3), Behçet disease (0.9, 95% CI = 0.6-1.1), dermatomyositis (DM; 0.7, 95% CI = 0.5-1.0), and polymyositis (PM; 0.6, 95% CI = 0.4-0.8). Females had a higher incidence ratio than did males, but a significant female/male incidence ratio was only observed for SLE (8.5, 95% CI = 6.1-12.0), Sjögrens syndrome (6.0, 95% CI = 4.8-7.6), RA (3.0, 95% CI = 2.6-3.5), and SS (2.6, 95% CI = 1.4-4.6). CONCLUSIONS ARDs are three to four times more common among women than among men in the Chinese population of Taiwan. The incidence of RA was the highest, followed by Sjögrens syndrome and SLE, while the incidence of Behçet disease was the lowest in this study. This nationwide, population-based, longitudinal epidemiological study of ARDs in Taiwan provides data for future global comparisons and may provide clues as to the etiology of these diseases.