Burden of gout in the Nordic region, 1990-2015: findings from the Global Burden of Disease Study 2015

Lifestyle factors predict gout outcomes: Results from the NOR-Gout longitudinal 2-year treat-to-target study

OBJECTIVE

Gout is associated with lifestyle, body mass index (BMI) and comorbidities, including dyslipidaemia. We studied how in actively treated patients, anthropometric measures and lipid levels changed over 2 years and whether they predicted gout outcomes.

METHODS

Patients with a recent gout flare and elevated serum urate (sUA) received gout education and treat-to-target urate-lowering therapy over 1 year. Anthropometric measures with BMI, waist circumference (WC) and waist-height ratio (WHR) as well as lipid levels were measured yearly over 2 years. We examined whether baseline anthropometric measures and lipid levels were related to flares and to achieving the sUA target.

RESULTS

At baseline, patients (n=211) were with mean age of 56.4 years and 95% were male. Over 2 years, anthropometric measures were largely unchanged while cholesterol and low-density lipoprotein cholesterol (LDL-C) were reduced at year 1. Anthropometric measures were associated with presence of tophi. Higher baseline WC (OR: 0.96 per cm, 95% CI: 0.93 to 0.99) decreased and high level of high-density lipoprotein cholesterol (OR: 5.1 per mmol/L, 95% CI: 1.2 to 22.1) increased the chance of sUA target achievement at year 2. High LDL-C (OR: 1.8 per mmol/L, 95% CI: 1.2 to 2.6) predicted the chance of having a gout flare during year 2.

CONCLUSION

In actively treated patients with gout, anthropometric measures were largely unchanged over 2 years and lipid levels were reduced. High WC and lipid levels predicted unfavourable gout outcomes after 2 years.

Course and predictors of work productivity in gout - results from the NOR-Gout longitudinal 2-year treat-to-target study

OBJECTIVES

In patients with gout there is a lack of longitudinal studies on the course of work productivity. We explored longitudinal changes in and predictors of work productivity over 2 years.

METHODS

Patients in the NOR-Gout observational study with a recent gout flare and serum urate (sUA) >360 µmol/l attended tight-control visits during escalating urate lowering therapy according to a treat-to-target strategy. From the Work Productivity and Activity Impairment (WPAI) questionnaire, scores for work productivity and activity impairment were assessed over 2 years together with the Beliefs about Medicines Questionnaire and a variety of demographic and clinical variables.

RESULTS

At baseline patients had a mean age of 56.4 years and 95% were males. WPAI scores at baseline were 5.0% work missed (absenteeism), 19.1% work impairment (presenteeism), 21.4% overall work impairment and 32.1% activity impairment. Work productivity and activity impairment improved during the first months, and remained stable at 1 and 2 years. Comorbidities were not cross-sectionally associated with WPAI scores at baseline, but predicted worse work impairment and activity impairment at year 1. The Beliefs about Medicines Questionnaire subscale with concerns about medicines at baseline independently predicted worse overall work impairment and worse activity impairment at year 1.

CONCLUSIONS

In patients with gout who were intensively treated to the sUA target, work productivity and activity impairment were largely unchanged and at 1 year predicted by comorbidities and patient concerns about medication.

Cause-Specific Mortality in Patients With Gout in the US Veterans Health Administration: A Matched Cohort Study

OBJECTIVE

To compare all-cause and cause-specific mortality risk between patients with gout and patients without gout in the Veteran's Health Administration (VHA).

METHODS

We performed a matched cohort study, identifying patients with gout in the VHA from January 1999 to September 2015 based on the presence of ≥2 International Classification of Diseases, Ninth Revision codes for gout (274.X). Gout patients were matched up to 1:10 on birth year, sex, and year of VHA enrollment with patients without gout and followed until death or end of study (December 2017). Cause of death was obtained from the National Death Index. Associations of gout with all-cause and cause-specific mortality were examined using multivariable Cox regression.

RESULTS

Gout (n = 559,243) and matched non-gout controls (n = 5,428,760) had a mean age of 67 years and were 99% male. There were 246,291 deaths over 4,250,371 patient-years in gout patients and 2,000,000 deaths over 40,441,353 patient-years of follow-up in controls. After matching, gout patients had an increased risk of death (hazard ratio [HR] 1.09 [95% confidence interval (95% CI) 1.08-1.09]), which was no longer present after adjusting for comorbidities (HR 0.98 [95% CI 0.97-0.98]). The strongest association of gout with cause-specific mortality was observed with genitourinary conditions (HR 1.50 [95% CI 1.47-1.54]). Gout patients were at lower risk of death related to neurologic (e.g., Alzheimer's disease and Parkinson's disease) (HR 0.63 [95% CI 0.62-0.65]) and mental health (HR 0.66 [95% CI 0.65-0.68]) conditions.

CONCLUSION

A higher risk of death among gout patients in the VHA was related to comorbidity burden. While deaths attributable to neurologic and mental health conditions were less frequent among gout patients, genitourinary conditions were the most overrepresented causes of death.

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.

Prevalence of Patients Receiving Urate-Lowering Medicine in Greenland and Denmark: A Cross-Sectional Case-Control Study

This study estimates the age- and sex-specific prevalence of patients receiving urate-lowering therapy (ULT) in Greenland and compares the results with estimates in Denmark. Characteristics of patients receiving ULT in Greenland were compared to age- and sex-matched controls. The study was designed as a cross-sectional case−control study based on nationwide data from medical and population registers in Greenland and Denmark. The prevalence of patients receiving ULT was significantly lower in Greenland (0.55%) compared to Denmark (1.40%) (p < 0.001). In both countries, the prevalence increased with age and was higher among men compared to women. In Greenland, patients receiving ULT were more often overweight, and more frequently received blood glucose-, lipid-, and blood pressure-lowering medicine including diuretics compared to age- and sex-matched controls. The prevalence of patients receiving ULT was significantly lower in Greenland compared to Denmark. Common life-style related risk factors for hyperuricemia and gout were observed frequently among ULT-treated patients compared to controls. Along with an increasing prevalence of lifestyle-related diseases in Greenland, the prevalence of patients receiving ULT may increase in the years to come. More focus on detection and management of hyperuricemia and gout in Greenland is warranted to improve quality of health care.

12-month results from the real-life observational treat-to-target and tight-control therapy NOR-Gout study: achievements of the urate target levels and predictors of obtaining this target

OBJECTIVES

Gout is often not adequately treated, and we aimed to apply urate lowering treatment (ULT) combined with individual information to achieve target serum urate (sUA) in clinical practice, and to identify predictors of achievement of this sUA target.

METHODS

Patients with a recent gout flare and sUA >360 µmol/L (>6 mg/dL) were consecutively included in a single-centre study and managed with a treat-to-target approach combining nurse-led information about gout with ULT. All patients were assessed with tight controls at baseline, 1, 2, 3, 6, 9 and 12 months including clinical examination, information on demographics, lifestyle, self-efficacy and beliefs about medicines. The treatment target was sUA <360 µmol/L and multivariable logistic regression was used to identify predictors of target attainment with ORs and 95% CIs.

RESULTS

Of 211 patients (mean age 56.4 years, disease duration 7.8 years, 95% males), 186 completed the 12-month study. Mean sUA levels decreased from baseline mean 500 to 311 µmol/L at 12 months with 85.5% achieving the treatment target. Alcohol consumption at least weekly versus less frequently (OR 0.14; 95% CI 0.04 to 0.55) as well as beliefs in overuse of medicines (OR per unit 0.77; 95 CI 0.62 to 0.94) decreased the chance of reaching the treatment target, while higher self-efficacy for arthritis symptoms (OR 1.49 per 10 units; 95% CI 1.09 to 2.05) increased the likelihood.

CONCLUSIONS

This study shows that target sUA can be achieved with ULT in most patients. Less self-reported alcohol consumption, low beliefs in overuse of medicines and higher self-efficacy are associated with treatment success.

Gout in China, 1990-2017: the Global Burden of Disease Study 2017

OBJECTIVE

The aim of the study was to estimate the gout burden and risk factors in China from 1990 to 2017.

STUDY DESIGN

The Global Burden of Disease (GBD) Study uses various analytical tools and a diverse set of data sources to generate comparable estimates of deaths and mortality rates broken down by age, sex, cause, year, and geography.

METHODS

We used the results from the GBD Study 2017 to compare disability-adjusted life years (DALYs), prevalence, incidence, and risk factors of gout in China. The median of the percentage change and 95% uncertainty intervals were determined for the period between 1990 and 2017.

RESULTS

The age-standardized DALY rate, prevalence, and incidence increased 6.92%, 6.88%, and 6.16%, respectively, in China from 1990 to 2017. Although the rates of gout both globally and in China were increasing, the range of change for males in China was larger than that of the global level. All risk factors combined accounted for 30.04% of gout DALYs in 2017. The leading risk factors for gout DALYs were high body mass index and impaired kidney function, and the proportion of high body mass index increased significantly from 10.67% to 24.31%, whereas the proportion of impaired kidney function remained basically unchanged.

CONCLUSIONS

The age-standardized DALY rate, prevalence, and incidence in China have increased progressively since 1990. Increasing attention on body weight management should be prioritized for controlling the rising prevalence of gout in the young and middle-aged population.

Educational inequalities in all-cause and cause-specific mortality among people with gout: a register-based matched cohort study in southern Sweden

Background

Gout is the most common inflammatory arthritis with a rising prevalence around the globe. While educational inequalities in incidence and prevalence of gout have been reported, no previous study investigated educational inequality in mortality among people with gout. The aim of this study was to assess absolute and relative educational inequalities in all-cause and cause-specific mortality among people with gout in comparison with an age- and sex-matched cohort free of gout in southern Sweden.

Methods

We identified all residents aged ≥30 years of Skåne region with doctor-diagnosed gout (ICD-10 code M10, n = 24,877) during 1998–2013 and up to 4 randomly selected age- and sex-matched comparators free of gout (reference cohort, n = 99,504). These were followed until death, emigration, or end of 2014. We used additive hazards models and Cox regression adjusted for age, sex, marital status, and country of birth to estimate slope and relative indices of inequality (SII/RII). Three cause-of-death attribution approaches were considered for RII estimation: “underlying cause”, “any mention”, and “weighted multiple-cause”.

Results

Gout patients with the lowest education had 1547 (95% CI: 1001, 2092) more deaths per 100,000 person-years compared with those with the highest education. These absolute inequalities were larger than in the reference population (1255, 95% CI: 1038, 1472). While the contribution of cardiovascular (cancer) mortality to these absolute inequalities was greater (smaller) in men with gout than those without, the opposite was seen among women. Relative inequality in all-cause mortality was smaller in gout (RII 1.29 [1.18, 1.41]) than in the reference population (1.46 [1.38, 1.53]). The weighted multiple-cause approach generally led to larger RIIs than the underlying cause approach.

Conclusions

Our register-based matched cohort study showed that low level of education was associated with increased mortality among gout patients. Although the magnitude of relative inequality was smaller in people with gout compared with those without, the absolute inequalities were greater reflecting a major mortality burden among those with lower education.

Cichorium intybus L. Extract Suppresses Experimental Gout by Inhibiting the NF-κB and NLRP3 Signaling Pathways

BACKGROUND

The production and maturation of interleukin (IL)-1β, regulated by the NF-κB and NLRP3 signaling pathways, lie at the core of gout. This study aimed to evaluate the antigout effect of Cichorium intybus L. (also known as chicory) in vivo and in vitro.

METHODS

A gout animal model was established with monosodium urate (MSU) crystal injections. Rats were orally administered with chicory extract or colchicine. Levels of ankle edema, inflammatory activity, and IL-1β release were observed. Several essential targets of the NF-κB and NLRP3 signaling pathways were detected. Primary macrophages were isolated to verify the antigout mechanism of chicory extract as well as chicoric acid in vitro.

RESULTS

Improvements of swelling degree, inflammatory activity, and histopathological lesion in MSU-injected ankles were observed in the treatment with chicory extract. Further, the chicory extract significantly decreased IL-1β release by suppressing the NF-κB and NLRP3 signaling pathways in gout rats. Similar to the in vivo results, IL-1β release was also inhibited by chicory extract and chicoric acid, a specific effective compound in chicory, through the NF-κB and NLRP3 signaling pathways.

CONCLUSION

This study suggests that chicory extract and chicoric acid may be used as promising therapeutic agents against gout by inhibiting the NF-κB and NLRP3 signaling pathways.

Romidepsin suppresses monosodium urate crystal-induced cytokine production through upregulation of suppressor of cytokine signaling 1 expression

Background

Acute gouty arthritis currently is the most common form of inflammatory arthritis in developed countries. Treatment is still suboptimal. Dosage of urate-lowering therapy is often too low to reach target urate levels, and adherence to therapy is poor. In this study, we therefore explore a new treatment option to limit inflammation in acute gout: specific histone deacetylase (HDAC) inhibition.

Methods

Peripheral blood mononuclear cells (PBMCs) were cultured with a combination of monosodium urate crystals (MSU) and palmitic acid (C16.0) in order to activate the NLRP3 inflammasome and induce IL-1β production. HDAC inhibitors and other compounds were added beforehand with a 1-h pre-incubation period.

Results

The HDAC1/2 inhibitor romidepsin was most potent in lowering C16.0+MSU-induced IL-1β production compared to other specific class I HDAC inhibitors. At 10 nM, romidepsin decreased IL-1β, IL-1Ra, IL-6, and IL-8 production. IL-1β mRNA was significantly decreased at 25 nM. Although romidepsin increased PTEN expression, PBMCs from patients with germline mutations in PTEN still responded well to romidepsin. Romidepsin also increased SOCS1 expression and blocked STAT1 and STAT3 activation. Furthermore, experiments with bortezomib showed that blocking the proteasome reverses the cytokine suppression by romidepsin.

Conclusions

Our results show that romidepsin is a very potent inhibitor of C16.0+MSU-induced cytokines in vitro. Romidepsin upregulated transcription of SOCS1, which was shown to directly target inflammatory signaling molecules for proteasomal degradation. Inhibiting the proteasome therefore reversed the cytokine-suppressive effects of romidepsin. HDAC1/2 dual inhibition could therefore be a highly potent new treatment option for acute gout, although safety has to be determined in vivo.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1834-x) contains supplementary material, which is available to authorized users.

Temporal trends and regional disparity in rheumatoid arthritis and gout hospitalizations in Sweden, 1998-2015

Hospitalization is an important component of rheumatoid arthritis (RA) and gout economic burden. This study aimed to assess temporal trends and regional disparities in RA and gout hospitalizations among people aged ≥ 20 years in Sweden during 1998–2015. Data on hospital admissions with a principal diagnosis of RA or gout were collected from the National Patient Register. Age-standardized hospitalization rates (ASHRs) were calculated by means of direct standardization. The absolute and relative regional disparities were assessed. The temporal trends in ASHR and proportion of RA and gout hospitalizations from all and musculoskeletal disorders hospitalizations were analyzed using joinpoint regression. Between 1998–2000 and 2013–2015, the ASHR for RA declined by 78.9% from 109.9 to 23.2 per 100,000 Swedish adults, while it almost doubled for gout (from 10.5 to 20.8 per 100,000 Swedish adults). While in 1998–2000, RA hospitalizations were 10.3 times more frequent than gout (0.54 vs 0.05% of all hospitalizations), this ratio declined to 1.1 in 2013–2015 (0.13 vs 0.11% of all hospitalizations). The joinpoint regression revealed that, on average, the ASHR for RA declined by 10.2% (95% CI: 9.3–11.1) per year whereas for gout, it rose by 4.3% (3.2–5.4) per year during 1998–2015. While the relative regional disparities were stable, the absolute regional disparity declined for RA and increased for gout over the study period. While substantial decline in RA hospitalization is encouraging, the substantial rise in gout hospitalization is of concern, reflecting potential increase in prevalence of gout and suboptimal management of the disease.