Increased cardiovascular mortality associated with gout: a systematic review and meta-analysis

Epidemiology and health-related services

PURPOSE OF REVIEW

This article presents recent epidemiologic contributions focusing on gout-related conditions, especially if controversial, to find plausible, despite hypothetical, mechanistic explanations from the clinician perspective.

RECENT FINDINGS

The prevalence of gout is increasing, but it is only partially clear that the incidence may be increasing as well. Direct associations of gout with increased risk of diabetes, black races, neurodegenerative disorders, and sugar-enriched foods have been recently questioned. A negative association with smoking has been reported, and new evidence shows that the impact of diet may be independent of obesity. Kidney disease and diuretics have been confirmed to be associated with gout, whereas new data on aging and menopause have come to challenge apparently established disease mechanisms. Regarding treatments, increase in bladder cancer associated with chronic allopurinol use has been reported, and the positive effect of urate-lowering treatment on cardiovascular events has been contested.

SUMMARY

Epidemiological data in gout-related conditions are still evolving and claim for future cohort or intervention studies to prove causality. Controversies in epidemiological results fertilize the ground for studies to prove mechanisms and causality and provides a unique opportunity for clinical intervention to improve outcomes, especially with regard to treatments.

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.

Gout is associated with organic and psychogenic erectile dysfunction

BACKGROUND

Gout is a deposition disease with an inflammatory response that can increase the risk of cardiovascular disease. Gout is stressful for affected individuals, and can cause erectile dysfunction (ED). The objective of this study was to identify the association between gout and psychogenic ED (PED) and organic ED (OED).

METHOD

We analyzed 35,265 patients from the National Health Insurance Research Database who had been diagnosed with gout between 2000 and 2011. A total of 70,529 matched controls were included in the study as a comparison. Patients with a history of PED and OED occurring before the index date, aged less than 20 years, or with incomplete demographic information were excluded. Control patients were selected from the population of people without a history of gout, PED, or OED. The following risk factors for PED and OED were included as covariates in the multivariable models: age, comorbidities of coronary artery disease (CAD), peripheral arterial disease, chronic kidney disease (CKD), hypertension, diabetes, hyperlipidemia, depression and anxiety.

RESULT

Men with gout were more likely to have an increased risk (1.21 times) of ED than were those without gout. Patients with gout were 1.52 times more likely to develop OED and 1.18 times more likely to develop PED than patients in the control group. The risk of developing ED was greater for patients with comorbidities of CKD, diabetes, hyperlipidemia, depression and anxiety.

CONCLUSION

Gout is associated with organic and psychogenic ED. Clinical physicians should consider this association when treating patients with gout.

Bidirectional Association between Self-Reported Hypertension and Gout: The Singapore Chinese Health Study

It has been hypothesized that the association between hypertension and gout is bidirectional, however, few studies have examined this in a prospective cohort. We analyzed data from the Singapore Chinese Health Study (SCHS) follow-up I (1999–2004) and II (2006–2010) interviews, when both physician-diagnosed hypertension and gout were self-reported. We included participants with data for both follow-up interviews and who were free of heart disease, stroke and cancer at follow-up I. The analysis of hypertension and risk of gout included 31,137 participants when prevalent gout cases were excluded, while the analysis of gout and risk of hypertension included 20,369 participants when prevalent hypertension cases were excluded. Cox proportional hazards models were used to estimate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). The mean age at follow-up I was 60.1 (SD 7.3) years, and the average follow-up was 6.8 (SD 1.4) years. In the analysis of hypertension and risk of gout, 682 incident cases were identified. Compared to normotensive participants, hypertensive patients had an88% increased risk of developing gout (HR 1.88; 95% CI 1.61–2.21). In the parallel analysis, 5,450 participants reported to have newly diagnosed hypertension during follow-up. Compared to participants without gout, those with gout had an18% increased risk of developing hypertension (HR 1.18; 95% CI 1.02–1.37). The bidirectional association was stronger in normal weight adults compared to overweight/obese individuals (P_interaction = 0.06 and 0.04, respectively). The hypertension to gout association was stronger in women compared to men (P_interaction = 0.04), while the gout to hypertension association was evident in women but not in men (P_interaction = 0.02). In conclusion, our results suggest that the hypertension-gout association is bidirectional in this cohort of Singapore Chinese adults. The potential interactions of the bidirectional association with obesity and sex deserve further investigations.

Gout and Risk of Myocardial Infarction: A Systematic Review and Meta-Analysis of Cohort Studies

Introduction

A high incidence of myocardial infarction among patients with gout has been suggested by several observational studies. We performed a meta-analysis to evaluate the association between gout and the risk of myocardial infarction.

Materials and Methods

The PubMed and Embase databases were searched from inception to October 2014 for cohort studies that evaluating the association between gout and the risk of myocardial infarction. Summary estimates were derived using a random-effects model and reported as relative risks (RRs) with 95% confidence intervals (CIs).

Results

Five studies involving 8,656,413 participants with a total of 1000 MI events were included. Overall, gout was associated with an increased risk of myocardial infarction (RR 1.45; 95% CI, 1.19–1.75; p<0.001), and the association referred to non-fatal myocardial infarction (RR 1.29; 95% CI, 1.19–1.39; p <0.001) but not fatal myocardial infarction (RR 1.11; 95% CI, 0.96–1.28; p = 0.174). The increased risk was observed in both women (RR 1.62; 95% CI, 1.18–2.21; p = 0.003) and men (RR 1.45; 95% CI, 1.21–1.74; p <0.001). Stratified analysis revealed a gradual increase in myocardial infarction risk with a younger age of gout onset (age 20–44 years old (RR 2.82; 95% CI, 1.38–5.79; p = 0.05); 45–69 years old (RR 1.85; 95% CI, 1.22–2.82; p = 0.04); ≥70 years old (RR 1.52; 95% CI, 1.22–1.88; p <0.001)).

Conclusion

This meta-analysis suggests that patients with gout have an increased risk of myocardial infarction.

A coronary artery disease-associated SNP rs6903956 contributed to asymptomatic hyperuricemia susceptibility in Han Chinese

Background

To investigate the association of a coronary artery disease (CAD) risk SNP rs6903956 with asymptomatic hyperuricemia (aHU) susceptibility in Han Chinese.

Methods

Two hundred and twenty one patients with aHU and 447 healthy controls were recruited for this study. SNP rs6903956 were genotyped using TaqMan probe.

Results

The overall genotype and allele frequency distribution of the rs6903956 showed significant difference between aHU cases and controls (p <0.001 for genotype and allele, respectively). AA genotype of rs6903956 was significantly associated with aHU (OR = 8.672, 95% CI 2.811-26.753, p <0.001) in our Han Chinese aHU cohort. Multivariate logistic regression analysis indicated that rs6903956 might be an independent risk factor for aHU susceptibility (OR = 10.642 [2.671- 42.400], p = 0.001 for codominant model and OR = 9.205 [2.336-36.280], p = 0.002 for recessive model) after adjustment for some well- known CAD risk factors including age, gender, body mass index, smoking, hypertension, diabetes mellitus, abnormal glycometabolism, lipid abnormality and alcohol intake. No significant genotype-specific difference in uric acid levels was observed in aHU patients and controls.

Conclusions

Our findings are the first to establish a genetic link of a CAD-associated rs6903956 with aHU in a Han Chinese population, providing the genetic evidence to support the close relationship between hyperuricemia and CAD.

Increased risk of vascular disease associated with gout: a retrospective, matched cohort study in the UK clinical practice research datalink

OBJECTIVES

To determine whether gout increases risk of incident coronary heart disease (CHD), cerebrovascular (CVD) and peripheral vascular disease (PVD) in a large cohort of primary care patients with gout, since there have been no such large studies in primary care.

METHODS

A retrospective cohort study was performed using data from the Clinical Practice Research Datalink (CPRD). Risk of incident CHD, CVD and PVD was compared in 8386 patients with an incident diagnosis of gout, and 39 766 age, sex and registered general practice-matched controls, all aged over 50 years and with no prior vascular history, in the 10 years following incidence of gout, or matched index date (baseline). Multivariable Cox Regression was used to estimate HRs and covariates included sex and baseline measures of age, Body Mass Index, smoking, alcohol consumption, Charlson comorbidity index, history of hypertension, hyperlipidaemia, chronic kidney disease, statin use and aspirin use.

RESULTS

Multivariable analysis showed men were at increased risk of any vascular event (HRs (95% CIs)) HR 1.06 (1.01 to 1.12), any CHD HR 1.08 (1.01 to 1.15) and PVD HR 1.18 (1.01 to 1.38), while women were at increased risk of any vascular event, HR 1.25 (1.15 to 1.35), any CHD HR 1.25 (1.12 to 1.39), and PVD 1.89 (1.50 to 2.38)) but not any CVD.

CONCLUSIONS

In this cohort of over 50s with gout, female patients with gout were at greatest risk of incident vascular events, even after adjustment for vascular risk factors, despite a higher prevalence of both gout and vascular disease in men. Further research is required to establish the reason for this sex difference.

Cardiovascular disease in patients with chronic inflammation: mechanisms underlying premature cardiovascular events in rheumatologic conditions

A variety of systemic inflammatory rheumatic diseases associate with an increased risk of atherosclerotic events and premature cardiovascular (CV) disease. Although this recognition has stimulated intense basic science and clinical research, the precise nature of the relationship between local and systemic inflammation, their interactions with traditional CV risk factors, and their role in accelerating atherogenesis remains unresolved. The individual rheumatic diseases have both shared and unique attributes that might impact CV events. Understanding of the positive and negative influences of individual anti-inflammatory therapies remains rudimentary. Clinicians need to adopt an evidence-based approach to develop diagnostic techniques to identify those rheumatologic patients most at risk of CV disease and to develop effective treatment protocols. Development of optimal preventative and disease-modifying approaches for atherosclerosis in these patients will require close collaboration between basic scientists, CV specialists, and rheumatologists. This interface presents a complex, important, and exciting challenge.

Risk of vascular events in patients with polymyalgia rheumatica

BACKGROUND

Polymyalgia rheumatica is one of the most common inflammatory rheumatologic conditions in older adults. Other inflammatory rheumatologic disorders are associated with an excess risk of vascular disease. We investigated whether polymyalgia rheumatica is associated with an increased risk of vascular events.

METHODS

We used the General Practice Research Database to identify patients with a diagnosis of incident polymyalgia rheumatica between Jan. 1, 1987, and Dec. 31, 1999. Patients were matched by age, sex and practice with up to 5 patients without polymyalgia rheumatica. Patients were followed until their first vascular event (cardiovascular, cerebrovascular, peripheral vascular) or the end of available records (May 2011). All participants were free of vascular disease before the diagnosis of polymyalgia rheumatica (or matched date). We used Cox regression models to compare time to first vascular event in patients with and without polymyalgia rheumatica.

RESULTS

A total of 3249 patients with polymyalgia rheumatica and 12 735 patients without were included in the final sample. Over a median follow-up period of 7.8 (interquartile range 3.3-12.4) years, the rate of vascular events was higher among patients with polymyalgia rheumatica than among those without (36.1 v. 12.2 per 1000 person-years; adjusted hazard ratio 2.6, 95% confidence interval 2.4-2.9). The increased risk of a vascular event was similar for each vascular disease end point. The magnitude of risk was higher in early disease and in patients younger than 60 years at diagnosis.

INTERPRETATION

Patients with polymyalgia rheumatica have an increased risk of vascular events. This risk is greatest in the youngest age groups. As with other forms of inflammatory arthritis, patients with polymyalgia rheumatica should have their vascular risk factors identified and actively managed to reduce this excess risk.

The emerging role of biotechnological drugs in the treatment of gout

One of the most important therapeutic advances obtained in the field of rheumatology is the availability of the so-called bio(techno)logical drugs, which have deeply changed treatment perspectives in diseases such as rheumatoid arthritis and ankylosing spondylitis. According to the steadily increasing attention on gout, due to well-established prognostic and epidemiology implications, in the last 5 years, the same change of perspective has been observed also for this disease. In fact, several bio(techno)logical agents have been investigated both for the management of the articular gout symptoms, targeting mainly interleukin-1β, as well as urate-lowering therapies such as recombinant uricases. Among the IL-1β inhibitors, the majority of studies involve drugs such as anakinra, canakinumab, and rilonacept, but other compounds are under development. Moreover, other potential targets have been suggested, as, for example, the TNF alpha and IL-6, even if data obtained are less robust than those of IL-1β inhibitors. Regarding urate-lowering therapies, the recombinant uricases pegloticase and rasburicase clearly showed their effectiveness in gout patients. Also in this case, new compounds are under development. The aim of this review is to focus on the various aspects of different bio(techno)logical drugs in gouty patients.