Seasonality of gout in Korea: a multicenter study

Trends in healthcare utilization by patients with gout: A cross-sectional study using Health Insurance Review and Assessment Service data

This study aimed to analyze the distribution of gout patients and the utilization of healthcare services in South Korea to provide valuable recommendations to clinicians and policymakers. A cross-sectional study was conducted. Claims data from the Health Insurance Review and Assessment Service spanning 2010 to 2019 were utilized, and a sample of 69,680 patients was included in the study. The incidence of gout was observed to be high in male patients over the age of 40, with most patients receiving outpatient care for gout management. Nonsteroidal anti-inflammatory drugs and urate-lowering agents were the most frequently prescribed medications, with prescriptions for colchicine and febuxostat increasing among urate-lowering agents. Musculoskeletal disorders were found to be the most common comorbidities among gout patients. Although the total costs of gout management increased, there was no significant increase in cost per patient. This study provides insights into the current state of healthcare utilization for gout patients in South Korea and trends in the disease burden and use of medications. The findings have crucial implications for clinicians and policymakers involved in decision-making regarding the management and treatment of gout.

Environmental factors and risk of gout

Gout is a chronic disease with inflammatory arthritis caused by monosodium urate (MSU) crystals deposition, an elevated serum urate level (hyperuricaemia) is the critical factor leading to MSU crystals deposition and promoting the progression of gout. The onset and development of gout is generally the result of multiple factors, such as diet, heredity and environmental factors. Although genetics and diet are thought to play as major factors, a growing body of research evidence has highlighted that environmental factors also play a significant role in the onset and exacerbation of gout. Recent studies have shown that air pollutants such as particulate matter, sulfur dioxide (SO₂) and carbon monoxide (CO) may increase the risk of hospitalizations for gout, and that the changes in temperature and humidity may affect uric acid (UA) levels. There is also seasonal trend in gout. It has been demonstrated that environmental factors may induce or accelerate the production and release of pro-inflammatory mediators, causing an unbalance oxidative stress and systemic inflammation, and then participating in the overall process or a certain link of gout. Moreover, several environmental factors have shown the ability to induce the production urate and regulate the innate immune pathways, involving in the pathogenesis of gout. Nevertheless, the role of environmental factors in the etiology of gout remains unclear. In this review, we summarized the recent literatures and aimed to discuss the relationship between environmental factors (such as microclimate, season, ambient/indoor air pollution and extreme weather) and gout. We further discussed the inflammatory mechanisms of environmental factors and gout and the comprehensive effects of environmental factors on gout. We also made a prospect of the management and treatment of gout, with special consideration to environmental factors associated with gout.

Are the levels of uric acid associated with biometeorological conditions?

Hyperuricemia is an independent risk factor for renal and cardiovascular diseases and is closely associated with gout episodes. It is caused, inter alia, by nutritional habits and genetic factors, and also displays seasonal variability conditioned by meteorological factors. The impact of meteorological factors, including both cold and heat stress, on the human physiology is presented based on the Universal Thermal Climate Index (UTCI) - a biometeorological index derived from an analysis of human thermal balance. The aim of our study was to establish whether seasonal variations significantly affect routinely measured urine acid (UA) levels and could eventually support the clinical decision making process, as well as assessing whether UTCI values are correlated with UA levels in blood serum. This work presents a retrospective epidemiological study of data collected in Olsztyn (Poland). Study material comprised 54,536 results of ambulatory tests measuring UA levels, performed during the period 2016-2019. The analysis concerned correlations between UA and the ages of female and male subjects as well as existing biometeorological conditions as represented by UTCI values in an annual cycle. UA levels in females were found to be lower (4.94 ± 1.37 SD) as compared to those of males (6.13 ± 1.43 SD) and demonstrated a strong positive correlation with age. UA values differed significantly (p < 0.05) on days characterized by cold stress and heat stress, for the oldest age group. UA levels were found to differ depending on the season, but these relationships were not statistically significant, except for significantly higher UA levels in females in autumn (p < 0.001). However, there was an evident difference in population UA levels under cold stress conditions (lower) and heat stress conditions (higher) in the elderly. The UTCI is an adequate predictor of population variations in UA levels since it takes into account the variability of local meteorological conditions.

Seasonal variation in the onset of acute calcific tendinitis of rotator cuff

Background

Calcific tendinitis of the rotator cuff is a disorder that causes acute onset of shoulder pain when spontaneous resorption of the calcification occurs. However, factors that trigger calcium resorption have not been clarified. The present study aimed to investigate the association between the onset of calcium resorption in calcific tendinitis and the season of onset.

Methods

We retrospectively reviewed 195 patients (female, 116; male, 79; mean age, 62.6 ± 14.2 years; median age, 62 [52, 73] years) diagnosed with the postcalcification stage of calcific tendinitis, which was defined as acute calcific tendinitis in this study, between 2006 and 2018. The onset date of acute calcific tendinitis for each patient was collected from clinical notes. We evaluated the incidence of acute calcific tendinitis in each season and month. Furthermore, we investigated the correlation between the incidence of acute calcific tendinitis and the mean monthly temperature or humidity levels for each year.

Results

The most common season of acute calcific tendinitis onset was summer (35.4%), followed by spring (24.6%), autumn (24.1%), and winter (15.9%) (P = 0.002). Monthly analyses showed the highest peak of onset was in July (15.4%) and the lowest peak was in February (3.1%) (P = 0.022). The incidence of acute calcific tendinitis had a weak association with mean monthly temperature (R² = 0.066; P = 0.001) but was not associated with mean monthly humidity levels (R² = 0.018; P = 0.099).

Conclusions

This study provides new information on seasonal variation of acute calcific tendinitis onset. The results of this study indicated that the onset of calcium resorption occurs most frequently in the summer in Japan; however, the reasons for seasonal variation remain unclear, and further studies will be needed.

Level of evidence

Level III.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-020-03773-6.

Seasonal Variations and Associated Factors of Gout Attacks: a Prospective Multicenter Study in Korea

BACKGROUND

We purposed to evaluate the seasonality and associated factors of the incidence of gout attacks in Korea.

METHODS

We prospectively enrolled patients with gout attacks who were treated at nine rheumatology clinics between January 2015 and July 2018 and followed them for 1-year. Demographic data, clinical and laboratory features, and meteorological data including seasonality were collected.

RESULTS

Two hundred-five patients (men, 94.1%) were enrolled. The proportion of patients with initial gout attacks was 46.8% (n = 96). The median age, body mass index, attack duration, and serum uric acid level at enrollment were 50.0 years, 25.4, 5.0 days, and 7.4 mg/dL, respectively. Gout attacks were most common during spring (43.4%, P < 0.001) and in March (23.4%, P < 0.001). A similar pattern of seasonality was observed in the group with initial gout attacks. Alcohol was the most common provoking factor (39.0%), particularly during summer (50.0%). The median diurnal temperature change on the day of the attack was highest in the spring (9.8°C), followed by winter (9.3°C), fall (8.6°C), and summer (7.1°C) (P = 0.027). The median change in humidity between the 2 consecutive days (the day before and the day of the attack) was significantly different among the seasons (3.0%, spring; 0.3%, summer; -0.9%, fall; -1.2%, winter; P = 0.015). One hundred twenty-five (61%) patients completed 1-year follow-up (51% in the initial attack group). During the follow-up period, 64 gout flares developed (21 in the initial attack group). No significant seasonal variation in the follow-up flares was found.

CONCLUSION

In this prospective study, the most common season and month of gout attacks in Korea are spring and March, respectively. Alcohol is the most common provoking factor, particularly during summer. Diurnal temperature changes on the day of the attack and humidity changes from the day before the attack to the day of the attack are associated with gout attack in our cohort.

Association Between Gout and Injury Risk: A National Retrospective Cohort Study

The association between gout and injury remains unclear. This study aimed to investigate the injury risk in patients with gout. Using the Longitudinal Health Insurance Database (LHID) from 2000 to 2010 in Taiwan, patients with gout (group CFG) and those without gout (group C) were enrolled for further analysis. The CFG group was separated into two subgroups (with and without medication) to determine whether the risk of injury was reduced with drug intervention. The follow-up period was defined as the time from the initial diagnosis of gout to the date of injury. A total of 257,442 individuals were enrolled in this study, with 85,814 people in group CFG and 171,628 people in group C. Using Cox regression analysis, group CFG showed a significant increase in the risk of injury. Traffic injuries, poisoning, falls, crushing/cutting/piercing injury, and suicides were prominent among these injuries. Furthermore, when urate-lowing drugs were used to treat the CFG group, there were no significant differences in the occurrence of injury. Patients with gout had an increased risk of injury overall, and drug intervention did not lower the risk of injury in these patients.

Elderly Patients Exhibit Stronger Inflammatory Responses during Gout Attacks

Gout attacks are often accompanied by systemic inflammatory response. The aim of the retrospective study was to compare gout patients in different age groups in terms of their clinical features at gout attacks. Patients, who were treated for gout attack in two tertiary medical centers between January 2000 and April 2014, were divided into young (≤ 50 years), middle-aged, and elderly (> 65 years) groups. Patients in three age groups were compared in terms of presence of fever (> 37.8°C), C-reactive protein (CRP) levels, and erythrocyte sedimentation ratio (ESR) at the gout attacks. Monocytes, which were isolated from 10 consecutive patients who previously experienced gout attacks, were stimulated with monosodium urate (MSU) crystals and cytokine production was measured by flow cytometry. Among 254 patients analyzed in this study, 48 were young, 65 were middle-aged, and 141 were elderly. The elderly patients were more likely to have fever (51.1%) during the attack than the young (20.8%) and middle-aged (30.8%) patients (P < 0.001 by χ² test). They were also more likely to have higher ESR and CRP levels than the young patients (P = 0.002 for ESR, P < 0.001 for CRP). Patients' age correlated significantly with CRP and ESR levels (both P < 0.001). After stimulation with MSU, the production of interleukin-1β by monocytes increased with patients' age (r = 0.670, P = 0.03). In conclusion, gout attacks in elderly patients are associated with fever and higher ESR and CRP levels, often resembling a septic arthritis.

Association between acute gouty arthritis and meteorological factors: An ecological study using a systematic review and meta-analysis

OBJECTIVES

The aims of this study were as follows: (1) to analyze the literature systematically regarding the seasonal and monthly variation of the occurrence of episodes of acute gouty arthritis, and (2) to investigate the relationship between the occurrence of episodes of acute gouty arthritis and meteorological parameters.

METHODS

The present authors systematically reviewed databases for articles published before November 2015. Studies with quantitative data on episodes of acute gouty arthritis by months and/or seasons were included. Meteorological data such as the highest temperature, lowest temperature, diurnal temperature range, change in mean temperature between neighboring days, relative humidity and wind speed for the geographic place(s), and study period where and when each study took place were obtained from meteorological websites.

RESULTS

Ten studies published between 1920 and 2015 were included. A meta-analysis by season showed that acute gouty arthritis occurred significantly more frequently in spring than in other seasons. Analysis by month showed an increase in episodes of acute gouty arthritis from March to July, being the highest in July. The trend reversed, and episodes of acute gouty arthritis started decreasing from July to September, being the lowest in September. The change in mean temperature between neighboring days was the only meteorological parameter that was significantly correlated with the number of monthly episodes of acute gouty arthritis.

CONCLUSIONS

Acute gouty arthritis seems to develop more frequently during the period in which the temperature increases significantly between neighboring days: spring by season and between March and July by month in the northern hemisphere.

Seasonal variations of urate in a Swedish adult population

Seasonality in the incidence and prevalence of gout has previously been reported but the cause of this seasonality in gout is not explained. The aim of this study was to evaluate possible seasonal variations of urate in a large unselected Swedish adult population. We analyzed 170,915 urate test results from patients at a tertiary care hospital between 2000 and 2016. The results were divided according to sex and sampling month of the year. The median urate values were overall higher in males compared to females and both males and females had peak urate concentrations in the summer months (June–August). There is a seasonal pattern for urate concentrations in a large Swedish population similar to the previously reported seasonality for gout. This may be clinically important and could contribute to the circannual variation of gout. The seasonal pattern should be recognized when evaluating patient results both in clinical practice and in research studies.

The associations among vitamin D deficiency, C-reactive protein, and depressive symptoms

OBJECTIVE

Vitamin D deficiency has been reported to be associated with depression, but the underlying mechanisms aren't well understood. Our study aims to investigate the associations among serum vitamin D, C-reactive protein (CRP) level, and depressive symptoms.

METHODS

Serum levels of Vitamin D and CRP were measured from 52,228 participants. Depressive symptoms were assessed using a Korean version of the CES-D scale. We used logistic regression to calculate the odds ratio (ORs) of depressive symptoms according to vitamin D and CRP levels. The regressions were adjusted for covariates, and each model was adjusted mutually for vitamin D and CRP levels.

RESULTS

A significant difference was found in vitamin D status between depressed and non-depressed participants, but CRP status was not significantly different. The OR for the presence of depressive symptoms was significantly increased in participants with vitamin D deficiency after adjusting for potentially confounding factors (Adjusted OR=1.158, 95% CI=1.003-1.336, p=0.046). The OR of depressive symptoms was not significantly increased in individuals with high (3.01-10mg/L) CRP level compared to individuals with low (≤3mg/L) CRP level (Adjusted OR=1.004, 95% CI=0.821-1.227, p=0.97). There was no significant association between vitamin D and CRP level. Additional adjustment for serum CRP level did not weaken the resulting association between vitamin D deficiency and the presence of depressive symptoms.

CONCLUSION

Vitamin D deficiency was associated with depressive symptoms, but elevated serum CRP level was not. The results indicate that CRP level does not account for the association between vitamin D deficiency and the presence of depressive symptoms.

Epidemiology of inpatient gout in Australia and New Zealand: temporal trends, comorbidities and gout flare site

AIM

To assess the epidemiology of inpatient gout in Australia and New Zealand during the years 2009-2014.

METHODS

Using the Health Roundtable Limited (HRT) dataset, all patients with a coded ICD10 primary or secondary discharge diagnosis of gout from a HRT participating Australian or New Zealand hospital between the years 2009 and 2014 were identified. The number of inpatient gout admissions, length of stay, body site of gout flare, temporal trends and comorbidities were assessed.

RESULTS

During 2009-2014, the number of gout admissions increased significantly in Australia and New Zealand. The rate of inpatient gout admissions relative to the population and total HRT admissions rose in Australia and stayed static in New Zealand. Lower limb presentations were the commonest anatomical site of gout in admitted patients. Length of stay over the course of the study decreased both in patients admitted for gout and in those in the entire HRT dataset. Patients admitted for gout have longer length of stay compared to patients admitted for other reasons. Cardiovascular disease, infection and stroke were the commonest conditions that were complicated by an episode of inpatient gout. There was no influence of month or season on the pattern of gout admissions.

CONCLUSION

The number of gout admissions rose in Australia numerically and as a proportion of the total population and total admissions. Gout is an increasing problem affecting individuals and the community as a whole in Australia.