Relation of temperature and humidity to the risk of recurrent gout attacks

Come rain or shine: Is weather a risk factor for musculoskeletal pain? A systematic review with meta-analysis of case-crossover studies

OBJECTIVES

The weather is frequently blamed for changes in musculoskeletal health behaviour and adverse events. However, despite the frequency with which this phenomenon is endorsed, past research is largely conflicting. This meta-analysis has reviewed, appraised and summarised case-crossover studies assessing the transient risk of musculoskeletal health events associated with weather parameters (e.g. temperature, relative humidity, air pressure, and precipitation).

METHODS

A meta-analysis of case-crossover studies was conducted. Two reviewers independently searched MEDLINE, EMBASE, CINAHL, Web of Science, Scopus, and PsycINFO from inception to 10/09/2023. Published studies that employed a case-crossover design to evaluate the risk of musculoskeletal health events (e.g. symptoms, hospitalisation) associated with weather parameters were included. Primary outcome was pain (new episodes of pain or flares). Quality of included studies was assessed based on selection bias, exposure assessment, confounding, and outcome assessment. Pooling of results was conducted using random effects models and separately performed for each condition and weather factor. Heterogeneity among included studies was assessed using I2 measures.

FINDINGS

Of the 1,107 studies identified in the search, 11 were included (15,315 participants), providing data on 28,010 events (102,536 control periods), for seven musculoskeletal conditions. Pooled analyses showed no association between relative humidity, air pressure, temperature, or precipitation and the risk of rheumatoid arthritis, knee pain or low back pain. High temperatures combined with low humidity were associated with increased pain, redness, and joint swelling in people with gout (Odds Ratio: 2.04; 95 % Confidence Interval: 1.26 to 3.30).

INTERPRETATION

Despite anecdotal reports from patients, changes in weather factors do not seem to be risk factors for rheumatoid arthritis, knee, hip, or low back pain, but may have a significant influence in gout disease.

Seasonal variations for newly prescribed urate-lowering drugs for asymptomatic hyperuricemia and gout in Japan

Background: Urate-lowering drugs (ULDs) have been approved for treatment of asymptomatic hyperuricemia and gout in Japan. Although serum urate levels and rates of gout onset are known to have seasonal variations, no survey results regarding the seasonality of ULD prescriptions for asymptomatic hyperuricemia and gout have been reported. Methods: A large-scale database of medical claims in Japan filed between January 2019 and December 2022 was accessed. In addition to total size of the recorded population for each month examined, the numbers of patients every month with newly prescribed ULDs for asymptomatic hyperuricemia and gout were noted, based on the International Classification of Diseases, 10th Revision, codes E79.0 and M10. Results: The results identified 201,008 patients with newly prescribed ULDs (median age 49.0 years, male 95.6%). Of those, 64.0% were prescribed ULDs for asymptomatic hyperuricemia and 36.0% for gout. The proportion of new ULD prescriptions was seasonal, with that significantly (p < 0.001) higher in summer (June-August) [risk ratio (RR) 1.322, 95% CI 1.218 to 1.436] and autumn (September-November) (RR 1.227, 95% CI 1.129-1.335) than in winter (December-February), whereas the proportion in spring (March-May) was not significantly different from winter. There was no significant difference after stratification by drug type (uric acid production inhibitor/uricosuric agent) or size of the medical institution, nor subgrouping by age or sex (p for interaction = 0.739, 0.727, 0.886, and 0.978, respectively). On the other hand, the proportions of new ULD prescriptions for asymptomatic hyperuricemia were significantly lower and for gout significantly higher in spring than winter, while those were similar in summer and autumn for both groups (p for interaction<0.001). Conclusion: The present findings indicate that new prescriptions for ULDs to treat asymptomatic hyperuricemia or gout in Japan show seasonal differences, with higher rates noted in summer and autumn as compared to winter.

Association between living environmental quality and risk of arthritis in middle-aged and older adults: a national study in China

Background

The association between combined environmental factors and the risk of arthritis is still scarcely studied. The present study performed cross-sectional and cohort studies to explore the association between risk score of living environment quality and the risk of arthritis in middle-aged and older adults in China.

Methods

The study was based on China Health and Retirement Longitudinal Study (CHARLS), and it recruited 17,218 participants in the cross-sectional study and 11,242 participants in the seven-year follow-up study. The living environment quality was measured by household fuel types, household water sources, room temperature, residence types, and ambient concentration of PM2.5. Logistic regression and Cox proportional hazard regression models were utilized to examine the association between the living environment quality and the risk of arthritis. Competing risk models and stratified analyses were applied to further verify our results.

Results

Compared with individuals in the suitable environment group, people who lived in moderate (OR:1.28, 95%CI: 1.14-1.43) and unfavorable environments (OR:1.49, 95%CI:1.31-1.70) showed higher risks of arthritis when considering the multiple living environmental factors (P for trend <0.001) in the cross-sectional analysis. In the follow-up study, similar results (P for trend = 0.021), moderate environment group (HR:1.26, 95%CI:1.01-1.56) and unfavorable environment group (HR: 1.36, 95%CI: 1.07-1.74), were founded.

Conclusion

Inferior living environment might promote the development of arthritis. It is necessary for the public, especially old people, to improve the living environment, which may be the key to the primary prevention of arthritis.

Immersion in Water Between 20-30oC Mediated Inflammations Marker to Reduced Pain Among Indonesian With Gout Arthritis: A Community-Based Randomized Controlled Trial

BACKGROUND

Gout is triggered by high urate levels and causes inflammation, pain, and an impaired quality of life. Immersion in water at 20-30°C reduces inflammation and pain in arthritis. Yet, relationships of immersion in water at 20-30°C with urate levels and the nucleotide-binding domain (NOD)-like receptor protein 1 (NLRP1) inflammasome have never been clarified.

OBJECTIVES

We aimed to investigate the effects of immersion in water at 20-30°C on urate levels, the NLRP1 inflammasome, pain, and quality of life among acute gout patients.

METHODS

A community-based randomized control trial design was used with 2 parallel-intervention groups: immersion in water at 20-30°C (20 min/day for 4 weeks) group and a control group. In total, 76 eligible participants in Tomohon City, Indonesia, were assigned using block randomization. We analyze the results (coef. β) and 95% confidence intervals (CIs) using a generalized estimating equation model. We analyzed mediating effects using a path analysis.

RESULTS

Significant pain alleviation (β = -2.06 [95% CI = -2.67∼-1.45]; β = -2.42 [95% CI = -2.97∼-1.87]) and improved quality of life (β = 5.34 [95% CI = 3.12-7.57]; β = 9.93 [95% CI = 7.02-12.83]) were detected at 2 and 4 weeks of follow-up compared to the pre-test and control group. Urate levels (β = -0.34 [95% CI = -0.52∼-0.16]) were reduced at the 2-week follow-up, but there was no significant change in the NLRP1 inflammasome compared to the pre-test and control group after immersion in water at 20-30°C. Both the NLRP1 inflammasome (β = -0.48 [95% CI = -0.63∼-0.34]); water 0.01) and urate levels (β = -0.11 [95% CI = -0.24∼-0.03]; p < 0.01) had partial indirect (mediating) effects on the link between immersion in water at 20-30°C and pain at the 4-week follow-up.

CONCLUSIONS

Immersion in water at 20-30°C significantly decreased pain and increased the quality of life. Immersion in water at 20-30°C mediated NLRP1 and urate levels to decrease pain, although it had no significant effect on the NLRP1 inflammasome concentration after 4 weeks of follow-up and reduced urate levels only at 2 weeks after immersion in water at 20-30°C.

Association of Area-Level Heat and Social Vulnerability With Recurrent Hospitalizations Among Individuals With Rheumatic Conditions

OBJECTIVE

Climate and social vulnerability contribute to morbidity and health care utilization. We examined associations between the neighborhood Social Vulnerability Index (SVI) and the Heat Vulnerability Index (HVI) and recurrent hospitalizations among individuals with rheumatic conditions.

METHODS

Using a Massachusetts multihospital centralized clinical data repository, we identified individuals ≥18 years of age with a rheumatic condition who received rheumatology care within 3 years of April 2021. We defined the index date as 2 years before the last encounter and the baseline period as 1 year pre-index date. Addresses were geocoded and linked by census tract to the SVI and the HVI. We used multilevel, multinomial logistic regression to examine the odds of 1-3 and ≥4 hospitalizations (reference = 0) over 2 years post index date by vulnerability index, adjusting for age, gender, race/ethnicity, insurance, and comorbidities.

RESULTS

Among 14,401 individuals with rheumatic conditions, the mean ± age was 61.9 ± 15.7 years, 70% were female, 79% White, 7% Black, and 2% Hispanic. There were 8,251 hospitalizations; 11,649 individuals (81%) had 0 hospitalizations, 2,063 (14%) had 1-3, and 689 (5%) had ≥4. Adjusting for individual-level factors, individuals living in the highest versus lowest SVI areas had 1.84 times higher odds (95% confidence interval [95% CI] 1.43-2.36) of ≥4 hospitalizations. Individuals living in the highest versus lowest HVI areas had 1.64 times greater odds (95% CI 1.17-2.31) of ≥4 hospitalizations.

CONCLUSION

Individuals with rheumatic conditions living in areas with high versus low social and heat vulnerability had significantly greater odds of recurrent hospitalizations. Studies are needed to determine modifiable factors to mitigate risks.

Environmental Triggers of Hyperuricemia and Gout

Gout is the most prevalent type of inflammatory arthritis worldwide and environmental factors contribute to hyperuricemia and risk for gout flare. Causes of hyperuricemia include increased purine consumption from meat, alcohol, and high fructose corn syrup as well as medications such as cyclosporine, low-dose aspirin, or diuretics. Triggers for gout flares include increased purine consumption and medication use such as urate lowering therapy and diuretics. Environmental exposures including lead exposure, particulate matter exposure, temperature fluctuations, and physiologic stress have been found to trigger flares. In the right clinical scenario, these factors should be considered when treating gout patients.

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.

Association between non-optimal temperature and hospitalizations for gout in Anqing, China: a time-series analysis

Previous studies have found that non-optimal temperature influences the development of gout, but the results have been inconsistent. The present study aimed to explore the effects of high temperature and high temperature variation on hospitalizations for gout in Anqing, China. We collected daily data on air pollutants, meteorological factors, and hospitalizations for gout between 1January 2016 and 31 December 2020 in Anqing City, China. We used Poisson generalized linear regression model and a distributed lag non-linear model (DLNM) to explore the relationship of high temperature, diurnal temperature range (DTR), and temperature change between neighboring days (TCN) with hospitalizations for gout. Stratified analysis by gender (male, female) and age (<65 years, ≥65 years) was conducted. Hospitalizations for gout attributed to high temperature, high DTR, and high TCN were also quantified. A total of 8675 hospitalized patients with gout were reported during the study period. We observed that exposure to high temperature was linked with an increased risk of hospitalizations for gout (lag 0, RR: 1.081, 95% confidence interval (CI): 1.011, 1.155). Exposure to high DTR was also associated with increased risk of hospitalizations for gout (lag9, RR: 1.017, 95% CI: 1.001,1.035). A large drop in temperature between neighboring days was associated an increased risk of hospitalizations for gout (lag 0-2 days, RR: 1.234, 95% CI: 1.017, 1.493). Stratified analysis results revealed that older adults and men were more sensitive to high-level DTR exposure than their counterparts. Nearly 15% of hospitalizations for gout could be attributable to high temperature (attributable fraction: 14.93%, 95% CI: 5.99%, 22.11%). This study suggests that high temperature and high temperature variation may trigger hospitalizations for gout, indicating that patients with gout need to take proactive actions in the face of days with non-optimal temperature.

Lower Temperatures Exacerbate NLRP3 Inflammasome Activation by Promoting Monosodium Urate Crystallization, Causing Gout

Gout is a recurrent and chronic form of arthritis caused by the deposition of monosodium urate (MSU) crystals in the joints. Macrophages intake MSU crystals, the trigger for NLRP3 inflammasome activation, which leads to the release of interleukin (IL)-1β and results in the flaring of gout. The effects of temperature, an environmental factor for MSU crystallization, on IL-1β secretion have not been well studied. This study examined the effects of temperature on inflammasome activation. Specific triggers activated canonical inflammasomes (NLRP3, NLRC4, and AIM2) in murine macrophages at various temperatures (25, 33, 37, 39, and 42 °C). The maturation of IL-1β and caspase-1 was measured as an indicator for inflammasome activation. As expected, the optimal temperature of inflammasome activation was 37 °C. The MSU crystal-mediated activation of inflammasome increased at temperatures lower than 37 °C and decreased at higher temperatures. MSU crystals at lower temperatures enhanced IL-1β secretion via the NLRP3 inflammasome pathway. A lower temperature promoted the formation of MSU crystals without changing phagocytosis. Overall, lower temperatures form more MSU crystals and enhance NLRP3 inflammasome activation. In light of these findings, it is possible that hyperthermia therapy may reduce gout flaring.

Are weather conditions associated with chronic musculoskeletal pain? Review of results and methodologies

Many people believe that weather influences chronic musculoskeletal pain. Previous studies on this association are narratively reviewed, with particular focus on comparing methodologies and summarising study findings in light of study quality. We searched 5 databases (Medline, Embase, Web of Science, PsycINFO, and Scopus) for observational studies on the association between weather variables and self-reported musculoskeletal pain severity. Of 4707 located articles, 43 were eligible for inclusion. The majority (67%) found some association between pain and a weather variable. Temperature, atmospheric pressure, relative humidity, and precipitation were most often investigated. For each weather variable, some studies found an association with pain (in either direction), and others did not. Most studies (86%) had a longitudinal study design, usually collecting outcome data for less than a month, from fewer than 100 participants. Most studies blinded participants to study aims but were at a high risk of misclassification of exposure and did not meet reporting requirements. Pain severity was most often self-reported (84%) on a numeric rating scale or visual analog scale. Weather data were collected from local weather stations, usually on the assumption that participants stayed in their home city. Analysis methods, preparation of weather data, and adjustment for covariates varied widely between studies. The association between weather and pain has been difficult to characterise. To obtain more clarity, future studies should address 3 main limitations of the previous literature: small sample sizes and short study durations, misclassification of exposure, and approach to statistical analysis (specifically, multiple comparisons and adjusting for covariates).

Wastewater-based prevalence trends of gout in an Australian community over a period of 8 years

Gout is a rheumatic arthritis disease which poses a health burden. Monitoring the prevalence of gout is key to reduce the community burden of gout disease and associated health costs. Allopurinol has been used as a first line gout preventive medication in Australia which is metabolised into oxypurinol and excreted in urine. Wastewater-based epidemiology (WBE) was applied to estimate temporal trends of gout prevalence in an Australian community over eight-years via the quantification of oxypurinol in wastewater. A total of 180 wastewater samples collected between 2012 and 2019 were analysed for oxypurinol to estimate allopurinol consumption in a community in South East Queensland, Australia. Annual gout prevalence was estimated by daily defined doses (DDD) consumed and ranged from 24 to 32 DDD/day/1000, an equivalent gout prevalence of 2.3 to 3.2% over the eight-year period. A statistically significant increase in allopurinol consumption was observed over the period (Slope = 0.094, p = 0.0001), equating to year-on-year increases in gout prevalence of 3.6% per year. To the best of our knowledge, this is the first long-term gout prevalence study using wastewater, adding epidemiological and public health insights in the gout research field.

Pathophysiology of Gout

Multiple interacting checkpoints are involved in the pathophysiology of gout. Hyperuricemia is the key risk factor for gout and is considered a prerequisite for monosodium urate (MSU) crystal formation. Urate underexcretion through renal and gut mechanisms is the major mechanism for hyperuricemia in most people. Multiple genetic, environmental, and metabolic factors are associated with serum urate and alter urate transport or synthesis. Urate supersaturation is the most important factor for MSU crystal formation, and other factors such as temperature, pH, and connective tissue components also play a role. The nucleotide-binding oligomerization domain leucine-rich repeats and pyrin domain-containing protein 3 inflammasome plays a pivotal role in the inflammatory response to MSU crystals, and interleukin 1β is the key cytokine mediating the inflammatory cascade. Variations in the regulatory mechanisms of this inflammatory response may affect an individual's susceptibility to developing gout. Tophus formation is the cardinal feature of advanced gout, and both MSU crystals and the inflammatory tissue component of the tophus contribute to the development of structural joint damage owing to gout. In this article, we review the pathophysiologic mechanisms of hyperuricemia, MSU crystal formation and the associated inflammatory response, tophus formation, and structural joint damage in gout.

Time changes in the spectrum of urinary stone composition: a role for climate variations?

BACKGROUND

An increase of the frequency of uric acid urinary stones compared to calcium-containing ones has been recently described. This study was aimed at assessing the frequency of different types of urinary stones in the population of northern Italy in the period 2016-18 compared to 2001-2003.

METHODS

Analyses by infrared spectroscopy of 1007 stones endoscopically removed at two institutions in the area of Milan (Northern Italy) were retrospectively considered. Stones were classified as calcium oxalate monohydrate (COM) and dihydrate (COD), mixed uric acid/calcium oxalate (UC); uric acid (UA), struvite (ST); apatite (CAP); mixed calcium oxalate / apatite (CAPOX); others. The patients were divided into two groups: 2001-2003 and 2016-2018. The average temperature values of the region over the two time periods were obtained by the national statistical institute.

RESULTS

The average age of the 2001-2003 group (45.8+/- 15.4 years) was significantly lower than the average age of the 2016-18 group (57.9+/- 14.8) (0.000). M / F ratio was similar in the two groups: 119 / 69 (1,0.58) in 2001-2003 and 527 / 292 (1,0.55) in 2016-18 (p = 0.862). COM stones tended to more frequent in 2016-18 group than in 2001-03. COD stones were significantly more frequent in 2001-03 than in 2016-18. ST stone frequency was increased from 2001 to 03 to 2016-18. No increase of uric acid containing stones was observed in 2016-18. Results were confirmed after adjustment by age. Averages annual regional temperatures increased from 14 °C to 15.4 °C during the two observation periods.

CONCLUSIONS

No increase of UA stones was observed, probably due to the limited impact of the global warming in our temperate climate.

Matrix Metalloproteinase-3 induces proteoglycan degradation in gouty arthritis model

BACKGROUND

Gout is an inflammatory arthritis resulting from precipitation of monosodium urate (MSU) crystals in joints and surrounding tissues. However, the mechanism underlying high levels of uric acid inducing gouty arthritis has not been clarified.

OBJECTIVE

The purpose was to investigate the role of Matrix Metalloproteinase-3 (MMP-3) in the development of gouty arthritis from hyperuricemia.

METHOD

MSU crystal-induced gouty arthritis model and chondrocytes were used to evaluate changes of MMP-3 levels. Western blot, qPCR and ELISA were performed to detect MMP-3, Tissue Inhibitors of Metalloproteinase-1 (TIMP-1) and A Disintegrin and Metalloproteinase with Thrombospondin Motifs-4 (ADAMTS-4) expressions in rabbit chondrocytes. Expression of proteoglycan was determined through toluidine blue staining. Concentrations of glycosaminoglycan, Interleukin-6 (IL-6), Interleukin-1β (IL-1β) and Tumor Necrosis Factor-α (TNF-α) in chondrocytes were assessed via ELISA kits. Concentration of uric acid in supernate was tested by Automatic Analyzer.

RESULTS

MMP-3 was significantly increased in rat serum, synovial fluid, cartilages and chondrocytes treated with high-level uric acid. Increased concentration of glycosaminoglycancould be observed in chondrocytes incubated with MMP-3, as well as the remarkable downregulation of proteoglycan expression. Furthermore, high-level uric acid contributed to the degradation of proteoglycan via the activation of MMP-3. IL-6, IL-1β and TNF-α concentrations were increased significantly in 35 °C compared to 37 °C with MMP-3 and high-level uric acid.

CONCLUSION

Our study showed that MMP-3 was enhanced by high levels of uric acid, which promoted proteoglycan degradation, and induced MSU crystallization in turn. A low temperature environment is an important factor in the development of gout.

Association of weather factors with the risk of pain exacerbations in people with hip osteoarthritis

Objectives: Our objective was to evaluate the association of weather factors with the risk of pain exacerbations in people with symptomatic hip osteoarthritis (OA). Method: Eligible participants with symptomatic hip OA were instructed to log on to the study website and complete questionnaires every 10 days and additionally whenever they considered they were experiencing a pain exacerbation (case period) during the 90 day follow-up. Pain exacerbation was defined as an increase of two points in pain intensity on an 11-point numeric rating scale (0-10) during the follow-up compared with baseline. Each case period was anchored to four control periods within a 35 day interval using a time-stratified approach. Weather data were obtained for both periods from the publicly available meteorological database of the Australian Bureau of Meteorology. We examined the association of weather factors across 72 h before the index date with the risk of pain exacerbation, using conditional logistic regression. Results: Among 252 participants recruited, 129 participants had at least one episode of pain exacerbation and were included in the analysis. A significant dose-response relationship was found between average daily temperature variation in the prior 72 h and risk of pain exacerbations (p = 0.04 for linear trend). There was no significant association between maximum daily temperature, minimum daily temperature, relative humidity, precipitation, or barometric pressure and hip pain exacerbations. Conclusion: The overall results suggest that only daily temperature variation among different weather factors was associated with hip pain exacerbations in people with symptomatic hip OA.

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.

Postoperative Recurrent Gout Flares: A Cross-sectional Study From China

OBJECTIVES

To investigate the morbidity, clinical characteristics, and risk factors for postoperative recurrent gout flares (PRGFs).

METHODS

This cross-sectional study included all surgical patients at 2 academic institutions between 2010 and 2018. Data including demographics, prior history of gout, clinical variables, medications, and the occurrence of PRGFs were abstracted from medical records. Forward stepwise multivariable logistic regression analysis was used in the statistical analyses.

RESULTS

Among the 518 (0.5% [518/114,760]) surgical patients with a prior diagnosis of gout, 474 had sufficient documentation for analysis. Of these, 191 (40.3%) had experienced a PRGF. Most PRGFs (54.4%) were polyarticular gout; 79.6% had a pretreatment pain score of PRGFs ≥7, and 59.2% required combination pharmacologic therapy. The mean (SD) serum urate (SU) level decreased postoperatively (500.33 [122.77] vs. 380.15 [118.35] μmol/L; p = 0.000), with an average decrease of 125.86 μmol/L. The decrease in the postsurgical SU level was greater in patients who received postoperative total parenteral nutrition (PTPN) than in those who did not (p = 0.009), and it was correlated with the duration of PTPN (r = 0.156, p = 0.031). Factors independently associated with PRGFs were decrease in the postsurgical SU level by ≥126 μmol/L, previous flares involving the ankle, failure to take prophylactic colchicine therapy, and abdominal surgery.

CONCLUSIONS

Recurrent gout flares often occur postoperatively and are severe. For high-risk patients, especially those undergoing abdominal surgeries, timely monitoring of postsurgical SU level, colchicine prophylaxis, and avoiding the overuse of PTPN may help prevent PRGFs.

Recognition of gout in rheumatoid arthritis: A case report

RATIONALE

Rheumatoid arthritis (RA) and gout are common rheumatic diseases. However, their coexistance has been rarely reported. Here in, we describe a case of a middle aged Chinese woman having RA complicated with atypical gout on both the knee joints.

PATIENT CONCERNS

A 44-year-old Chinese woman complained of swelling and tenderness of multiple joints since 10 months. She had a positive rheumatoid factor and high titers of anti-CCP antibody. She was diagnosed with RA, and commenced on methotrexate, leflunomide, and methylprednisolone. Her symptoms of pain and swelling over interphalangeal and wrists joints subsided except the knee joints. She was started with treat to target treatment (TTT) for RA and rest of her medications was adjusted accordingly. Surprisingly, her symptoms did not improve ever after the addition of a biologic agent, tumor necrosis factor (TNF)-α receptor antagonist.

DIAGNOSIS

Presence of urate crystals in the synovium was viewed under polarization microscope which was extracted from one of the knee joint. Hence, we established the diagnosis of RA complicated with gout.

INTERVENTIONS

We commenced her on TNF-α receptor antagonist, colchicines, and febuxostat.

OUTCOMES

Her symptoms of pain and swelling improved significantly on both the knees and no longer recurred.

LESSONS

Coexistence of RA and gout has been rarely reported as it is not frequently seen in clinical practice. Hence, when patients with RA with oligoarthritis repeatedly do not respond to TTT, a standard antirheumatism treatment, the possibility of RA complicating with gout should be rule out.

The influence of weather on the risk of pain exacerbation in patients with knee osteoarthritis - a case-crossover study

OBJECTIVE

To quantify the risk of knee pain exacerbation associated with temperature, relative humidity, air pressure and precipitation in persons with knee osteoarthritis.

METHOD

A web-based case-crossover study was conducted. Participants with a diagnosis of symptomatic, radiographic knee osteoarthritis were measured at baseline and followed for 3 months. Participants were instructed to log on to the study website if they perceived experiencing knee pain exacerbation (hazard period). Pain exacerbation was defined as an increase of ≥2 on a 0-10 numeric rating scale (NRS) from the participant's mildest pain reported at baseline. A time-stratified case-crossover study was conducted to anchor the corresponding hazard date to four control periods within a particular 35-day interval. Data on maximum and minimum temperature (°C), relative humidity (%), barometric pressure (hPa) and precipitation (mm) were obtained for the hazard and control periods from the publicly available meteorological database of the Australian Bureau of Meteorology. The associations were assessed using conditional logistic regression.

RESULTS

Of the 345 participants recruited, 171 participants (women: 64%, mean age: 62 years, mean BMI: 30.2 kg/m²) experienced at least one episode of pain exacerbation, yielding 1,425 observations included in the analyses. There was no apparent association between temperature, relative humidity, air pressure or precipitation and risk of knee pain exacerbation.

CONCLUSION

Despite anecdotal reports from patients, change in weather factors does not appear to influence the risk of pain exacerbation in persons with knee osteoarthritis. Additional studies should quantify the association of weather and risk of pain exacerbation in regions with more extreme weather conditions.

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.