Inverse association between air pressure and rheumatoid arthritis synovitis

Forecasting rheumatoid arthritis patient arrivals by including meteorological factors and air pollutants

The burden of rheumatoid arthritis (RA) has gradually elevated, increasing the need for medical resource redistribution. Forecasting RA patient arrivals can be helpful in managing medical resources. However, no relevant studies have been conducted yet. This study aims to construct a long short-term memory (LSTM) model, a deep learning model recently developed for novel data processing, to forecast RA patient arrivals considering meteorological factors and air pollutants and compares this model with traditional methods. Data on RA patients, meteorological factors and air pollutants from 2015 to 2022 were collected and normalized to construct moving average (MA)- and autoregressive (AR)-based and LSTM models. After data normalization, the root mean square error (RMSE) was adopted to evaluate models' forecast ability. A total of 2422 individuals were enrolled. Not using the environmental data, the RMSEs of the MA- and AR-based models' test sets are 0.131, 0.132, and 0.117 when the training set: test set ratio is 2:1, 3:1, and 7:1, while they are 0.110, 0.130, and 0.112 for the univariate LSTM models. Considering meteorological factors and air pollutants, the RMSEs of the MA- and AR-based model test sets were 0.142, 0.303, and 0.164 when the training set: test set ratio is 2:1, 3:1, and 7:1, while they were 0.108, 0.119, and 0.109 for the multivariable LSTM models. Our study demonstrated that LSTM models can forecast RA patient arrivals more accurately than MA- and AR-based models for datasets of all three sizes. Considering the meteorological factors and air pollutants can further improve the forecasting ability of the LSTM models. This novel method provides valuable information for medical management, the optimization of medical resource redistribution, and the alleviation of resource shortages.

Climate temperature and seasonal influences on the prevalence of temporomandibular disorders in South Korea

This study aimed to explore seasonal variations in temporomandibular disorder (TMD) prevalence in South Korea, utilizing nationwide population-based big data. Data corresponding to the Korean Standard Classification of Diseases code of K07.6, which identifies TMD, were extracted from the Health Insurance Review and Assessment Service online platform for the period from 2010 to 2022. Additionally, we integrated these data with climate temperature records from the Korean Meteorological Administration. We subsequently conducted a statistical analysis of TMD patient data on a monthly and seasonal basis over the past 13 years to assess prevalence. Over the past 13 years, the number of TMD patients in Korea has steadily increased. The prevalence of TMD rose from 0.48% (224,708 out of a total population of 50,515,666) in 2010 to 0.94% (482,241 out of a total population of 51,439,038) in 2022, marking a 1.96-fold increase. Among children under 10 years of age, no significant differences were observed in TMD prevalence between boys and girls. However, a distinct female predominance emerged after the age of 10, with an average female-to-male ratio of 1.51:1. The peak prevalence of TMD occurred in individuals in their 20 s, followed by adolescents in their late 10 s. The majority of TMD patients were concentrated in Seoul and Gyeonggi province, with metropolitan areas accounting for 50% of the total patient count. Seasonally, TMD patient numbers showed no significant increase in winter compared with spring or summer. The temperature difference, defined as the absolute difference between the highest and lowest temperatures for each month, showed a positive correlation with TMD patient counts. A greater temperature difference was associated with higher patient counts. The strongest correlation between temperature differences and TMD patient numbers was observed in winter (r = 0.480, p < 0.01), followed by summer (r = 0.443, p < 0.01), and spring (r = 0.366, p < 0.05). Temperature differences demonstrated a significantly stronger correlation with the increase in the number of TMD patients than absolute climate temperatures. This aspect should be a key consideration when examining seasonal trends in TMD prevalence in South Korea.

Lupus nephritis or not? A simple and clinically friendly machine learning pipeline to help diagnosis of lupus nephritis

OBJECTIVE

Diagnosis of lupus nephritis (LN) is a complex process, which usually requires renal biopsy. We aim to establish a machine learning pipeline to help diagnosis of LN.

METHODS

A cohort of 681 systemic lupus erythematosus (SLE) patients without LN and 786 SLE patients with LN was established, and a total of 95 clinical, laboratory data and 17 meteorological indicators were collected. After tenfold cross-validation, the patients were divided into training set and test set. The features selected by collective feature selection method of mutual information (MI) and multisurf were used to construct the models of logistic regression, decision tree, random forest, naive Bayes, support vector machine (SVM), light gradient boosting (LGB), extreme gradient boosting (XGB), and artificial neural network (ANN), the models were compared and verified in post-analysis.

RESULTS

Collective feature selection method screens out antistreptolysin (ASO), retinol binding protein (RBP), lupus anticoagulant 1 (LA1), LA2, proteinuria and other features, and the hyperparameter optimized XGB (ROC: AUC = 0.995; PRC: AUC = 1.000, APS = 1.000; balance accuracy: 0.990) has the best performance, followed by LGB (ROC: AUC = 0.992; PRC: AUC = 0.997, APS = 0.977; balance accuracy: 0.957). The worst performance is naive Bayes model (ROC: AUC = 0.799; PRC: AUC = 0.822, APS = 0.823; balance accuracy: 0.693). In the composite feature importance bar plots, ASO, RF, Up/Ucr, and other features play important roles in LN.

CONCLUSION

We developed and validated a new and simple machine learning pathway for diagnosis of LN, especially the XGB model based on ASO, LA1, LA2, proteinuria, and other features screened out by collective feature selection.

Effect of climatic environment on immunological features of rheumatoid arthritis

The aim of this study was to clarify the effect of climatic environment on the immunological features of rheumatoid arthritis (RA). Blood samples were collected from patients with RA and healthy controls (HCs), matched by age and sex, living in two locations, Tsukuba and Karuizawa, which differ in their altitude and average air temperature and atmospheric pressure. Analysis of peripheral blood mononuclear cells (PBMCs) revealed that the proportion of T and B cell subpopulations in HCs and RA patients were significantly different between two sites. Inverse probability weighting adjustment with propensity scores was used to control for potential confounding factors. The results revealed that, in comparison with RA patients in Tsukuba, those in Karuizawa showed a significant increase in cTh1, cTfh1, and Tph cells, and significant decrease in cTh17, cTh17.1, and CD8+ Treg in T cell subpopulations, and a significant increase in DNB, DN1, DN2, and class-switched memory B cells, and a significant decrease in unswitched memory B, naïve B cells, and ABCs in B cell subpopulations. Our results suggest the possibility that climatic environment might have an effect on immune cell proportion and function, and be related to the pathogenic mechanism of RA.

Seasonal exacerbation of rheumatoid arthritis detected by big claims data analysis: A retrospective population study

OBJECTIVES

The objective of the study was to determine the seasonal changes in the initiation of biological disease-modifying antirheumatic drugs (bDMARDs) and methotrexate (MTX) using big claims data.

METHODS

We counted the monthly number of initial administrations of each bDMARD and MTX in patients with rheumatoid arthritis (RA) between April 2010 and March 2017. Data were collected from the National Database of Health Insurance Claims and Specific Health Checkups of Japan. This database covers more than 95% of Japanese citizens. Seasonal changes in the number of initiations were determined. Patient claims were also classified according to drugs, districts, gender, and ages.

RESULTS

The initiation of bDMARDs and MTX administration varied according to the season in a sine curve shape, with the highest numbers in May to July and the lowest numbers in November to January. The same changing pattern was observed among each bDMARD, district, gender, and age groups particularly when the number was on the higher side.

CONCLUSION

We noted an apparent seasonal change in the number of bDMARDs initiated, with a peak during spring, suggesting an exacerbation of RA in the spring in Japan. These changes are overlooked in daily practice and are only visible using big data.

Effect of ambient temperature on outpatient admission for osteoarthritis and rheumatoid arthritis in a subtropical Chinese city

Background

Current findings on the impact of weather conditions on osteoarthritis (OA) and rheumatoid arthritis (RA) are sparse and not conclusive. This study aimed to investigate the relationship between temperature change and OA/RA admission.

Methods

Daily OA/RA admission, meteorological data and pollutants from 1 January 2014 to 31 December 2017 in Hefei, China, were collected. We quantified the relationship between ambient temperature and OA/RA admission using a distributed lag nonlinear model (DLNM). Stratified analyses by gender and age were also examined.

Results

Temperature decrease was significantly associated with RA admission (25th percentile of temperature versus 50th percentile of temperature), with the acute and largest effect at current days lag (RR: 1.057, 95%CI: 1.005–1.111). However, no significant association between temperature and OA admission was observed. When conducting subgroup analyses by individual characteristics, we found that females and patients aged 41–65 years were more vulnerable to temperature decrease than males, patients aged 0–40 and ≧66 years, respectively.

Conclusions

This study suggested that temperature decrease was a risk factor for increases in RA admission. Females and patients aged 41–65 years were particularly vulnerable to the effect of temperature decrease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11994-0.

Temperature might increase the hospital admission risk for rheumatoid arthritis patients in Anqing, China: a time-series study

Temperature has been studied in relation to many health outcomes. However, few studies have explored its effect on the risk of hospital admission for rheumatoid arthritis (RA). A distributed lag non-linear model (DLNM) was used to analyze associations between mean temperature, diurnal temperature range (DTR), temperature change between neighboring days (TCN), and daily admissions for RA from 2015 to 2019 in Anqing, China. Subgroup analyses based on age, gender, rheumatoid factors, and admission route were performed. In total, 1456 patients with RA were hospitalized. Regarding the cumulative-lag effects of extreme cold temperature (5th percentile = 3℃), the risks of admissions for RA were increased and highest at lag 0-11 (RR = 2.68, 95% CI: 1.23-5.86). Exposing to low (5th percentile = 1.9℃) and high (95th percentile = 14.2℃) DTRs both had increased risks of RA admission, with highest RRs of 1.40 (95% CI: 1.03-1.91) and 1.24 (95% CI: 1.0-1.53) at lag 0 day, respectively. As for TCN, the marginal risk of admission in RA patients was found when exposed to high TCN (95th percentile = 2.9℃) with the largest single-day effect at lag 10 (RR = 1.11, 95% CI: 1.01-1.23). In subgroup analyses, females were more susceptible to extreme cold temperature, low and high DTRs, and high TCN. In regard to extreme cold temperature, significant risk of hospital admission in females only appeared at lag 2 (RR = 1.48, 95% CI: 1.02-2.15) and lag 0-2 (RR = 2.35, 95% CI: 1.11-4.95). It is clear that RA patients exposed to changing temperature may increase risks of admission.

Weather sensitivity associated with quality of life in patients with fibromyalgia

Background

Fibromyalgia is characterized by chronic widespread pain, and more than half of patients with fibromyalgia report that weather-related variables aggravate their symptoms. However, the differences in actual symptoms have not been measured between those with and without weather sensitivity. The present study aimed to investigate whether weather sensitivity associated with the minimal clinically important difference values of quality of life in patients with fibromyalgia, between those with and without weather sensitivity.

Methods

Sixty-four consecutive outpatients with fibromyalgia on their first visit to our tertiary center were included. Weather sensitivity was measured using self-perceived symptoms. Pain intensity was measured using the 0–10 Numerical Rating Scale (NRS). Quality of life was measured using the Euro Quality of life-5 Dimensions-3 level (EQ-5D-3L) scale. The variables were subjected to univariable and multivariable analysis using the EQ-5D-3L scale.

Results

The mean age of the patients was 50 years. Forty-eight patients (75%) were women. The mean EQ-5D-3L score was 0.55. Thirty-seven patients (58%) reported weather sensitivity. In univariable analysis, the welfare recipient, weather sensitivity, and NRS values were associated with EQ-5D-3L scale scores. In multivariable analysis, NRS value and weather sensitivity were independently associated with EQ-5D-3L scale scores. The NRS and EQ-5D-3L scale scores were significantly worse in those with weather sensitivity than those without weather sensitivity. The difference in NRS values was less than 1.5 points between groups. The differences in EQ-5D-3L scale scores were 0.16 points between groups.

Conclusions

Weather sensitivity was significantly associated with quality of life in patients with fibromyalgia. There was an association with weather sensitivity and the minimal clinically important difference values of quality of life in patients with fibromyalgia. The presence of weather sensitivity could have a key role in the quality of life in patients with fibromyalgia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41927-021-00185-4.

Intake frequency of vegetables or seafoods negatively correlates with disease activity of rheumatoid arthritis

Objective

To clarify the relationship between dietary habit and disease activity of rheumatoid arthritis (RA).

Methods

This study enrolled RA patients who met the ACR/EULAR 2010 classification criteria from Kyoto University Rheumatoid Arthritis Management Alliance (KURAMA) cohort in 2015. 22-item food frequency questionnaire (FFQ) was taken for the measurement of dietary habit in a single-institution cohort of RA (Kyoto University Rheumatoid Arthritis Management Alliance: KURAMA) in 2015. The disease activities of RA using the Disease Activity Score calculated based on the erythrocyte sedimentation rate (DAS28-ESR), Simplified Disease Activity Index (SDAI), Health Assessment Questionnaire (HAQ), and serum matrix metalloproteinase-3 (MMP-3) level, the use of disease-modifying anti-rheumatic drugs (DMARDs), disease duration, rheumatoid factor, anti-cyclic citrullinated antibody, and body mass index were also examined. All of them were combined and statistically analyzed.

Results

441 RA patients (81% women; mean age 65 years; mean disease duration 15 years) were enrolled from the KURAMA cohort. Average Disease Activity Score-28 using the erythrocyte sedimentation rate (DAS28-ESR) was 2.7. Univariate analysis showed that intake frequency of vegetables had a statistically significant negative correlation with disease activity markers, such as DAS28-ESR (ρ = −0.11, p<0.01), Simplified Disease Activity Index (SDAI) (ρ = −0.16, p<0.001), matrix metalloproteinase-3 (MMP-3) (ρ = −0.21, p<0.0001), and Health Assessment Questionnaire (HAQ) (ρ = −0.13, p<0.01). Factor analysis with varimax rotation was done to simplify the relevance of disease activity to various food items. 22 foods were categorized into five dietary patterns: “seafoods”, “vegetables/fruits”, “meats/fried foods”, “snacks”, and “processed foods”. The multivariate analysis adjusted for clinically significant confounders showed that “seafoods” had statistically significant negative correlations with DAS28-ESR (β = −0.15, p<0.01), SDAI (β = −0.18, p<0.001), MMP-3 (β = −0.15, p<0.01), and HAQ (β = −0.24, p<0.0001). “Vegetables/fruits” had statistically significant negative correlations with SDAI (β = −0.11 p<0.05), MMP-3 (β = −0.12, p<0.01), and HAQ (β = −0.11, p<0.05)

Conclusions

These results suggest that high intake frequency of vegetables/fruits and/or seafoods might correlate with low disease activity.

Association between rainfall and readmissions of rheumatoid arthritis patients: a time-stratified case-crossover analysis

It has been reported that local weather is associated with the symptoms of joint pain in patients with rheumatoid arthritis (RA), and many people believe their pain becomes worse when facing rainy days. However, limited studies explored the effects of weather on RA patients' healthcare-seeking behavior. Our study aimed to investigate the relationship between rainfall and readmission behavior of patients with RA in Hefei, China, based on hospitalization data from the First Affiliated Hospital of Anhui University of Chinese Medicine from May 2012 to June 2016 and weather data from National Meteorological Information Center during the same study period. Using a time-stratified case-crossover study design and conditional logistic regression, we found a negative association between current day rainfall and readmission (unadjusted: OR = 0.82, p < 0.05; adjusted: OR = 0.83, p < 0.1), which is contrary to our common belief. In lagged models, we observed that rainfall was significantly and positively associated with readmissions at lag 6 days (unadjusted: OR = 1.12, p < 0.1; adjusted: OR = 1.17, p < 0.05) and lag 7 days (unadjusted: OR = 1.13, p < 0.05; adjusted: OR = 1.21, p < 0.01). Additionally, stratified analyses showed the unanticipated finding was only statistically significant for younger patients (< 65 years) and females. Our study adds new evidence that the association between the healthcare-seeking behavior of patients with RA and local rainfall may be different, compared with the positive relationship between symptoms of joint pain and rainfall.

Soluble Lectin-like Oxidized Low-Density Lipoprotein Receptor 1 Predicts the Changes of Rheumatoid Factor Titers in Rheumatoid Arthritis

OBJECTIVE

The aim of this longitudinal study was to examine the clinical significance of soluble lectin-like oxidized low-density lipoprotein receptor 1 (sLOX-1) in patients with rheumatoid arthritis.

METHODS

We gathered demographic and clinical data for a large rheumatoid arthritis cohort at 3 time points. Blood samples were collected at each time point; the number of samples was 282 cases in 2012, 431 cases in 2013, and 500 cases in 2014. Plasma sLOX-1 was measured by enzyme-linked immunosorbent assay. Correlations between sLOX-1 and clinical data were analyzed. Predictive factors associated with changes in sLOX-1 and rheumatoid factor (RF) were analyzed by multivariate linear regression.

RESULTS

Plasma sLOX-1 level was significantly correlated with RF titer and other clinical parameters. The longitudinal analyses showed that changes in sLOX-1 were significantly correlated with changes in RF titers and with those at baseline. Multivariate linear regression analysis revealed that changes in RF and baseline RF were predictive factors for changes in sLOX-1. Conversely, the changes in RF were significantly correlated with the changes in sLOX-1 in all years. A stepwise regression analysis showed that the change in sLOX-1 was a predictive factor for the change in RF.

CONCLUSIONS

The change in sLOX-1 has predictive value for assessing the change in RF, indicating the usefulness of sLOX-1 in clinical practice.

Influence of seasonal changes on disease activity and distribution of affected joints in rheumatoid arthritis

BACKGROUND

Previous studies suggest that RA activity is sensitive to seasonal changes. This study explored the influence of season on RA activity, particularly the distribution of affected joints, using a nationwide database in Japan.

METHODS

We investigated 12,839 patients whose RA activity was recorded in spring (n = 3250), summer (n = 916), fall (n = 1021), and winter (n = 7652). Disease activity score (DAS) 28-CRP, simplified disease activity index (SDAI), and clinical disease activity index (CDAI) were used as indices of disease activity. Disease activity was also assessed according to DAS28-CRP scores (remission, low, moderate, or high). The affected joint distribution was investigated using novel joint indices (x, y, z), where x and y are indices for the upper and lower joints, respectively, and z is the index for large joint predominance.

RESULTS

Mean DAS28-CRP and median SDAI and CDAI scores were highest in spring and lowest in fall. There was a significant difference in the DAS28-CRP for fall versus spring and winter. Fall was associated with a higher remission rate, and spring and winter with high and moderate RA activity, respectively. Significant differences in x, y, SDAI, and CDAI scores were found for spring versus summer, fall, and winter, in addition to fall versus winter (except in y). There was no seasonal difference in the z index.

CONCLUSIONS

RA activity in the upper and lower extremities may be highest in spring, followed by winter. Seasonal changes should be considered in patients with RA to better understand their symptoms.

Elderly onset of early rheumatoid arthritis is a risk factor for bone erosions, refractory to treatment: KURAMA cohort

AIM

Age at disease onset has been implicated as an indicator of disease activity and severity in rheumatoid arthritis (RA). This study aimed to investigate how old age at disease onset affects patient treatment and prognosis in early RA.

METHODS

Data from the Kyoto University Rheumatoid Arthritis Management Alliance (KURAMA) cohort was analyzed. From 2011 to 2015, a total of 2182 patients with RA were enrolled in the cohort; 239 patients were newly diagnosed with RA and were followed up for 2 years. The patients were divided into the following two groups: the young-onset RA (YORA) which included patients <60 years old (n = 117) and elderly-onset RA (EORA) which comprised patients ≥60 years old (n = 122). The clinical and laboratory data were compared at baseline, at 1 year, and at 2 years after onset.

RESULTS

Disease activity was higher in EORA than in YORA at baseline. Although disease activity was equivalent between EORA and YORA at 1 or 2 years, more EORA patients had bone erosions at baseline and at 2 years. More than 25% of the anti-citrullinated protein autoantibody (ACPA)-positive EORA patients without erosions at baseline had bone erosions even if they attained clinical remission at 1 or 2 years, while ~10% of YORA patients had erosions.

CONCLUSION

Bone erosions were more frequently found in EORA. Clinical remission at 1 or 2 years was not enough to protect bone erosions in the ACPA-positive EORA patients. Optimal treatment strategies preventing radiological damage should be considered for EORA.

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.

A case-control study of rheumatoid arthritis revealed abdominal obesity and environmental risk factor interactions in northern China

BACKGROUND

The aim of this study was to evaluate new and previously hypothesized environmental risk factors and their interaction with rheumatoid arthritis (RA).

METHODS

Four hundred patients recently diagnosed with RA and 400 controls frequency-matched by gender and birth year using Propensity Score Matching (PSM) were selected from northern China. Investigation was performed using self-reported data from interviewer-administered surveys. Associations between exposure variables and risk of RA were evaluated using multifactor non-conditional logistic regression.

RESULTS

It showed that damp localities, draft indoor, abdominal obesity (AO), and family history of RA among first-degree relatives were independent risk factors and drinking of milk was independent protective factors for RA. Besides these risk factors, in women, infrequent delivery times, early age at menopause, and late age at menarche were also independent risk factors for RA. Both the additive model and the multiplication model suggested that there was an interaction relationship between AO and damp localities (p < .001), and only the additive model suggested that there was interaction relationship between AO and no milk drinking (p < .001) in our study population. In women, there was interaction relationship between AO and damp localities (p < .001) and between AO and age at menopause (p < .001).

CONCLUSIONS

In northern China, damp localities, draft indoor, AO, family history of RA among first-degree relatives, and no milk drinking may be important risk factors of RA patients.

Systemic effects of surgical intervention on disease activity, daily function, and medication in patients with rheumatoid arthritis

OBJECTIVES

Although tight control of rheumatoid arthritis (RA) has been achieved through the development of effective medication, surgical intervention is still required for a certain subpopulation of patients. To examine the systemic effects of orthopaedic surgery, we evaluated improvements in disease activity, daily function, and medication after surgery.

METHOD

A prospective cohort study was conducted in 196 cases of elective orthopaedic surgery in 150 patients with RA from January 2011 to March 2014 in our institution. The 28-joint count Disease Activity Score based on erythrocyte sedimentation rate (DAS28-ESR) and modified Health Assessment Questionnaire (mHAQ) scores just before surgery and at 6 and 12 months after surgery were examined prospectively. Concomitant medications were also investigated.

RESULTS

Significant improvement was seen in the DAS28-ESR and mHAQ scores for replacement surgery in both the upper and lower extremities, and for arthroplasty/arthrodesis in the upper extremities at the 12-month follow-up. Partial mHAQ scores for the lower extremities were significantly reduced in lower replacement surgery, and partial mHAQ scores for the upper extremities were significantly reduced in upper arthroplasty/arthrodesis surgery. Although the use of conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs) did not decrease after surgery, the dose of prednisolone (PSL) decreased significantly at 12 months after surgery, especially in the well-controlled group and in surgical procedures in the lower extremities.

CONCLUSIONS

Elective orthopaedic surgery improves both systemic disease activity and general functional impairment. Orthopaedic surgery is effective in reducing the amount of medication required postoperatively.

Periarticular osteoporosis of the forearm correlated with joint destruction and functional impairment in patients with rheumatoid arthritis

The relationship between periarticular osteoporosis in the distal forearm and joint destruction or functional impairment in patients with rheumatoid arthritis (RA) is not sufficiently elucidated. From a single institutional cohort study, we found a strong correlation between periarticular forearm bone mineral density (BMD) and joint destruction or functional impairment.

INTRODUCTION

This study was conducted to investigate (1) the difference between various periarticular regions of interest (ROIs) of BMD of the forearm, (2) the correlation between periarticular forearm BMD and joint destruction and physical function, (3) the independent variables for predicting BMD of the forearm, and (4) the forearm BMD of different ROIs in the early stage of RA.

METHODS

We conducted a cross-sectional study in an RA cohort. Measurements included BMD of the distal forearm, joint destruction of the hands assessed by modified total Sharp score (mTSS), functional impairment assessed by a health assessment questionnaire (HAQ), and other clinical data. Variables affecting the forearm BMD values were analyzed by correlation and stepwise regression analyses.

RESULTS

Of the 405 patients enrolled in the present study, 370 (average age; 62.9 years) were identified as having definite RA with a complete set of data. BMD in the distal end of the forearm (BMDud) was significantly reduced compared with that in the distal third of the forearm (BMD1/3). In a stepwise regression analysis, the mTSS in BMD1/3 was an independent predicting variable, while age and partial HAQ scores associated with the upper extremity were common independent variables in BMDud and BMD1/3. BMDud was significantly less than BMD1/3, even in patients with a short duration of the disease. BMD1/3 was significantly less in non-remission group compared with that in remission group in patients with a short duration of the disease.

CONCLUSION

Periarticular BMD in the distal forearm is closely correlated with joint destruction and functional impairment in RA. Periarticular BMD in the distal forearm may be already reduced at the clinical manifestation of the disease.

Serological and Progression Differences of Joint Destruction in the Wrist and the Feet in Rheumatoid Arthritis - A Cross-Sectional Cohort Study

Objective

To investigate clinical and radiological differences between joint destruction in the wrist and the feet in patients with RA.

Methods

A cross-sectional clinical study was conducted in an RA cohort at a single institution. Clinical data included age, sex and duration of disease. Laboratory data included sero-positivity for anti-cyclic citrullinated peptide (CCP) antibody and RF. Radiological measurements included Larsen grades and the modified Sharp/van der Heijde method (SHS) for the hands/wrists and the feet. Statistical analyses were performed using the Kruskal—Wallis H-test, a dummy variable linear regression model and multivariate logistic regression analysis with 95% confidence interval and odds ratios.

Results

A total of 405 patients were enrolled, and 314 patients were analysed in this study. The duration of disease in the foot-dominant group was significantly less than that in the wrist-dominant group. When patients were subdivided by duration of disease, the Larsen grade of the feet was significantly higher than that of the wrist in the first quadrant subgroup, but this was reversed with increasing duration of disease. Anti-CCP status was a significant predictive factor for joint destruction in the wrist but not in the feet, while RF status was not predictive in either the wrist or the feet.

Conclusions

Joint destruction in the feet started earlier than in the wrist, but the latter progresses faster with increasing duration of disease. Anti-CCP status predicts joint destruction in the wrist better than in the feet.