OBJECTIVE: To investigate the significance of anti-histidyl tRNA synthetase (Jo-1) antibody in idiopathic inflammatory myopathies (IIM) and its diseases spectrum. METHODS: We enrolled all the patients who were tested positive for anti-Jo-1 antibody by immunoblotting in Peking University People's Hospital between 2016 and 2022. And the patients diagnosed with anti-synthetase antibody syndrome (ASS) with negative serum anti-Jo-1 antibody were enrolled as controls. We analyzed the basic information, clinical characteristics, and various inflammatory and immunological indicators of the patients at the onset of illness. RESULTS: A total of 165 patients with positive anti-Jo-1 antibody were enrolled in this study. Among them, 80.5% were diagnosed with connective tissue disease. And 57.6% (95/165) were diagnosed with IIM, including ASS (84/165, 50.9%), immune-mediated necrotizing myopathy (7/165, 4.2%) and dermatomyositis (4/165, 2.4%). There were 23.0% (38/165) diagnosed with other connective tissue disease, mainly including rheumatoid arthritis (11/165, 6.7%), undifferentiated connective tissue disease (5/165, 3.0%), interstitial pneumonia with autoimmune features (5/165, 3.0%), undifferentiated arthritis (4/165, 2.4%), Sjögren's syndrome (3/165, 1.8%), systemic lupus erythematosus (3/165, 1.8%), systemic vasculitis (3/165, 1.8%), and so on. Other cases included 3 (1.8%) malignant tumor patients, 4 (2.4%) infectious cases and so on. The diagnoses were not clear in 9.1% (15 /165) of the cohort. In the analysis of ASS subgroups, the group with positive serum anti-Jo-1 antibody had a younger age of onset than those with negative serum anti-Jo-1 antibody (49.9 years vs. 55.0 years, P=0.026). Clinical manifestations of arthritis (60.7% vs. 33.3%, P=0.002) and myalgia (47.1% vs. 22.2%, P=0.004) were more common in the ASS patients with positive anti-Jo-1 antibody. With the increase of anti-Jo-1 antibody titer, the incidence of the manifestations of arthritis, mechanic hands, Gottron sign and Raynaud phenomenon increased, and the proportion of abnormal creatine kinase and α-hydroxybutyric dehydrogenase index increased in the ASS patients. The incidence of myalgia and myasthenia were significantly more common in this cohort when anti-Jo-1 antibody-positive ASS patients were positive for one and more myositis specific antibodies/myositis associated autoantibodies (P < 0.05). CONCLUSION The disease spectrum in patients with positive serum anti-Jo-1 antibody includes a variety of diseases, mainly ASS. And anti-Jo-1 antibody can also be found in many connective tissue diseases, malignant tumor, infection and so on.
Humans ; Middle Aged ; Myalgia ; Myositis/epidemiology* ; Autoantibodies ; Connective Tissue Diseases ; Arthritis, Rheumatoid ; Neoplasms

OBJECTIVE: To study the correlation between dyslipidemia and rheumatoid arthritis associa-ted interstitial lung disease (RA-ILD) by retrospective analysis of the clinical data. METHODS: The clinical data of patients with rheumatoid arthritis (RA), who were hospitalized in the Department of Rheumatism and Immunology of Peking University Shenzhen Hospital from January 2015 to July 2020 and fulfilled the criteria of the 2010 Rheumatoid Arthritis Classification Criteria established by American College of Rheumatology/European League Against Rheumatism collaborative initiative, were collected and analyzed. RESULTS: There were 737 RA patients included, of whom 282(38.26%)were with interstitial lung disease (ILD). The median time from the onset of the first RA-related clinical symptoms to the onset of ILD was 13 years (95%CI 11.33-14.67). By multivariate Logistic regression analysis, we found that low-density lipoprotein cholesterol (LDL-C) was an independent risk factor for RA-ILD (OR 1.452, 95%CI 1.099-1.918, P=0.009), whereas high-density lipoprotein cholesterol (HDL-C) was a protective factor for RA-ILD (OR 0.056, 95%CI 0.025-0.125, P < 0.001). The RA patients with high LDL-C or low HDL-C had higher incidence of ILD than that of the RA patients with normal LDL-C or HDL-C(57.45% vs. 36.96%, P < 0.001; 47.33% vs. 33.81%, P < 0.001, respectively). The median time of ILD onset in the RA patients with low HDL-C was shorter than that of the RA patients with normal HDL-C [10.0(95%CI 9.33-10.67)years vs.17.0 (95%CI 14.58-19.42) years, P < 0.001]. HDL-C level was negatively correlated with disease activity. Among the RA-ILD patients, the patients with low HDL-C had higher percentage of usual interstitial pneumonia (UIP) then that of the patients with normal HDL-C (60.00% vs. 53.29%, P=0.002). The RA-ILD patients with high LDL-C had higher incidence rate of decrease in forced vital capacity (FVC) than that of the RA-ILD patients with normal LDL-C (50.00% vs. 21.52%, P=0.015). The RA-ILD patients with low HDL-C had higher incidence rate of decrease in FVC (26.92% vs. 16.18%, P=0.003) and carbon monoxide diffusion (80.76% vs. 50.00%, P=0.010) than that of RA-ILD patients with normal HDL-C. CONCLUSION LDL-C was possibly a potential independent risk factor for RA-ILD. HDL-C was possibly a potential protective factor for RA-ILD. HDL-C level was negatively correlated with disease activity of RA. The median time of ILD onset in the RA patients with low HDL-C was significantly shorter than that of the RA patients with normal HDL-C.
Humans ; Retrospective Studies ; Cholesterol, LDL ; Arthritis, Rheumatoid/complications* ; Lung Diseases, Interstitial/complications* ; Dyslipidemias/epidemiology*

OBJECTIVE: To analyze the clinical features of overweight and obese rheumatoid arthritis (RA)patients, and the relationship between body mass index (BMI) and disease characteristics. METHODS: The demographic data, extra-articular manifestations, comorbidities, and disease activity of RA patients admitted to the Rheumatology and Immunology Department of Peking University Third Hospital from January 2015 to December 2020 were collected, and the above characteristics of overweight and obese RA patients were retrospectively analyzed. According to the WHO, BMI≥30 kg/m² referred to obese individuals, 25≤BMI < 30 kg/m² referred to overweight individuals, 18.5≤BMI < 25 kg/m² referred to normal individuals, BMI < 18.5 kg/m² referred to reduced body mass individuals. t test was used for the quantitative data in accordance with normal distribution. Wilcoxon rank sum test was used for the quantitative data of non-normal distribution. The qualitative data were analyzed by chi square test. But while 1≤theoretical frequency < 5, Chi square test of corrected four grid table was used. And Fisher exact probability method was used when theoretical frequency < 1. Analyzing whether overweight or obesity was associated with comorbidities using Logistic regression adjusted confounding factors. RESULTS: A total of 481 RA patients were included in this study, with an average BMI value of (23.28±3.75) kg/m².Of the patients, 31 cases (6.5%) were with BMI < 18.5 kg/m², 309 cases (64.2%) with 18.5≤ BMI < 25 kg/m², amounting to 340 cases (70.7%). There were 119 overweight individuals (25≤ BMI < 30 kg/m², 24.7%) and 22 obese individuals (BMI≥30 kg/m², 4.6%), totaling 141 (29.3%).The proportion of the overweight and obese RA patients suffering from hypertension (57.4% vs. 39.1%, P < 0.001), diabetes (25.5% vs. 15.0%, P=0.006), hyperlipidemia (22.7% vs. 10.9%, P=0.001), fatty liver (28.4% vs. 7.4%, P < 0.001), osteoarthritis (39.0% vs. 29.4%, P=0.040) was significantly higher, and the proportion of the patients with osteoporosis(59.6% vs. 70.9%, P=0.016) and anemia (36.2% vs. 55.6%, P < 0.001) was significantly lower. However, there was no difference between the two groups in coronary heart disease (5.7% vs. 7.6%, P=0.442), cerebrovascular disease (6.4% vs. 8.8%, P=0.372) and peripheral atherosclerosis (9.2% vs. 7.6%, P=0.565).The median C-reactive protein (CRP, 1.52 mg/dL vs. 2.35 mg/dL, P=0.008), median erythrocyte sedimentation rate (ESR, 34.0 mm/h vs. 50.0 mm/h, P=0.003), pain visual simulation score (VAS) (3.66±3.08 vs. 4.40±2.85, P=0.011), and 28 joint disease activity scores (DAS-28, 5.05±1.60 vs. 5.45±1.52, P=0.010) in the overweight and obese RA group were all lower than those in the normal and reduced weight groups. Multivariate regression analysis showed that overweight and obesity was an independent risk factor for hypertension, diabetes, hyperlipidemia and fatty liver, and had protective effects on osteoporosis and anemia. CONCLUSION In RA patients, RA disease activity is lower in overweight and obesity patients. Overweight and obesity is associated with hypertension, diabetes and hyperlipidemia, but not with cardiovascular and cerebrovascular diseases.
Humans ; Body Mass Index ; Overweight/epidemiology* ; Retrospective Studies ; Arthritis, Rheumatoid/epidemiology* ; Obesity/epidemiology* ; Diabetes Mellitus ; Hypertension/complications* ; Fatty Liver/complications* ; Hyperlipidemias/complications* ; Osteoporosis/complications* ; Anemia

Objective: To describe the distribution and trend of rheumatoid arthritis (RA) in adults in the Yinzhou district from 2011 to 2020 and compare the incidence differences in different ages and genders. Methods: Using the retrospective cohort design, we collected all new cases diagnosed with RA between 2011 to 2020 from the Yinzhou Regional Health Information Platform (YRHIP). Poisson distribution was used to estimate RA's incidence density and 95%CI. Results: From 2011 to 2020, 1 280 012 permanent residents in Yinzhou district were included, of which 665 361 were female (51.98%). The total follow-up person-years were 7 198 513.61, and the median follow-up person-year was 5.41 years (P₂₅=3.50, P₇₅=8.32). During the study period, there were 2 350 new cases of RA, of which 1 460 were female (62.13%). The 10-year incidence density of the population was 32.65/100 000 person-years (95%CI: 31.34/100 000 person-years-33.99/100 000 person-years), that of females was 39.17/100 000 person-years (95%CI: 37.19/100 000 person-years-41.24/100 000 person-years), and that of the male was 25.64/100 000 person-years (95%CI: 23.98/100 000 person-years-27.38/100 000 person-years), the gender difference was statistically significant (P<0.001). The incidence risk in all age groups above 30 years old was higher than that in the 18-29 years old group (P<0.001), and the incidence risk increased with age from 18-79 years old while decreased slightly with age ≥80 years old. The lowest incidence density was 15.30/100 000 person-years in 2013 (95%CI:12.62/100 000 person-years-18.38/100 000 person- years), and the highest was 56.70/100 000 person-years in 2016 (95%CI: 51.24/100 000 person- years - 62.58/100 000 person-years), with statistically significant differences among different years (P=0.004). Conclusions: From 2011 to 2020, the incidence density of RA in adults in Yinzhou district first increased, then decreased, and tended to stabilize. There were differences in incidence density in different years, ages, and genders.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Arthritis, Rheumatoid/epidemiology* ; Cohort Studies ; Female ; Humans ; Incidence ; Male ; Middle Aged ; Retrospective Studies ; Sex Factors ; Young Adult

BACKGROUND: Few studies have assessed the relationship between multimorbidity patterns and mortality risk in the Chinese population. We aimed to identify multimorbidity patterns and examined the associations of multimorbidity patterns and the number of chronic diseases with the risk of mortality among Chinese middle-aged and older adults. METHODS: We used data from the China Kadoorie Biobank and included 512,723 participants aged 30 to 79 years. Multimorbidity was defined as the presence of two or more of the 15 chronic diseases collected by self-report or physical examination at baseline. Multimorbidity patterns were identified using hierarchical cluster analysis. Cox regression was used to estimate the associations of multimorbidity patterns and the number of chronic diseases with all-cause and cause-specific mortality. RESULTS: Overall, 15.8% of participants had multimorbidity. The prevalence of multimorbidity increased with age and was higher in urban than rural participants. Four multimorbidity patterns were identified, including cardiometabolic multimorbidity (diabetes, coronary heart disease, stroke, and hypertension), respiratory multimorbidity (tuberculosis, asthma, and chronic obstructive pulmonary disease), gastrointestinal and hepatorenal multimorbidity (gallstone disease, chronic kidney disease, cirrhosis, peptic ulcer, and cancer), and mental and arthritis multimorbidity (neurasthenia, psychiatric disorder, and rheumatoid arthritis). During a median of 10.8 years of follow-up, 49,371 deaths occurred. Compared with participants without multimorbidity, cardiometabolic multimorbidity (hazard ratios [HR] = 2.20, 95% confidence intervals [CI]: 2.14 - 2.26) and respiratory multimorbidity (HR = 2.13, 95% CI:1.97 - 2.31) demonstrated relatively higher risks of mortality, followed by gastrointestinal and hepatorenal multimorbidity (HR = 1.33, 95% CI:1.22 - 1.46). The mortality risk increased by 36% (HR = 1.36, 95% CI: 1.35 - 1.37) with every additional disease. CONCLUSION Cardiometabolic multimorbidity and respiratory multimorbidity posed the highest threat on mortality risk and deserved particular attention in Chinese adults.
Aged ; Arthritis, Rheumatoid ; Asians ; China/epidemiology* ; Humans ; Hypertension ; Middle Aged ; Multimorbidity

OBJECTIVE: To determine the prevalence, factors associated with and patterns of concomitant Chinese medicine (CM) with Western treatment use among patients with rheumatoid arthritis (RA) in a tertiary referral centre (Singapore General Hospital) in Singapore. METHODS: We conducted a cross-sectional interviewer-administered survey of a consecutive sample of patients with RA in Singapore General Hospital centre regarding their CM use including data on patient demographics, disease characteristics, concomitant use of CM and reasons, concerns and disclosure patterns from March to August 2015. Univariate and multivariate logistic regression analyses were performed to determine the associations of CM use. RESULTS: Prevalence of CM use among the 258 patients surveyed (male: female 42: 216; Chinese: Malay: Indian 191: 29: 34; mean age: 61 years; mean duration of RA: 10 years) was 46.1% (119/258). On multivariate analysis, Chinese ethnicity (OR, 95% CI: 4.11, 1.49-11.36), Chinese speakers (OR, 95% CI: 2.35, 1.03-5.54), middle-income group (OR, 95% CI: 2.53, 1.01-6.31) and greater learned helplessness (OR, 95% CI: 1.13, 1.04-1.22) were significantly associated with CM use. More CM users disclosed their CM use to CM physicians (87.3%, 96/110), sought advice from them on treatment interactions (59.4%, 57/96) and how best to combine treatments (49.0%, 47/96) than did so with rheumatologists (42.0%, 50/119; 40.0%, 20/50; and 42.0%, 21/50, respectively). Forty-two percentage (29/69) of patients who concealed CM use from rheumatologists because their rheumatologists did not specifically enquire about CM use. CONCLUSIONS Concomitant CM use among patients with RA treated in a tertiary referral centre in Singapore is high but voluntary disclosure is low. The associations identified can help doctors identify and enquire about CM use, minimizing potential adverse interactions.
Arthritis, Rheumatoid/epidemiology* ; Cross-Sectional Studies ; Ethnicity ; Female ; Humans ; Male ; Medicine, Chinese Traditional ; Middle Aged ; Prevalence

Objective: To investigate the characteristics of non-alcoholic fatty liver disease (NAFLD) and its associated factors in rheumatoid arthritis (RA) patients. Methods: This cross-sectional study recruited 385 RA patients [including 72 (18.7%) male and 313 (81.3%) female] who received abdominal sonographic examination from August 2015 to May 2021 at Department of Rheumatology, Sun Yat-Sen Memorial Hospital. There were 28 RA patients at 16-29 years old and 32, 80, 121, 99, 25 at 30-39, 40-49, 50-59, 60-69, ≥ 70 years old, respectively. Demographic and clinical data were collected including age, gender, history of alcohol consumption, disease duration, body mass index (BMI), waist circumference, blood pressure, RA disease activity indicators and previous medications. Logistic regression analyses were used to identify the associated factors of NAFLD in RA patients. Results: The prevalence of NAFLD was 24.2% (93/385) in RA patients, 26.3% (21/80) in 40-49 age group and 33.1% (40/121) in 50-59 age group. There were 22.1% (85/385) and 3.6% (14/385) RA patients with overweight and obese, in which the prevalence of NAFLD was 45.9% (39/85) and 78.6% (11/14) respectively, which was 2.6 folds and 4.5 folds that of RA patients with normal BMI. Although there was no significant difference of age, gender and RA disease activity indicators between RA patients with or without NAFLD, those with NAFLD had higher proportions of metabolic diseases including obese (11.8% vs. 1.0%), central obesity (47.3% vs. 16.8%), hypertension (45.2% vs. 29.8%) and type 2 diabetes mellitus (24.7% vs. 12.0%), consistent with higher levels of total cholesterol [(5.33±1.31) mmol/L vs. (4.73±1.12) mmol/L], triglyceride [(1.51±1.08) mmol/L vs. (0.98±0.54) mmol/L] and low-density lipoprotein cholesterol [(3.37±0.97) mmol/L vs. (2.97±0.78) mmol/L, all P<0.05]. Multivariate logistic regression analysis showed that BMI (OR=1.314) and triglyceride (OR=1.809) were the independent factors positively associated with NAFLD in RA patients. Conclusion: NAFLD is a common comorbidity in RA patients, especially in those with middle-aged, overweight or obese, which is associated with high BMI or high triglyceride. Screening and management of NAFLD in RA patients especially those with overweight, obese or dyslipidemia should be emphasized.
Adolescent ; Adult ; Aged ; Arthritis, Rheumatoid/epidemiology* ; Cholesterol, LDL ; Cross-Sectional Studies ; Female ; Humans ; Male ; Middle Aged ; Non-alcoholic Fatty Liver Disease/epidemiology* ; Obesity/epidemiology* ; Overweight/epidemiology* ; Triglycerides ; Young Adult

OBJECTIVE: To investigate the clinical and serological features of rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) overlap syndrome (Rhupus syndrome). METHODS: We retrospectively reviewed the medical records of 21 patients with Rhupus syndrome who were hospitalized at Department of Rheumatology and Immunology, People's Hospital of Xinjiang Uygur Autonomous Region between January 2010 and January 2018. We compared the joint involvement, autoantibodies and clinical manifestations of Rhupus syndrome with 81 cases of RA-alone and 51 cases of SLE-alone. RESULTS: In 21 patients with Rhupus syndrome, there are 3 males and 18 females. Compared with the SLE-alone group, the patients with Rhupus syndrome were older [(49.43±11.66) vs. (40.59±12.73), P=0.008]. The median age of the patients with Rhupus syndrome at RA onset was significantly younger than that of the RA-alone patients [(32.58±11.14) vs. (43.11±11.83), P=0.010]. Of the 21 patients with Rhupus syndrome, the initial diagnosis was RA in 57% (12/21), except 2 male patients, the other 10 patients with SLE manifestations were menopause, the mean age of amenorrhea or menopause was (44.30±5.33) (36-50) years. The mean interval between the onset of SLE and RA was 10.83 years. Two patients started with SLE manifestations. Moreover, both diseases simultaneously developed in 33.3% of the patients. Except one male patient, 3 patients were in menopause stage when RA and SLE appeared. The positive rate of specific antibody Rhupus syndrome was similar to that of RA. Renal damage was relatively rare in SLE related manifestations, but the incidence of interstitial lung disease was higher. There were no significant differences in the prevalence of complements C3 and C4, antinuclear antibody (ANA), anti-double-stranded DNA (anti-dsDNA), anti-SSA or anti-SSB antibody between the Rhupus syndrome and SLE-alone group. CONCLUSION Rhupus syndrome is an overlapping syndrome in which RA and SLE coexist. Most of the diseases occur in RA and the related manifestations of RA are more serious than those of SLE. The incidence of Rhupus syndrome may be related to the change of sex hormone levels.
Adult ; Antibodies, Antinuclear ; Arthritis, Rheumatoid/epidemiology* ; Autoantibodies ; Female ; Humans ; Lupus Erythematosus, Systemic/epidemiology* ; Male ; Middle Aged ; Retrospective Studies

OBJECTIVE: To investigate the clinical characteristics, risk factors and prognosis of ulcerative keratitis (UK) in patients with rheumatoid arthritis (RA). METHODS: Sixteen patients with UK (the UK group) were screened among 4 773 RA patients hospitalized at Peking University People's Hospital from January 2003 to May 2021, and 72 patients with RA without UK in the control group were selected by propensity score matching (PSM). The clinical features, laboratory data and medications between the two groups were collected and analyzed. RESULTS: The average age of the patients with RA was 60 years at the time of the complication of UK. UK appeared on average in the 16th year of RA, with the majority of UK occurring in the 7th year of RA and beyond (14 cases), however, a minority of UK was the first symptom of RA (1 case). UK associated with RA manifested as simple marginal UK in 8 cases, marginal UK with perforation in 5 cases, marginal UK with uveitis in 2 cases and central UK with perforation in 1 case. The number of swollen joints was significantly higher in the UK group than in the control group [6.0(2.5, 23.0) vs. 3.0(1.0, 9.8), Z=-2.047, P=0.041], and the proportion of secondary Sjögren syndrome (SS, 37.5% vs. 6.9%, χ²=11.175, P=0.004) and interstitial lung disease (ILD, 37.5% vs. 8.3%, χ²=9.456, P=0.008) were significantly higher in the RA patients with UK than the patients without UK. The uses of sulfasalazine (12.5% vs. 48.6%, χ²=7.006, P=0.008), leflunomide (31.3% vs. 63.9%, χ²=5.723, P=0.017) and gold salt(6.3% vs. 33.8%, χ²=4.841, P=0.032)were significantly lower in the UK group than in the control group. However, there was no statistically significant comparison between the two groups for the 28-joint disease activity score-erythrocyte sedimentation rate (5.3±1.8 vs. 5.1±1.6, t=0.309, P=0.761). Logistic analysis showed the number of swollen joints (OR=1.148), secondary SS (OR=79.118), complicated with ILD (OR=6.596) and the use of sulfasalazine (OR=0.037) were independent relevant factors (P < 0.05) for UK in RA patients. CONCLUSION The number of swollen joints, secondary SS, complicated with ILD and the use of sulfasalazine are independent relevant factors for UK in patients with RA.
Arthritis, Rheumatoid/epidemiology* ; Corneal Ulcer/etiology* ; Humans ; Middle Aged ; Minority Groups ; Risk Factors

OBJECTIVE: To analyse the clinical and laboratory characteristics of antinuclear antibody (ANA) positive rheumatoid arthritis (RA) patients. METHODS: The clinical and laboratory data of 428 RA cases from Department of of Rheumatology and Immunology Peking University Third Hospital from Jan 2013 to Dec 2018 were collected and used to analyse characters between ANA positive group and ANA negative group. T test was used for the quantitative data in accordance with normal distribution. Wilcoxon rank sum test was used for the quantitative data of non normal distribution. The qualitative data were analyzed by chi square test. But while 1≤theoretical frequency < 5, chi square test of corrected four grid table was used. And Fisher exact probability method was used when theoretical frequency < 1. RESULTS: The number of ANA positive group was 231 (54%). The female rate was obviously higher in ANA positive group (82.7% vs. 63.5%, χ²=20.355, P < 0.01). The rate of metatarsophalangeal joints (MTPJs) involvement was lower in ANA positive group (22.1%) than in ANA negative group (33.0) (χ²=6.414, P < 0.05). The incidence of secondary Sjögren's syndrome (sSS) was much higher in ANA positive group(19.5% vs. 4.1%, χ²=23.300, P < 0.01). The positivity of rheumatoid factor (RF), as well as the positivity of anti-cyclic citrullinated peptide(CCP) antibody was much higher in ANA positive group (77.1% vs. 53.8%, χ²=25.743, P < 0.01, 74.9% vs. 59.4%, χ²=11.694, P < 0.01, respectively). The levels of immunoglobulin G (IgG) and immunoglobulin M (IgM) of ANA positive group were higher [(15.1±5.1) g/L vs. (13.8±5.3) g/L, t=2.359, P < 0.05, 1.25 (0.92) g/L vs. 1.05 (0.65) g/L, Z=-3.449, P < 0.01, respectively]. But the levels of hemoglobin (Hb) and platelet (PLT) was lower in ANA positive group[(109.64±17.98) vs. (114.47±18.48) g/L, t=-2.734, P < 0.01; (266.4×10⁹±104.6×10⁹) vs. (295.9×10⁹±100.1×10⁹) /L, t=-2.970, P < 0.01, respectively]. CONCLUSION The incidence of sSS was obviously higher in ANA positive group than in ANA negative group. Serum IgG of ANA positive group was higher, but Hb and PLT were lower.
Antibodies, Antinuclear ; Arthritis, Rheumatoid/epidemiology* ; Autoantibodies ; Female ; Humans ; Laboratories ; Peptides, Cyclic ; Rheumatoid Factor