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1.
Data Brief ; 17: 820-829, 2018 Apr.
Article in English | MEDLINE | ID: mdl-29527544

ABSTRACT

Carotid Intima-media thickness (CIMT) and plaque are well established markers of subclinical atherosclerosis and are widely used for identifying subclinical atherosclerotic disease. We performed association analyses using Metabochip array to identify genetic variants that influence variation in CIMT and plaque, measured using B-mode ultrasonography, in rheumatoid arthritis (RA) patients. Data on genetic associations of common variants associated with both CIMT and plaque in RA subjects involving Mexican Americans (MA) and European Americans (EA) populations are presented in this article. Strong associations were observed after adjusting for covariate effects including baseline clinical characteristics and statin use. Susceptibility loci and genes and/or nearest genes associated with CIMT in MAs and EAs with RA are presented. In addition, common susceptibility loci influencing CIMT and plaque in both MAs and EAs have been presented. Polygenic Risk Score (PRS) plots showing complementary evidence for the observed CIMT and plaque association signals are also shown in this article. For further interpretation and details, please see the research article titled "A Genetic Association Study of Carotid Intima-Media Thickness (CIMT) and Plaque in Mexican Americans and European Americans with Rheumatoid Arthritis" which is being published in Atherosclerosis (Arya et al., 2018) [1].(Arya et al., in press) Thus, common variants in several genes exhibited significant associations with CIMT and plaque in both MAs and EAs as presented in this article. These findings may help understand the genetic architecture of subclinical atherosclerosis in RA populations.

2.
Atherosclerosis ; 271: 92-101, 2018 04.
Article in English | MEDLINE | ID: mdl-29482039

ABSTRACT

BACKGROUND AND AIMS: Little is known about specific genetic determinants of carotid-intima-media thickness (CIMT) and carotid plaque in subjects with rheumatoid arthritis (RA). We have used the Metabochip array to fine map and replicate loci that influence variation in these phenotypes in Mexican Americans (MAs) and European Americans (EAs). METHODS: CIMT and plaque were measured using ultrasound from 700 MA and 415 EA patients with RA and we conducted association analyses with the Metabochip single nucleotide polymorphism (SNP) data using PLINK. RESULTS: In MAs, 12 SNPs from 11 chromosomes and 6 SNPs from 6 chromosomes showed suggestive associations (p < 1 × 10-4) with CIMT and plaque, respectively. The strongest association was observed between CIMT and rs17526722 (SLC17A2 gene) (ß ± SE = -0.84 ± 0.18, p = 3.80 × 10-6). In EAs, 9 SNPs from 7 chromosomes and 7 SNPs from 7 chromosomes showed suggestive associations with CIMT and plaque, respectively. The top association for CIMT was observed with rs1867148 (PPCDC gene, ß ± SE = -0.28 ± 0.06, p = 5.11 × 10-6). We also observed strong association between plaque and two novel loci: rs496916 from COL4A1 gene (OR = 0.51, p = 3.15 × 10-6) in MAs and rs515291 from SLCA13 gene (OR = 0.50, p = 3.09 × 10-5) in EAs. CONCLUSIONS: We identified novel associations between CIMT and variants in SLC17A2 and PPCDC genes, and between plaque and variants from COL4A1 and SLCA13 that may pinpoint new candidate risk loci for subclinical atherosclerosis associated with RA.


Subject(s)
Arthritis, Rheumatoid/ethnology , Carotid Arteries/diagnostic imaging , Carotid Artery Diseases/ethnology , Carotid Artery Diseases/genetics , Carotid Intima-Media Thickness , Mexican Americans/genetics , Plaque, Atherosclerotic , Polymorphism, Single Nucleotide , White People/genetics , Aged , Arthritis, Rheumatoid/diagnosis , Carboxy-Lyases/genetics , Carotid Artery Diseases/diagnostic imaging , Female , Gene Expression Profiling/methods , Genetic Association Studies , Genetic Predisposition to Disease , Glucose Transport Proteins, Facilitative/genetics , Humans , Male , Middle Aged , Oligonucleotide Array Sequence Analysis , Phenotype , Predictive Value of Tests , Risk Assessment , Risk Factors , Sodium-Phosphate Cotransporter Proteins, Type I/genetics , Texas/epidemiology
3.
J Clin Rheumatol ; 23(3): 144-148, 2017 Apr.
Article in English | MEDLINE | ID: mdl-28277344

ABSTRACT

BACKGROUND/PURPOSE: We examined the association between hydroxychloroquine (HCQ) and plasma lipid and glucose levels in rheumatoid arthritis (RA) cohort. METHODS: This is a retrospective cohort analysis of 1261 RA patients comparing fasting lipid profiles and plasma glucose between patients who were and were not taking HCQ. We divided patients into 3 groups based on HCQ exposure during follow-up: those who had never taken HCQ, those who took it intermittently, and those who took it continuously. We used multivariable models and propensity scoring to compensate for the effect of nonrandom treatment assignment. RESULTS: We followed 1261 RA patients for a total of 4605 observations between 1996 and 2014. After adjusting for age, sex, ethnicity, other disease-modifying antirheumatic drugs (DMARDs), lipid-lowering medications, body mass index (BMI), and smoking, patients taking HCQ at baseline had significantly lower total cholesterol (TC) (P ≤ 0.001), low-density lipoprotein (LDL) (P ≤ 0.001), triglycerides (P = 0.013), and lipid profile ratios TC/high-density lipoprotein (HDL) (P ≤ 0.001) and LDL/HDL (P ≤ 0.001), as well as higher HDL (P ≤ 0.001).In longitudinal analyses, after adjusting for confounders, patients who continuously took HCQ showed significantly lower TC, LDL, TC/HDL, and LDL/HDL and higher HDL (P ≤ 0.01). Fasting plasma glucose levels were not significantly associated with HCQ exposure. CONCLUSIONS: Hydroxychloroquine use was associated with lower lipid levels but not with the plasma glucose in this RA cohort. These findings support the need for a randomized trial to establish the role of HCQ in cardiovascular disease prevention in RA patients.


Subject(s)
Arthritis, Rheumatoid , Hydroxychloroquine/administration & dosage , Lipid Metabolism/drug effects , Antirheumatic Agents/administration & dosage , Arthritis, Rheumatoid/diagnosis , Arthritis, Rheumatoid/drug therapy , Arthritis, Rheumatoid/metabolism , Blood Glucose/analysis , Body Mass Index , Cholesterol/blood , Female , Follow-Up Studies , Humans , Lipoproteins, LDL/blood , Male , Medication Therapy Management , Middle Aged , Triglycerides/blood , United States
4.
BMC Musculoskelet Disord ; 16: 277, 2015 Oct 05.
Article in English | MEDLINE | ID: mdl-26438345

ABSTRACT

BACKGROUND: Death certificates can be used to assess disease prevalence and incidence; however, rheumatoid arthritis (RA) often remains unreported in death certificates. We sought to determine to what extent RA is underreported and what demographic and clinical characteristics could predict mention of RA in the death certificate. METHODS: We recruited 1328 patients with RA from private, public and military rheumatology practices and followed them prospectively for yearly evaluations. A rheumatologist assessed clinical characteristics of RA and comorbidities at each evaluation. Deaths were identified through family members, other physicians, obituaries and public death databases. All were confirmed with state-issued death certificates. Patients with and without RA in death certificate were compared using bivariate and multivariate analyses. RESULTS: By December 2013, 326 deaths had occurred. We received and reviewed death certificates for all confirmed deaths, of which 58 (17.7 %) mentioned RA on the death certificate. Bivariate analysis revealed that younger age, a greater number of deformities, higher Sharp score and lower socioeconomic status were each associated with recording RA. Multivariable analyses revealed that comorbidity [OR (95 % CI) = 0.84 (0.73, 0.97); P = 0.022] was inversely associated with listing RA on the death certificate, while the number of deformities [OR (95 % CI) = 1.04 (1.00, 1.07); P = 0.033] and a certified physician's signature on the death certificate [OR (95 % CI) = 4.79 (1.35, 16.9); P = 0.015] increased likelihood of reporting RA. CONCLUSION: In this cohort, RA was not listed in over 80 % of death certificates. Younger patients with fewer comorbidities and more joint deformities were more likely to have RA reported. DISCUSSION: RA is often not included in death certificates. The findings of this study suggest that older patients may have a greater number of comorbidities, thus decreasing the likelihood that RA be included when completing the death certificate.


Subject(s)
Arthritis, Rheumatoid/mortality , Aged , Aged, 80 and over , Death Certificates , Female , Humans , Male , Middle Aged , Prospective Studies , Texas/epidemiology
5.
Genet Epidemiol ; 39(8): 678-88, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26498133

ABSTRACT

Joint destruction in rheumatoid arthritis (RA) is heritable, but knowledge on specific genetic determinants of joint damage in RA is limited. We have used the Immunochip array to examine whether genetic variants influence variation in joint damage in a cohort of Mexican Americans (MA) and European Americans (EA) with RA. We studied 720 MA and 424 EA patients with RA. Joint damage was quantified using a radiograph of both hands and wrists, scored using Sharp's technique. We conducted association analyses with the transformed Sharp score and the Immunochip single nucleotide polymorphism (SNP) data using PLINK. In MAs, 15 SNPs from chromosomes 1, 5, 9, 17 and 22 associated with joint damage yielded strong p-values (p < 1 × 10(-4) ). The strongest association with joint damage was observed with rs7216796, an intronic SNP located in the MAP3K14 gene, on chromosome 17 (ß ± SE = -0.25 ± 0.05, p = 6.23 × 10(-6) ). In EAs, 28 SNPs from chromosomes 1, 4, 6, 9, and 21 showed associations with joint damage (p-value < 1 × 10(-4) ). The best association was observed on chromosome 9 with rs59902911 (ß ± SE = 0.86 ± 0.17, p = 1.01 × 10(-6) ), a synonymous SNP within the CARD9 gene. We also observed suggestive evidence for some loci influencing joint damage in MAs and EAs. We identified two novel independent loci (MAP3K14 and CARD9) strongly associated with joint damage in MAs and EAs and a few shared loci showing suggestive evidence for association.


Subject(s)
Arthritis, Rheumatoid/genetics , Arthritis, Rheumatoid/pathology , CARD Signaling Adaptor Proteins/genetics , Joints/pathology , Protein Serine-Threonine Kinases/genetics , Arthritis, Rheumatoid/ethnology , Female , Genetic Association Studies/methods , Genetic Predisposition to Disease , Genotype , Humans , Male , Mexican Americans/genetics , Middle Aged , Phenotype , Polymorphism, Single Nucleotide/genetics , United States , White People/genetics , NF-kappaB-Inducing Kinase
6.
Clin Rheumatol ; 34(9): 1529-36, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26255186

ABSTRACT

OBJECTIVE: The objective of this study is to examine the clinical, genetic, and environmental factors associated with interstitial lung disease (ILD) in rheumatoid arthritis (RA). METHOD: We recruited patients with RA from rheumatology practices at the time of a scheduled visit. Each patient participated in a comprehensive assessment that included ascertainment of age, sex, joint tenderness and swelling, subcutaneous nodules, disease severity, use of methotrexate and prednisone, smoking status, rheumatoid factor (RF), antibodies against cyclic citrullinated peptide (anti-CCP),erythrocyte sedimentation rate (ESR), the 28-joint Disease Activity Score (DAS28), and the presence of the HLA-DRB1 shared epitope (SE). As part of a thorough quantification of comorbidity, we identify all comorbid conditions, including ILD. We examined variables associated with ILD using logistic regression. We tested interaction terms between SE and other covariates. RESULTS: We studied 779 RA patients, among whom, ILD was recognized clinically in 69 (8.8 %). Variables significantly associated with ILD in a multivariable analysis included male sex, RA duration, the ESR, the DAS28, anti-CCP, and RF. There was a significant interaction between the HLA-DRB1 SE and smoking, ILD being associated with smoking only in the presence of SE. The association between ILD and anti-CCP, RF, and the ESR displayed a biological gradient, higher titers being more strongly associated with ILD. CONCLUSION: Anti-CCP antibodies and the RF may be pathogenically related to ILD. The association between ILD and smoking is dependent on the HLA-DRB1 SE, which may reflect gene-environment interaction.


Subject(s)
Arthritis, Rheumatoid/complications , HLA-DRB1 Chains/genetics , Lung Diseases, Interstitial/diagnosis , Lung Diseases, Interstitial/immunology , Peptides, Cyclic/immunology , Smoking/immunology , Adult , Aged , Alleles , Arthritis, Rheumatoid/drug therapy , Blood Sedimentation , Disease Progression , Female , Genetic Predisposition to Disease , Humans , Logistic Models , Male , Methotrexate/therapeutic use , Middle Aged , Rheumatoid Factor/immunology , Risk Factors , Texas
7.
Arthritis Care Res (Hoboken) ; 67(7): 940-6, 2015 Jul.
Article in English | MEDLINE | ID: mdl-25581770

ABSTRACT

OBJECTIVE: To examine the association of socioeconomic status (SES) and delays in disease-modifying antirheumatic drug (DMARD) treatment with clinical measures in rheumatoid arthritis (RA) patients. METHODS: RA patients were recruited from rheumatology practices. We assessed SES based on education, occupation, and income, and divided patients into tertiles. The time from RA symptom onset to DMARD initiation (DMARD lag) was determined by self-report of the 2 dates, and distance to the rheumatologist (Distance) was obtained from Google Maps. We examined disease activity, determined by the Disease Activity Score in 28 joints using the erythrocyte sedimentation rate (DAS28-ESR); joint damage, determined from hand radiographs by Sharp scores; and physical disability, determined by the modified Health Assessment Questionnaire (M-HAQ). We used linear regression models to examine the relationship between clinical measures and SES, Distance, and DMARD lag. RESULTS: We recruited 1,209 RA patients, 1,159 of whom had received DMARD treatment. Mean ± SD DMARD lag was 6.9 ± 9.0 years. On average, patients with lower SES waited 8.5 ± 10.2 years after onset of RA symptoms to begin DMARD treatment, compared to those in the middle and upper SES tertiles who waited 6.1 ± 7.9 years (P = 0.002) and 6.1 ± 8.6 years (P = 0.009), respectively. Each year of delayed treatment was associated with a DAS28-ESR increase of 0.02 (P ≤ 0.001), a Sharp score increase of 1.33 (P ≤ 0.001), and an M-HAQ score increase of 0.01 (P ≤ 0.001). CONCLUSION: Low SES was associated with delay in DMARD initiation, and both were independently associated with worse clinical measures in RA. Strategies to reduce treatment delay in low-SES RA patients are needed.


Subject(s)
Antirheumatic Agents/economics , Arthritis, Rheumatoid/drug therapy , Arthritis, Rheumatoid/economics , Disabled Persons , Health Services Accessibility/economics , Severity of Illness Index , Adult , Aged , Aged, 80 and over , Antirheumatic Agents/administration & dosage , Arthritis, Rheumatoid/diagnosis , Female , Humans , Joints/drug effects , Joints/pathology , Male , Middle Aged , Time Factors , Treatment Outcome , Young Adult
8.
Ann Rheum Dis ; 74(6): 1118-23, 2015 Jun.
Article in English | MEDLINE | ID: mdl-24845391

ABSTRACT

OBJECTIVE: To estimate atherosclerosis progression and identify influencing factors in rheumatoid arthritis (RA). METHODS: We used carotid ultrasound to measure intima-media thickness (IMT) in RA patients, and ascertained cardiovascular (CV) risk factors, inflammation markers and medications. A second ultrasound was performed approximately 3 years later. We calculated the progression rate by subtracting the baseline from the follow-up IMT, divided by the time between the two scans. We used logistic regression to identify baseline factors predictive of rapid progression. We tested for interactions of erythrocyte sedimentation rate (ESR) with CV risk factors and medication use. RESULTS: Results were available for 487 RA patients. The mean (SD) common carotid IMT at baseline was 0.571 mm (0.151). After a mean of 2.8 years, the IMT increased by 0.050 mm (0.055), p≤0.001, a progression rate of 0.018 mm/year (95% CI 0.016 to 0.020). Baseline factors associated with rapid progression included the number of CV risk factors (OR 1.27 per risk factor, 95% CI 1.01 to 1.61), and the ESR (OR 1.12 per 10 mm/h, 95% CI 1.02 to 1.23). The ESR×CV risk factor and ESR×medication product terms were significant, suggesting these variables modify the association between the ESR and IMT progression. CONCLUSIONS: Systemic inflammation and CV risk factors were associated with rapid IMT progression. CV risk factors may modify the role of systemic inflammation in determining IMT progression over time. Methotrexate and antitumour necrosis factor agents may influence IMT progression by reducing the effect of the systemic inflammation on the IMT.


Subject(s)
Arthritis, Rheumatoid/immunology , Atherosclerosis/immunology , Carotid Intima-Media Thickness , Peptides, Cyclic/immunology , Rheumatoid Factor/immunology , Aged , Anticholesteremic Agents/therapeutic use , Antihypertensive Agents/therapeutic use , Antirheumatic Agents/therapeutic use , Arthritis, Rheumatoid/drug therapy , Arthritis, Rheumatoid/genetics , Atherosclerosis/diagnostic imaging , Atherosclerosis/epidemiology , Blood Sedimentation , Cardiovascular Diseases/diagnostic imaging , Cardiovascular Diseases/epidemiology , Cardiovascular Diseases/immunology , Carotid Arteries/diagnostic imaging , Carotid Artery Diseases/diagnostic imaging , Diabetes Mellitus/drug therapy , Diabetes Mellitus/epidemiology , Disease Progression , Female , HLA-DRB1 Chains/genetics , Humans , Hypercholesterolemia/blood , Hypercholesterolemia/drug therapy , Hypercholesterolemia/epidemiology , Hypertension/drug therapy , Hypertension/epidemiology , Hypoglycemic Agents/therapeutic use , Inflammation/immunology , Longitudinal Studies , Male , Middle Aged , Obesity/epidemiology , Risk Factors , Smoking/epidemiology
9.
Arthritis Rheumatol ; 66(2): 264-72, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24504798

ABSTRACT

OBJECTIVE: To delineate daily and cumulative glucocorticoid dose thresholds associated with increased mortality rates in rheumatoid arthritis (RA). METHODS: We studied RA patients recruited from rheumatology clinics. Annually, we assessed the glucocorticoid dose, demographic, socioeconomic, clinical, and laboratory features of RA, cardiovascular (CV) risk factors, and vital status. We used Cox proportional hazards regression to assess associations between the daily or cumulative glucocorticoid dose and death, adjusting for potential confounders and for the propensity to receive glucocorticoids. We tested strata of the glucocorticoid dose to delineate the threshold associated with death. RESULTS: We studied 779 RA patients with a total of 7,203 person-years of observation, during which 237 of them died, yielding a mortality rate of 3.2 per 100 person-years (95% confidence interval [95% CI] 2.8-3.7). One hundred twenty of the deaths were due to CV causes, yielding a CV mortality rate of 1.8 (95% CI 1.5-2.1). Exposure to glucocorticoids was associated with a dose-dependent increase in death from all causes, with a ratio (HR) of 1.07 per mg of prednisone per day (95% CI 1.05-1.08). Compared to patients who were not receiving corticosteroids, the minimum daily prednisone dose threshold associated with an increase in all-cause mortality was 8-15 mg, with an adjusted HR of 1.78 (95% CI 1.22-2.60). For the cumulative dose of glucocorticoids, the minimum dosage associated with all-cause mortality was 40 gm (HR 1.74 [95% CI 1.25-2.44]). CONCLUSION: Glucocorticoid use in RA is associated with a dose-dependent increase in mortality rates, with a daily threshold dose of 8 mg, at which the number of deaths increased in a dose-dependent manner. These findings may assist clinicians in selecting the appropriate glucocorticoid dosage for RA patients who require these agents.


Subject(s)
Arthritis, Rheumatoid/drug therapy , Cardiovascular Diseases/mortality , Glucocorticoids/adverse effects , Glucocorticoids/therapeutic use , Maximum Tolerated Dose , Adult , Dose-Response Relationship, Drug , Female , Humans , Incidence , Male , Middle Aged , Prednisone/adverse effects , Prednisone/therapeutic use , Proportional Hazards Models , Retrospective Studies , Risk Factors , Survival Rate
10.
Arthritis Care Res (Hoboken) ; 66(7): 972-9, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24339449

ABSTRACT

OBJECTIVE: Despite lower socioeconomic status (SES) and higher disease burden, Hispanics in the US paradoxically display equal or lower mortality on average than non-Hispanic whites. Our objective was to determine if the "Hispanic paradox" occurs among patients with rheumatoid arthritis (RA). METHODS: In a cohort of 706 RA patients, we compared differences in RA severity and comorbidity between Hispanic and non-Hispanic white ethnic groups at baseline. Cox proportional hazards models were used to estimate and compare mortality risk between Hispanics and non-Hispanic whites. RESULTS: We studied 706 patients with RA, of whom 434 were Hispanic and 272 were non-Hispanic white. Hispanics had significantly lower SES, greater inflammation, as well as higher tender and swollen joint counts. Patients were observed for 6,639 patient-years, during which time 229 deaths occurred by the censoring date (rate 3.4 per 100 person-years; 95% confidence interval 3.0, 3.9). Age- and sex-adjusted mortality was not significantly different between the 2 ethnic groups (hazard ratio [HR] 0.96). After adjustment for comorbidities, RA severity, and level of acculturation, mortality among Hispanics was lower (HR 0.56, P = 0.004). CONCLUSION: Despite greater severity in most clinical manifestations and lower SES among Hispanics, paradoxically, their mortality was not increased. Further research is needed to understand the mechanisms underlying this survival paradox.


Subject(s)
Arthritis, Rheumatoid/ethnology , Arthritis, Rheumatoid/mortality , Hispanic or Latino/ethnology , Adult , Aged , Cohort Studies , Female , Follow-Up Studies , Humans , Male , Middle Aged , Survival Analysis , Texas/epidemiology
11.
Arthritis Rheum ; 63(5): 1211-20, 2011 May.
Article in English | MEDLINE | ID: mdl-21305526

ABSTRACT

OBJECTIVE: The role of atherosclerosis in the acute coronary syndromes (ACS) that occur in patients with rheumatoid arthritis (RA) has not been quantified in detail. We undertook this study to determine the extent to which ACS are associated with carotid atherosclerosis in RA. METHODS: We prospectively ascertained ACS, defined as myocardial infarction, unstable angina, cardiac arrest, or death due to ischemic heart disease, in an RA cohort. We measured carotid atherosclerosis using high-resolution ultrasound. We used Cox proportional hazards models to estimate the association between ACS and atherosclerosis, adjusting for demographic features, cardiovascular (CV) risk factors, and RA manifestations. RESULTS: We performed carotid ultrasound on 636 patients whom we followed up for 3,402 person-years. During this time, 84 patients experienced 121 new or recurrent ACS events, a rate of 3.5 ACS events per 100 patient-years (95% confidence interval [95% CI] 3.0-4.3). Among the 599 patients without a history of ACS, 66 incident ACS events occurred over 3,085 person-years, an incidence of 2.1 ACS events per 100 person-years (95% CI 1.7-2.7). The incidence of new ACS events per 100 patient-years was 1.1 (95% CI 0.6-1.7) among patients without plaque, 2.5 (95% CI 1.7-3.8) among patients with unilateral plaque, and 4.3 (95% CI 2.9-6.3) among patients with bilateral plaque. Covariates associated with incident ACS events independent of atherosclerosis included male sex, diabetes mellitus, and a cumulative glucocorticoid dose of ≥ 20 gm. CONCLUSION: Atherosclerosis is strongly associated with ACS in RA. RA patients with carotid plaque, multiple CV risk factors (particularly diabetes mellitus or hypertension), many swollen joints, and a high cumulative dose of glucocorticoids, as well as RA patients who are men, are at high risk of ACS.


Subject(s)
Acute Coronary Syndrome/etiology , Arthritis, Rheumatoid/complications , Atherosclerosis/complications , Carotid Arteries/diagnostic imaging , Carotid Artery Diseases/complications , Acute Coronary Syndrome/diagnostic imaging , Acute Coronary Syndrome/epidemiology , Adult , Aged , Arthritis, Rheumatoid/diagnostic imaging , Arthritis, Rheumatoid/epidemiology , Atherosclerosis/diagnostic imaging , Atherosclerosis/epidemiology , Carotid Artery Diseases/diagnostic imaging , Carotid Artery Diseases/epidemiology , Female , Humans , Incidence , Male , Middle Aged , Prospective Studies , Risk Factors , Severity of Illness Index , Ultrasonography
13.
BMC Proc ; 3 Suppl 7: S84, 2009 Dec 15.
Article in English | MEDLINE | ID: mdl-20018080

ABSTRACT

While genetic and environmental factors and their interactions influence susceptibility to rheumatoid arthritis (RA), causative genetic variants have not been identified. The purpose of the present study was to assess the effects of covariates and genotype x sex interactions on the genome-wide association analysis (GWAA) of RA using Genetic Analysis Workshop 16 Problem 1 data and a logistic regression approach as implemented in PLINK. After accounting for the effects of population stratification, effects of covariates and genotype x sex interactions on the GWAA of RA were assessed by conducting association and interaction analyses. We found significant allelic associations, covariate, and genotype x sex interaction effects on RA. Several top single-nucleotide polymorphisms (SNPs) (~22 SNPs) showed significant associations with strong p-values (p < 1 x 10-4 - p < 1 x 10-24). Only three SNPs on chromosomes 4, 13, and 20 were significant after Bonferroni correction, and none of these three SNPs showed significant genotype x sex interactions. Of the 30 top SNPs with significant (p < 1 x 10-4 - p < 1 x 10-6) interactions, ~23 SNPs showed additive interactions and ~5 SNPs showed only dominance interactions. Those SNPs showing significant associations in the regular logistic regression failed to show significant interactions. In contrast, the SNPs that showed significant interactions failed to show significant associations in models that did not incorporate interactions. It is important to consider interactions of genotype x sex in addition to associations in a GWAA of RA. Furthermore, the association between SNPs and RA susceptibility varies significantly between men and women.

17.
Arthritis Rheum ; 59(4): 523-30, 2008 Apr 15.
Article in English | MEDLINE | ID: mdl-18383416

ABSTRACT

OBJECTIVE: To evaluate the association between peripheral arterial function and cortical bone thickness in rheumatoid arthritis (RA). METHODS: In a cross-sectional study, we measured the combined cortical thickness (CCT) of the second metacarpal bone from hand radiographs, and the ankle-to-arm systolic blood pressure ratio, also known as ankle-brachial index (ABI), in RA patients. We evaluated the association between the 2 using multinomial logistic regression. RESULTS: We obtained CCT and ABI measurements in 588 RA patients. The mean +/- SD CCT was 3.62 +/- 1.16 mm. The proportion of patients with > or =1 ABI value < or =0.9, indicating obstructed lower limb arteries, increased from 18 (9.2%) of 191 patients in the highest CCT tertile to 25 (12.5%) of 200 in the middle CCT tertile to 38 (19.2%) of 198 in the lowest CCT tertile (P for trend 0.005). We noted a similar pattern for ABI values >1.3, indicative of arterial incompressibility (frequencies in high, middle, and low CCT tertiles were 4.7%, 9.5%, and 19.9%, respectively; P for trend < or =0.001). These trends remained significant after multivariable adjustment for potential confounders. After adjustment for the manifestations of RA and cumulative glucocorticoid dose, the association between CCT and arterial obstruction remained significant, but that with arterial incompressibility weakened considerably. CONCLUSION: There is an association between metacarpal cortical bone thinning and obstruction or incompressibility of the peripheral arteries in RA. The association with incompressibility may be mediated by systemic inflammation and/or glucocorticoids, but that with obstruction is independent of a wide array of potential confounders. Clinicians should be alert to the possibility of impaired arterial function RA patients with thinned metacarpal cortical bone.


Subject(s)
Arteries/physiopathology , Arthritis, Rheumatoid/pathology , Arthritis, Rheumatoid/physiopathology , Bone and Bones/pathology , Aged , Blood Pressure , Cohort Studies , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Regional Blood Flow
18.
Atherosclerosis ; 195(2): 354-60, 2007 Dec.
Article in English | MEDLINE | ID: mdl-17097659

ABSTRACT

Patients with rheumatoid arthritis (RA) are predisposed to atherosclerosis and cardiovascular disease. This is thought to be caused in part, by exposure to chronic systemic inflammation during the course of the disease. We hypothesized that RA disease duration augments the effect of age on atherosclerosis. We measured the carotid artery intima-media thickness (IMT) in 631 consecutive RA patients. We ascertained age, sex and disease duration, established CV risk factors, RA clinical manifestations and markers of inflammation. We used multivariable regression to model IMT, with age as the independent variable. We then added RA duration quartile x age interaction terms to estimate the IMT-age relationship within RA duration strata. We found that the rate at which the IMT increased per unit of age steepened in proportion to the RA duration, from 0.154 mm/10 years among patients with RA for 7 years or less, to 0.295 mm/10 years among patients with RA for 20 years or more (P

Subject(s)
Arthritis, Rheumatoid/complications , Atherosclerosis , Carotid Artery Diseases , Carotid Artery, Internal/pathology , Tunica Intima/pathology , Tunica Media/pathology , Adult , Age Factors , Aged , Atherosclerosis/complications , Atherosclerosis/pathology , Carotid Artery Diseases/complications , Carotid Artery Diseases/pathology , Carotid Artery, Internal/diagnostic imaging , Female , Humans , Longitudinal Studies , Male , Middle Aged , Risk Factors , Time Factors , Tunica Intima/diagnostic imaging , Tunica Media/diagnostic imaging , Ultrasonography
19.
J Rheumatol ; 33(3): 508-16, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16511920

ABSTRACT

OBJECTIVE: To identify factors associated with the loss of cortical diaphyseal bone over time in patients with rheumatoid arthritis (RA). METHODS: We measured the combined cortical thickness (CCT) of the second metacarpal bone from digitized hand radiographs in an RA cohort. We estimated the rate of loss of CCT, and tested the effect of factors that could accelerate the rate. RESULTS: We studied 649 patients, who had 2990 hand radiographs. The median interval between the first and last followup radiograph was 2 years (range 0 to 23 yrs). The mean CCT at baseline was 4.04 mm (standard deviation 1.18). CCT loss was greatest during the earliest observation stages, following a square-root function of time at a rate of 0.393 mm/year(1/2) (95% CI 0.360, 0.423). Patients with a mean erythrocyte sedimentation rate (ESR) < 30 mm/h lost CCT at a rate of 0.303 mm/year(1/2) (95% CI 0.247, 0.358); those with a mean ESR > 30 and < or = 60 mm/h lost CCT at 0.395 mm/year(1/2) (95% CI 0.345, 0.446); and those with ESR > 60 mm/h lost CCT at 0.554 mm/year(1/2) (95% CI 0.480, 0.628). Patients who received a cumulative dose of glucocorticoids > or = 11.7 g lost CCT at 0.659 mm/year(1/2) (95% CI 0.577, 0.742), compared to 0.361 mm/year(1/2) (0.323, 0.401) in patients who did not receive glucocorticoids. In a multivariable model, the effect of the ESR and cumulative glucocorticoids was independent of age at RA onset, RA duration, sex, ethnic group, body mass index, presence of rheumatoid nodules, rheumatoid factor, and the HLA-DRB1 shared epitope. CONCLUSION: Early rapid loss of cortical diaphyseal bone occurs in patients with RA, followed by gradual slowing. Systemic inflammation and glucocorticoids seem to accelerate bone loss independently of other risk factors. Cortical diaphyseal bone may be an important target of the disease process in RA.


Subject(s)
Arthritis, Rheumatoid/pathology , Bone Resorption/pathology , Glucocorticoids/adverse effects , Inflammation/pathology , Metacarpal Bones/pathology , Osteoporosis/pathology , Arthritis, Rheumatoid/complications , Arthritis, Rheumatoid/diagnostic imaging , Bone Resorption/drug therapy , Diaphyses/diagnostic imaging , Diaphyses/drug effects , Diaphyses/pathology , Female , Humans , Inflammation/etiology , Longitudinal Studies , Male , Metacarpal Bones/diagnostic imaging , Metacarpal Bones/drug effects , Middle Aged , Osteoporosis/etiology , Radiography
20.
Arthritis Rheum ; 52(11): 3413-23, 2005 Nov.
Article in English | MEDLINE | ID: mdl-16255018

ABSTRACT

OBJECTIVE: To estimate the contribution of cardiovascular (CV) risk factors and rheumatoid arthritis (RA) disease manifestations to atherosclerosis in RA. METHODS: We used high-resolution carotid ultrasound to measure the carotid intima-media thickness (IMT) and plaque in 631 RA patients. Using R(2) measures from multivariable models, we estimated the contribution of demographic characteristics (age, sex, and ethnic group), CV risk factors (diabetes mellitus, hypercholesterolemia, cigarette smoking, hypertension, and body mass index, and RA manifestations (joint tenderness, swelling, and deformity, nodules, erythrocyte sedimentation rate [ESR], C-reactive protein, rheumatoid factor, the HLA-DRB1 shared epitope, and cumulative glucocorticoid dose) to each of the outcomes. Estimates were obtained in the full sample, and within strata defined by age, sex, and ethnic group. We tested for interaction between CV risk factors and RA manifestations. RESULTS: The contribution of demographic factors, CV risk factors, and RA manifestations to IMT and plaque R(2) varied depending on the patients' age stratum. Demographic features explained 11-16% of IMT variance, CV risk factors explained 4%-12%, and RA manifestations explained 1-6%. The greatest contribution of RA manifestations occurred in the youngest age group, while that of CV risk factors occurred in the older age groups. Results for carotid plaque were similar. There was a significant interaction between the number of CV risk factors present and the ESR, suggesting that the ESR's effect on IMT varied according to the number of CV risk factors. CONCLUSION: Both established CV risk factors and manifestations of RA inflammation contribute significantly to carotid atherosclerosis in RA, and may modify one another's effects. These findings may have implications regarding the prevention of atherosclerosis in RA.


Subject(s)
Arthritis, Rheumatoid/complications , Atherosclerosis/etiology , Carotid Artery Diseases/etiology , Arthritis, Rheumatoid/epidemiology , Arthritis, Rheumatoid/pathology , Atherosclerosis/diagnostic imaging , Atherosclerosis/epidemiology , Carotid Artery Diseases/diagnostic imaging , Carotid Artery Diseases/epidemiology , Female , Humans , Male , Middle Aged , Risk Factors , Texas/epidemiology , Tunica Intima/diagnostic imaging , Ultrasonography
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