Inmaculada del Rincón

How much disability in rheumatoid arthritis is explained by rheumatoid arthritis

OBJECTIVE To measure the proportion of disability explained by disease manifestations compared with nondisease factors in rheumatoid arthritis (RA). METHODS A hypothetical model of the disablement process specific for RA was constructed using the demographic, sociocultural, and clinical characteristics of a consecutive cohort of RA patients. Disability was measured with the modified Health Assessment Questionnaire (M-HAQ) and the physical function scale of the Medical Outcomes Study Short Form 36 (SF-36) questionnaire. Independent variables, grouped according to their position in the RA disablement process model, were sequentially entered in a series of hierarchical regression models. The proportion of variance in disability explained by each group of variables was measured by the groups incremental R2. RESULTS The overall proportion of disability explained by the full model was 59%. Factors in the main disease-disability pathway explained 33%, of which 3% was explained by disease duration, 5% by the Westergren erythrocyte sedimentation rate, 14% by articular signs and symptoms, and 11% by performance-based functional limitations. External modifiers and contextual variables explained 26% of the variance in disability, of which age and sex accounted for 2%, formal education 4%, psychological status 17%, and symptoms of depression 3%. CONCLUSION Both the main disease-disability pathway and factors external to this pathway contribute significantly to disability in RA. These findings provide evidence of the relative influence of psychosocial factors, compared with disease manifestations, on the disability of patients with RA.

CAROTID ATHEROSCLEROSIS PREDICTS INCIDENT ACUTE CORONARY SYNDROMES IN RHEUMATOID ARTHRITIS

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.

Glucocorticoid Dose Thresholds Associated With All-Cause and Cardiovascular Mortality in Rheumatoid Arthritis

To delineate daily and cumulative glucocorticoid dose thresholds associated with increased mortality rates in rheumatoid arthritis (RA).

Recipients of hip replacement for arthritis are less likely to be Hispanic, independent of access to health care and socioeconomic status.

OBJECTIVE To compare the proportion of Hispanics among recipients of hip replacements for primary articular disorders, recipients of knee replacements for the same reason, and persons hospitalized for other reasons. METHODS Twelve of the 17 accredited hospitals in Bexar County, Texas, in which hip or knee replacement surgery is performed permitted us to review their medical records. From 1993 through 1995, 3,100 elective, non-fracture-related, hip or knee replacements were performed. These individuals were matched by age, sex, hospital, and month of admission with 4,604 persons hospitalized for other reasons. Age, sex, ethnic background, type of medical insurance, median household income by zip code of residence, joint replaced, and surgical diagnosis were abstracted from the medical records. The validity of variables abstracted from the medical records was tested by comparison with self-report data in 115 patients interviewed prior to elective hip or knee replacement surgery. RESULTS During the study period, 2,275 subjects had a total knee replacement and 825 had a total hip replacement. Recipients of hip replacements were significantly less likely to be Hispanic than were recipients of knee replacements (19.5% versus 29.9%; odds ratio [OR] 0.57, 95% confidence interval [95% CI] 0.46-0.71; P < or = 0.001) or persons hospitalized for other reasons (29.4% Hispanic; OR 0.67, 95% CI 0.55-0.81). The under-representation of Hispanics was more pronounced among persons undergoing hip replacement for osteoarthritis compared with recipients of knee replacements for the same disease (OR 0.48, 95% CI 0.37-0.62). This pattern persisted after adjusting for age, sex, type of medical insurance, and median household income by the zip code of residence. Concordance between medical records and self-report data on ethnic background was high (kappa = 0.93). CONCLUSION Recipients of hip replacement are less likely to be Hispanic than are other hospitalized persons with a similar level of access to care. The reasons for this under-representation probably involve factors in addition to lack of access to health care and low socioeconomic status. Further research is needed to understand the nature of such factors.

Disparity in Total Hip Replacement Affecting Hispanic Medicare Beneficiaries

Objective. To compare the utilization of total hip replacement (THR) between Hispanic persons and non-Hispanic persons in a sample with health insurance. Research Design. Case-control study using Medicare claims data. Patients. The cases were Medicare beneficiaries from Arizona, Illinois, New Mexico, or Texas who underwent a primary THR. The controls were Medicare beneficiaries who did not receive a THR, matched by age, sex, and county of residence. Measures. Beneficiary surnames and the race indicator in Medicare records were used to classify beneficiaries’ probability of being Hispanic. Conditional logistic regression was used to estimate the odds of receiving of THR, adjusting for Medicaid eligibility. Results. Six thousand four hundred thirty-seven recipients of a primary THR were matched to 12,874 controls. According to the Medicare race indicator, 1% of recipients of THR and 3.3% of controls were Hispanic (P ≤0.001). The odds of THR decreased as the probability of Hispanic ethnicity increased, from an odds ratio (OR) of 1.00 among beneficiaries with non-Hispanic surnames, to an OR of 0.36 among those with heavily Hispanic surnames (95% CI, 0.31, 0.43). Poverty, as reflected by eligibility for Medicaid, did not modify the low odds of THR among Hispanic persons (OR, 0.25 among Medicaid-eligible Hispanic persons; 95% CI, 0.19, 0.33; and OR, 0.30 among Hispanic persons not Medicaid eligible; 95% CI, 0.24, 0.38). Conclusion. Hispanic persons with Medicare receive THR at lower rates than do non-Hispanic persons. Because Medicare covers THR, our findings suggest that under utilization of THR by Hispanic persons cannot be attributed to lack of health insurance alone.

Symptoms of depression and psychological distress among Hispanics with rheumatoid arthritis.

OBJECTIVE To explore the roles played by Hispanic ethnic background and acculturation to the mainstream English language culture of the United States in the depressive symptoms and mental health of rheumatoid arthritis (RA) patients. METHODS Members of a consecutive cohort of patients with RA were studied cross-sectionally. All underwent a comprehensive clinical and psychosocial evaluation. Depressive symptoms were measured with the Center for Epidemiologic Studies Depression Scale (CES-D), and psychological distress was measured with the Medical Outcomes Study Short Form 36 (SF-36) mental health scale. RESULTS Two hundred thirty-six patients were studied. Women had significantly higher median CES-D scores than men (19 versus 14, P = 0.0004), Hispanics scored higher than non-Hispanics (14 versus 8, P = 0.0002), and foreign-born scored higher than US-born patients (14 versus 10, P = 0.009). Compared with those who were fully acculturated, patients who were partially acculturated were more likely to have a score > or = 16 on the RA-adjusted CES-D (odds ratio [OR] = 1.79, 95% confidence interval [95% CI] 1.37 to 2.35, P < or = 0.001). Among unacculturated patients, the likelihood of a score > or = 16 increased 6-fold (OR = 6.68; 95% CI 3.50 to 12.72; P < or = 0.001). A similar, inverse pattern was observed for the SF-36 mental health scale. In multivariate models accounting for age, sex, education, income, articular pain, deformity, and the level of disability, low acculturation was independently associated with high depressive symptoms, and a Hispanic background was independently associated with lower SF-36 mental health. CONCLUSIONS In this consecutive series of RA patients, Hispanics, particularly those who are not fully acculturated to the mainstream Anglo society, had more depressive symptoms and psychological distress than did non-Hispanics.

Systemic inflammation and cardiovascular risk factors predict rapid progression of atherosclerosis in rheumatoid arthritis

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.

Epidemiology and impact of rheumatic disorders in the United States Hispanic population.

The emergence of a sizable Hispanic population in the US is a relatively recent historical phenomenon, and thus much is still unknown about this group of North Americans. Data from national surveys suggest small differences between Hispanic and non-Hispanic white populations in the age-adjusted prevalence of self-reported arthritic conditions. However, the rate of activity-limitation attributable to arthritis is higher among Hispanic patients. This likely reflects the poorer socioeconomic conditions and lack of health insurance that prevail among Hispanic populations, which may limit their access to rheumatologic care. Osteoporotic vertebral and hip fractures are less frequent, and proximal femoral mineral density is higher, in Hispanic individuals than in non-Hispanic white individuals. The mechanisms for these observations are currently under investigation. There have been no studies of the prevalence of osteoarthritis, rheumatoid arthritis, or systemic lupus erythematosus among Hispanic populations. However, important immunogenetic, clinical, and psychosocial differences between Hispanic and non-Hispanic patients in regard to rheumatoid arthritis and systemic lupus erythematosus have been reported. There is no published information on the prevalence or characteristics of other rheumatic diseases in the US Hispanic population. Emerging evidence suggests considerable underuse of certain health services for arthritis among Hispanic patients, likely due in part to socioeconomic factors. Further research is needed to determine whether biologic, cultural or psychosocial factors contribute to underuse as well. There is clearly a need for data on the prevalence and characteristics of arthritis and other rheumatic and musculoskeletal diseases in this emerging US population.

Measurement of global functional performance in patients with rheumatoid arthritis using rheumatology function tests

Outcome assessment in patients with rheumatoid arthritis (RA) includes measurement of physical function. We derived a scale to quantify global physical function in RA, using three performance-based rheumatology function tests (RFTs). We measured grip strength, walking velocity, and shirt button speed in consecutive RA patients attending scheduled appointments at six rheumatology clinics, repeating these measurements after a median interval of 1 year. We extracted the underlying latent variable using principal component factor analysis. We used the Bayesian information criterion to assess the global physical function scales cross-sectional fit to criterion standards. The criteria were joint tenderness, swelling, and deformity, pain, physical disability, current work status, and vital status at 6 years after study enrolment. We computed Guyatts responsiveness statistic for improvement according to the American College of Rheumatology (ACR) definition. Baseline functional performance data were available for 777 patients, and follow-up data were available for 681. Mean ± standard deviation for each RFT at baseline were: grip strength, 14 ± 10 kg; walking velocity, 194 ± 82 ft/min; and shirt button speed, 7.1 ± 3.8 buttons/min. Grip strength and walking velocity departed significantly from normality. The three RFTs loaded strongly on a single factor that explained ≥70% of their combined variance. We rescaled the factor to vary from 0 to 100. Its mean ± standard deviation was 41 ± 20, with a normal distribution. The new global scale had a stronger fit than the primary RFT to most of the criterion standards. It correlated more strongly with physical disability at follow-up and was more responsive to improvement defined according to the ACR20 and ACR50 definitions. We conclude that a performance-based physical function scale extracted from three RFTs has acceptable distributional and measurement properties and is responsive to clinically meaningful change. It provides a parsimonious scale to measure global physical function in RA.

A model of impairment and functional limitation in rheumatoid arthritis

BackgroundWe have previously proposed a theoretical model for studying physical disability and other outcomes in rheumatoid arthritis (RA). The purpose of this paper is to test a model of impairment and functional limitation in (RA), using empirical data from a sample of RA patients. We based the model on the disablement process framework.MethodsWe posited two distinct types of impairment in RA: 1) Joint inflammation, measured by the tender, painful and swollen joint counts; and 2) Joint deformity, measured by the deformed joint count. We hypothesized direct paths from the two impairments to functional limitation, measured by the shirt-button speed, grip strength and walking velocity. We used structural equation modeling to test the hypothetical relationships, using empirical data from a sample of RA patients recruited from six rheumatology clinics.ResultsThe RA sample was comprised of 779 RA patients. In the structural equation model, the joint inflammation impairment displayed a strong significant path toward the measured variables of joint pain, tenderness and swelling (standardized regression coefficients 0.758, 0.872 and 0.512, P ≤ 0.001 for each). The joint deformity impairment likewise displayed significant paths toward the measured upper limb, lower limb, and other deformed joint counts (standardized regression coefficients 0.849, 0.785, 0.308, P ≤ 0.001 for each). Both the joint inflammation and joint deformity impairments displayed strong direct paths toward functional limitation (standardized regression coefficients of -0.576 and -0.564, respectively, P ≤ 0.001 for each), and explained 65% of its variance. Model fit to data was fair to good, as evidenced by a comparative fit index of 0.975, and the root mean square error of approximation = 0.058.ConclusionThis evidence supports the occurrence of two distinct impairments in RA, joint inflammation and joint deformity, that together, contribute strongly to functional limitations in this disease. These findings may have implications for investigators aiming to measure outcome in RA.