Cross-cultural adaptation of a brief outcome questionnaire for Spanish-speaking arthritis patients

Measurement properties of the Michigan hand outcomes questionnaire: Rasch analysis of responses from a traumatic hand injury population

PURPOSE

This study aimed to use Rasch analysis to test the content, scoring, and measurement properties of the Michigan Hand Outcomes Questionnaire (MHQ).

METHODS

MHQ scores from 196 patients with hand and wrist conditions were collected in an outpatient hand rehabilitation facility. Rasch analysis was conducted to assess the fit statistics of MHQ to confirm the scaling structure of disability subscales, and to identify differential item functioning.

RESULTS

The MHQ did not fit with the Rasch model (χ² = 2376.78, df = 74, p < 0.001), and most thresholds of item responses were disordered. The original scoring algorithm derived from 5-point Likert response options was adjusted to 3-point Likert (10 items) and 4-point Likert (11 items) based on the visual inspection of the thresholds map. Differential item functioning was present in the revised scale based on the age, sex, and dominant hand. Only 3 revised subscales of the MHQ including activities daily living (one hand), aesthetics, and satisfaction showed acceptable fit to the Rasch model. Unidimensionality was achieved in all revised subscales.

CONCLUSIONS

The overall MHQ had a substantial misfit from the Rasch model. Despite efforts of item reduction and rescoring, we did not reach a satisfactory solution. This calls into question the validity of the statistical evaluations performed on this scale using the traditional scoring.Implications for rehabilitationThe MHQ was designed to measure different dimensions of pain and disability but demonstrates multiple measurement problems that undermine it use in present form.It is not appropriate to sum all 37 items of the MHQ into a single score.Three subscales of activities daily living (one hand), aesthetics, and satisfaction can provide unidimensional subscales scores with interval level scaling if scored with our proposed Rasch-based revised scoring.The 27-item version of the MHQ is shown to have strong psychometric properties for administration with patients with hand injuries; however, it requires further validation.

Carotid atherosclerosis in patients with rheumatoid arthritis and rheumatoid nodules

OBJECTIVE

To determine whether an association exists between the presence of rheumatoid nodules and thickening of the intima-media and plaque of the carotid artery, which is evidence of atherosclerosis.

MATERIALS AND METHODS

Observational, cross-sectional study of 124 patients with rheumatoid arthritis from a University Hospital clinic from 2005 to 2006. We divided the patients into 2 groups, 62 with rheumatoid nodules and 62 without rheumatoid nodules, matched for age and sex. Medical history, erythrocyte sedimentation rate, anti-cyclic citrullinated peptide, rheumatoid factor, and a high resolution doppler ultrasound of the carotid arteries were performed.

RESULTS

Women comprised 89.5% of the patients. The prevalence of a carotid plaque was 57% in our population. The presence of a plaque was associated with age, arterial hypertension and abdominal circumference. Average intima-media thickness (IMT) in patients with a plaque was 0.085 cm (± 0.02). There was no correlation between laboratory parameters and thickening of the intima-media of the carotid artery. Subcutaneous nodules were present in 33 (47%) of the 70 patients with a carotid plaque and in 29 (54%) of patients without a carotid plaque (p=.471).

CONCLUSIONS

We did not find an association between rheumatoid nodules and the presence of a carotid plaque and thickening of the intima-media of the carotid in patients with rheumatoid arthritis.

Reactions to disability in patients with early versus established rheumatoid arthritis

OBJECTIVES

This study examined differences in reactions to disability between early and established rheumatoid arthritis (RA) patients, and whether these reactions were related to age, physical functioning, acceptance of illness, or self-efficacy.

METHODS

Thirty-four patients with early RA (< 2 years since diagnosis) and 84 patients with established RA (> 4 years since diagnosis) completed the Reactions to Impairment and Disability Inventory (RIDI), and measures of anxiety, depression, acceptance of illness, self-efficacy, and physical functioning.

RESULTS

Early RA patients reported greater future denial than established RA patients. Younger patients reported more hostility than older patients. Accepting the illness was uniquely related to less anger and hostility. Higher self-efficacy for pain specifically related to greater shock, while patients with poorer self-efficacy for other symptoms reported worse anxiety, depression, shock, and anger.

CONCLUSIONS

Denial may be a coping strategy in the early stages of RA: anxiety, depression, shock, and anger appear to persist. Longitudinal studies of RA patients from diagnosis are required to plan interventions timed to maximize patient benefit and optimize healthcare resource utilization.

Psychological well-being across 1 year with rheumatoid arthritis: coping resources as buffers of perceived stress

OBJECTIVES

Using the transactional model of stress and coping, the present study investigated whether specific coping resources act as buffers of the relationship between perceived stress and psychological well-being among rheumatoid arthritis (RA) patients.

DESIGN

A longitudinal observational study was carried out with assessments at baseline, 6 months and 1 year.

METHODS

Measures of perceived stress, coping resources (optimism/pessimism, social support and explicit active coping strategies) and psychological well-being (anxiety, depression and life satisfaction) were completed by 134 RA patients. Demographics, RA duration, pain, fatigue, functional disability, antidepressant use and physical comorbidities were recorded and statistically controlled for.

RESULTS

Perceived stress had the strongest relationship with psychological well-being at baseline, and affected anxiety after 6 months. Optimism and pessimism predicted psychological well-being across 1 year. Active behavioural coping buffered an association of stress with depression at baseline, while baseline active cognitive coping buffered the effect of baseline stress on life satisfaction after 6 months.

CONCLUSIONS

Patients with RA under greater perceived stress who do not use active coping strategies appear to be at risk of psychological comorbidity and may therefore benefit from interventions teaching specific active coping strategies. Larger observational studies and interventions are required to confirm and extend these findings.

The relationship of medical, demographic and psychosocial factors to direct and indirect health utility instruments in rheumatoid arthritis

OBJECTIVES

Cost-effectiveness analysis (CEA) is essential for the comparison of treatments for rheumatoid arthritis (RA). CEA centres on accurate measurement of health utility (HU) preferences. Direct measures of HU in RA patients demonstrate weaker correlations with health status (functional disability and pain) than indirect measures. We examined whether demographic and psychosocial factors relate to HU in RA patients.

METHODS

HU was measured for 142 RA patients (76% women; mean age 58.75 yr) directly through standard gamble (SG) and time trade-off (TTO), and indirectly on the EuroQol (EQ-5D). Current pain (100 mm visual analogue scale) and recent functional disability (Health Assessment Questionnaire; HAQ) were assessed. A subsample of 48 provided demographic and psychosocial information (education, employment, marital/family status, knowledge about RA, medication beliefs, desirable responding, social support, optimism, and the Hospital Anxiety and Depression Scale; HADS).

RESULTS

Direct HU had higher means (SG = 0.88, TTO = 0.86) than indirect HU (EQ-5D = 0.52). HAQ functional disability correlated with SG (r = - 0.28), TTO (r = - 0.31) and EQ-5D (r = - 0.67). Current pain correlated with TTO (r = - 0.19) and EQ-5D (r = - 0.36). HADS depression correlated with TTO (r = - 0.35) and EQ-5D (r = - 0.64); HADS anxiety also correlated with EQ-5D (r = - 0.46).

CONCLUSIONS

Demographic and psychosocial factors cannot completely explain either the significant differences between direct and indirect HUs in RA patients or the moderate correlations of direct HUs with health status. Characteristics of the SG and TTO may make them inappropriate for HU assessment and CEA among RA patients.

Latent variable approach to the measurement of physical disability in rheumatoid arthritis

OBJECTIVE

To measure physical disability in rheumatoid arthritis (RA) using a latent variable derived from a generic and a disease-specific self-reported disability instrument and an observer-assessed functional status scale.

METHODS

Consecutive patients with RA completed the modified Health Assessment Questionnaire (M-HAQ) and the Short Form 36 (SF-36) physical function scale. An observer assigned a Steinbrocker functional classification. We used principal component factor analysis to extract a latent variable from the 3 scales. We used the Bayesian Information Criterion to compare how well the new latent variable and the 3 primary scales fit the criterion standards of current work status; vital status at 6 years; grip strength; walking velocity; the timed-button test; pain; and joint tenderness, swelling, and deformity.

RESULTS

Complete data were available for 776 RA patients. The extracted latent variable explained 75% of the variance in the 3 primary scales. On a scale of 0-100, higher scores representing less disability, its mean +/- SD was 56.4 +/- 22.5. Correlation between the latent variable and the M-HAQ was -0.87; between the latent variable and SF-36 physical function scale was 0.89, and between the latent variable and Steinbrocker class was -0.85. Multivariate models that included the latent variable had superior fit than did models containing the primary scales for the criteria of current working; death by 6 years; pain; joint tenderness, swelling, or deformity; grip strength; walking velocity; and timed button test.

CONCLUSION

A latent variable derived from the M-HAQ, the SF-36 physical function scale, and the Steinbrocker functional class provides a parsimonious scale to measure physical disability in RA. The fit of the latent variable to comparison standards is equivalent or superior to that of the primary scales.

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 scale's 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 Guyatt's 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.

Association of mortality with disease severity in rheumatoid arthritis, independent of comorbidity

OBJECTIVE

To measure the extent to which mortality in rheumatoid arthritis (RA) is associated with disease severity, independent of the presence of coexistent diseases (comorbidity).

METHODS

We measured disease severity and comorbidity among RA patients attending scheduled appointments at a rheumatology clinic. We used the Duke Severity of Illness Checklist (DUSOI), a clinical judgment-based measure of the severity of disease. We disaggregated the DUSOI into an RA component (RADUSOI), which we used to measure RA disease severity, together with a physician-rated 10-point global RA severity assessment. We measured comorbidity using the non-RA component of the DUSOI (COMDUSOI) and using the Charlson Comorbidity Index. Patients were contacted periodically for up to 6 years, during which we recorded deaths. We estimated the effect of disease severity and comorbidity on mortality using Kaplan-Meier survival curves, Cox proportional hazards models, and logistic regression with receiver operating characteristics (ROC) curve analysis.

RESULTS

The sample comprised 779 patients. Followup ranged from 0.1 year to 6.3 years (mean 2.52 years), for an observation period of 2,315 patient-years. Seventy-five patients died (9.6%), for a total mortality of 3.2 per 100 patient-years (95% confidence interval 2.6-4.1). Both disease severity and comorbidity displayed significant bivariate associations with mortality. In multivariate Cox models adjusted for age, sex, and disease duration, the RADUSOI and global RA severity scores were associated with mortality independent of either the COMDUSOI or Charlson Comorbidity scores. The area under the ROC curve for a logistic model on mortality increased from 0.79 with age, sex, and disease duration included, to 0.84 after adding RA severity and comorbidity (P < or = 0.005 for the increase in ROC area).

CONCLUSION

RA disease severity is significantly associated with mortality regardless of the presence of comorbid disease. Combined with each patient's age, sex, and disease duration, information on RA severity and comorbidity allows an accurate prediction of mortality among patients with RA.

The Impact of Disease Activity on the Quality of Life, Mental Health Status, and Family Dysfunction in Colombian Patients With Rheumatoid Arthritis

This study investigated the relationship between activity of disease, mental health status, quality of life, and family dysfunction in northwestern Colombian patients with rheumatoid arthritis (RA). Seventy-nine patients completed a 2-phase study that included physical examination (objective measurement of disease activity according to adapted American College of Rheumatology criteria) and a pretested questionnaire that sought information on helplessness, disability, depression, anxiety, quality of life, arthritis self-efficacy for pain, and other symptoms, as well as family dysfunction and socioeconomic status. Nineteen patients (24%) had active RA, 48 (61%) had moderately active RA, and 12 (15%) were in remission. Symptoms of depression, helplessness, disability, pain, anxiety, lower quality of life, and self-efficacy were associated with RA activity regardless of age, sex, and duration of the disease. Symptoms of depression were directly correlated with anxiety, helplessness, pain, and disability and inversely correlated with quality of life and self-efficacy. Although family dysfunction was present in 39% of patients, no associations between family dysfunction, activity of RA, mental health variables, socioeconomical status or quality of life were observed. These results indicate that RA activity significantly influences mental health status and quality of life in this population. Accordingly, a holistic conception of therapy should guide the treatment of patients with RA.

Puerto Rican understandings of child disability: methods for the cultural validation of standardized measures of child health

Validating the cultural context of health is important for obtaining accurate and useful information from standardized measures of child health adapted for cross-cultural applications. This paper describes the application of ethnographic triangulation for cultural validation of a measure of childhood disability, the Pediatric Evaluation of Disability Inventory (PEDI) for use with children living in Puerto Rico. The key concepts include macro-level forces such as geography, demography, and economics, specific activities children performed and their key social interactions, beliefs, attitudes, emotions, and patterns of behavior surrounding independence in children and childhood disability, as well as the definition of childhood disability. Methods utilize principal components analysis to establish the validity of cultural concepts and multiple regression analysis to identify intracultural variation. Findings suggest culturally specific modifications to the PEDI, provide contextual information for informed interpretation of test scores, and point to the need to re-standardize normative values for use with Puerto Rican children. Without this type of information, Puerto Rican children may appear more disabled than expected for their level of impairment or not to be making improvements in functional status. The methods also allow for cultural boundaries to be quantitatively established, rather than presupposed.

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.

The Spanish version of Skindex-29

BACKGROUND

Most currently available dermatologic quality-of-life measures were originally created in English, and must be translated and adapted for use in other cultures. Our purpose was to translate and adapt culturally into Spanish a skin-related quality-of-life measure, Skindex-29, and to begin preliminary assessments of its reliability and validity.

METHODS

Transcultural adaptation and cross-sectional questionnaire studies were performed. One hundred and fourteen adult persons (patients and healthy people) responded to the Spanish version of Skindex-29. Evaluations of the semantic equivalence of back-translated items, reliability, construct validity, and content validity of the Spanish version were the main outcome measures. Comparison between Spanish and American responses was also performed.

RESULTS

Six problematic items required a second translation and back-translation to achieve satisfactory agreement with the original instrument. The final Spanish version of Skindex-29 was internally reliable (range of Cronbach alpha for the scales, 0.70-0.87). The instrument demonstrated both construct and content validity. As hypothesized, scores for dermatologic patients were higher than those for healthy persons (mean global scores 21 vs. 5, P < 0.01) and scores for patients with inflammatory diseases were higher than those for persons with isolated skin lesions (mean global scores 32 vs. 11, P < 0.01), indicating a poorer quality of life. In addition, most patients' responses to an open-ended question about their skin disease were addressed by items in the instrument. Skindex scale scores of American and Spanish respondents were similar.

CONCLUSIONS

We have developed a semantically equivalent translation of Skindex-29 into Spanish. Our preliminary evaluation of its measurement properties suggests that it is a reliable and valid measure of the effects of skin disease on the quality of life in Spanish patients.

Examination adaptation: translating the national nurse-midwifery/midwifery certification examination

The national certification examination in nurse-midwifery/midwifery was adapted to the Puerto-Rican Spanish language. Specific attention was paid to creating a version of the examination that was both culturally and linguistically relevant, while remaining appropriately representative of national standards of practice. The procedures used in translation and cultural adaptation are described. The process used in review of the examination followed usual and customary practice. This included consideration of item critiques received from candidates (qualitative data) and the computation of standard measures of item performance, including item difficulty indices and the standard error of measurement (quantitative data). Additional analyses conducted for this specific purpose included the calculation of an index of differential item performance between both language versions. All measures of assessment indicated that the adapted language version was of high quality and psychometrically equivalent to the English language version, which was the comparison standard.

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.

Cross-cultural equivalence of a brief helplessness scale for Spanish-speaking rheumatology patients in the United States

OBJECTIVE

To show evidence of the cross-cultural equivalence between the original English version of a 5-item scale for measuring helplessness and a translated Spanish version.

METHODS

English and Spanish versions of the 5 items that constitute the helplessness factor of the Rheumatology Attitudes Index were tested in 3 separate groups of patients: 1) 20 bilingual rheumatology patients; 2) 100 consecutive English- and 50 consecutive Spanish-speaking monolingual rheumatology patients; and 3) 192 English- and 44 Spanish-speaking patients with rheumatoid arthritis who were consecutively enrolled in a cohort to study disease outcomes. English-Spanish concordance among bilingual subjects was measured using intraclass correlation coefficients (ICC). Internal consistency was measured by Cronbach's coefficient alpha. Associations between the helplessness scale and variables measured simultaneously in English- and Spanish-speaking patients were measured by correlation analysis.

RESULTS

Agreement between the English and Spanish versions of the helplessness scale among bilingual subjects was excellent (ICC = 0.87), and internal consistency among monolingual subjects was acceptable (coefficient alpha = 0.73 in English and 0.87 in Spanish). The correlation between helplessness and most other measured variables was of similar size and direction in English as in Spanish (10-point pain scale r = -0.53 and -0.52; modified Health Assessment Questionnaire physical disability r = -0.45 and -0.43; self-assessed joint count r = 0.36 and 0.36; Medical Outcomes Study Short Form 36 [SF-36] physical function r = 0.37 and 0.39; SF-36 mental health r = 0.27 and 0.35; Center for Epidemiological Studies Depression scale r = -0.37 and -0.33, respectively).

CONCLUSION

The evidence shown supports the cross-cultural equivalence between the original 5-item helplessness scale developed in English and our translated Spanish version.

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 group's 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.

Translation to Spanish, reproducibility, and cross-cultural adaptation of the Miller-Rahe Recent Life Change Questionnaire in Venezuela

OBJECTIVE

To translate into Spanish a version of the Miller-Rahe Recent Life Change Questionnaire and to adapt it to Venezuelan cultural values.

METHODS

The Spanish version and cross-cultural adaptation of the Miller-Rahe Recent Life Change Questionnaire was done following recently proposed guidelines to preserve semantic, idiomatic, and conceptual equivalence in translations of health assessment instruments. We performed one or more translations into the new language, as well as back-translation, test-retest reliability, and weighting score for the translated instrument.

RESULTS

A Spanish version of the Recent Life Change Questionnaire was obtained. Validity of translations was demonstrated with a significant agreement for the nonliteral translations (kappa value = 0.97, P < 0.05). The conceptual equivalence was demonstrated by significant agreement in the back-translations (kappa value = 0.84, P < 0.05). The translated instrument met acceptable levels of reliability, as assessed by Spearman's rank correlation coefficients (> 0.60 for all categories of the questionnaire). The cross-cultural adaptation of the translated instrument required addition and exclusion of items as well as changes of the ranking and scaling of life units in the original questionnaire.

CONCLUSION

A valid and reliable Spanish version of the Miller-Rahe Recent Life Change Questionnaire was produced and adapted to Venezuelan cultural values.

HLA-DRB1 alleles associated with susceptibility or resistance to rheumatoid arthritis, articular deformities, and disability in Mexican Americans

OBJECTIVE

To study the genetics (HLA-DRB1 allele associations) of rheumatoid arthritis (RA) susceptibility and severity among Mexican Americans, an important, but understudied, US population.

METHODS

HLA-DRB1 alleles were compared between 141 Mexican American patients with RA and 54 unrelated Mexican Americans without RA, and the association of these alleles with articular deformities and disability was examined. HLA-DRB1 alleles were typed using polymerase chain reaction-sequence-specific primer amplification and were classified according to the 1996 World Health Organization nomenclature.

RESULTS

Of the 141 patients, 105 (74%) had at least 1 copy of the shared epitope (SE) sequence, compared with 29 (54%) of the 54 controls (P = 0.007). A significant gene-dose effect was observed, with 31 patients (22%) being homozygous for the SE compared with 1 (2%) of the controls (P = 0.004). In terms of disease severity, only 3% of RA patients who were "null" for the SE were outliers in the rate of development of articular deformities, compared with 10% of heterozygotes and 27% of homozygotes (P = 0.002). Patients who were DRB1*08 positive had significantly fewer deformities per year of disease and a slower rate of development of disability than did patients with other DRB1 alleles.

CONCLUSION

HLA-DRB1 alleles containing the SE are associated with susceptibility to RA in Mexican Americans, and may also be associated with a more rapid development of articular deformities and disability. HLA-DRB1*08 appears to have a protective influence on RA susceptibility and disease severity in Mexican Americans.

What do self-administered joint counts tell us about patients with rheumatoid arthritis?

OBJECTIVE

This report presents data from two sources showing that a self-administered joint count (SAJC) suitable for use in clinical settings provides information comparable with that of observer-assessed joint counts.

METHODS

Patients were tested with a 1-page form containing a 40-joint mannequin on which they could mark their painful or swollen joints. The first sample of 110 patients was used to compare the SAJC with the tender or swollen joint counts (TJC or SJC) performed by a rheumatologist and to a battery of clinical and laboratory measurements. The second sample consisted of 240 rheumatoid arthritis (RA) patients enrolled in a cohort study of RA outcomes, in whom the relationship between the SAJC and health-related quality of life measures was examined.

RESULTS

Test-retest reliability of the SAJC was excellent (ri = 0.89), as was its agreement with the observer-assessed TJC (ri = 0.78). The SAJC was significantly correlated (P < or = 0.01) to pain on a 10-point scale (r = 0.33), the McGill Pain Questionnaire (r = 0.27), the pain subscale of the Arthritis Impact Measurement Scales (AIMS) (r = 0.32), the duration of morning stiffness (r = 0.27), and to the AIMS subscales of physical function (r = 0.20), impact (r = 0.31), and global health (r = 0.29). The SAJC was inversely related to formal education (r = -0.32), but did not correlate significantly with the modified Health Assessment Questionnaire, walking velocity, grip strength, or erythrocyte sedimentation rate. The responsiveness of the SAJC was comparable with that of other measures commonly employed to assess RA outcomes. Either the SAJC or the TJC could be included alternatively in multivariate models to explain 7 of the 8 subscales of the Medical Outcomes Study Short Form-36 (SF-36) questionnaire.

CONCLUSION

The SAJC is a reliable and responsive measure that agrees highly with the observer-assessed TJC and is significantly associated to the health-related quality of life of patients with RA. Given its low cost and ease of administration, it is suggested that SAJC be included in future studies of RA outcome in routine clinical practice.

Measuring chronic rheumatic pain in Mexican Americans: cross-cultural adaptation of the McGill Pain Questionnaire

We performed a cross-cultural adaptation of the McGill Pain Questionnaire (MPQ) from English to Spanish for studying Mexican Americans in South Texas. Each of the 78 single-word pain descriptors in the original MPQ was translated into Spanish by a panel of nine bilingual health researchers, preserving the original structure of the questionnaire. The pain-intensity content (PIC) of the words in each language was then rated on a 100 mm visual analog scale by 8 bilingual health care providers and 10 bilingual health-care consumers. The correlation between Spanish and English average PIC ratings was strong (r = 0.85 for providers, r = 0.80 for consumers). The translated Spanish version was compared to the original English in a group of 50 bilingual Mexican-American patients with musculoskeletal pain, who completed the MPQ in both languages. There was no difference in Average Pain Rating Index between the Spanish and English versions (29.8 +/- 14.7 vs 29.1 +/- 15.8, p = 0.55), and agreement between the two language versions was almost perfect (ri = 0.85). Test-retest reliability was measured in two groups of hospitalized patients (25 per group), one composed of monolingual Spanish speakers and the other of monolingual English speakers. Each subject completed the MPQ, the McGill Pain Map, two 10-cm visual analog scales measuring pain now and within the past week, the bodily pain items of the MOS-SF36 survey, and the Modified Health Assessment Questionnaire, on two occasions one day apart. Test-retest reliability of the Spanish and English components of the MPQ was not significantly different and was comparable to that of the other pain and health status instruments. We conclude that the Spanish MPQ is cross-culturally equivalent to the original English and has similar concurrent validity and reliability. This questionnaire is suitable for cross-cultural studies of pain comparing Spanish-speaking Mexican Americans with English-speaking members of the same and other ethnic groups.