Evaluation of the clinimetric properties of the Early Inflammatory Arthritis--self-administered comorbidity questionnaire.

OBJECTIVES: To adapt the self-administered comorbidity questionnaire (SCQ) into the Early Inflammatory Arthritis-SCQ (EIA-SCQ) and assess its clinimetric properties in EIA. METHODS: The EIA-SCQ and indices of disease activity, function, pain, health-related quality of life (HRQoL) and health resource utilization were administered to 320 patients with EIA. Twenty patients completed the EIA-SCQ a second time 1 week later. Construct validity was evaluated by testing the hypotheses that a valid comorbidity index would correlate well with age, weakly with HRQoL and recent resource utilization and poorly with indices of disease activity, function and pain. RESULTS: The intra-class correlation coefficient between repeat scores was 0.93 (95% CI 0.83-0.97). Kappa values for individual items ranged from 0.64 to 1.0. EIA-SCQ scores correlated moderately with age (Tau B = 0.29, P < 0.001) and weakly with function (HAQ-DI Tau B = 0.09, P = 0.03), pain (McGill Pain Questionnaire Tau B = 0.09, P = 0.05), some measures of HRQoL [the SF-36 mental component score (MCS) Tau B = - 0.08, P < 0.05; World Health Organization Disease Assessment Schedule II score Tau B = 0.09, P = 0.03] and a measure of resource utilization (number of tests in the last 4 months Tau B = 0.10, P = 0.04). The EIA-SCQ did not correlate with other measures of disease activity, another HRQoL measure [SF-36 physical component score (PCS)] or other measures of resource utilization. CONCLUSIONS: The EIA-SCQ is reliable and valid for use in EIA. It has the potential to become a useful measure of comorbidity in outcome studies of EIA when the resources for a full medical chart review are unavailable.

Symptoms of depression predict the trajectory of pain among patients with early inflammatory arthritis: a path analysis approach to assessing change.

OBJECTIVE: To assess the longitudinal relationships, including directionality, among chronic pain, symptoms of depression, and disease activity in patients with early inflammatory arthritis (EIA). METHODS: One hundred eighty patients with EIA completed an examination, including swollen joint count, and were administered the Center for Epidemiological Studies Depression Scale (CES-D) and the McGill Pain Questionnaire (MPQ) at 2 timepoints 6 months apart. Cross-lagged panel path analysis was used to simultaneously assess concurrent and longitudinal relationships among pain, symptoms of depression, and number of swollen joints. RESULTS: Pain, symptoms of depression, and number of swollen joints decreased over time (p < 0.001) and were prospectively linked to pain, symptoms of depression, and number of swollen joints, respectively, at 6 months. Symptoms of depression and pain were correlated with each other at baseline (0.47) and at 6-month followup assessments (0.28). Baseline symptoms of depression significantly predicted pain symptoms at 6 months (standardized regression coefficient = 0.28, p = 0.001), whereas pain and disease activity did not predict the course of any other variable after controlling for baseline values. CONCLUSION: Symptoms of depression predicted the trajectory of pain from baseline to 6 months. In addition, there were reciprocal/bidirectional associations between pain and symptoms of depression over time. More research is needed to better understand the relationship between pain and depressive symptoms and how to best manage patients with EIA who have high levels of both.

The clinimetric properties of the World Health Organization Disability Assessment Schedule II in early inflammatory arthritis.

OBJECTIVE: To assess the clinimetric properties of a new health-related quality of life (HRQOL) instrument, the World Health Organization Disability Assessment Schedule II (WHODAS II), in patients with early inflammatory arthritis. METHODS: Internal consistency as well as criterion, construct, and discriminative validity of the WHODAS II were assessed in 172 patients with early inflammatory arthritis who completed the WHODAS II, the Medical Outcomes Study Short Form 36 (SF-36), and other measures of disease severity, functioning, pain, depression, and resource use. Test-retest reliability of the WHODAS II was assessed by having a subset of 20 patients complete the WHODAS II a second time, 1 week after the first assessment. RESULTS: The WHODAS II had high internal consistency (Cronbach's alpha = 0.96 for patients working or in school and 0.93 for patients not working or in school). Test-retest intraclass correlation coefficients of the WHODAS II total score and subscales ranged from 0.82-0.96. The WHODAS II total score was strongly correlated with the SF-36 physical component score (Kendall's tau-b 0.51, P < 0.001) and moderately correlated with the SF-36 mental component score (tau-b 0.43, P < 0.001). WHODAS II correlations with disease outcomes ranged from Kendall's tau-b 0.15-0.55. The WHODAS II significantly differentiated between every aspect of disease severity assessed with the exception of measures of health resource use. CONCLUSION: The WHODAS II is a valid and reliable measure of HRQOL in cross-sectional studies of patients with early inflammatory arthritis. Research is still required to investigate potential item redundancy and determine its usefulness in longitudinal studies.