Patterns of psychosocial risk and long-term outcomes in rheumatoid arthritis

Abstract

This study examined the extent to which patterns of psychosocial risk were uniquely associated with long-term outcomes of rheumatoid arthritis (RA), after demographic factors and self-reported symptom severity over time were accounted for. Data were collected over an 8-year period from 561 individuals with RA who were participants in the ongoing UCSF RA Panel Study in 1995. Panel members were interviewed annually, using a comprehensive structured telephone interview. Psychosocial factors assessed included mastery, perceptions about adequacy of social support, the impact of RA and self-assessed ability to cope with RA and satisfaction with health and function. Cluster analysis of psychosocial factors identified three distinctive patterns/levels of psychosocial risk (high, medium and low risk). The unique effects of psychosocial risk status on changes in depressive symptoms, basic functional limitations, global pain ratings and average annual doctor visits over an 8-year period were estimated, using growth curve analyses. Analyses controlled for demographic factors (gender, marital/partner status, education, age and ethnicity), disease duration and year in the panel and time-varying self-reported symptom severity (morning stiffness, swollen joint counts, co-morbid medical conditions, extra-articular RA symptoms and changes in joint appearance), as well as self-reported medications taken over time (disease-modifying antirheumatic drugs [DMARDS], and prednisone). Overall, 32.4% of total variance in depressive symptoms was accounted for by the fully-estimated model, with 12.9% uniquely associated with psychosocial risk status. Half of the total variance (50.0%) in basic functional limitations was explained, with 12.1% of variance uniquely predicted by psychosocial risk status. Psychosocial risk status accounted for comparatively little total explained variance in global pain ratings (total = 38.6%, incremental = 3.2%), and average annual total doctor visits (total = 10.9%, incremental = 1.5%). Thus, psychosocial risk factors are more closely linked to depressive symptoms and function over time. Global pain and utilization appear to be more closely related to disease factors.

Estimation of a numerical value for joint damage-related physical disability in rheumatoid arthritis clinical trials

“…The results for f DAM (HAQ/TSS) were similar irrespective of the trial types (observational or RCTs), treatments (glucocorticoids, DMARDs, TNF inhibitors) or patient populations (early or longstanding RA), ranging from 0.007–0.020 HAQ units per TSS unit with a median of 0.0133 (mean: 0.0137). Our method might have overestimated the effect of TSS on DAM-HAQ, because the latter is also influenced by other causes than joint damage 8–10 25. Therefore we obtained a more conservative estimate of f DAM , using the lower quartile of data from BELIRA patients, which corresponded well with the lower quartile obtained in RCT treatment arms, providing the final f DAM of 0.01.…”

“…Therefore, it likely includes also other, unmeasured causes of disability 8–10. Consequently, mean or median f DAM in HAQ/TSS units will overestimate the damage/TSS effects on HAQ.…”

“…The reasons for this simplification were the following: major comorbidities and age over 70 influence the HAQ,25 26 but in the context of the trials studied here major comorbidities had been excluded and mean age ranged from 49–58 years with only few patients above 70 years; also other aspects, such as psychosocial and educational factors, may matter for the HAQ,9 27 but using the current trial dataset patients with no joint damage, when achieving clinical remission, attained a mean HAQ of 0,11 speaking against a major influence of these factors. All these considerations suggested that in the populations studied here the mentioned simplification bears soundness.…”

“…However, since—as broadly discussed earlier—residual disability may partly be related to other reasons than joint damage8–10 25 27 and f DAM may, therefore, overestimate disability if mean values were used, we applied a more conservative approach selecting the value of the first quartile of the data as the final f DAM . In this situation, where the contribution of other measures is unknown but must be predicted to influence the irreversible HAQ and where a strictly linear relationship as modelled may not be fully valid, the lower quartile was deemed an intuitive and straightforward midpoint between the mean or median which, might exaggerate the relationship and the minimum or the 10th percentile, which might underestimate it.…”

“…Indeed, in early RA, disability, measured by Health Assessment Questionnaire Disability Index (HAQ-DI), is correlated with disease activity, whereas correlation with joint damage increases with time 3–7. However, disability is also related to other factors, such as age, psychosocial aspects or comorbidities 8–10. Nevertheless, looking at clinical trial patients attaining stringent remission who have no activity governing disability, the residual HAQ is closely related to joint damage11 and apparently not importantly influenced by other factors.…”