Background/Purpose:

Depression is highly prevalent in
RA. In trials, depression has been found to be associated with higher disease
activity and impaired treatment response. However data are limited and subject to
methodological limitations such as being derived from highly selected trial
populations. Our aim was to examine the long-term association between
depression and RA disease outcomes in routine care.

Methods:

Data were collected using
electronic records from an inner city hospital in London, UK. The presence of
depression/anxiety was identified using PHQ9 and GAD7 respectively. Patients
were included in this analysis if they had completed a PHQ9/GAD7 on at least 2
occasions. The first ever PHQ9/GAD7 record was taken as the baseline visit.
Follow up included all visit information over the subsequent 12-months. The
relationship between anxiety/depression and DAS outcome was analysed using two
approaches: 1) we calculated the likelihood of an individual achieving
remission during follow up using Cox proportional hazards, adjusted for age,
gender, disease duration and disease activity; 2) we modelled DAS trajectory
using generalised estimating equations (GEE).

Results:

From a total cohort of 1,375, 385
patients were eligible for analysis. The mean age was 59 (SD 15), with 81%
female (see table). At baseline, depression/anxiety were associated with higher
disease activity and disability. The presence of depression/anxiety at baseline
was associated with significantly higher disease activity throughout follow-up
(b= 0.92, SE= 0.15, p<0.001, 95%CI: 0.53 to 1.21), after adjusting for age,
gender and disease duration. Using a GEE model DAS was significantly higher for
patients with anxiety or depression (b=.85; 95% CI:.54
to 1.16), but reduced slightly over time (b/year=-.11 95% CI: -.21 to -.01).
This change may reflect more aggressive treatment of patients with anxiety or
depression that have higher DAS, the correlation between a change in DAS and
anxiety or depression status of r=.28. Patients with
baseline anxiety or depression were less likely to attain a state of remission
(adjusted hazard ratio: 0.51, 95%CI: 0.35 to 0.75). 

Conclusion:

Our data reveal a high prevalence
of psychological comorbidity in RA. The presence of depression/anxiety
associated with larger differences in patient reported components of outcomes
(tender joint count, patient global, HAQ) than objective measures. Patients
with baseline anxiety/depression had higher disease activity that remained high
during follow up. Comparing change in DAS over time revealed no material
difference in the DAS trajectory in patients with or without anxiety or
depression. It is clear that psychological factors are linked to the clinical
outcome measures used in rheumatology. However, how depression/anxiety
influence prognosis is unclear.

Table