Background/Purpose :
Previous studies in rheumatoid arthritis (RA) have shown that patient
socioeconomic status (SES) impacts patient prognosis. We
hypothesized that public vs. private healthcare coverage would be a surrogate
of low SES. The aim of this analysis was to assess the association between
patient health insurance coverage and disease parameters with emphasis on functional
activity in RA patients initiating treatment with anti-TNF agents in Canadian
routine clinical practice.

Methods :
BioTRAC is an ongoing, prospective registry of patients initiating treatment
for RA, ankylosing spondylitis, or psoriatic arthritis with infliximab (IFX) or
golimumab (GLM). Eligible people for this analysis included RA patients treated
with IFX who were enrolled since 2002 or with GLM enrolled since 2010. Independent
predictors of HAQ were identified using generalized linear models.

Results:
A total of 1144 patients were included of whom 598 (52.3%) had public
insurance. Patients with public insurance were older (59.7 vs. 51.8 years;
P<0.001), had longer disease duration (9.3 vs. 7.5 years; P=0.029), and were
more likely to be from British Columbia (81.2% vs. 18.8%) and Manitoba (68.8%
vs. 31.3%) but less likely to be from the Maritimes (30.6% vs. 69.4%)
(P<0.001). With respect to disease activity, patients with public insurance
had higher CDAI (37.3 vs. 30.3; P<0.001), DAS28 (6.0 vs. 5.2; P<0.001),
swollen joint count (11.0 vs. 8.5; P<0.001), tender joint count (12.8 vs.
10.3; P<0.001), patient global (62.1 vs. 55.5; P<0.001), and HAQ (1.74
vs. 1.36; P<0.001).  

Multivariate
analysis adjusting for age (P=0.028), gender (P<0.001), anti-TNF agent (P=0.227),
and CDAI (P<0.001) showed that private insurance type was a significant
independent predictor of lower HAQ (1.28 vs. 1.52; P<0.001). Furthermore,
rheumatology practice was also identified as a significant predictor of HAQ
(P=0.027; Figure 1).

Conclusion:
The results of this analysis suggest that,
upon adjusting for patient demographics and disease activity, significant
variation exists in the HAQ score based on the type of health insurance
coverage and the rheumatology practice which may reflect differences inherent
to the patient SES or to the manner of administration of the HAQ instrument.

Figure
1. Mean (SD) Adjusted HAQ by Participating Site