Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


Age at Onset and Comorbidities Correlate with the Health Assessment Questionnaire and Clinical Disease Activity Index (CDAI) Responses to Etanercept in Rheumatoid Arthritis Patients.

Shim6,  Man R., Paulus1,  Harold E., Chaudhari3,  Sandeep, Feng2,  JingYaun, Elashoff4,  David A., Ranganath5,  Veena K.

Encino, CA
Amgen
Kforce Clinical Research/Amgen
UCLA
UCLA School of Med Rehab 32–59, Los Angeles, CA
UCLA/ VA Greater Los Angeles Healthcare System, Los Angeles, CA

Objective:

To investigate the influence of age of onset of rheumatoid arthritis (RA) and comorbidities on the health assessment questionnaire and clinical disease activity index (CDAI) responses in patients with active RA after 6 months of treatment with etanercept (ETN).

Methods:

A cohort of 1,960 RA patients enrolled in the RA Disease-Modifying Anti-Rheumatic Drug (DMARD) Intervention and Utilization Study (RADIUS) 2 met the following inclusion criteria: initiated ETN, continued therapy for at least 6 months, and were not in remission at baseline (CDAI <= 2.8). Seventeen patient-reported comorbidities were recorded at baseline, and patients were classified by five quintiles of age of onset, <32, 32–41, 42–48, 49–55, and >55 years. Changes in HAQ and CDAI scores over 6 months were analyzed across the age categories using ANOVA. Linear and logistic regression models were constructed to evaluate the independent association between age of onset and number of comorbidities with change in HAQ/CDAI scores or achieving low disease activity (CDAI<10) after accounting for other covariates.

Results:

Seventy-seven percent of patients were female, average age was 44 yrs, mean disease duration was 8.6yrs and average CDAI was 35.6. Baseline tender joint count and CDAI were statistically different across the age quintiles (Bsl CDAI grp1 33.9, grp2 35.5, grp3 35.4, grp4 37.2, grp5 36.3), however not clinically different. HAQ, patient global, physician global, swollen joint count and pain visual analogue scales (VAS) were similar across the age groups at baseline. Improvement in HAQ and CDAI scores after at least 6 months of treatment was not clinically different across the age groups, although both were statistically different across age. The results of the multiple linear regression model demonstrated that younger age at onset, higher baseline HAQ/CDAI score, positive rheumatoid factor, shorter disease duration, male gender, and fewer comorbidities at baseline were independently associated with both improvement in HAQ and CDAI. Similarly, achieving CDAI low disease activity after treatment with ETN for at least 6 months, was associated with younger age of onset, lower baseline CDAI, shorter disease duration, male gender, and fewer comorbidities (Table 1).

Table 1. Regression Models for Change in HAQ, Change in CDAI and CDAI Low Disease Activity

 Change in HAQChange in CDAICDAI Low Disease Activity
 Beta-Coeff (SE)p-valueBeta-Coeff (SE)p-valueOR (95% CI)p-value
Age at onset (yrs)0.01 (0.00)<0.00010.06 (0.02)0.01901.01 (1.00–1.02)0.0027
Baseline CDAI/HAQ-0.29 (0.02)<0.0001-0.68 (0.02)<0.00011.04 (1.03–1.04)<0.0001
Baseline Off Prednisone0.02 (0.02)0.52220.33 (0.58)0.57041.09 (0.89–1.33)0.4063
Baseline Negative RF0.08 (0.03)0.00951.79 (0.68)0.00871.21 (0.96–1.53)0.1105
Disease Duration0.01 (0.00)<0.00010.10 (0.04)0.00791.02 (1.00–1.03)0.0083
Gender (Female)0.08 (0.03)0.00831.22 (0.68)0.00741.35 (1.07–1.71)0.0116
# Comorbidities0.05 (0.01)0.00031.20 (0.32)0.00021.18 (1.06–1.32)0.0037
Race (Non-White)0.00 (0.03)0.89850.99 (0.76)0.19331.23 (0.94–1.59)0.1260

Conclusion:

In a large prospective cohort of RA patients who received at least 6 months of ETN therapy, younger age of onset and fewer comorbidities were associated with HAQ/CDAI improvement and with CDAI low disease activity after adjusting for other clinically relevant variables. These results confirm the importance of the number of reported comorbidities and age of onset in impacting RA response to anti-TNF treatment, and suggest that physicians should consider these factors when initiating therapy.

To cite this abstract, please use the following information:
Shim, Man R., Paulus, Harold E., Chaudhari, Sandeep, Feng, JingYaun, Elashoff, David A., Ranganath, Veena K.; Age at Onset and Comorbidities Correlate with the Health Assessment Questionnaire and Clinical Disease Activity Index (CDAI) Responses to Etanercept in Rheumatoid Arthritis Patients. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1789
DOI: 10.1002/art.29554

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