Purpose: �Real world drug utilization studies among biologic-treated Rheumatoid Arthritis (RA) patients may be confounded by differences in clinical, demographic, socioeconomic, or behavioral characteristics� This study describes key demographic/clinical differences observed between patients treated with adalimumab (ADA); etanercept (ETA); and golimumab (GLM).
Method: The Optum Insight Clinformatics dataset was used to identify adult patients with �≥60 days supply of their assigned biologic medication, ≥ 2 claims with RA diagnoses (ICD-9:� 714.xx) and ≥24 months of continuous medical and pharmacy eligibility. Assignment to an index group ( ADA, ETA or GLM) was based upon the most recent biologic used during the enrollment period (1/1/ 2009 to 3/31/2011). Demographic and clinical characteristics were summarized for the year prior to the index date using descriptive statistics.
Result: � A total of 2,222 ADA; 3,168 ETA, and 347 GLM patients met inclusion criteria.� The GLM group was younger than the ETA group (p < .0005;); and had more female patients, a higher proportion of patients with cerebrovascular disease ,osteoarthritis,hypertension depression, chronic pain, (p's < .05) and a higher proportion with prior biologic medication use (p's < .0001) compared to both ADA and ETA groups; see TABLE. Likewise, in the pre-index year, total RA-specific and non-RA health care costs were higher for GLM patients compared to the other groups. (p's < .001); see TABLE.
TABLE:� Pre-Index Demographic and Clinical Characteristics and Related Costs | ||||
Variable | ADA | ETA | GLM | omnibus test p value |
n = 2222 | n = 3168 | n = 347 | ||
Characteristics | % | % | % |
|
Female | 75.2% | 74.6% | 81.3% | 0.023 |
< age 65 years | 91.7% | 89.4% | 93.4% | 0.003 |
Prior Biologic Use | 15.4% | 8.0% | 60.5% | 0.000 |
Cerebrovascular Disease | 2.9% | 2.9% | 5.5% | 0.029 |
Osteoarthritis | 55.7% | 52.9% | 64.8% | 0.000 |
Hypertension | 35.5% | 34.4% | 42.1% | 0.017 |
Depression | 10.3% | 8.8% | 15.3% | 0.000 |
Chronic Pain | 4.0% | 3.6% | 9.2% | 0.000 |
Costs | Mean | Mean | Mean |
|
RA-specific Costs | $14,631 | $14,020 | $18,691 | 0.000 |
Non RA-specific Costs | $16,962 | $16,823 | $25,241 | 0.000 |
Conclusion: � The GLM group was younger, sicker, and incurred greater total health care costs compared to the ADA and ETA groups.� These findings suggest that direct comparison of patients using these products is confounded with pre-index disease severity and other indicators.� Research studies adjusting for patient differences should be employed when studying overall drug utilization patterns or healthcare costs.