Anti-TNF Drugs to Treat Rheumatoid Arthritis

Washington, DC—For patients with rheumatoid arthritis (RA), treatment with anti-tumor necrosis factor (anti-TNF) drugs may reduce the need for hip or knee surgeries as well as the need for hospital admissions. Despite the higher costs of these drugs compared to the traditional nonbiologic disease-modifying antirheumatic drugs (DMARDs), anti-TNF drugs may be a cost-effective treatment.

This is suggested by the results of a study presented at the ACR meeting by investigators in Ireland who found a significant reduction in elective surgeries and RA hospital admissions in patients with RA after initiation of anti-TNF therapy in 1999, which coincided with a significant reduction in overall annual costs of RA treatment.

“Despite the high unit cost of anti-TNF drugs, they may, in fact, be cost effective, when used appropriately, given their profound effect on morbidity associated with rheumatoid arthritis,” said Leonard C. Harty, MD, co-investigator of the study and a rheumatologist at St. Vincent’s University Hospital in Dublin, Ireland.

Dr. Harty and colleagues undertook the study to evaluate the potential effect of prescribing anti-TNF therapy for RA on measures of cost and quality of life to contribute to the ongoing debate on whether the benefits of anti-TNF therapy justify its high cost.

Using data from the Hospital In-Patient Enquiry Scheme, a national system in Ireland that records information on hospital bed utilization, the investigators identified and retrospectively reviewed 57,744 patients admitted to 57 hospitals with a diagnosis of RA from 1995 to 2010. Of these patients, 66% were female and the average age was 66 years.

To assess the effect of anti-TNF therapy in this cohort of patients, the investigators analyzed separately the annual prescription data for anti-TNF usage from 2000 to 2010. The annual prescription of anti-TNF therapy increased by 156% per annum from 2389 units in 2000 to 116,747 units in 2010.

The study found a highly significant negative correlation between the prescription of anti-TNF drugs and orthopedic operations for RA patients from 2000 to 2010. There was an average of 550 orthopedic operations for RA prior to 2002 with a subsequent reduction of 10% per annum to an average of 291 in 2010, which represented a 47% decrease in all musculoskeletal surgical procedures.

According to Dr. Harty, this reduction was specifically high for elective hip and knee replacement surgery, which decreased by about 50% from 2002 to 2010. The study found 71 elective hip procedures prior to 2002 with a subsequent reduction of 8% per annum to 40 in 2010, representing a 44% decrease. For knee surgery, 70 procedures were reported prior to 2002 with a subsequent 7% per annum reduction to 37 in 2010, representing a 47% decrease.

Overall, the study found almost 50,000 inpatient days recorded in 2002 and just over 300,000 in 2010, which represented a 13% per annum reduction in inpatient days from 2002 to 2010. According to Dr. Harty, this represents a cost savings of about $20,000,000 in US dollars based on current inpatient hospital costs.

Although the investigators attributed the use of anti-TNF agents after 2000 to these reductions in RA hospital inpatient stays, orthopedic surgeries, and overall cost, they also specified that factors other than anti-TNF usage could have contributed to the improved patient outcomes.

Limitations of the study included the lack of data from 20 private hospitals in Ireland (the study focused on public hospitals), and the lack of data on RA disease duration prior to joint replacement surgery.

According to Dr. Harty, the results seen in this study will likely only expand with longer usage of anti-TNF drugs. “Given the lag effect of newly discovered drugs on a population basis, we are likely only seeing the start of the beneficial effects of anti-TNF drugs for patients who do not go into remission on methotrexate alone,” he said.