Background/Purpose: Comorbidities, joint destruction leading to orthopaedic intervention and physical disability are predictable outcomes of uncontrolled Rheumatoid Arthritis (RA). Synthetic DMARDS have a slow mechanism of action and used as monotherapy induce remission in <20% of RA patients. Tumour Necrosis Factor inhibitors (TNFi) were first prescribed in 1999, have a faster mechanism of action and in combination with methotrexate in early RA induce remission in up to 50%. It is argued that the clinical, functional and quality of life benefits of TNFi may not be sufficient to justify their significant economic cost (National expense, >€100 million/year in 2010). We thus sought to evaluate the number of hospital inpatient days and of musculoskeletal surgical procedures (MSKSPs) in RA patients from 1995 to 2010 and to assess whether there is any association with TNFi usage.

Methods: The Hospital In-Patient Enquiry system (HIPE), which is a national system recording information on hospital bed utilization, was evaluated from 57 hospitals from 1995-2010 for patients admitted with a diagnosis of RA. Age group, number of inpatient days, gender and reason for admission (ICD codes) were also recorded. Annual prescription data for TNFi usage nationally was separately analysed from 2000 to 2010. Descriptive analyses are presented as totals, mean (standard deviation (SD)) and mean % change. Correlations were examined by Spearman’s rho; p<0.05 was considered statistically significant.

Results: 57,774 inpatient records in RA patients were reviewed from 1995-2010; F: M 2:1, mean age 66 (16). Annual TNFi prescribing has increased by 156% per annum (pa) from 2389 units in 2000 to 116,747 in 2010. An increase in TNFi prescribing coincided with a decrease in RA inpatient days for any reason:  49,000 (4880) pa pre-2002, reducing by 13% pa thereafter to 31000 pa in 2010 (r= -0.78, p=0.0055), likely contributing significantly to savings of approximately €16,000,000 pa based on current inpatient hospital costing. 550 (51) pa MSKSPs were recorded on RA in-patients pre-2002 with a subsequent reduction of 10% pa to 291 in 2010 (overall 47% decrease) and correlating significantly but negatively with number of TNFi prescriptions (r= -0.96, p<0.0001). 71 (27) pa elective hip procedures (64 replacements) were recorded pre-2002 with a subsequent reduction of 8% pa to 40 in 2010 (r= -0.88, p=0.0007), a 44% decrease on pre 2002. 79 (12) pa elective knee procedures (64 replacements) were recorded pre-2004 with a subsequent 7% pa reduction to 37 in 2010 (r= -0.96, p=0.003), a 53% decrease on pre-2004.

Conclusion: Increased prescription of TNFi drugs for RA patients negatively correlates with reduction in RA hospital inpatient bed days and likely contributed significantly to estimated €16,000,000 pa savings. TNFi usage also correlates negatively with a reduction in all MSKSPs and specifically with both elective hip and knee procedures. It is recognised that factors other than TNFi usage, such as improved use of non-biologic disease-modifying treatments and prevention of comorbidities, may also have contributed to these improved patient outcomes. Further analysis of these data including the economic impact is underway.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/prescription-of-tumour-necrosis-factor-%ce%b1-antagonists-is-strongly-associated-with-a-reduction-in-hospital-admissions-and-in-musculoskeletal-surgical-procedures-for-rheumatoid-arthritis-based/