The Effect of Initiation of Anti-TNF Therapy on the Subsequent Direct Health Care Costs of Inflammatory Bowel Disease.

Background: Anti-tumor necrosis factor (anti-TNF) drugs are highly effective in the treatment of moderate-to-severe Crohn's disease (CD) and ulcerative colitis (UC), but they are very costly. Due to their effectiveness, they could potentially reduce future health care spending on other medical therapies, hospitalization, and surgery. The impact of downstream costs has not previously been quantified in a real-world population-based setting.

Methods: We used the University of Manitoba IBD Database to identify all persons in a Canadian province with CD or UC who received anti-TNF therapy between 2004 and 2016. All inpatient, outpatient, and drug costs were enumerated both in the year before anti-TNF initiation and for up to 5 years after anti-TNF initiation. Costs before and after anti-TNF initiation were compared, and multivariate linear regression analyses were performed to look for predictors of higher costs after anti-TNF initiation.

Results: A total of 928 people with IBD (676 CD, 252 UC) were included for analyses. The median cost of health care in the year before anti-TNF therapy was $4698 for CD vs $6364 for UC. The median cost rose to $39,749 and $49,327, respectively, in the year after anti-TNF initiation, and to $210,956 and $245,260 in the 5 years after initiation for continuous anti-TNF users. Inpatient and outpatient costs decreased in the year after anti-TNF initiation by 12% and 7%, respectively, when excluding the cost of anti-TNFs.

Conclusions: Direct health care expenditures markedly increase after anti-TNF initiation and continue to stay elevated over pre-initiation costs for up to 5 years, with only small reductions in the direct costs of non-drug-related health care.