Table 1:

Recent observational studies evaluating biologic timing before surgery

Study	Population	Treatment	Results	Limitations
Zahr, Rheum Int 2015[19]	896 RA; various surgeries	Various biologics	Stop vs. continue: Infection OR 1.52 (0.88-2.62)	Potential misclassification of biologic timing, no inclusion of disease activity
George, AC&R 2017[20]	4288 RA, PsA, AS, IBD; hip/knee arthroplasty	Infliximab	Stop vs. continue (8-12 weeks vs. < 4 weeks): Infection OR 1.11 (0.75-1.67)*; PJI HR 1.02 (0.54-1.92)*	No inclusion of disease activity
Latourte, Rheumatology 2017[24]	263 RA; various surgeries	Abatacept	Median time before surgery in patients with and without complications: 5.1 vs. 5.6 weeks (p = 0.41)	Limited power
George, ARD 2018 (abstract)[25]	1537 RA; hip/knee arthroplasty	Abatacept	Stop vs. continue (≥8 weeks vs. <4 weeks): Infection OR 1.11 (0.69-1.79); PJI HR 0.71 (0.25-2.03)	No inclusion of disease activity
Momohara, Mod Rheumatol 2013[22]	169 RA; orthopedic surgery	Tocilizumab	3 surgical site infections, unable to evaluate associations between timing and infection	Too few outcomes to assess timing
Godot, AC&R 2013[23]	140 RA; various surgeries	Rituximab	Median time between rituximab infusion and surgery in patients with and without complications: 6.43 vs. 6.49 months (p = 1.0)	Limited power
Lau, Ann Surg 2015[21]	331 IBD; abdominal surgery	Infliximab	Infliximab level ≥3 vs. <3 μg/mL: Infection OR 2.86 (1.01-8.08), only in Crohn’s disease	No infliximab timing or dose, no disease activity, different results in Crohn’s and ulcerative colitis

^*OR and HR from this study inverted to provide results for stopping vs. continuing. OR = odds ratio, HR = hazard ratio, RA = rheumatoid arthritis, PsA = psoriatic arthritis, AS = ankylosing spondylitis, IBD = inflammatory bowel disease, PJI = prosthetic joint infection