Anticonvulsant hypocalcaemia.
Authors: A Richens, D J Rowe
Journal: BMJ (1972)

<h3>Background</h3> Guidelines recommend holding biologic DMARDs before major surgery, but few studies have examined perioperative timing of individual biologic therapies.<sup>1</sup> <h3>Objectives</h3> We aimed to determine whether holding abatacept infusions before elective hip or knee arthroplasty is associated with lower risk of adverse post-operative outcomes. <h3>Methods</h3> This retrospective cohort study using U.S. Medicare claims data from 2006-September 2015 evaluated adults with ≥2 ICD9 codes for RA who received abatacept by infusion within 6 months of inpatient primary or revision total hip or knee arthroplasty. Infusions were selected as these procedures can be precisely dated in claims data. Patients with hip fracture, malignancy, pre-existing infection, non-elective procedures, or surgery after hospital day 3 were excluded. Logistic and Cox regression were used to assess associations between abatacept stop timing (time between most recent infusion and surgery in 4 week intervals based on dosing interval) and adverse outcomes: 1) hospitalised infection within 30 days (from discharge diagnoses, PPV &gt;80%), 2) rate of prosthetic joint infection (PJI, ICD9 996.66) within 1 year, and 3) 30 day readmission (among patients with discharge to home, rehabilitation facility, or skilled nursing facility). Propensity scores based on the probability of being in each abatacept stop timing group were used to balance confounders across exposure groups using inverse probability weighting. Risk of hospitalised infection associated with methotrexate or with average glucocorticoid dose in the 3 months prior to surgery was assessed in abatacept treated patients using a reduced multivariable logistic regression model. <h3>Results</h3> Among 1537 surgeries in 1410 patients, there were 158 (10.3%) hospitalised infections within 30 days (most commonly urinary, skin/soft tissue, and pneumonia), 34 (2.6/100 person-years) PJI within 1 year, and 108/1448 (7.5%) 30 day readmissions. There were no significant differences in the rates of hospitalised infection, prosthetic joint infection, or 30 day readmission in patients who received abatacept within 4 weeks of surgery vs patients with longer stop timing (table 1). Among abatacept treated patients, glucocorticoid use (vs. none) was associated with a dose-dependent increase in the risk of hospitalised infection:≤5 mg [aOR 1.32 (0.88–1.98)], 5–10 mg [aOR 2.40 (1.54–3.73)],&gt;10 mg [aOR 1.73 (0.74–4.06)]. Concomitant use of methotrexate was not associated with hospitalised infection risk [aOR 0.97 (0.68–1.38)] (table 2). <h3>Conclusions</h3> Holding intravenous abatacept for ≥4 weeks (one dosing interval) was not associated with a lower risk of hospitalised infection, prosthetic joint infection, or 30 day readmission. Glucocorticoid use even at 5–10 mg per day was associated with significantly greater risk of post-operative infection. <h3>Reference</h3> [1] Goodman SM, et al. ACR/AAHKS Guideline for the Perioperative Management of Antirheumatic Medication in Patients With Rheumatic Diseases Undergoing Elective Total Hip or Total Knee Arthroplasty. Arthritis &amp; Rheum2017;69:1538–1551. <h3>Disclosure of Interest</h3> M. George Grant/research support from: Bristol Myers Squibb, J. Baker: None declared, K. Winthrop Grant/research support from: Abbvie, Astellis, Galapagos, Eli Lilly, Pfizer, BMS, Roche, UCB, Consultant for: Abbvie, Astellis, Galapagos, Eli Lilly, Pfizer, BMS, Roche, UCB, E. Alemao Employee of: Bristol Myers Squibb, L. Chen: None declared, S. Connolly Employee of: Bristol Myers Squibb, T. Simon Employee of: Bristol Myers Squibb, Q. Wu: None declared, F. Xie: None declared, S. Yang: None declared, J. Curtis Grant/research support from: Pfizer, Amgen, UCB, Myriad genetics, Bristol Myers Squibb, Consultant for: Pfizer, Amgen, UCB, Myriad genetics, Bristol Myers Squibb, Janssen