Impact of Sub-therapeutic Tacrolimus Troughs at Discharge from Index Admission on Short-Term Outcomes in Kidney Transplant Recipients Receiving Rabbit Anti-Thymocyte Globulin Induction
1Pharmacy, Hosp of Univ of Pennsylvania, Philadelphia, PA, 2Penn Transplant Institute and Pharmacy Dept, Hosp of Univ of Pennsylvania, Philadelphia, PA, 3Penn Transplant Institute, Hosp of Univ of Pennsylvania, Philadelphia, PA
Meeting: 2022 American Transplant Congress
Abstract number: 1654
Keywords: FK506, Kidney transplantation, Length of stay, Safety
Topic: Clinical Science » Pharmacy » 30 - Non-Organ Specific: Clinical Pharmacy/Transplant Pharmacotherapy
Session Information
Session Time: 7:00pm-8:00pm
Presentation Time: 7:00pm-8:00pm
Location: Hynes Halls C & D
*Purpose: Kidney transplant (KTx) recipients are often discharged with subtherapeutic tacrolimus (TAC) troughs due to short hospital lengths of stay (LOS) for index KTx admissions. The study aim was to compare short-term graft outcomes of KTx recipients with subtherapeutic TAC troughs (<8 ug/L) at discharge from index admission vs. therapeutic TAC troughs (≥8 ug/L).
*Methods: This single-center, retrospective study evaluated adults who received a primary or secondary KTx from 10/2017-12/2019, and were discharged on TAC, received rabbit anti-thymocyte globulin (rATG) induction, and had ≥6 months (mo) of follow up. Recipients were excluded if they were HIV positive, received a non-KTx transplant, were switched off TAC within 1 yr of KTx, or if index admission LOS was >5 days. Primary outcome was a composite endpoint of: biopsy-proven or clinically treated rejection, graft loss (GL), or development of de novo donor specific antibodies (dnDSA) within 3 mo post-KTx. Secondary outcomes included composite and individual outcomes at 6 and 12 mo, biopsy need within 3 mo and graft function at 6 and 12 mo.
*Results: Of 498 KTx performed in this time, 316 met inclusion criteria and were analyzed. TAC was subtherapeutic at discharge in 259 (82%) vs. 57 (18%) therapeutic. Baseline characteristics were similar (Table 1). Primary and secondary outcomes were similar between both groups (Table 2). No GL or death occurred. No prespecified risk factors were associated with development of primary outcome in the subtherapeutic TAC group.
Table 1 Demographics
| Subtherapeutic TAC (n = 259) | Therapeutic TAC (n = 57) | p-value | |
| Age (yrs), median [IQR] | 51 [39 – 62] | 53 [44 – 62] | 0.17 |
| Black Race (%) | 79 (30.5) | 19 (33.3) | 0.75 |
| Male Sex (%) | 149 (57.5) | 34 (59.7) | 0.77 |
| BMI (kg/m2), median [IQR] | 27.6 [24.3 – 31.5] | 26.7 [24.4 – 30.7] | 0.78 |
| ESRD due to autoimmune causes* (%) | 63 (24.3) | 13 (22.8) | 0.87 |
| cPRA, median [IQR] | 0 [0 – 12] | 0 [0 – 0] | 0.32 |
| Deceased donor KTx (%) | 152 (58.7) | 32 (56.1) | 0.72 |
| KDPI, median [IQR] | 47.5 [27.5 – 60.5] | 52 [28 – 61] | 0.83 |
| Total rATG (mg/kg/course), median [IQR] | 4.6 [4.2 – 5.0] | 4.6 [4.2 – 4.9] | 0.83 |
| DGF (%) | 37 (14.3) | 12 (21.1) | 0.20 |
| Time to Therapeutic TAC (days), median [IQR] | 8 [6 – 12] | 3 [3 – 4] | < 0.01 |
*autoimmune causes include FSGS, IgA nephropathy, SLE, MPGN
Table 2 Outcomes
| Subtherapeutic TAC (n = 259) | Therapeutic TAC (n = 57) | p-value | |
| Primary outcome (%) | 21 (8.2) | 5 (8.9) | 0.85 |
| Biopsy need within 3 mo (%) | 8 (3.1) | 0 | 0.18 |
| dnDSA development within 3 mo (%) | 14 (5.4) | 5 (8.8) | 0.33 |
| Composite outcome at 6 mo (%) | 22 (8.5) | 6 (10.5) | 0.61 |
| Composite outcome at 12 mo (%) | 31 (12.0) | 6 (10.5) | 1.00 |
| Rejection at 12 mo (%) | 14 (5.4) | 0 | – |
| Time to biopsy-proven rejection (days), median [IQR] | 106 [22 – 267] | 0 [0 – 0] | – |
| Time to dnDSA development (days), median [IQR] | 32 [26 – 87] | 31 [27 – 32] | 0.51 |
| Creatinine at 12 mo (mg/dL), median [IQR] | 1.2 [1.0 – 1.5] | 1.2 [1.0 – 1.4] | 0.56 |
*Conclusions: KTx recipients discharged from index admission with subtherapeutic TAC troughs have comparable short-term graft outcomes vs those with therapeutic troughs. This suggests that delaying discharge to reach therapeutic TAC troughs under rATG induction is of less concern.
To cite this abstract in AMA style:
Liu X, Trofe-Clark J, Sawinski D, Steiner B, Sharma S, Witek S, Fallah T, Norris M, Sammons C, Malat G. Impact of Sub-therapeutic Tacrolimus Troughs at Discharge from Index Admission on Short-Term Outcomes in Kidney Transplant Recipients Receiving Rabbit Anti-Thymocyte Globulin Induction [abstract]. Am J Transplant. 2022; 22 (suppl 3). https://atcmeetingabstracts.com/abstract/impact-of-sub-therapeutic-tacrolimus-troughs-at-discharge-from-index-admission-on-short-term-outcomes-in-kidney-transplant-recipients-receiving-rabbit-anti-thymocyte-globulin-induction/. Accessed May 16, 2025.« Back to 2022 American Transplant Congress