Clinical predictors of SARS-CoV-2 vaccine immunogenicity in kidney transplant recipients at a rural center

Table 1 Comparison of demographic and clinical characteristics between responders and non-responders, n (%)

Variable	Non-responders (n = 45)	Responders (n = 63)	P value
Mean age (years)	60.8	58.9	0.59
Mean BMI	31.5	30.6	0.51
Mean eGFR (mL/minute/1.73 m2)	44.1	54.7	0.01
Male	23 (51.1)	30 (47.6)	1
Caucasian	11 (24.4)	14 (22.2)	0.82
Black	33 (73.3)	48 (76.2)	0.82
Tacrolimus	41 (91.1)	62 (98.4)	0.2
MPA	44 (97.8)	57 (90.5)	0.24
Steroid	43 (95.6)	63 (100.0)	0.17
Basiliximab	5 (11.1)	16 (25.4)	0.09
Thymoglobulin	34 (75.6)	43 (68.3)	0.4
Diabetes mellitus	12 (26.7)	24 (38.1)	0.3
Hypertension	16 (35.6)	23 (36.5)	1
Moderna vaccine	23 (51.1)	36 (57.1)	0.7
Pfizer vaccine	21 (46.7)	26 (41.3)	0.56
Kidney only transplant	42 (93.3)	56 (88.9)	0.52
Days from transplant to 1st vaccine	2200.3	2156.6	0.73

MPA: Mycophenolic acid; BMI: Body mass index; eGFR: Estimated glomerular filtration rate.

Table 2 Multivariate logistic regression analysis of factors associated with antibody response

Variable	Odds ratio	Standard error	95%CI	P value
Age (per year increase)	0.95	0.028	0.90-1.01	0.101
Gender (male vs female)	0.75	0.44	0.24-2.39	0.631
Race
Caucasian vs other	23.88	47.14	0.50-1143.83	0.108
Black vs other	43.08	82.52	1.01-1839.96	0.049
BMI	0.99	0.049	0.89-1.09	0.767
eGFR	1.05	0.018	1.02-1.09	0.002
Tacrolimus level	0.93	0.14	0.70-1.24	0.637
MPA dose (mg/day)	0.99	0.002	0.99-1.00	0.01
Basiliximab induction (yes vs no)	31.3	49.1	1.45-677.30	0.028
Thymoglobulin Induction (yes vs no)	16.44	25	0.83-323.82	0.066
Days from transplant to vaccine	1	0.0003	1.00-1.00	0.082
Days from 2nd vaccine to sample testing	1.01	0.0035	1.00-1.01	0.055
Diabetes mellitus	1.39	0.8	0.47-4.13	0.564
Hypertension	1.71	0.94	0.61-4.79	0.307
Vaccine type
Moderna vs other	0.78	0.46	0.28-2.18	0.639
Pfizer vs other	0.57	0.34	0.20-1.66	0.307
SPK or kidney alone	1.03	0.62	0.31-3.42	0.956
History of rituximab use	0.99	0.8	0.20-4.93	0.993
Type of donor (living vs deceased)	1.62	0.92	0.55-4.78	0.38
Previous transplant (yes vs no)	0.82	0.58	0.24-2.75	0.747
Primary ESRD etiology	1.41	0.36	0.90-2.19	0.135
Constant	0.01	0.02	0.00-60.94	0.263

Reference categories for regression models were female sex, other race, absence of induction therapy, absence of calcineurin inhibitor, absence of antimetabolite therapy, absence of steroid therapy, receipt of non-mRNA vaccine, deceased donor transplantation, and absence of the listed comorbidities, unless otherwise specified. BMI: Body mass index; eGFR: Estimated glomerular filtration rate; MPA: Mycophenolic acid; SPK: Simultaneous pancreas kidney; ESRD: End stage renal disease; 95%CI: 95% confidence interval.

Table 3 Linear regression analysis of factors associated with log-transformed antibody titer among responders

Variable	Coefficient	Standard error	95%CI	P value
Age (per year increase)	-22.6	47.5	-118.2 to 73.1	0.64
Gender (male vs female)	-1153.4	1138.2	-3444.4 to 1137.6	0.32
Race	-148.9	1488.7	-3145.5 to 2847.6	0.92
Days from transplant to first vaccine	-0.2	0.5	-1.2 to 0.7	0.62
Days from 2nd vaccine to sample testing	2.1	7.8	-13.6 to 17.9	0.79
Tacrolimus level	-42.5	303.5	-653.5 to 568.5	0.89
MPA dose (mg/day)	1.9	2.9	-3.9 to 7.8	0.51
Diabetes mellitus	-1957.9	1701	-5381.8 to 1466.0	0.26
Hypertension	-98.3	1568.2	-3254.8 to 3058.2	0.95
Vaccine type	-232.3	1011.9	-2269.2 to 1804.6	0.82
SPK or kidney alone	-1152.1	2005	-5188.1 to 2883.8	0.57
History of rituximab use	950.3	1837.7	-2748.7 to 4649.4	0.61
Type of donor (living vs deceased)	-547.1	1798.1	-4166.5 to 3072.2	0.76
Previous transplant (yes vs no)	-2029.9	1537	-5123.7 to 1063.8	0.19
Primary ESRD etiology	-202.5	332.3	-871.3 to 466.3	0.55
Constant	23867.3	5273.3	13252.8 to 34481.8	0

Reference categories for regression models were female sex, other race, absence of induction therapy, absence of calcineurin inhibitor, absence of antimetabolite therapy, absence of steroid therapy, receipt of non-mRNA vaccine, deceased donor transplantation, and absence of the listed comorbidities, unless otherwise specified. MPA: Mycophenolic acid; SPK: Simultaneous pancreas kidney; ESRD: End stage renal disease; 95%CI: 95% confidence interval.