Machine perfusion distribution across clinical phenotypes in kidney transplantation: A national cohort study using unsupervised clustering

Table 7 Machine perfusion subgroup features standardized mean differences by cluster

Characteristic	Cluster 1 (n = 41)	Cluster 2 (n = 59)	Cluster 3 (n = 93)	Cluster 4 (n = 36)	Cluster 5 (n = 97)	Cluster 6 (n = 218)
Recipient age	-0.52238	0.935377	-0.17692	-0.14135	-0.5752	0.624424
Recipient BMI	-0.33675	0.341342	0.100018	0.104799	-0.29737	0.077307
Recipient sex
Female	-0.12192	-0.47267	0.037357	0.329161	0.231682	-0.05627
Male	0.121923	0.472666	-0.03736	-0.32916	-0.23168	0.05627
Recipient ABO blood group
A	0.00696	0.193519	-0.00775	0.011911	-0.07437	-0.13309
AB	0.173135	-0.16482	0.013513	-0.08419	0.062414	-0.0548
B	-0.07912	0.001768	-0.32229	0.169568	-0.01784	0.17967
O	-0.03561	-0.13813	0.183969	-0.09859	0.058822	0.026817
Recipient ethnicity
Asian	-0.07204	-0.10315	-0.33003	0.507309	-0.00709	-0.10166
Black	0.177035	0.076748	-0.40214	0.282133	-0.15149	-0.13602
White	-0.06636	0.031694	0.534651	-0.65321	0.100554	0.173304
Recipient diabetes	-0.11318	0.251095	-0.25194	0.133863	-0.36278	0.217526
Recipient positive CMV status	-0.16999	-0.02122	-0.31585	0.471722	0.070829	-0.01996
Dialysis status at registration
Hemodialysis	-0.04066	0.256224	-0.24872	0.630677	-0.46044	-0.11067
Not	-0.16484	-0.04565	0.272456	-0.43957	0.263876	0.070191
Peritoneal	0.261768	-0.34949	-0.02704	-0.32742	0.252628	0.060744
Dialysis at transplant	0.060974	0.136638	-0.17833	0.330709	-0.08688	-0.18986
Type of dialysis at transplant
Hemodialysis	-0.26222	0.116985	-0.06999	0.45709	-0.08642	-0.08056
Not	0.235702	-0.10426	-0.10426	-0.10426	-0.10426	-0.10426
Peritoneal	0.203308	-0.1042	0.083027	-0.4446	0.099488	0.093619
Donor organ
Left kidney	-0.03682	0.012793	0.082894	-0.20909	-0.11916	0.271376
Right kidney	0.036822	-0.01279	-0.08289	0.209092	0.119164	-0.27138
Highly sensitised status flag	-0.04705	-0.24711	-0.07932	0.239504	0.207115	-0.20468
Waiting list time	0.293259	0.292544	-0.51323	0.140545	-0.11534	-0.19133
Recipient deprivation group
Quartile 1 most deprived	0.144294	0.009881	0.047681	-0.19907	-0.02608	0.012131
Quartile 2 second most deprived	-0.29413	0.468065	-0.08528	-0.02003	-0.2488	0.103914
Quartile 3 second least deprived	-0.06986	-0.25307	-0.02343	0.291574	0.042275	-0.0128
Quartile 4 least deprived	0.171772	-0.25815	0.053363	-0.09517	0.199419	-0.10384
Donor age	-0.68036	0.878226	0.228306	-0.07469	-1.10569	0.959388
Donor BMI	-0.43307	0.415931	0.055243	-0.05396	-0.33119	0.259145
Donor sex
Female	-0.29708	0.014101	0.296941	0.079911	-0.35442	0.227365
Male	0.297078	-0.0141	-0.29694	-0.07991	0.354417	-0.22736
Donor ABO blood group
A	0.045051	0.172103	-0.00267	-0.07713	-0.01967	-0.11994
AB	0.151565	-0.07105	-0.03261	0.015795	-0.03985	-0.05891
B	-0.03287	0.048817	-0.33718	0.218087	-0.09518	0.118041
O	-0.08087	-0.18356	0.190299	-0.07592	0.087987	0.05895
Donor ethnicity
Asian	-0.09388	0.172408	-0.09388	-0.09388	-0.09388	0.019577
Black	0.235702	-0.10426	-0.10426	-0.10426	-0.10426	-0.10426
White	-0.18284	-0.10107	0.140638	0.140638	0.140638	0.050717
Donor positive CMV status	-0.15319	-0.07133	-0.12388	0.179753	0.047903	0.118171
Donor positive EBV status	-0.09206	0.003988	-0.01369	0.12261	0.002437	-0.0115
Donor positive toxoplasmosis status	0.085221	-0.05017	0.100121	-0.19446	-0.10309	0.136286
Donor cardiac disease	-0.02698	0.549406	-0.207	-0.07812	-0.37416	-0.01591
Donor diabetes	-0.37831	0.475118	-0.20372	0.007774	-0.13606	-0.02641
Donor family history of diabetes	-0.06424	0.279421	-0.16018	-0.023	-0.03486	-0.0104
Donor history of drug abuse	0.834764	-0.49937	-0.67434	0.437373	0.154552	-0.65409
Donor hypertension	-0.67428	1.019971	-0.23869	-0.06014	-0.66262	0.343796
Donor smoker	0.18875	0.098478	-0.23545	0.284012	0.191422	-0.50291
Donor history of UTI	-0.01377	0.183746	-0.15672	0.14669	-0.2279	-0.00165
Donor allergy	0.153133	0.428873	-0.21322	0.413296	-0.60394	-0.24876
Donor creatinine at retrieval	0.125502	-0.42356	-0.02563	-0.096	0.351898	0.014002
Donor type
DBD	0.007415	-0.10228	-0.03346	0.273614	-0.09862	-0.10432
DCD	-0.00741	0.102277	0.033465	-0.27361	0.098615	0.10432
Donor cause of death
Neurological	0.26055	0.454746	-0.35274	0.090477	-0.15611	-0.07575
Other	-0.26055	-0.45475	0.352744	-0.09048	0.156112	0.075749
Cold ischemia time	-0.04488	0.342452	-0.45242	0.597162	-0.26049	-0.19252
Perfusate used
HTK	-0.03971	0.03199	-0.06026	0.294468	-0.16003	-0.21855
Marshalls	-0.34773	0.217686	0.179445	-0.42416	-0.04817	0.282263
Wisconsin	0.338959	-0.21966	-0.14738	0.191593	0.106176	-0.19929
Perfusion quality
Fair	-0.39856	0.091242	0.122445	-0.11029	0.215936	-0.02153
Good	0.225004	-0.18566	-0.09372	0.166457	-0.10417	0.027697
Poor	0.074921	0.158416	-0.00977	-0.11489	-0.12394	-0.01525
Machine perfusion type
HMP	-0.62818	-0.18049	0.573901	-0.58306	0.42157	0.439779
NMP	0.62818	0.180493	-0.5739	0.583062	-0.42157	-0.43978
Donor homozygous at A locus	0.021713	0.146149	0.112907	-0.25555	-0.0396	-0.01395
Donor homozygous at B locus	0.02525	-0.02818	0.14671	-0.49644	0.237927	-0.03754
Donor homozygous at DR locus	-0.10806	-0.12001	0.626996	-0.51105	0.071818	-0.15142
Recipient homozygous at A locus	0.044589	-0.14692	-0.41768	0.125595	0.168964	0.146465
Recipient homozygous at B locus	-0.3114	-0.08202	-0.28739	0.408741	0.074077	0.066697
Recipient homozygous at DR locus	-0.54784	-0.41639	-0.35489	0.589812	0.238174	0.188202
Number of mismatches at A locus
One	0.097199	-0.10749	0.212251	-0.03473	-0.08176	-0.08028
Two	-0.29478	0.128613	-0.58751	0.229485	0.228751	0.173743
Zero	0.19625	-0.01389	0.309202	-0.26653	-0.18904	-0.1127
Number of mismatches at B locus
One	0.048535	-0.00741	0.204379	-0.86645	0.476811	0.170374
Two	-0.48232	0.012601	-0.83654	1.326824	-0.2564	-0.04173
Zero	0.40401	-0.00523	0.446308	-0.5802	-0.39206	-0.2065
Number of mismatches at DR locus
One	0.483892	0.361597	-1.98063	0.104253	0.122609	0.334855
Two	-0.4994	-0.18924	-0.4994	0.968966	-0.23929	-0.08191
Zero	-0.25134	-0.26978	2.62874	-1.17182	0.002459	-0.30515
HLA mismatch group
(0 DR and 2B) OR (1 DR and 1/0 B)	0.673474	0.521873	-1.75727	-0.62392	0.28404	0.447561
(1 DR and 2 B) OR (2 DR)	-0.63189	-0.11729	-0.7675	1.718072	-0.36943	-0.1061
0 DR and 1/0 B	-0.18083	-0.42722	1.80884	-0.94859	0.05366	-0.34678
0 Mismatches	-0.26696	-0.26696	0.644658	-0.26696	-0.26696	-0.26696
Initial graft function
DGF	-0.29227	0.364925	-0.0898	0.109398	-0.13641	-0.00691
Immediate	0.191538	-0.4476	0.15867	-0.0392	0.205079	-0.02326
PNF	0.181014	0.220671	-0.24713	-0.24713	-0.24713	0.07753
Predniscolone/predniscone immunosuppression 3 months post-transplant
No	-0.08321	-0.32889	0.146769	0.159979	-0.00221	0.079611
Yes	0.083214	0.328894	-0.14677	-0.15998	0.002211	-0.07961
Graft status
Died functioning	-0.33468	0.076472	-0.04423	0.029598	-0.22774	0.38821
Died unknown function	-0.06428	-0.06428	-0.06428	-0.06428	0.144338	-0.06428
Failed	-0.07421	0.396202	-0.12747	-0.11402	-0.26933	0.103673
Functioning	0.299809	-0.38451	0.136365	0.068689	0.35079	-0.39189
Allocation matchability score	-0.89236	-0.89449	-0.31801	1.168311	0.775282	0.397993
Serum creatinine (umol/L) at 3 months post-transplant	-0.49329	1.139701	0.037743	-0.50205	-0.92856	0.25578
Serum creatinine (umol/L) at 12 months post-transplant	-0.5095	0.901736	-0.009	-0.24362	-0.87226	0.279751
Follow-up time	-0.81744	-1.51375	1.030244	-1.33825	1.48027	0.590485
Transplant year
2014	-0.70809	-0.36308	0.425425	-0.55108	0.447064	0.3227
2015	-0.54249	-0.24363	0.335796	-0.54249	0.373961	0.224117
2016	-0.21921	0.022467	0.247963	-0.43858	-0.02	0.268664
2017	-0.41371	-0.2814	0.045193	-0.0506	0.359465	0.11809
2018	0.099585	-0.20458	0.044465	0.058397	0.067217	-0.09786
2019	0.387393	-0.0166	-0.17485	0.02006	-0.23666	-0.07566
2020	0.153595	0.41158	-0.52733	0.399002	-0.53008	-0.26831
2021	0.546193	0.314455	-0.56336	0.269375	-0.56604	-0.4434
2022	0.353089	-0.20301	-0.20301	0.091326	-0.20301	-0.20301
2023	0.180164	0.11638	-0.12913	-0.12913	-0.12913	-0.12913
2024	-0.32116	0.146404	-0.21728	0.54339	-0.32116	-0.32116
Kidney used by local centre
No	0.400771	0.574001	-0.35512	0.431431	-0.53165	-0.49953
Yes	-0.40077	-0.574	0.355118	-0.43143	0.531653	0.499525

BMI: Body mass index; UTI: Urinary tract infection; DBD: Donation after brain death; CMV: Cytomegalovirus; EBV: Epstein-Barr virus; DCD: Donation after cardiac death; HTK: Histidine-tryptophan-ketoglutarate solution; HMP: Hypothermic machine perfusion; NMP: Normothermic machine perfusion; HLA: Human leukocyte antigen; DGF: Delayed graft function; PNF: Primary non-function.