Sex and gender as predictors for allograft and patient-relevant outcomes after kidney transplantation.
Sex, as a biological construct, and gender, defined as the cultural attitudes and behaviours attributed by society, may be associated with allograft loss, death, cancer, and rejection. Other factors, such as recipient age and donor sex, may modify the association between sex/gender and post-transplant outcomes.
We sought to evaluate the prognostic effects of recipient sex and, separately, gender as independent predictors of graft loss, death, cancer, and allograft rejection following kidney or simultaneous pancreas-kidney (SPK) transplantation. We aimed to evaluate this prognostic effect by defining the relationship between recipient sex or gender and post-transplantation outcomes identifying reasons for variations between sexes and genders, and then quantifying the magnitude of this relationship.
We searched MEDLINE and EMBASE databases from inception up to 12 April 2023, through contact with the Cochrane Kidney and Transplant Information Specialist, using search terms relevant to this review and no language restrictions.
Cohort, case-control, or cross-sectional studies were included if sex or gender were the primary exposure and clearly defined. Studies needed to focus on our defined outcomes post-transplantation. Sex was defined as the chromosomal, gonadal, and anatomical characteristics associated with the biological sex, and we used the terms "males" and "females". Gender was defined as the attitudes and behaviours that a given culture associates with a person's biological sex, and we used the terms "men" and "women".
Two authors independently assessed the references for eligibility, extracted the data and assessed the risk of bias using the Quality in Prognosis Studies (QUIPS) tool. Whenever appropriate, we performed random-effects meta-analyses to estimate the mean difference in outcomes. The outcomes of interest included the Standardised Outcomes in Nephrology-Kidney Transplant (SONG-Tx) core outcomes, allograft loss, death, cancer (overall incidence and site-specific) and acute or chronic graft rejection.
Fifty-three studies (2,144,613 patients; range 59 to 407,963) conducted between 1990 and 2023 were included. Sixteen studies were conducted in the Americas, 12 in Europe, 11 in the Western Pacific, four in the Eastern Mediterranean, three in Africa, two in Southeast Asia, and five across multiple regions. All but one study focused on sex rather than gender as the primary exposure of interest. The number identified as male was 54%; 49 studies included kidney transplant recipients, and four studies included SPK transplant recipients. Twenty-four studies included adults and children, 25 studies included only adults, and four studies included only children. Data from 33 studies were included in the meta-analyses. Among these, six studies presented unadjusted hazard ratios (HRs) that assessed the effect of recipient sex on kidney allograft loss. The other studies reported risk ratios (RRs) for the pre-defined outcomes. Notably, the decision to restrict the meta-analyses to unadjusted estimates arose from the variation in covariate adjustment methods across studies, lacking a common set of adjusted variables. Only three studies considered the modifying effect of recipient age on graft loss or death, which is likely crucial to evaluating sex differences in post-transplant outcomes. No studies considered the modifying effect of recipient age on cancer incidence or allograft rejection risk. In low certainty evidence, compared with male recipients, being female may make little or no difference in kidney allograft loss post-transplantation (7 studies, 5843 patients: RR 0.91, 95% CI 0.73 to 1.12; I2 = 73%). This was also observed in studies that included time-to-event analyses (6 studies, 238,937 patients; HR 1.07, 95% CI, 0.95 to 1.20; I2 = 44%). Two recent large registry-based cohort studies that considered the modifying effects of donor sex and recipient age showed that female recipients under 45 years of age had significantly higher graft loss rates than age-matched male recipients in the setting of a male donor. In contrast, female recipients 60 years and older had lower graft loss rates than age-matched male recipients, regardless of donor sex. Compared with male recipients, being female may make little or no difference in death up to 30 years post-transplantation; however, the evidence is very uncertain (13 studies, 60,818 patients: RR 0.94, 95% CI 0.81 to 1.09; I2 = 92%). Studies that considered the modifying effect of recipient age and donor sex showed that female recipients had a higher excess death risk than males under 45 years of age in the setting of a male donor. Compared with male recipients, being female may make little or no difference in cancer incidence up to 20 years post-transplantation; however, the evidence is very uncertain (7 studies, 25,076 patients; RR 0.84, 95% CI 0.70 to 1.01; I2 = 60%). Compared with male recipients, being female may make little or no difference in the incidence of acute and chronic kidney allograft rejection up to 15 years post-transplantation (9 studies, 6158 patients: RR 0.89, 95% CI 0.75 to 1.05; I2 =54%; low certainty evidence). One study assessed gender and reported that when compared with men, women experienced better five-year survival in high (HR 0.71, 95% CI 0.59 to 0.87) and middle-income areas (HR 0.82, 95% CI 0.74 to 0.92), with no difference in low-income areas (HR 0.85, 95% CI 0.72 to 1.01). There was considerable uncertainty regarding any association between sex or gender and post-transplant patient-relevant outcomes. This was primarily due to clinical and methodological heterogeneity. The observed clinical heterogeneity between studies could be attributed to diverse patient characteristics within sample populations. As a result of limited sex-stratified demographic data being provided, further investigation of this heterogeneity was constrained. However, factors contributing to this finding may include recipient age, donor age, types, and sex. Methodological heterogeneity was noted with the interchangeable use of sex and gender, outcome misclassification, the use of different measures of effects, inconsistent covariate profiles, and disregard for important effect modification.
There is very low to low certainty evidence to suggest there are no differences in kidney and pancreas allograft survival, patient survival, cancer, and acute and chronic allograft rejection between male and female kidney and SPK transplant recipients.
Jayanti S
,Beruni NA
,Chui JN
,Deng D
,Liang A
,Chong AS
,Craig JC
,Foster B
,Howell M
,Kim S
,Mannon RB
,Sapir-Pichhadze R
,Scholes-Robertson NJ
,Strauss AT
,Jaure A
,West L
,Cooper TE
,Wong G
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《Cochrane Database of Systematic Reviews》
Normothermic and hypothermic machine perfusion preservation versus static cold storage for deceased donor kidney transplantation.
Kidney transplantation is the optimal treatment for kidney failure. Donation, transport and transplant of kidney grafts leads to significant ischaemia reperfusion injury. Static cold storage (SCS), whereby the kidney is stored on ice after removal from the donor until the time of implantation, represents the simplest preservation method. However, technology is now available to perfuse or "pump" the kidney during the transport phase ("continuous") or at the recipient centre ("end-ischaemic"). This can be done at a variety of temperatures and using different perfusates. The effectiveness of these treatments manifests as improved kidney function post-transplant.
To compare machine perfusion (MP) technologies (hypothermic machine perfusion (HMP) and (sub) normothermic machine perfusion (NMP)) with each other and with standard SCS.
We contacted the information specialist and searched the Cochrane Kidney and Transplant Register of Studies until 15 June 2024 using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov.
All randomised controlled trials (RCTs) and quasi-RCTs comparing machine perfusion techniques with each other or versus SCS for deceased donor kidney transplantation were eligible for inclusion. All donor types were included (donor after circulatory death (DCD) and brainstem death (DBD), standard and extended/expanded criteria donors). Both paired and unpaired studies were eligible for inclusion.
The results of the literature search were screened, and a standard data extraction form was used to collect data. Both of these steps were performed by two independent authors. Dichotomous outcome results were expressed as risk ratios (RR) with 95% confidence intervals (CI). Survival analyses (time-to-event) were performed with the generic inverse variance meta-analysis of hazard ratios (HR). Continuous scales of measurement were expressed as a mean difference (MD). Random effects models were used for data analysis. The primary outcome was the incidence of delayed graft function (DGF). Secondary outcomes included graft survival, incidence of primary non-function (PNF), DGF duration, economic implications, graft function, patient survival and incidence of acute rejection. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.
Twenty-two studies (4007 participants) were included. The risk of bias was generally low across all studies and bias domains. The majority of the evidence compared non-oxygenated HMP with standard SCS (19 studies). The use of non-oxygenated HMP reduces the rate of DGF compared to SCS (16 studies, 3078 participants: RR 0.78, 95% CI 0.69 to 0.88; P < 0.0001; I2 = 31%; high certainty evidence). Subgroup analysis revealed that continuous (from donor hospital to implanting centre) HMP reduces DGF (high certainty evidence). In contrast, this benefit over SCS was not seen when non-oxygenated HMP was not performed continuously (low certainty evidence). Non-oxygenated HMP reduces DGF in both DCD and DBD settings in studies performed in the 'modern era' and when cold ischaemia times (CIT) were short. The number of perfusions required to prevent one episode of DGF was 7.69 and 12.5 in DCD and DBD grafts, respectively. Continuous non-oxygenated HMP versus SCS also improves one-year graft survival (3 studies, 1056 participants: HR 0.46, 0.29 to 0.75; P = 0.002; I2 = 0%; high certainty evidence). Assessing graft survival at maximal follow-up confirmed a benefit of continuous non-oxygenated HMP over SCS (4 studies, 1124 participants (follow-up 1 to 10 years): HR 0.55, 95% CI 0.40 to 0.77; P = 0.0005; I2 = 0%; high certainty evidence). This effect was not seen in studies where HMP was not continuous. The effect of non-oxygenated HMP on our other outcomes (PNF, incidence of acute rejection, patient survival, hospital stay, long-term graft function, duration of DGF) remains uncertain. Studies performing economic analyses suggest that HMP is either cost-saving (USA and European settings) or cost-effective (Brazil). One study investigated continuous oxygenated HMP versus non-oxygenated HMP (low risk of bias in all domains); the simple addition of oxygen during continuous HMP leads to additional benefits over non-oxygenated HMP in DCD donors (> 50 years), including further improvements in graft survival, improved one-year kidney function, and reduced acute rejection. One large, high-quality study investigated end-ischaemic oxygenated HMP versus SCS and found end-ischaemic oxygenated HMP (median machine perfusion time 4.6 hours) demonstrated no benefit compared to SCS. The impact of longer periods of end-ischaemic HMP is unknown. One study investigated NMP versus SCS (low risk of bias in all domains). One hour of end ischaemic NMP did not improve DGF compared with SCS alone. An indirect comparison revealed that continuous non-oxygenated HMP (the most studied intervention) was associated with improved graft survival compared with end-ischaemic NMP (indirect HR 0.31, 95% CI 0.11 to 0.92; P = 0.03). No studies investigated normothermic regional perfusion (NRP) or included any donors undergoing NRP.
Continuous non-oxygenated HMP is superior to SCS in deceased donor kidney transplantation, reducing DGF, improving graft survival and proving cost-effective. This is true for both DBD and DCD kidneys, both short and long CITs, and remains true in the modern era (studies performed after 2008). In DCD donors (> 50 years), the simple addition of oxygen to continuous HMP further improves graft survival, kidney function and acute rejection rate compared to non-oxygenated HMP. Timing of HMP is important, and benefits have not been demonstrated with short periods (median 4.6 hours) of end-ischaemic HMP. End-ischaemic NMP (one hour) does not confer meaningful benefits over SCS alone and is inferior to continuous HMP in an indirect comparison of graft survival. Further studies assessing NMP for viability assessment and therapeutic delivery are warranted and in progress.
Tingle SJ
,Thompson ER
,Figueiredo RS
,Moir JA
,Goodfellow M
,Talbot D
,Wilson CH
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《Cochrane Database of Systematic Reviews》
Safety of Kidney Transplantation from Donors with HIV.
Kidney transplantation from donors with human immunodeficiency virus (HIV) to recipients with HIV is an emerging practice. It has been performed since 2016 under the U.S. congressional HIV Organ Policy Equity Act and is currently approved for research only. The Department of Health and Human Services is considering expanding the procedure to clinical practice, but data are limited to small case series that did not include donors without HIV as controls.
In an observational study conducted at 26 U.S. centers, we compared transplantation of kidneys from deceased donors with HIV and donors without HIV to recipients with HIV. The primary outcome was a safety event (a composite of death from any cause, graft loss, serious adverse event, HIV breakthrough infection, persistent failure of HIV treatment, or opportunistic infection), assessed for noninferiority (margin for the upper bound of the 95% confidence interval, 3.00). Secondary outcomes included overall survival, survival without graft loss, rejection, infection, cancer, and HIV superinfection.
We enrolled 408 transplantation candidates, of whom 198 received a kidney from a deceased donor; 99 received a kidney from a donor with HIV and 99 from a donor without HIV. The adjusted hazard ratio for the composite primary outcome was 1.00 (95% confidence interval [CI], 0.73 to 1.38), which showed noninferiority. The following secondary outcomes were similar whether the donor had HIV or not: overall survival at 1 year (94% vs. 95%) and 3 years (85% vs. 87%), survival without graft loss at 1 year (93% vs. 90%) and 3 years (84% vs. 81%), and rejection at 1 year (13% vs. 21%) and 3 years (21% vs. 24%). The incidence of serious adverse events, infections, surgical or vascular complications, and cancer was similar in the groups. The incidence of HIV breakthrough infection was higher among recipients of kidneys from donors with HIV (incidence rate ratio, 3.14; 95%, CI, 1.02 to 9.63), with one potential HIV superinfection among the 58 recipients in this group with sequence data and no persistent failures of HIV treatment.
In this observational study of kidney transplantation in persons with HIV, transplantation from donors with HIV appeared to be noninferior to that from donors without HIV. (Funded by the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT03500315.).
Durand CM
,Massie A
,Florman S
,Liang T
,Rana MM
,Friedman-Moraco R
,Gilbert A
,Stock P
,Mehta SA
,Mehta S
,Stosor V
,Pereira MR
,Morris MI
,Hand J
,Aslam S
,Malinis M
,Haidar G
,Small CB
,Santos CAQ
,Schaenman J
,Baddley J
,Wojciechowski D
,Blumberg EA
,Ranganna K
,Adebiyi O
,Elias N
,Castillo-Lugo JA
,Giorgakis E
,Apewokin S
,Brown D
,Ostrander D
,Eby Y
,Desai N
,Naqvi F
,Bagnasco S
,Watson N
,Brittain E
,Odim J
,Redd AD
,Tobian AAR
,Segev DL
,HOPE in Action Investigators
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