Sex matching does not impact the outcome after simultaneous pancreas-kidney transplantation

Sex and gender as predictors for allograft and patient-relevant outcomes after kidney transplantation

BACKGROUND

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.

OBJECTIVES

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.

SEARCH METHODS

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.

SELECTION CRITERIA

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".

DATA COLLECTION AND ANALYSIS

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.

MAIN RESULTS

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.

AUTHORS' CONCLUSIONS

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.

HLA Compatibility and Graft Survival Rates Among Related and Unrelated Donors in Renal Transplantation

Human leukocyte antigen (HLA) compatibility between donors and recipients plays a critical role in graft survival in renal transplantation. This study evaluates the impact of HLA mismatching on graft survival and rejection among renal transplant recipients with related and unrelated donors, considering factors such as age, sex, ABO blood type, and anti-HLA antibodies. We investigated the graft survival rates between related and unrelated donors in a prospective cohort study conducted from 2018 to 2020 at Cho Ray Hospital and People's Hospital 115 in Vietnam, involving 126 related and 82 unrelated donor-recipient pairs. Over 32 months of follow-up, there was no significant difference in the rates of suspected graft rejection (P = .75) or graft loss (P = .095) between the 2 groups. However, related donors exhibited significantly higher overall survival (P = .0086) and better event-free survival (P = .0025) compared with unrelated donors. HLA matching and ABO type did not show any association with suspected graft rejection in either group. Notably, unrelated donors older than 5 years increased the risk of suspected graft rejection (hazard ratio, 4.22), and positive anti-HLA antibodies also increased this risk (hazard ratio, 4.5). Conversely, male-male donor-recipient pairs significantly decreased the risk of graft rejection by 88% compared with female-female pairs. The study concludes that although HLA matching is not different for related and unrelated donor groups, factors such as donor age, same-sex pairs, and the presence of anti-HLA antibodies are significant risk factors for graft rejection in unrelated donors. Enhancing monitoring and developing strategies for unrelated donors are essential to improve graft survival outcomes in renal transplantation.

Influence of donor and recipient sex on outcomes following simultaneous pancreas-kidney transplantation in the new millennium: Single-center experience and review of the literature

INTRODUCTION

The influence of sex on outcomes following simultaneous pancreas-kidney transplantation (SPKT) in the modern era is uncertain.

METHODS

We retrospectively studied 255 patients undergoing SPKT from 11/2001 to 8/2020. Cases were stratified according to donor (D) sex, recipient (R) sex, 4 D/R sex categories, and D/R sex-matched versus mismatched.

RESULTS

D-male was associated with slightly higher patient (p = .08) and kidney (p = .002) but not pancreas (p = .23) graft survival rates (GSR) compared to D-female. There were no differences in recipient outcomes other than slightly higher pancreas thrombosis (8% R-female vs. 4.2% R-male, p = .28) and early relaparotomy rates in female recipients (38% R-female vs. 29% R-male, p = .14). When analyzing the 4 D/R sex categories, the two D-male groups had higher kidney GSRs compared to the two D-female groups (p = .01) whereas early relaparotomy and pancreas thrombosis rates were numerically higher in the D-female/R-female group compared to the other three groups. Finally, there were no significant differences in outcomes between sex-matched and sex-mismatched groups although overall survival outcomes were lower with female donors irrespective of recipient sex.

CONCLUSIONS

The influence of D/R sex following SPKT is subject to multiple confounding issues but survival rates appear to be higher in D-male/R-male and lower in D-female/R-male categories.

Sex and gender as predictors for allograft and patient‐relevant outcomes after kidney transplantation

This is a protocol for a Cochrane Review (prognosis). The objectives are as follows:

To evaluate the prognostic effect of the recipient's (i) sex and gender separately (ii) gender as an independent predictor of patient‐relevant outcomes at any time period following kidney or SPK transplantation (Table 1 ) and explore sources of heterogeneity. We aim to evaluate this prognostic effect by (a) clearly defining the relationship between recipient sex/gender and post‐transplantation outcomes, which would involve identifying reasons for variations between sexes and genders, and then (b) quantifying the magnitude of this relationship. 

Influence of Donor and Recipient Sex Matching in Simultaneous Pancreas-Kidney Transplantation Outcomes

BACKGROUND

Several studies in solid organ transplantation have shown a correlation between donor and recipient sex mismatch and risk of graft loss; however, it is possible influence is not well established. The aim of our study was to review the outcomes of pancreatic and kidney grafts in our series depending on sex matching.

METHODS

We retrospectively analyzed a cohort of 199 patients who underwent simultaneous pancreas-kidney transplantation from February 1989 to June 2019 at the Reina Sofia University Hospital.

RESULTS

Survival of patients in the series was 93.5% at 5 years, 84.3% at 10 years, and 71.5% at 15 years. In the sex-discordant group, survival of patients in the series at 5, 10, and 15 years was 94%, 82.3%, and 71.7% compared with 92.3%, 85.1%, and 72.2% in the concordant group, with no statistically significant differences (P = .86). Pancreatic graft survival censored for death at 5, 10, and 15 years was 79.5%, 60.8%, and 57.5% in the group with discordant sex vs 77.5%, 67.8%, and 65.5% in the concordant group, finding no statistically significant differences (P = .54). Kidney graft survival censored for death at 5, 10, and 15 years was 89.3%, 85%, and 78.1% in the sex-discordant group vs 87.3%, 83.5%. and 78.8% in the concordant group, with no differences (P = .69). No differences were observed between the 2 groups in the rate of serious postoperative complications or acute rejection.

CONCLUSION

Our study shows that donor-recipient sex mismatch in simultaneous pancreas-kidney transplantation does not negatively influence perioperative outcomes and survival of the patient and both grafts.

Post-Transplant Malignancies following Pancreas Transplantation: Incidence and Implications on Long-Term Outcome from a Single-Center Perspective

Chronic immunosuppression is associated with an increased risk of malignancy. The main objective of this study is to evaluate the incidence and effect of post-transplant malignancies (PTMs) following pancreas transplantation. The 348 first pancreas transplants performed between 1985 and 2015 were retrospectively analyzed in this study. Incidences of PTMs, as well as patient and graft survival, were evaluated. Out of 348 patients, 71 (20.4%) developed a PTM. Median time to diagnosis was 130 months. Thirty-six patients (50.7%) developed skin cancers (four patients with melanoma, 32 with NMSCs). Solid organ malignancy occurred in 25 (35.2%), hematologic malignancy in ten patients (14.1%). Affected patients were transplanted earlier [2000 (IQR 1993−2004) vs. 2003 (IQR 1999−2008); p < 0.001]. No differences in induction therapy were seen, both groups demonstrated comparable patient and graft survival. Pancreas transplant recipients with solid organ and hematologic malignancies had a three- and six-fold increased hazard of death compared to those with skin cancers [aHR 3.04 (IQR 1.17–7.91); p = 0.023; aHR 6.07 (IQR 1.87–19.71); p = 0.003]. PTMs affect every fifth patient following pancreas transplantation. Skin cancers are the most common malignancies accounting for 50% of all PTMs. These results underscore the importance of close dermatologic follow-up.

Recipient age and outcome after pancreas transplantation: a retrospective dual-center analysis

With a later onset of diabetes complications and thus increasing age of transplant candidates, many centers have extended upper age limits for pancreas transplantation. This study investigates the effect of recipient and donor age on outcomes after pancreas transplantation.We retrospectively analyzed 565 pancreas transplants performed at two Eurotransplant centers. The cohort was split at a recipient and donor age of 50 and 40 years, respectively. Median recipient age in old patients (≥50 years; 27.2%) was 54 years and 40 years in young patients (<50 years). Compared to young recipients, old recipients had an inferior patient survival rate (≥50: 5yr, 82.8%; 10yr, 65.6%; <50: 5yr, 93.3%; 10yr, 82.0%; P < 0.0001). Old recipients demonstrated comparable death-censored pancreas (≥50: 1yr, 80.6%; 5yr, 70.2%; <50: 1yr, 87.3%; 5yr, 77.8%; P = 0.35) and kidney graft survival (≥50: 1yr, 97.4%; 5yr, 90.6%; <50: 1yr, 97.8%; 5yr, 90.2%; P = 0.53) compared to young recipients. Besides a lower rate of kidney rejection, similar relative risks for postoperative complications were detected in old and young patients. This study shows that despite an increased mortality in old recipients, excellent graft survival can be achieved similar to that of young patients. Age alone should not exclude patients from receiving a pancreas transplant.

Donor cardiac arrest and cardiopulmonary resuscitation: impact on outcomes after simultaneous pancreas-kidney transplantation - a retrospective study

Donor cardiac arrest and cardiopulmonary resuscitation (CACPR) has been considered critically because of concerns over hypoperfusion and mechanical trauma to the donor organs. We retrospectively analyzed 371 first simultaneous pancreas–kidney transplants performed at the Medical University of Innsbruck between 1997 and 2017. We evaluated short‐ and long‐term outcomes from recipients of organs from donors with and without a history of CACPR. A total of 63 recipients received a pancreas and kidney graft from a CACPR donor. At 1, and 5‐years, patient survival was similar with 98.3%, and 96.5% in the CACPR and 97.0%, and 90.2% in the non‐CACPR group (log rank P = 0.652). Death‐censored pancreas graft survival was superior in the CACPR group with 98.3%, and 91.4% compared to 86.3%, and 77.4% (log rank P = 0.028) in the non‐CACPR group, which remained statistically significant even after adjustment [aHR 0.49 (95% CI 0.24–0.98), P = 0.044]. Similar relative risks for postoperative complications Clavien Dindo > 3a, pancreatitis, abscess, immunologic complications, delayed pancreas graft function, and relative length of stay were observed for both groups. Donors with a history of CACPR are, in the current practice, safe for transplantation. Stringent donor selection and short CPR durations may allow for outcomes surpassing those of donors without CACPR.

Sex matching does not impact the outcome after simultaneous pancreas-kidney transplantation

Background

Several studies in solid organ transplantation have shown a correlation between donor and recipient sex mismatch and risk of graft loss. In this study, we aimed to analyze the impact of donor and recipient sex matching on patient and pancreas graft survival in a large single‐center cohort.

Methods

We retrospectively analyzed all first simultaneous pancreas‐kidney transplants performed between 1979 and 2017 at the Medical University of Innsbruck.

Results

Of 452 patients, 54.6% (247) received a sex‐matched transplant. Patient survival (P = .86), death‐censored pancreas graft survival (dcPGS, P = .26), and death‐censored kidney graft survival (dcKGS, P = .24) were similar between the sex‐matched and sex‐mismatched groups. Patient survival and dcPGS at 1, 5, and 15 years were 95.9%, 90.0%, and 62.1% and 86.1%, 77.1%, and 56.7% in the sex‐matched group and 93.6%, 86.2%, and 62.4% and 83.1%, 73.3%, and 54.3% in the sex‐mismatched group. Sex matching led to a lower odds of severe postoperative complications (41.2% vs 49.0%; OR 0.57, 95%CI 0.33‐0.97; P = .038); however, no increased odds of other adverse postoperative outcomes was detected.

Conclusion

Our study demonstrates that sex matching reduced the odds of postoperative complications but did not impact other early and late outcome parameters in our cohort.