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
... -
《Cochrane Database of Systematic Reviews》
Urinary Dickkopf-3 Reflects Disease Severity and Predicts Short-Term Kidney Function Decline in Renal Ciliopathies.
Phenotypic heterogeneity and unpredictability of individual disease progression present enormous challenges in ultrarare renal ciliopathies. The tubular-derived glycoprotein, Dickkopf-related protein 3 (DKK3) is a promising biomarker for kidney fibrosis and prediction of kidney function decline. Here, we measured urinary DKK3 (uDKK3) levels in 195 pediatric patients with renal ciliopathy to assess its potential as a discriminative and prediction marker.
uDKK3 concentration was measured in 357 spot urine samples from 247 individuals, including 52 healthy age-matched controls. Disease entities comprised nephronophthisis (NPH) (n = 37), autosomal recessive polycystic kidney disease (ARPKD) (n = 61), Bardet Biedl syndrome (BBS) (n = 57), and hepatocyte nuclear factor 1 beta (HNF1B)-nephropathy (n = 40). The results were correlated with chronic kidney disease (CKD) stage and annual estimated glomerular filtration rate (eGFR) decline.
Median uDKK3-to-creatinine ratios (uDKK3/crea) in all disease entities were significantly higher compared with healthy controls (11pg/mg uDKK3/crea, P < 0.001): NPH, 1.219 pg/mg; HNF1B, 731 pg/mg; BBS, 541 pg/mg; and ARPKD, 437 pg/mg. A significant correlation of CKD stage with uDKK3 levels was observed for all disease entities (P < 0.0001) with no other clinical parameter having a relevant impact. In our cohort, uDKK3 values >4.700 pg/mg were associated with a significantly greater annual eGFR loss independently of diagnosis and eGFR (P = 0.0029). Although we observed a trend toward lower uDKK3 levels in glomerulopathies compared to renal ciliopathies, there was no discriminative difference between individual ciliopathy entities (P = 0.2637).
In renal ciliopathies, uDKK3 is a marker to assess disease severity and estimate short-term kidney function decline.
Dahmer-Heath M
,Gerß J
,Fliser D
,Liebau MC
,Speer T
,Telgmann AK
,Burgmaier K
,Pennekamp P
,Pape L
,Schaefer F
,Konrad M
,König JC
,NEOCYST Consortium
... -
《Kidney International Reports》