Association between serum osteoprotegerin level and mortality in kidney transplant recipients - a prospective observational cohort study.

Paradoxically, higher serum levels of osteoprotegerin (OPG: a vascular calcification inhibitor) have been associated with increased arterial stiffness, risk of cardiovascular disease and all-cause mortality. A few studies reported that post-transplant OPG levels are associated with mortality in kidney transplant (KT) recipients. In this study, this association was assessed in a cohort of prevalent KT recipients, adjusting for previously untested potential confounders, including fibroblast growth factor 23 (FGF23) and interleukin 6 (IL-6). Socio-demographic and clinical parameters, medical and transplant history, and laboratory data were collected from 982 prevalent KT recipients. The association between serum OPG and all-cause mortality over a 6-year follow-up period was examined using Kaplan-Meier survival curves and multivariable-adjusted Cox regression models. Participants with high serum OPG were more likely female, older, deceased donor KT recipients and have more comorbidity, lower eGFR, higher FGF23, higher IL-6, and longer dialysis vintage. Each 1 pmol/l higher serum OPG level was associated with a 49% higher risk of mortality (hazard ratio (HR) [95% confidence interval (CI)]: 1.49 [1.40-1.61]). This association persisted after adjusting for confounders (HR [95% CI]: 1.20 [1.10-1.30]). In conclusion, serum OPG was associated with all-cause mortality independent of several novel confounders in prevalent KT recipients.

Evaluating symptom burden in kidney transplant recipients: validation of the revised Edmonton Symptom Assessment System for kidney transplant recipients - a single-center, cross-sectional study.

We assessed the validity of the Edmonton Symptom Assessment System (ESAS-r) in kidney transplant recipients (KTR). A cross-sectional sample of 252 KTR was recruited. Individual ESAS-r symptom scores and symptom domain scores were evaluated. Internal consistency, convergent validity, and construct validity were assessed with Cronbach's α, Spearman's rank correlations, and a priori-defined risk group comparisons. Mean (SD) age was 51 (16), 58% were male, and 58% Caucasian. ESAS-r Physical, Emotional, and Global Symptom Scores demonstrated good internal consistency (α > 0.8 for all). ESAS-r Physical and Global Symptom Scores strongly correlated with PHQ-9 scores (0.72, 95% CI: 0.64-0.78 and 0.74, 95% CI: 0.67-0.80). For a priori-defined risk groups, individual ESAS-r symptom score differed between groups with lower versus higher eGFR [pain: 1 (0-3) vs. 0 (0-2), delta = 0.18; tiredness: 3 (1-5) vs. 1.5 (0-4), delta = 0.21] and lower versus higher hemoglobin [tiredness: 3 (1-6) vs. 2 (0-4), delta = 0.27]. ESAS-r Global and Physical Symptom Scores differed between groups with lower versus higher hemoglobin [13 (6-29) vs. 6.5 (0-18.5), delta = 0.3, and 9 (2-19) vs. 4 (0-13), delta = 0.24] and lower versus higher eGFR [11 (4-20) vs. 6.5 (2-13), delta = 0.21, and 7 (2-16) vs. 3 (0-9), delta = 0.26]. These data support reliability and construct validity of ESAS-r in KTR. Future studies should explore its clinical utility for symptom assessment among KTR.

Validation of the Patient-Reported Outcomes Measurement Information System (PROMIS)-57 and -29 item short forms among kidney transplant recipients.

OBJECTIVE: The Patient-Reported Outcomes Measurement Information System (PROMIS) aims to address the lack of generalizable and universal measure of patient-reported outcomes to assess health-related quality of life. It has not been validated for patients with chronic kidney disease. We aim to validate the PROMIS-57 and PROMIS-29 questionnaires among kidney transplant recipients. METHODS: A cross-sectional sample of stable kidney transplant recipients was recruited. Each participant completed PROMIS-57, a 57-question instrument covering seven domains-physical function, anxiety, depression, fatigue, pain, sleep disturbance, and social functioning-alongside validated legacy questionnaires [Patient Health Questionnaire (PHQ9), General Anxiety Disorder (GAD7), Edmonton Symptom Assessment Scale revised (ESASr), and Kidney Disease Quality of Life (KDQoL-36)]. PROMIS-29, a 29-question instrument, is nested within PROMIS-57 and measures the same domains. Structural validity of PROMIS was assessed with confirmatory factor analysis, reported using the Comparative Fit Index (CFI). Construct validity was assessed with known-groups comparisons. Internal consistency was evaluated with Cronbach's α and convergent validity was assessed with Spearman's Rho. Test-retest reliability was assessed through the intraclass correlation coefficient (ICC). RESULTS: Mean (± SD) age of the 177 participants was 50 (± 17), 57% were male and 55% Caucasian. Internal consistency of each domain was high (Cronbach's α > 0.88). Confirmatory factor analysis showed good structural validity for most domains (CFI > 0.95, RMSEA < 0.05). Test-retest reliability indicated good agreement (ICC > 0.6). Known-groups comparisons by clinical and socio-demographic differences were found as hypothesized. CONCLUSIONS: Our results provide evidence that PROMIS-57 and PROMIS-29 are highly reliable and valid instruments among kidney transplant recipients. We propose it as a valuable tool to assess important domains of the illness experience.

Older Age is Associated With Lower Utilization of Living Donor Kidney Transplant.

Introduction: Older adults (65 years or older) constitute a substantial and increasing proportion of patients with kidney failure, potentially needing kidney replacement therapy. Living donor kidney transplant (LDKT) offers superior outcomes for suitable patients of all ages. However, exploring LDKT and finding a living donor could be challenging for older adults. Here, we assessed the association between age and utilization of LDKT and assessed effect modification of key variables such as ethnicity and language. Methods: This is a retrospective cohort study of patients with kidney failure referred for kidney transplant (KT) assessment in Toronto between January 2006 and December 2013. The association between age and having a potential living donor identified was assessed using logistic regression and the association between age and the receipt of LDKT was assessed using Cox proportional hazards models. Results: Of the 1617 participants, 50% were middle-aged (45-64 years old), and 17% were ≥65 years old. In our final multivariable adjusted models, compared to young adults, middle-aged and older adults had lower odds of having a potential living donor identified (odds ratio [OR], 0.47; confidence interval [CI], [0.35-0.63]; OR, 0.30; CI, [0.20-0.43]; P < 0.001, for middle-aged and older adults, respectively), and were less likely to receive LDKT (hazard ratio [HR], 0.79; CI, [0.63-0.99]; P = 0.04; HR, 0.47; CI, [0.30-0.72]; P = 0.001, for middle-aged and older adults, respectively.). Conclusion: Age is an independent predictor of receiving LDKT. Considering that nearly 90% of patients with kidney failure in Canada are >45 years of age, these results point to important and potentially modifiable age-related barriers to LDKT.