Frailty and sarcopenia in older kidney transplant recipients: a cross-sectional study.

Purpose: The aging of the kidney transplant population is accelerating, and measures against geriatric syndromes including frailty and sarcopenia, which elevate the risk of needing long-term care and even death, are being considered important. Recently, both the frailty and sarcopenia criteria for Asians were revised based on various research reports and clinical experiences. The purpose of this study is twofold: firstly, to investigate the prevalence of frailty based on the revised Japanese version of the Cardiovascular Health Study (J-CHS) criteria and the Kihon Checklist (KCL) and that of sarcopenia based on the Asian Working Group for Sarcopenia (AWGS) 2019 as well as the relationship between frailty and sarcopenia, and secondly, to determine the concurrent validity of the KCL with the revised J-CHScriteria in older kidney transplant recipients.

Methods: This study was a single-center cross-sectional investigation carried out on older kidney transplant recipients who visited our hospital from August 2017 to February 2019. The diagnosis of frailty was assessed using the revised J-CHS criteria and the KCL. The diagnosis of sarcopenia was made by low skeletal muscle mass and either low physical performance or low muscle strength based on the AWGS 2019. To examine the relationship between frailty and sarcopenia, categorical variables were compared using chi-squared test and continuous variables Mann-Whitney U test. Spearman's correlation analysis was used to investigate the correlation between the KCL score and the revised J-CHS score. The concurrent validity of the KCL for estimating frailty based on the revised J-CHS criteria was evaluated using the receiver operating characteristics (ROC) curve analysis.

Results: A total of 100 older kidney transplant recipients were enrolled in this study. The median age was 67, 63 (63%) were males, and the median time after transplant was 95 months. The prevalence of frailty based on the revised J-CHS criteria and the KCL, and sarcopenia based on the AWGS 2019 was 15%, and 19%, and 16% respectively. Sarcopenia was significantly associated with frailty based on the KCL (p = 0.016), while not with frailty based on the revised J-CHS criteria (p = 0.11). The KCL score significantly correlated with the revised J-CHS score (p < 0.001). The area under the ROC curve was 0.91.

Conclusion: Frailty and sarcopenia are interrelated complex geriatric syndromes that are risk factors for adverse health outcomes. In older kidney transplant recipients, frailty and sarcopenia were highly prevalent and frequently co-existed. Furthermore, the KCL was verified as a useful tool for frailty screening in these patient. Easy identification of patients with frailty, which is reversible, can help clinicians institute appropriate corrective measures for kidney transplant recipients to improve transplant outcomes.