Faculty Bibliography

BACKGROUND:Few objective tests can be performed at admission for kidney transplantation [KT] to discern risk of increased length of stay [LOS], which is important for patient counseling and is associated with increased costs and mortality. The short physical performance battery [SPPB] is an easily administered, potentially modifiable, 3-part test of lower extremity function. SPPB score is associated with longer hospital LOS in older adults, and may provide similar utility in KT recipients given that ESRD is a disease of accelerated aging. The aim of this study was to characterize the association between SPPB-derived lower extremity function and LOS. METHODS:The SPPB was administered at KT admission in a prospective cohort of 595 recipients (8/2009-6/2016). The independent association between SPPB impairment (score ≤ 10) and LOS was tested with an adjusted conventional generalized gamma parametric survival model. RESULTS:Impaired recipients experienced longer LOS (median: 10 vs. 8 days; P <  0.001) with the greatest difference in percent discharged on day 10 (impaired: 54.5%, unimpaired: 73.3%). Discharge typically took 13% longer in the impaired group (relative time = 1.13; 95%CI: 1.05, 1.21, P = 0.001). Discharge for impaired recipients compared to unimpaired was least likely at day 5 (hazard ratio = 0.71; 95% CI:0.68, 0.74, P <  0.001). No differences in the SPPB impairment-LOS relationship were found by age (interaction P = 0.74). CONCLUSIONS:Pre-KT SPPB impairment was independently associated with longer LOS regardless of age, indicating that it is a useful, objective tool for pre-KT risk assessment in younger and older recipients that may help inform discharge planning.

OBJECTIVES/OBJECTIVE:Evidence suggests vitamin D deficiency is associated with developing frailty. However, cardiometabolic factors are related to both conditions and may confound and/or mediate the vitamin D-frailty association. We aimed to determine the association of vitamin D concentration with incidence of frailty, and the role of cardiometabolic diseases (cardiovascular disease, diabetes, hyperlipidemia, hypertension) in this relationship. DESIGN/METHODS:Prospective longitudinal cohort study (7 visits from 1994-2008). SETTING/METHODS:Baltimore, Maryland. PARTICIPANTS/METHODS:Three hundred sixty-nine women from the Women's Health and Aging Study II aged 70-79 years, free of frailty at baseline. MEASUREMENTS/METHODS:Serum circulating 25-hydroxyvitamin D (25[OH]D) concentration was assessed at baseline and categorized as: <10; 10-19.9; 20-29.9; and ≥30 ng/mL. Frailty incidence was determined based on presence of three or more criteria: weight loss, low physical activity, exhaustion, weakness, and slowness. Cardiometabolic diseases were ascertained at baseline. Analyses included Cox regression models adjusted for key covariates. RESULTS:Incidence rate of frailty was 32.2 per 1,000 person-years in participants with 25(OH)D < 10 ng/mL, compared to 12.9 per 1,000 person-years in those with 25(OH)D ≥ 30 ng/mL (mean follow-up = 8.5 ± 3.7 years). In cumulative incidence analyses, those with lower 25(OH)D exhibited higher frailty incidence, though differences were non-significant (P = .057). In regression models adjusted for demographics, smoking, and season, 25(OH)D < 10 ng/mL (vs ≥30 ng/mL) was associated with nearly three-times greater frailty incidence (hazard ratio (HR) = 2.77, 95% CI = 1.14, 6.71, P = .02). After adjusting for BMI, the relationship of 25(OH)D < 10 ng/mL (vs ≥30 ng/mL) with incident frailty persisted, but was attenuated after further accounting for cardiometabolic diseases (HR = 2.29, 95% CI = 0.92, 5.69, P = .07). CONCLUSION/CONCLUSIONS:Low serum vitamin D concentration is associated with incident frailty in older women; interestingly, the relationship is no longer significant after accounting for the presence of cardiometabolic diseases. Future studies should explore mechanisms to explain this relationship.

BACKGROUND:After kidney transplantation, early readmission is independently associated with graft loss and mortality. The mechanism of this association is poorly understood. Understanding the timeline of risk, that is, during the readmission hospitalization versus periods postreadmission, will provide additional insights. METHODS:We used national registry data to study 56 076 adult Medicare-primary first-time kidney transplant recipients from December 1999 to October 2011. Piecewise Cox proportional hazard models were used to estimate the association between graft loss, mortality, and readmission for 2 periods: readmission hospitalization and postreadmission. RESULTS:During the readmission hospitalization, graft loss was substantially higher (deceased donor kidney transplant [DDKT] without delayed graft function [DGF] hazard ratio: 24.634.447.9, P < 0.001; with DGF: 10.815.221.4, P < 0.001; live donor kidney transplant [LDKT]: 18.136.774.2, P < 0.001) and mortality was substantially higher (DDKT without DGF: 14.120.830.7, P < 0.001; with DGF: 9.0312.818.0, P < 0.001; LDKT: 9.0018.241.3, P < 0.001). Immediately after readmission discharge, graft loss (DDKT without DGF: 2.082.402.77, P < 0.001; with DGF: 1.832.142.51, P < 0.001; LDKT: 2.002.503.13, P < 0.001), and mortality (DDKT without DGF: 2.162.432.73, P < 0.001; with DGF: 1.832.162.88, P < 0.001; LDKT: 1.902.342.88, P < 0.001) remained elevated, but much less so. After readmission, the hazard of graft loss remained, but decreased 19% per year for DDKT recipients (time varying coefficient 0.780.810.85, P < 0.001) and 14% per year for LDKT recipients (0.790.860.93, P < 0.001). The hazard of mortality remained, but decreased 14% per year for DDKT recipients (0.830.860.89, P < 0.001) and 9% per year for LDKT recipients (0.850.910.98, P < 0.001). CONCLUSIONS:In conclusion, readmission is most strongly associated with graft loss and mortality during the readmission hospitalization, but also portends a lasting, albeit attenuated, risk postreadmission.

Older patients with ESRD who receive a kidney transplant (KT) may develop post-KT dementia and Alzheimer's disease (AD) associated with their long-standing kidney disease and/or neurotoxic immunosuppressant agents. To investigate this possibility, we studied 40,918 older (aged ≥55 years) KT recipients (January 1, 1999 to December 31, 2011) linked to Medicare claims through the US Renal Data System. We estimated dementia and AD risk (cumulative incidence) and studied factors associated with these sequelae using competing risks models. We estimated the risk of death-censored graft loss and mortality after developing dementia or the AD subtype of dementia, separately, using adjusted Cox proportional hazards models. Older recipients had a 10-year dementia risk ranging from 5.1% for recipients aged 55-60 years to 17.0% for recipients aged ≥75 years; 10-year AD risk ranged from 1.0% to 6.7%, respectively. The strongest predictors for dementia and AD were older recipient age and pretransplant diabetes. The 10-year graft loss risk was 28.8% for those who did not develop dementia and 43.1% for those who did, and the corresponding mortality risks were 55.7% and 89.9%, respectively. Older recipients with dementia had a 1.52-fold (95% confidence interval, 1.39 to 1.68) increased risk of graft loss and a 2.38-fold (95% confidence interval, 2.26 to 2.49) increased risk of mortality. We observed similar results for AD. We conclude that older KT recipients have a high risk of post-KT dementia and AD, and these sequelae associate with a profound effect on patient and graft survival.

BACKGROUND:There is increasing evidence questioning the use of warfarin for atrial fibrillation (AF) among older adults with end stage renal disease (ESRD). We assessed the patterns and determinants of warfarin utilization among these patients in the US. METHODS:We assembled a cohort of older adults (age ≥65) undergoing dialysis with incident AF from July 2007 to November 2011 from the US Renal Data System (USRDS). We used descriptive statistics to characterize warfarin utilization within 30 days of AF discharge, and logistic regression to quantify patient characteristics associated with warfarin initiation. RESULTS:Among 5730 older adults undergoing dialysis with incident AF, 15.5% initiated warfarin. Among 2906 patients with high risk of bleeding, 12.7% initiated warfarin; whereas 14.9% initiated warfarin among 4824 patients with high risk of stroke. After adjustment for patient characteristics, warfarin initiation was lower among patients who were older [odds ratio (OR) = 0.74 per 10-year increase, 95% confidence interval (CI) 0.66-0.83] and those with a history of diabetes (OR = 0.75, 95% CI 0.63-0.90), myocardial infarction (OR = 0.64, 95% CI 0.50-0.80), or bleeding (OR = 0.63, 95% CI 0.50-0.80). There was no association between sex, race, or dialysis modality and warfarin initiation. Among patients who initiated warfarin, 46.8% discontinued warfarin use after a median treatment length of 8.6 months. CONCLUSION/CONCLUSIONS:Despite the unclear benefit and increased bleeding risk of warfarin treatment in patients with ESRD, 1 in 8 older adults undergoing dialysis with incident AF in the US who had high risk of bleeding used warfarin. Changes to warfarin therapy due to discontinuation were common after initiation.

BACKGROUND:Frail individuals are at increased risk for poor outcomes, including adverse drug events. Kidney function is often compromised in frailty and is a key consideration in medication choice and dosing; however, creatinine-based measures of kidney function may be biased in frail individuals. STUDY DESIGN/METHODS:Observational study. SETTING & PARTICIPANTS/METHODS:4,987 community-dwelling older men and women with complete data who participated in visit 5 of the Atherosclerosis Risk in Communities (ARIC) Study (2011-2013). PREDICTORS/METHODS:) and urine albumin-creatinine ratio. OUTCOME/RESULTS:Frailty, defined using established criteria of 3 or more frailty characteristics (weight loss, slowness, exhaustion, weakness, and low physical activity). RESULTS:). Hyperpolypharmacy (taking ≥10 classes of medications) was more common in frail individuals (54% vs 38% of nonfrail), including classes requiring kidney clearance (eg, digoxin) and associated with falls and subsequent complications (eg, hypnotic/sedatives and anticoagulants). LIMITATIONS/CONCLUSIONS:Cross-sectional study design. CONCLUSIONS:. Given the substantial medication burden and uncertainty in chronic kidney disease classification, confirmation of kidney function with alternative biomarkers may be warranted to ensure careful prescribing practices in this vulnerable population.

OBJECTIVE:To test whether frailty, a novel measure of physiologic reserve, is associated with longer kidney transplant (KT) length of stay (LOS), and modifies the association between LOS and mortality. BACKGROUND:Better understanding of LOS is necessary for informed consent and discharge planning. Mortality resulting from longer LOS has important regulatory implications for hospital and transplant programs. Which recipients are at risk of prolonged LOS and its effect on mortality are unclear. Frailty is a novel preoperative predictor of poor KT outcomes including delayed graft function, early hospital readmission, immunosuppression intolerance, and mortality. METHODS:We used registry-augmented hybrid methods, a novel approach to risk adjustment, to adjust for LOS risk factors from the Scientific Registry of Transplant Recipients (n = 74,859) and tested whether (1) frailty, measured immediately before KT in a novel cohort (n = 589), was associated with LOS (LOS: negative binomial regression; LOS ≥2 weeks: logistic regression) and (2) whether frailty modified the association between LOS and mortality (interaction term analysis). RESULTS:Frailty was independently associated with longer LOS [relative risk = 1.15, 95% confidence interval (CI): 1.03-1.29; P = 0.01] and LOS ≥2 weeks (odds ratio = 1.57, 95% CI: 1.06-2.33; P = 0.03) after accounting for registry-based risk factors, including delayed graft function. Frailty also attenuated the association between LOS and mortality (nonfrail hazard rate = 1.55 95% CI: 1.30-1.86; P < 0.001; frail hazard rate = 0.97, 95% CI: 0.79-1.19, P = 0.80; P for interaction = 0.001). CONCLUSIONS:Frail KT recipients are more likely to experience a longer LOS. Longer LOS among nonfrail recipients may be a marker of increased mortality risk. Frailty is a measure of physiologic reserve that may be an important clinical marker of longer surgical LOS.