Faculty Bibliography

Estimating the total coronavirus disease 2019 (COVID-19) mortality burden of solid organ transplant recipients (SOTRs), both directly through COVID-19 infection and indirectly through other impacts on the healthcare system and society, is critical for understanding the disease's impact on the SOTR population. Using SRTR data, we modeled expected mortality risk per month pre-COVID (January 2015-February 2020) for kidney/liver/heart/lung SOTRs, and compared monthly COVID-era deaths (March 2020-March 2021) to expected rates, overall and among subgroups. Deaths above expected rates were designated "excess deaths." Between March 2020 and March 2021, there were 3739/827/265/252 excess deaths among kidney/liver/heart/lung SOTRs, respectively, representing a 41.2%/27.4%/18.5%/15.0% increase above expected deaths. 93.0% of excess deaths occurred in patients age≥50. The observed:expected ratio was highest among Hispanic SOTRs (1.82) and lowest among White SOTRs (1.20); 56.0% of excess deaths occurred among Black or Hispanic SOTRs. 64.7% of excess deaths occurred among patients who had survived ≥5 years post-transplant. Excess deaths peaked in January 2021; geographic distribution of excess deaths broadly mirrored COVID-19 incidence. COVID-19 likely caused over 5000 excess deaths among SOTRs in the US in a 13-month period, representing 1 in 75 SOTRs and a substantial proportion of all deaths among SOTRs during this time. SOTRs will remain at elevated mortality risk until the COVID-19 pandemic can be controlled.

BACKGROUND:Frailty predicts adverse post-kidney transplant (KT) outcomes, yet the impact of frailty assessment on center-level outcomes remains unclear. We sought to test whether transplant centers assessing frailty as part of clinical practice have better pre- and post-KT outcomes in all adult patients (≥18 years) and older patients (≥65 years). METHODS:In a survey of US transplant centers (11/2017-4/2018), 132 (response rate = 65.3%) centers reported their frailty assessment practices (frequency and specific tool) at KT evaluation and admission. Assessment frequency was categorized as never, sometime, and always; type of assessment tool was categorized as none, validated (for post-KT risk prediction), and any other tool. Center characteristics and clinical outcomes for adult patients during 2017-2019 were gleaned from the transplant national registry (Scientific Registry of Transplant Recipients). Poisson regression was used to estimate incidence rate ratios (IRRs) of waitlist outcomes (waitlist mortality, transplantation) in candidates and IRRs of post-KT outcomes (all-cause mortality, death-censored graft loss) in recipients by frailty assessment frequency. We also estimated IRRs of waitlist outcomes by type of assessment tool at evaluation. All models were adjusted for case mix and center characteristics. RESULTS:Assessing frailty at evaluation was associated with lower waitlist mortality rate (always IRR = 0.91,95%CI:0.84-0.99; sometimes = 0.89,95%CI:0.83-0.96) and KT rate (always = 0.94,95%CI:0.91-0.97; sometimes = 0.88,95%CI:0.85-0.90); the associations with waitlist mortality rate (always = 0.86,95%CI:0.74-0.99; sometimes = 0.83,95%CI:0.73-0.94) and KT rate (always = 0.82,95%CI:0.77-0.88; sometimes = 0.92,95%CI:0.87-0.98) were stronger in older patients. Furthermore, using validated (IRR = 0.90,95%CI:0.88-0.92) or any other tool (IRR = 0.90,95%CI:0.87-0.93) at evaluation was associated lower KT rate, while only using a validated tool was associated with lower waitlist mortality rate (IRR = 0.89,95%CI:0.83-0.96), especially in older patients (IRR = 0.82,95%CI:0.72-0.93). At admission for KT, always assessing frailty was associated with a lower graft loss rate (IRR = 0.71,95%CI:0.54-0.92) but not with mortality (IRR = 0.93,95%CI:0.76-1.13). CONCLUSIONS:Assessing frailty at evaluation is associated with lower KT rate, while only using a validated frailty assessment tool is associated with better survival, particularly in older candidates. Centers always assessing frailty at admission are likely to have better graft survival rates. Transplant centers may utilize validated frailty assessment tools to secure KT access for appropriate candidates and to better allocate health care resources for patients identified as frail, particularly for older patients.

Physical frailty and impaired cognition are common in patients with cirrhosis. Physical frailty can be assessed using performance-based tests, but the extent to which impaired cognition may impact performance is not well characterized. We assessed the relationship between impaired cognition and physical frailty in patients with cirrhosis. We enrolled 1,623 ambulatory adult patients with cirrhosis waiting for liver transplantation at 10 sites. Frailty was assessed with the liver frailty index (LFI; "frail," LFI ≥ 4.4). Cognition was assessed at the same visit with the number connection test (NCT); continuous "impaired cognition" was examined in primary analysis, with longer NCT (more seconds) indicating worse impaired cognition. For descriptive statistics, "impaired cognition" was NCT ≥ 45 seconds. Linear regression associated frailty and impaired cognition; competing risk regression estimated subhazard ratios (sHRs) of wait-list mortality (i.e., death/delisting for sickness). Median NCT was 41 seconds, and 42% had impaired cognition. Median LFI (4.2 vs. 3.8) and rates of frailty (38% vs. 20%) differed between those with and without impaired cognition. In adjusted analysis, every 10-second NCT increase associated with a 0.08-LFI increase (95% confidence interval [CI], 0.07-0.10). In univariable analysis, both frailty (sHR, 1.63; 95% CI, 1.43-1.87) and impaired cognition (sHR, 1.07; 95% CI, 1.04-1.10) associated with wait-list mortality. After adjustment, frailty but not impaired cognition remained significantly associated with wait-list mortality (sHR, 1.55; 95% CI, 1.33-1.79). Impaired cognition mediated 7.4% (95% CI, 2.0%-16.4%) of the total effect of frailty on 1-year wait-list mortality. Conclusion: Patients with cirrhosis with higher impaired cognition displayed higher rates of physical frailty, yet frailty independently associated with wait-list mortality while impaired cognition did not. Our data provide evidence for using the LFI to understand mortality risk in patients with cirrhosis, even when concurrent impaired cognition varies.

Acute kidney injury (AKI) and frailty are major drivers of outcomes among patients with cirrhosis. What is unknown is the impact of physical frailty on the development of AKI. We included adults with cirrhosis without hepatocellular carcinoma listed for liver transplantation at nine US centers (n = 1,033). Frailty was assessed using the Liver Frailty Index (LFI); "frail" was defined by LFI ≥ 4.2. Chronic kidney disease as a baseline estimated glomerular filtration rate <60 mL/min/1.73 m² . Our primary outcome, AKI, was defined as an increase in serum creatinine ≥0.3 mg/dL or a serum creatinine ≥1.5-fold increase. Wait-list mortality was defined as either a death on the wait list or removal for being too sick. We performed Cox regression analyses to estimate the hazard ratios (HRs) for AKI and wait-list mortality. Of 1,033 participants, 41% were frail and 23% had CKD. Twenty-one percent had an episode of AKI during follow-up. Frail versus nonfrail patients were more likely to develop AKI (25% vs. 19%) and wait-list mortality (21% vs. 13%) (P < 0.01 for each). In multivariable Cox regression, each of the following groups was associated with a higher risk of AKI as compared with not frail/no CKD: frail/no CKD (adjusted HR [aHR] = 1.87, 95% confidence interval [CI] = 1.29-2.72); not frail/CKD (aHR = 4.30, CI = 2.88-6.42); and frail/CKD (aHR = 4.85, CI = 3.33-7.07). We use a readily available metric, LFI, to identify those patients with cirrhosis most at risk for AKI. We highlight that serum creatinine and creatinine-based estimations of glomerular filtration rate may not fully capture a patient's vulnerability to AKI among the frail phenotype. Conclusion: Our work lays the foundation for implementing physical frailty in clinical practice to identify AKI earlier, implement reno-protective strategies, and expedite liver transplantation.