Comparison of COVID-19 versus influenza on the incidence, features, and recovery from acute kidney injury in hospitalized United States Veterans.

Acute kidney injury is a common complication in patients hospitalized with SARSCoV-2 (COVID-19), with prior studies implicating multiple potential mechanisms of injury. Although COVID-19 is often compared to other respiratory viral illnesses, few formal comparisons of these viruses on kidney health exist. In this retrospective cohort study, we compared the incidence, features, and outcomes of acute kidney injury among Veterans hospitalized with COVID-19 or influenza and adjusted for baseline conditions using weighted comparisons. A total of 3402 hospitalizations for COVID-19 and 3680 hospitalizations for influenza admitted between October 1, 2019 and May 31, 2020 across 127 Veterans Administration hospitals nationally were studied using the electronic medical record. Acute kidney injury occurred more frequently among those with COVID-19 compared to those with influenza (40.9% versus 29.4%, weighted analysis) and was more severe. Patients with COVID-19 were more likely to require mechanical ventilation and vasopressors and experienced higher mortality. Proteinuria and hematuria were frequent in both groups but more common in COVID-19. Recovery of kidney function was less common in patients with COVID-19 and acute kidney injury but was similar among survivors. Thus, findings from this study confirm that acute kidney injury is more common and severe among patients hospitalized with COVID-19 compared to influenza, a finding that may be driven largely by illness severity. Hence, the combined impact of these two illnesses on kidney health may be significant and have important implications for resource allocation.

Renin-angiotensin aldosterone inhibitor use at hospital discharge among patients with moderate to severe acute kidney injury and its association with recurrent acute kidney injury and mortality.

Recurrent episodes of acute kidney injury (AKI) are common among AKI survivors. Renin-angiotensin aldosterone inhibitors (RAASi) are often indicated for these patients but may increase the risk for recurrent AKI. Here, we examined whether RAASi associates with a higher risk for recurrent AKI and mortality among survivors of moderate to severe AKI in a retrospective cohort of Veterans who survived Stage II or III AKI. The primary exposure was RAASi at hospital discharge and the primary endpoint was recurrent AKI within 12 months. Cox proportional hazards models were fit on a propensity score-weighted cohort to compare time to recurrent AKI and mortality by RAASi exposure. Among 96,983 patients, 40% were on RAASi at discharge. Compared to patients who continued RAASi use, those discontinuing use experienced no difference in risk for recurrent AKI but had a significantly higher risk of mortality [hazard ratio 1.33 (95% confidence interval1.26-1.41)]. No differences in recurrent AKI risk was observed for non-users started or not on RAASi compared to prevalent users who continued RAASi. Subgroup analyses among those with diabetes, chronic kidney disease, heart failure, and malignancy were similar with exception of a modest reduction in recurrent AKI risk among RAASi discontinuers with chronic kidney disease. Thus, RAASi use among survivors of moderate to severe AKI was associated with little to no difference in risk for recurrent AKI but was associated with improved survival. Reinitiating or starting RAASi among patients with strong indications is warranted but should be balanced with individual overall risk for recurrent AKI and with adequate monitoring.

Timing of Recovery From Moderate to Severe AKI and the Risk for Future Loss of Kidney Function.

RATIONALE & OBJECTIVE: The extent of recovery of kidney function following acute kidney injury (AKI) is known to be associated with future chronic kidney disease. Less is known about how the timing of recovery affects the rate of future loss of kidney function. STUDY DESIGN: We performed a retrospective cohort study examining the independent association between the timing of recovery from moderate to severe AKI and future loss of kidney function. SETTING & PARTICIPANTS: 47,903 adult US veterans with stage 2 or 3 AKI who recovered to within 120% of baseline creatinine level within 90 days of peak injury. EXPOSURE: The timing of recovery of kidney function from peak inpatient serum creatinine level grouped into 1 to 4, 5 to 10, 11 to 30, and 31 to 90 days. OUTCOME: A sustained 40% decline in estimated glomerular filtration rate below that calculated from the last serum creatinine level available during the 90-day recovery period or kidney failure (2 outpatient estimated glomerular filtration rates<15mL/min/1.73m2, dialysis procedures > 90 days apart, kidney transplantation, or registry within the US Renal Data System). ANALYTICAL APPROACH: Time to the primary outcome was examined using multivariable Cox proportional hazards regression. RESULTS: Among 47,903 patients, 29,316 (61%), 10,360 (22%), 4,520 (9%), and 3,707 (8%) recovered within 1 to 4, 5 to 10, 11 to 30, and 31 to 90 days, respectively. With a median follow-up of 42 months, unadjusted incidence rates for the kidney outcome were 2.01, 3.55, 3.86, and 3.68 events/100 person-years, respectively. Compared with 1 to 4 days, recovery within 5 to 10, 11 to 30, and 31 to 90 days was associated with increased rates of the primary outcome: adjusted HRs were 1.33 (95% CI, 1.24-1.43), 1.41 (95% CI, 1.28-1.54), and 1.58 (95% CI, 1.43-1.75), respectively. LIMITATIONS: Predominately male population, residual confounding, and inability to make causal inferences because of the retrospective observational study design. CONCLUSIONS: The timing of recovery provides an added dimension to AKI phenotyping and prognostic information regarding the future occurrence of loss of kidney function. Studies to identify effective interventions on the timing of recovery from AKI are warranted.

Tissue sodium stores in peritoneal dialysis and hemodialysis patients determined by 23-sodium magnetic resonance imaging.

BACKGROUND: Tissue sodium content in patients on maintenance hemodialysis (MHD) and peritoneal dialysis (PD) were previously explored using 23Sodium magnetic resonance imaging (23NaMRI). Larger studies would provide a better understanding of sodium stores in patients on dialysis as well as the factors influencing this sodium accumulation. METHODS: In this cross-sectional study, we quantified the calf muscle and skin sodium content in 162 subjects (10 PD, 33 MHD patients, and 119 controls) using 23NaMRI. Plasma levels of interleukin-6 (IL-6) and high-sensitivity C-reactive protein (hsCRP) were measured to assess systemic inflammation. Sixty-four subjects had repeat 23NaMRI scans that were analyzed to assess the repeatability of the 23NaMRI measurements. RESULTS: Patients on MHD and PD exhibited significantly higher muscle and skin sodium accumulation compared to controls. African American patients on dialysis exhibited greater muscle and skin sodium content compared to non-African Americans. Multivariable analysis showed that older age was associated with both higher muscle and skin sodium. Male sex was also associated with increased skin sodium deposition. Greater ultrafiltration was associated with lower skin sodium in patients on PD (Spearman's rho=-0.68, P = 0.035). Higher plasma IL-6 and hsCRP levels correlated with increased muscle and skin sodium content in the overall study population. Patients with higher baseline tissue sodium content exhibited greater variability in tissue sodium stores on repeat measurements. CONCLUSIONS: Our findings highlight greater muscle and skin sodium content in dialysis patients compared to controls without kidney disease. Tissue sodium deposition and systemic inflammation seen in dialysis patients might influence one another bidirectionally.

Acute Kidney Injury and Subsequent Frailty Status in Survivors of Critical Illness: A Secondary Analysis.

OBJECTIVES: Acute kidney injury frequently complicates critical illness and is associated with high morbidity and mortality. Frailty is common in critical illness survivors, but little is known about the impact of acute kidney injury. We examined the association of acute kidney injury and frailty within a year of hospital discharge in survivors of critical illness. DESIGN: Secondary analysis of a prospective cohort study. SETTING: Medical/surgical ICU of a U.S. tertiary care medical center. PATIENTS: Three hundred seventeen participants with respiratory failure and/or shock. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Acute kidney injury was determined using Kidney Disease Improving Global Outcomes stages. Clinical frailty status was determined using the Clinical Frailty Scale at 3 and 12 months following discharge. Covariates included mean ICU Sequential Organ Failure Assessment score and Acute Physiology and Chronic Health Evaluation II score as well as baseline comorbidity (i.e., Charlson Comorbidity Index), kidney function, and Clinical Frailty Scale score. Of 317 patients, 243 (77%) had acute kidney injury and one in four patients with acute kidney injury was frail at baseline. In adjusted models, acute kidney injury stages 1, 2, and 3 were associated with higher frailty scores at 3 months (odds ratio, 1.92; 95% CI, 1.14-3.24; odds ratio, 2.40; 95% CI, 1.31-4.42; and odds ratio, 4.41; 95% CI, 2.20-8.82, respectively). At 12 months, a similar association of acute kidney injury stages 1, 2, and 3 and higher Clinical Frailty Scale score was noted (odds ratio, 1.87; 95% CI, 1.11-3.14; odds ratio, 1.81; 95% CI, 0.94-3.48; and odds ratio, 2.76; 95% CI, 1.34-5.66, respectively). In supplemental and sensitivity analyses, analogous patterns of association were observed. CONCLUSIONS: Acute kidney injury in survivors of critical illness predicted worse frailty status 3 and 12 months postdischarge. These findings have important implications on clinical decision making among acute kidney injury survivors and underscore the need to understand the drivers of frailty to improve patient-centered outcomes.

Acute Kidney Injury as a Risk Factor for Delirium and Coma during Critical Illness.

RATIONALE: Acute kidney injury may contribute to distant organ dysfunction. Few studies have examined kidney injury as a risk factor for delirium and coma. OBJECTIVES: To examine whether acute kidney injury is associated with delirium and coma in critically ill adults. METHODS: In a prospective cohort study of intensive care unit patients with respiratory failure and/or shock, we examined the association between acute kidney injury and daily mental status using multinomial transition models adjusting for demographics, nonrenal organ failure, sepsis, prior mental status, and sedative exposure. Acute kidney injury was characterized daily using the difference between baseline and peak serum creatinine and staged according to Kidney Disease Improving Global Outcomes criteria. Mental status (normal vs. delirium vs. coma) was assessed daily with the Confusion Assessment Method for the ICU and Richmond Agitation-Sedation Scale. MEASUREMENTS AND MAIN RESULTS: Among 466 patients, stage 2 acute kidney injury was a risk factor for delirium (odds ratio [OR], 1.55; 95% confidence interval [CI], 1.07-2.26) and coma (OR, 2.04; 95% CI, 1.25-3.34) as was stage 3 injury (OR for delirium, 2.56; 95% CI, 1.57-4.16) (OR for coma, 3.34; 95% CI, 1.85-6.03). Daily peak serum creatinine (adjusted for baseline) values were also associated with delirium (OR, 1.35; 95% CI, 1.18-1.55) and coma (OR, 1.44; 95% CI, 1.20-1.74). Renal replacement therapy modified the association between stage 3 acute kidney injury and daily peak serum creatinine and both delirium and coma. CONCLUSIONS: Acute kidney injury is a risk factor for delirium and coma during critical illness.

Sarcopenic Obesity Definitions by Body Composition and Mortality in the Hemodialysis Patients.

OBJECTIVE: Sarcopenic obesity (SO), a combination of low muscle mass and high fat mass, is considered as risk factor for mortality in general population. It is unclear if SO affects mortality in maintenance hemodialysis (MHD) patients. In this study, we aimed to determine whether body composition as assessed by currently available SO definitions is related to all-cause mortality in MHD subjects. We also examined the impact of applying different definitions on the prevalence of SO in our MHD database. DESIGN: Retrospective analysis. SUBJECTS: Adult patients on MHD for at least 3 months with no acute illness studied in the clinical research center between 2003 and 2011. INTERVENTION: Assessment of body composition was performed using dual energy x-ray absorptiometry. SO (appendicular skeletal mass: arm lean mass + leg lean mass and fat mass) was defined according to Baumgartner definition, Janssen criteria 1, and Janssen criteria 2. MAIN OUTCOME MEASURE: All-cause mortality and prevalence of SO. Patient deaths were ascertained from medical records and United States social security death index. RESULTS: Of 122 participants, 62% were male; mean age was 46 years (interquartile range: 40, 54) in men and 50 years (44, 61) in women. Prevalence of SO ranged from 12% to 62% in men and 2% to 74% in female according to different definitions. SO prevalence was lowest using the Baumgartner criteria (all: 8%, men 12%, women: 2%) and highest according to the Janssen criteria 2 (all: 57%, men 46%, women 74%). There were 45 deaths during a median follow-up period of 44 (20, 76) months. SO by any definition was not statistically significantly associated with mortality during follow-up. CONCLUSIONS: The current SO definitions are not applicable to predict increased risk of death in MHD patients. We found high degree of variation in the rates of SO when using different definitions. Future studies should focus on establishing MHD population-specific thresholds of muscle mass and adiposity for accurate prognostication.

Linear Association Between Hypoalbuminemia and Increased Risk of Acute Respiratory Distress Syndrome in Critically Ill Adults.

We hypothesized that low serum albumin would contribute to pulmonary edema formation, thereby independently increasing the risk of developing acute respiratory distress syndrome in critically ill patients. DESIGN: Retrospective analysis of prospective cohort. SETTING: Medical, surgical, and cardiovascular ICUs at Vanderbilt University Medical Center. PATIENTS: Patients (n = 993) with serum albumin measured for clinical reasons within 24 hours of study enrollment on ICU day 2 were included. MEASUREMENTS AND MAIN RESULTS: The primary outcome was presence of acute respiratory distress syndrome at any time during the first 4 days in the ICU, as defined by the Berlin definition. Secondary outcomes included ventilator-free days and ICU length of stay. In an unadjusted analysis, lower serum albumin levels were associated with a higher occurrence rate of acute respiratory distress syndrome (p < 0.001). In a multivariable analysis controlling for prespecified confounders, lower serum albumin was independently associated with an increased risk of acute respiratory distress syndrome (odds ratio, 1.48 per 1-g/dL decrease in albumin; 95% CI, 1.14-1.94; p = 0.004). Additionally, lower serum albumin was associated with increased mortality (odds ratio, 1.56 per 1-g/dL decrease in albumin; 95% CI, 1.19-2.04; p = 0.001), increased ICU length of stay (incidence rate ratio, 1.19; 95% CI, 1.15-1.23; p < 0.001), higher Sequential Organ Failure Assessment score (p < 0.001), and fewer ventilator-free days (incidence rate ratio, 1.21; 95% CI, 1.19-1.24; p < 0.001). CONCLUSIONS: Among adult ICU patients, lower serum albumin was independently associated with increased risk of acute respiratory distress syndrome after controlling for severity of illness and potential confounders. These findings support the hypothesis that low plasma oncotic pressure contributes to pulmonary edema formation in patients at risk for acute respiratory distress syndrome, independent of severity of illness.

An automated approach to calculating the daily dose of tacrolimus in electronic health records.

Clinical research often requires extracting detailed drug information, such as medication names and dosages, from Electronic Health Records (EHR). Since medication information is often recorded as both structured and unstructured formats in the EHR, extracting all the relevant drug mentions and determining the daily dose of a medication for a selected patient at a given date can be a challenging and time-consuming task. In this paper, we present an automated approach using natural language processing to calculate daily doses of medications mentioned in clinical text, using tacrolimus as a test case. We evaluated this method using data sets from four different types of unstructured clinical data. Our results showed that the system achieved precisions of 0.90-1.00 and recalls of 0.81-1.00.

Race, kidney disease progression, and mortality risk in HIV-infected persons.

BACKGROUND AND OBJECTIVES: The burden of HIV-associated chronic kidney disease (CKD) is growing in the United States, partially because of increased HIV-infection rates among African Americans. We determined the prevalence, incidence, and risk of rapid estimated GFR (eGFR) decline, ESRD, and death among HIV-infected (HIV+) African-American and non-African-American individuals cared for at the Comprehensive Care Center in Nashville, Tennessee, from January 1, 1998, through December 31, 2005. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Mixed effects, competing risks, and Poisson and Cox regression models were used to assess the risk of rapid eGFR decline (defined as ≥50% decrease in baseline eGFR), CKD5/ESRD, and death. The Chronic Kidney Disease Epidemiology Collaboration equation was used to calculate eGFR. Confounders were adjusted with a propensity score that related patient characteristics to the probability of being African American. Mixed effects models compared the rate of rapid eGFR decline for HIV-infected African Americans and non-African Americans. RESULTS: There were 2468 HIV-infected individuals in the study: 33% African American; 21% female. Among all patients, HIV-infected African Americans did not have a statistically significant increased risk for rapid eGFR decline compared with non-African Americans. However, African Americans had a significantly higher risk of ESRD and tended toward a higher risk of death. CONCLUSIONS: HIV-infected African Americans did not have a statistically significant difference in the risk of eGFR decline when compared with HIV-infected non-African Americans. The findings in this study have potential public health significance.