Dialysis-requiring Acute Kidney Injury Research Articles

Effect of endotoxin absorption by polymixin B hemoperfusion in dialysis-requiring acute kidney injury

Endotoxin absorption treatment using polymixin B direct hemoperfusion (PMX-DHP) has been clinically applied to septic shock patients for the last two decades in Japan. The total number of filter usage appears to be more than 200,000. However, no clinical trial has been conducted with sufficient statistical power so far.

High Risk of Herpes Zoster among Patients with Advance Acute Kidney Injury--A Population-Based Study.

The risk for herpes zoster (HZ) in acute kidney injury (AKI) survivors was never explored. We identified 2,387 adults in the Taiwan National Health Insurance Research Database who recovered from dialysis-requiring AKI and matched them with non-recovery and non-AKI patients by propensity score. During a mean follow-up of 2.7 years, the incidences of HZ were 6.9, 8.2 and 4.8 episodes per 1,000 person-years in AKI-non-recovery, AKI-recovery and non-AKI group, respectively. The recovery group was more likely to develop herpes zoster than those without acute kidney injury [incidence-rate ratios 1.71, 95% confidence interval 1.16–2.52; p = 0.007]. Patients without acute kidney injury were less likely to develop herpes zoster than those AKI, recovered from dialysis or not (hazard ratio HR 0.66, 95% CI 0.46–0.95). Dialysis-requiring acute kidney injury poses a long-term risk of herpes zoster after hospital discharge. Even patients who have recovered from dialysis still carry a significantly higher risk of developing herpes zoster.

Dialysis-requiring acute kidney injury among hospitalized adults with documented hepatitis C Virus infection: a nationwide inpatient sample analysis.

Chronic hepatitis C virus (HCV) infection may cause kidney injury, particularly in the setting of cryoglobulinemia or cirrhosis; however, few studies have evaluated the epidemiology of acute kidney injury in patients with HCV. We aimed to describe national temporal trends of incidence and impact of severe acute kidney injury (AKI) requiring renal replacement 'dialysis-requiring AKI' in hospitalized adults with HCV. We extracted our study cohort from the Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project using data from 2004 to 2012. We defined HCV and dialysis-requiring acute kidney injury based on previously validated ICD-9-CM codes. We analysed temporal changes in the proportion of hospitalizations complicated by dialysis-requiring AKI and utilized survey multivariable logistic regression models to estimate its impact on in-hospital mortality. We identified a total of 4,603,718 adult hospitalizations with an associated diagnosis of HCV from 2004 to 2012, of which 51,434 (1.12%) were complicated by dialysis-requiring acute kidney injury. The proportion of hospitalizations complicated by dialysis-requiring acute kidney injury increased significantly from 0.86% in 2004 to 1.28% in 2012. In-hospital mortality was significantly higher in hospitalizations complicated by dialysis-requiring acute kidney injury vs those without (27.38% vs 2.95%; adjusted odds ratio: 2.09; 95% confidence interval: 1.74-2.51). The proportion of HCV hospitalizations complicated by dialysis-requiring acute kidney injury increased significantly between 2004 and 2012. Similar to observations in the general population, dialysis-requiring acute kidney injury was associated with a twofold increase in odds of in-hospital mortality in adults with HCV. These results highlight the burden of acute kidney injury in hospitalized adults with HCV infection.

Cardiac surgery-associated acute kidney injury: risk factors analysis and comparison of prediction models

Cardiac surgery-associated acute kidney injury (AKI) is a well-known factor influencing patients' long-term morbidity and mortality. Several prediction models of AKI requiring dialysis (AKI-D) have been developed. Only a few direct comparisons of these models have been done. Recently, a new, more uniform and objective definition of AKI has been proposed [Kidney Disease: Improve Global Outcomes (KDIGO)-AKI]. The performance of these prediction models has not yet been tested. Preoperative demographic and clinical characteristics of 1056 consecutive adult patients undergoing cardiac surgery were collected retrospectively for the period 2012-2014. Multivariable logistic regression analysis was used to determine the independent predictors of AKI-D and the KDIGO-AKI stages. Risk scores of five prediction models were calculated using corresponding subgroups of patients. The discrimination of these models was calculated by the c-statistics (area under curve, AUC) and the calibration was evaluated for the model with the highest AUC by calibration plots. The incidence of AKI-D was 3.5% and for KDIGO-AKI 23% (17.3% for Stage 1, 2.1% for Stage 2 and 3.6% for Stage 3). Older age, atrial fibrillation, NYHA class III or IV heart failure, previous cardiac surgery, higher preoperative serum creatinine and endocarditis were independently associated with the development of AKI-D. For KDIGO-AKI, higher body mass index, older age, female gender, chronic obstructive pulmonary disease, previous cardiac surgery, atrial fibrillation, NYHA class III or IV heart failure, higher preoperative serum creatinine and the use of cardiopulmonary bypass were independent predictors. The model by Thakar et al. showed the best performance in the prediction of AKI-D (AUC 0.837; 95% CI = 0.810-0.862) and also in the prediction of KDIGO-AKI stage 1 and higher (AUC = 0.731; 95% CI = 0.639-0.761), KDIGO-AKI stage 2 and higher (AUC = 0.811; 95% CI = 0.783-0.838) and for KDIGO-AKI stage 3 (AUC = 0.842; 95% CI = 0.816-0.867). The performance of known prediction models for AKI-D was found reasonably well in the prediction of KDIGO-AKI, with the model by Thakar having the highest predictive value in the discrimination of patients with risk for all KDIGO-AKI stages.

The burden of dialysis-requiring acute kidney injury among hospitalized adults with HIV infection: a nationwide inpatient sample analysis.

The objective of this study was to describe the incidence of acute kidney injury (AKI) requiring renal replacement therapy ('dialysis-requiring AKI') and the impact on in-hospital mortality among hospitalized adults with HIV infection. A longitudinal analysis of a nationally representative administrative database. We reviewed the Healthcare Cost and Utilization Project's Nationwide Inpatient Sample Database, a large, nationally representative sample of inpatient hospital admissions, to identify all adult hospitalizations with an associated diagnosis of HIV infection from 2002 to 2010. We analysed temporal trends in the incidence of dialysis-requiring AKI and the associated odds of in-hospital mortality. We also explored potential reasons behind temporal changes. Among 183 0041 hospitalizations with an associated diagnosis of HIV infection, the proportion complicated by dialysis-requiring AKI increased from 0.7% in 2002 to 1.35% in 2010. This temporal rise was completely explained by changes in demographics and an increase in concurrent comorbidities and procedure utilization. The adjusted odds of in-hospital mortality associated with dialysis-requiring AKI also increased over the study period, from 1.45 [95% confidence interval (95% CI) 0.97-2.12] in 2002 to 2.64 (95% CI 2.04-3.42) in 2010. These data suggest that the incidence of dialysis-requiring AKI among hospitalized adults with HIV infection continues to increase, and that severe AKI remains a significant predictor of in-hospital mortality in this population. The increased incidence of dialysis-requiring AKI was largely explained by ageing of the HIV population and increasing prevalence of chronic non-AIDS comorbidities, suggesting that these trends will continue.

SP267VALIDATING A SCORING TOOL TO PREDICT ACUTE KIDNEY INJURY (AKI) FOLLOWING CARDIAC SURGERY

Background: Acute kidney injury (AKI) after cardiac surgery is associated with an increased risk of mortality. Preoperative risk scores can identify patients at risk for AKI and facilitate preventive strategies. Currently, validated risk scores are used to predict AKI requiring dialysis (AKI-D); less is known about whether these tools predict less severe forms of AKI. Objective: To evaluate the Cleveland Clinic scoring tool in predicting both AKI-D and less severe stages of AKI in patients after cardiac surgery in a Canadian tertiary care center. Design: Retrospective case–control study. Setting: Regina Qu’Appelle Health Region (RQHR) from 2007 to 2011. Patients: Patients who underwent cardiac surgery and developed postoperative kidney injury (n = 2316). Measurements: Data on risk factors for AKI and outcomes of cardiac surgery were collected from a retrospective chart review. Methods: The primary outcome was AKI, defined as Stage 1 (increase in serum creatinine 1.5-1.9 X baseline within 5 days), Stage 2 (increase 2.0-2.9 X baseline), or Stage 3 (increase 3.0 X baseline or more OR initiation of dialysis during hospital stay). We assessed the performance of a modified version of the Cleveland Clinic tool using receiver operating curve analyses. Results: The incidence of AKI was 6.1% (Stage 1), 2.6% (Stage 2), and 5.8% (Stage 3). The area under the curve (AUC) for the Cleveland score was 0.61 (95% CI: 0.56 to 0.65; p < 0.001) for Stage 1, 0.61 (95% CI: 0.54 to 0.68; p< 0.01) for Stage 2, and 0.78 (95% CI: 0.74 to 0.82; p< 0.001) for Stage 3. Greater level of risk on the Cleveland tool was associated with a higher risk of Stage 3 AKI. Limitations: Lack of prospective validation. Conclusions: The modified Cleveland Clinic tool was valid in identifying patients with severe stages of AKI but did not have strong discrimination for early AKI stages.

Validating a scoring tool to predict acute kidney injury (AKI) following cardiac surgery.

BackgroundAcute kidney injury (AKI) after cardiac surgery is associated with an increased risk of mortality. Preoperative risk scores can identify patients at risk for AKI and facilitate preventive strategies. Currently, validated risk scores are used to predict AKI requiring dialysis (AKI-D); less is known about whether these tools predict less severe forms of AKI.ObjectiveTo evaluate the Cleveland Clinic scoring tool in predicting both AKI-D and less severe stages of AKI in patients after cardiac surgery in a Canadian tertiary care center.DesignRetrospective case–control study.SettingRegina Qu’Appelle Health Region (RQHR) from 2007 to 2011.PatientsPatients who underwent cardiac surgery and developed postoperative kidney injury (n = 2316).MeasurementsData on risk factors for AKI and outcomes of cardiac surgery were collected from a retrospective chart review.MethodsThe primary outcome was AKI, defined as Stage 1 (increase in serum creatinine 1.5-1.9 X baseline within 5 days), Stage 2 (increase 2.0-2.9 X baseline), or Stage 3 (increase 3.0 X baseline or more OR initiation of dialysis during hospital stay). We assessed the performance of a modified version of the Cleveland Clinic tool using receiver operating curve analyses.ResultsThe incidence of AKI was 6.1% (Stage 1), 2.6% (Stage 2), and 5.8% (Stage 3). The area under the curve (AUC) for the Cleveland score was 0.61 (95% CI: 0.56 to 0.65; p < 0.001) for Stage 1, 0.61 (95% CI: 0.54 to 0.68; p < 0.01) for Stage 2, and 0.78 (95% CI: 0.74 to 0.82; p < 0.001) for Stage 3. Greater level of risk on the Cleveland tool was associated with a higher risk of Stage 3 AKI.LimitationsLack of prospective validation.ConclusionsThe modified Cleveland Clinic tool was valid in identifying patients with severe stages of AKI but did not have strong discrimination for early AKI stages.Electronic supplementary materialThe online version of this article (doi:10.1186/s40697-015-0037-x) contains supplementary material, which is available to authorized users.

Ambulatory care after acute kidney injury: an opportunity to improve patient outcomes.

Purpose of reviewAcute kidney injury (AKI) is an increasingly common problem among hospitalized patients. Patients who survive an AKI-associated hospitalization are at higher risk of de novo and worsening chronic kidney disease, end-stage kidney disease, cardiovascular disease, and death. For hospitalized patients with dialysis-requiring AKI, outpatient follow-up with a nephrologist within 90 days of hospital discharge has been associated with enhanced survival. However, most patients who survive an AKI episode do not receive any follow-up nephrology care. This narrative review describes the experience of two new clinical programs to care for AKI patients after hospital discharge: the Acute Kidney Injury Follow-up Clinic for adults (St. Michael’s Hospital and University Health Network, Toronto, Canada) and the AKI Survivor Clinic for children (Cincinnati Children’s Hospital, USA).Sources of informationMEDLINE, PubMed, ISI Web of ScienceFindingsThese two ambulatory clinics have been in existence for close to two (adult) and four (pediatric) years, and were developed separately and independently in different populations and health systems. The components of both clinics are described, including the target population, referral process, medical interventions, patient education activities, and follow-up schedule. Common elements include targeting patients with KDIGO stage 2 or 3 AKI, regular audits of the inpatient nephrology census to track eligible patients, medication reconciliation, and education on the long-term consequences of AKI.LimitationsDespite the theoretical benefits of post-AKI follow-up and the clinic components described, there is no high quality evidence to prove that the interventions implemented in these clinics will reduce morbidity or mortality. Therefore, we also present a plan to evaluate the adult AKI Follow-up Clinic in order to determine if it can improve clinical outcomes compared to patients with AKI who do not receive follow-up care.ImplicationsFollow-up of AKI survivors is low, and this review describes two different clinics that care for patients who survive an AKI episode. We believe that sharing the experiences of the AKI Follow-up Clinic and AKI Survivor Clinic provide physicians with a feasible framework to implement their own clinics, which may help AKI patients receive outpatient care commensurate with their high risk status.Electronic supplementary materialThe online version of this article (doi:10.1186/s40697-015-0071-8) contains supplementary material, which is available to authorized users.

Changing Incidence and Outcomes Following Dialysis-Requiring Acute Kidney Injury Among Critically Ill Adults: A Population-Based Cohort Study

Dialysis-requiring acute kidney injury (AKI) is common among critically ill patients, but little is known about trends in the incidence and outcomes of this condition over time. Population-based cohort study. All adult patients admitted to an intensive care unit in Ontario, Canada, 1996 to2010. Year and era (1996-2000, 2001-2005, and 2006-2010) of cohort entry. Mortality and dialysis dependence, each evaluated at 90 and 365 days after initiation of dialysis therapy for AKI. The annual incidence proportion of dialysis-requiring AKI was evaluated and patients with this condition were characterized by era. Associations between era and the outcomes of interest were evaluated with Cox proportional hazards (for time to death) and logistic regression (for dialysis dependence), with adjustment for relevant demographic and clinical variables. The annual incidence of dialysis-requiring AKI among critically ill patients increased from 0.8% in 1996 to 3.0% in 2010 (P for trend< 0.001). 90-day mortality declined from 50% in 1996 to 2000 to 45% in 2006 to 2010 (adjusted HR, 0.83 [95% CI, 0.79-0.87] compared to 1996-2000). Dialysis dependence among surviving patients at 90 days was marginally lower in 2006 to 2010 (25.1%) compared to 1996 to 2000 (27.2%), but after adjustment for confounding factors, was not significantly different (adjusted OR, 0.91; 95% CI, 0.80-1.03). Unmeasured confounding by factors that may have changed in patients with dialysis-requiring AKI during the different eras; data set does not allow for mechanistic explanation for the findings; and lack of access to laboratory investigations after hospital discharge. The incidence proportion of dialysis-requiring AKI among critically ill patients increased by almost 4-fold between 1996 and 2010. This was accompanied by a significant decline in mortality, but the risk of long-term dialysis dependence continues to affect a substantial minority of surviving patients with no clear evidence of improvement over time.

Proteinuria predicts postcardiotomy acute kidney injury in patients with preserved glomerular filtration rate

Acute kidney injury is a common and serious problem after cardiac surgery. Postoperative acute kidney injury is independently associated with in-hospital mortality and long-term morbidity, even after adjustment for comorbid diseases. Chronic kidney disease has been recognized as a strong risk factor of acute kidney injury after cardiac surgery. The association between proteinuria and postcardiotomy acute kidney injury in patients with preserved glomerular filtration rate remains uncertain. Patients with an estimated glomerular filtration rate greater than 60 mL/min/1.73 m(2) who underwent cardiac surgery between January 2003 and December 2007 in a tertiary medical center were retrospectively analyzed. Dipstick urinalysis was performed before surgery. Proteinuria was categorized into negative, trace, 1+, 2+, or 3+. Postoperative acute kidney injury was defined by the Acute Kidney Injury Network criteria. Multinomial logistic regression was used to clarify whether proteinuria is an independent risk factor of postoperative acute kidney injury. A total of 1246 patients were included in this study, with a mean estimated glomerular filtration rate of 80 ± 13 mL/min/1.73 m(2). Proteinuria was present in 290 patients (23.4%). Postoperative acute kidney injury developed in 434 patients (34.8%), and 36 patients (2.9%) required renal replacement therapy. Proteinuria was independently associated with all stages of postcardiotomy acute kidney injury and dialysis-requiring acute kidney injury. The crude risk of acute kidney injury was greater in patients with a higher grade of proteinuria. In subgroup analysis for gender, diabetes, and surgical type, preoperative proteinuria remains a strong risk factor of acute kidney injury after cardiac surgery. Urine analysis is usually neglected before cardiac surgery despite the fact that proteinuria is the earliest manifestation of kidney dysfunction. In the current study, we show that urine protein is strongly and independently associated with postoperative acute kidney injury in subjects with preserved estimated glomerular filtration rate. These data suggest that such a relatively simple and clinically easy to use tool as a urinary dipstick may be useful to identify patients at high risk of acute kidney injury before cardiac surgery.

Predictors of progression to chronic dialysis in survivors of severe acute kidney injury: a competing risk study.

BackgroundSurvivors of acute kidney injury are at an increased risk of developing irreversible deterioration in kidney function and in some cases, the need for chronic dialysis. We aimed to determine predictors of chronic dialysis and death among survivors of dialysis-requiring acute kidney injury.MethodsWe used linked administrative databases in Ontario, Canada, to identify patients who were discharged from hospital after an episode of acute kidney injury requiring dialysis and remained free of further dialysis for at least 90 days after discharge between 1996 and 2009. Follow-up extended until March 31, 2011. The primary outcome was progression to chronic dialysis. Predictors for this outcome were evaluated using cause-specific Cox proportional hazards models, and a competing risk approach was used to calculate absolute risk.ResultsWe identified 4 383 patients with acute kidney injury requiring temporary in-hospital dialysis who survived to discharge. After a mean follow-up of 2.4 years, 356 (8%) patients initiated chronic dialysis and 1475 (34%) died. The cumulative risk of chronic dialysis was 13.5% by the Kaplan-Meier method, and 10.3% using a competing risk approach. After accounting for the competing risk of death, previous nephrology consultation (subdistribution hazard ratio (sHR) 2.03; 95% confidence interval (CI) 1.61-2.58), a history of chronic kidney disease (sHR3.86; 95% CI 2.99-4.98), a higher Charlson comorbidity index score (sHR 1.10; 95% CI 1.05-1.15/per unit) and pre-existing hypertension (sHR 1.82; 95% CI 1.28-2.58) were significantly associated with an increased risk of progression to chronic dialysis.ConclusionsAmong survivors of dialysis-requiring acute kidney injury who initially become dialysis independent, the subsequent need for chronic dialysis is predicted by pre-existing kidney disease, hypertension and global comorbidity. This information can identify patients at high risk of progressive kidney disease who may benefit from closer surveillance after cessation of the acute phase of illness.

Six-year single-center survey on AKI requiring renal replacement therapy: epidemiology and health care organization aspects.

Evidence regarding hospital-based acute kidney injury (AKI) reveals a continuous increase in incidence over the years, at least in intensive care units (ICU). Fewer reports are available for non critically-ill patients admitted to general or specialist wards other than ICU (non-ICU). The consequence of greater incidence is an increase in therapies such as dialysis; but how the health care organization deals with this problem is not clearly known. Here we quantified the incidence of dialysis-requiring AKI (AKI-D) among patients admitted to a University Hospital which serves a population of 354,000 inhabitants. Between 2007 and 2012, the incidence of AKI-D increased from 209 to 410 per million population (pmp)/year; age of patients and cardiovascular comorbid pathologies also increased. AKI-D was more frequent in non-ICU and 32% of patients were admitted to ICU. Considering the site of treatment of non-ICU patients, in 2007 the ratio of patients admitted to non-ICU wards apart from Nephrology to those admitted to Nephrology was 1:1, but in 2012 the ratio increased to 2.4:1 (p < 0.05). The complexity of acute disease, measured with the New Simplified Acute Physiology Score (SAPS II), did not reveal differences over the years. The number of dialysis treatments/year increased by 82%, and the total hours/year increased by 86%. Low-efficiency daily dialysis was performed in 52.4% of patients admitted to ICU, but dialysis sessions longer than 8 h were performed in only 40% of cases. Overall, 6-year mortality was 48.8%, without significant differences over the years. Mortality in ICU was 65.6%, and in non-ICU 41.2% (p < 0.001). Dialysis treatments needed to be continued after hospital discharge in 21% of patients. We conclude that dialysis-requiring AKI is becoming more common, and that two-thirds of patients are admitted as non-ICU: in these patients, during the last year of the study, the treatment site was more frequently in non-ICUs other than Nephrology. Over the 6-year period, the local healthcare organization had to dispense 80% more dialysis treatments/year in terms of total number and hours of treatment. One-fifth of surviving patients needed to continue dialysis after hospital discharge. Our data highlight the public health importance of AKI and the need for adequate resources for Nephrology.

An ACE in the Hole for Patients With Advanced Chronic Kidney Disease?

In the treatmentofpatientswithadvancedchronickidneydisease (CKD) (which can be considered present when the estimated glomerular filtration rate [GFR] falls to <20 mL/min/ 1.73m2 and individuals become eligible to accrue time on the kidney transplant waiting list in the United States), a paramount goal is preventing or retarding progression to endstage renal disease and the requirement of dialysis. At earlier stages of CKD, blockade of the renin-angiotensinaldosteronesystem(RAAS) is amainstay therapy; angiotensinconverting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) clearly slow renal function decline, especially among thosewith proteinuria. However, the use of ACEIs or ARBs in advanced CKD remains uncertain. This important clinical question is the subject of a new study by Hsu and colleagues.1 Physiciansmayhesitate to prescribeACEIs or ARBs in advanced CKD for several reasons. Angiotensin-converting enzymeinhibitorsandARBs increaseserumpotassiumlevels, and their use in advanced CKDmay lead to dangerous hyperkalemia. InitiationofRAASblockade isoftenassociatedwithshorttermreductions inGFR,asmuchas30%.This reduction is generally believed to be due to reductions in intraglomerular pressure, hemodynamically reversible and self-limited (unless there are unusual coexisting conditions, such as severe renal artery stenosis).2,3 However, in advancedCKD, a 30% difference in GFR may determine whether the patient needs immediate initiation of dialysis. There have also been reports of substantial increase in GFR (more than 30%) after cessation of ACEI or ARB therapy in advanced CKD, resulting in postponement of dialysis.4 Other investigatorshaveemphasized that theuseofACEIs andARBsheightens the riskof acute-on-chronic renal failure.5 PatientswithCKDareat increased risk for acutekidney injury,6 andnumerouspatientswithmoderateoradvancedCKDdonot recover fromanepisodeof dialysis-requiring acute kidney injury but instead become dependent on long-term dialysis. Therefore, a superimposed episodeof severe acute kidney injury can immediately precipitate end-stage renal disease in some CKD patients.7 Thus, although somedata from randomized clinical trials suggest that RAAS blockade can be implemented safely and is efficacious in advanced CKD,8,9 much uncertainty remains about use of ACEIs andARBs in non–clinical trial participants with advancedCKD,particularly the elderly. The studybyHsu andcolleagues1usesacomprehensiveTaiwanesedatabase that captures health care utilization data of more than 95% of the hospitals in Taiwan and99%of the country’s population of 23 million. The investigators studied 28497patientswith stable, hypertensive, advanced CKD receiving erythropoiesisstimulatingagent (ESA) therapywhohaveserumcreatinine levels greater than 6 mg/dL (to convert to micromoles per liter, multiplyby88.4).Of these, 14 117usedACEIs/ARBs, and14380 werenonusers.UseofACEIs/ARBswasassociatedwitha lower hazard ratio for long-term dialysis (0.94 [95% CI, 0.91-0.97]) andthecompositeoutcomeof long-termdialysisordeath (0.94 [0.92-0.97]). Similar results were seen in several sensitivity analyses. The strengths of this study include its large size and its being nationally representative. The large proportion of patients with diabetes mellitus enhances generalizability because these patientswere excluded fromprior studies.8,9Hsu and colleagues1 provide reassuring information complementing the data from randomized clinical trials that RAAS blockadecanbesafely implementedeven inadvancedCKD.8,9Based on the age and sex distribution provided (more than half the patientswere older than65years and female), all patients had an estimated GFR of 12 mL/min/1.73m2 or less. A large, randomized clinical trial seems unlikely to be undertaken in this subset of patients in the foreseeable future. However, several caveats must be kept in mind when interpreting these data. No information regarding blood pressure,proteinuria,orother importantpatient-level clinical characteristics was provided. Themajor weakness of this study is that the actual levels of renal function were unknown because the database did not contain serum creatinine values. Instead, the level of renal functionwas inferred based onprescription of an ESA. The authors’ claim that the 28 497 patients studied had serum creatinine levels of greater than 6 mg/dL (andhematocrit levels of <28%) is basedonTaiwanNational Health Insurance reimbursement regulations bywhich patients meeting these criteria “could receive ESA treatment tomaintainahematocrit levelnot exceeding36%.”1Thus, confoundingbydifferences in the level ofGFRbetweenusers and nonusers of ACEIs/ARBs is a concern. The strength of the association between the level of GFR and the need for dialysis is very strong,10 at anorder ofmagnitude stronger than the association between the level of GFR and other adverse outcomes, such as cardiovascular disease.11 Hence, if ACEI/ARB users had on average even slightly higher levels of GFR, confounding may account for the rather modest observed effect size (approximately 6%). BlockadeofRAAS is known to lower hematocrit levels in CKDpatients12; hence, use of anESAmay be triggered amongACEI/ARBusers at higher GFR levels than ACEI/ARB nonusers. In addition,patientswithadvancedCKDwhoaremoreadherent to treatment regimens may be more likely to be prescribedACEIs/ARBs because nephrologistsmay trust them to come reliably for follow-up appointments and toundergo freRelated article page 347 Renin-Angiotensin System Blockade in CKD Original Investigation Research

Dialysis-requiring acute kidney injury increases risk of long-term malignancy: a population-based study

Acute kidney injury (AKI) is gaining worldwide attention recently, emerging as a major public health threat. However, the association between the development of AKI and subsequent malignancy has not been studied before. We conducted a population study based on the Taiwan National Health Insurance database, using 1,000,000 representative database during 2000-2008. All patients' survival to discharge from index hospitalization with recovery from dialysis-requiring AKI were identified (recovery group), and matched with those without recovery and those without AKI, at a 1:1:1 ratio. We identified 625 individuals more than 18 years old [352 male (56.5%); mean age, 63.3 years] in recovery group and matched 625 individuals in each group. During a mean followed-up of 3.7 years, the incidences of new-onset malignancy were 4.2, 2.9, and 2.6 per 100 person-year among the non-recovery, the recovery, and the non-AKI group, respectively. After adjustment, the recovery group was more likely to develop long-term de novo malignancy than those without AKI [hazard ratio (HR) 1.44, 95% confidence interval (CI) 1.02-2.03; p = 0.04], while less likely than those who did not recover (HR 0.66, 95% CI 0.45-0.98; p = 0.04). Dialysis-requiring AKI can post a long-term risk of de novo malignancy for those who survive from the initial insult. Even patients who have recovered from dialysis still carry a significantly higher possibility of developing malignancy than those without AKI episode.

The Impact of Acute Kidney Injury With Temporary Dialysis on the Risk of Fracture

Acute kidney injury (AKI) has a negative impact on long-term renal function and prognosis. However, the association between acute renal dysfunction and long-term effects on bone disorders has not yet been characterized. Using a population-based cohort study, we aimed to evaluate associations between AKI and long-term effects on bone fractures. We identified relevant data of all hospitalized patients aged >18 years with histories of dialysis-requiring AKI, with subsequent recovery and discharge, from the claim records of the Taiwan National Health Insurance database between 2000 and 2008. We determined long-term de novo bone fracture and all-cause mortality after patients' index-hospitalization discharge using propensity score-adjusted Cox proportional hazard model. Varying-time models were used to adjust for long-term effects of end-stage renal disease (ESRD) on main outcomes. Among 448 AKI patients who had dialysis and survived 90 days after index-hospitalization discharge without reentering dialysis, 273 were male (60.9%) with a mean age of 61.4 ± 16.6 years. Controls included 1792 hospitalized patients without AKI, dialysis, or bone fracture history. In the AKI recovery group, bone fracture incidence was 320 per 10,000 person-years and hazard ratio (HR) of long-term bone fracture was 1.25 (p = 0.049) compared with the control group, independent of subsequent ESRD status (HR = 1.55; p = 0.01). Both AKI recovery status (HR = 2.31; p < 0.001) and time varying factor of bone fracture (HR = 1.43; p < 0.001) were independent predictors of mortality compared with controls. In conclusion, AKI requiring temporary dialysis independently increases long-term risk of bone fracture, regardless of subsequent progression to ESRD. Long-term bone fractures may negatively impact patient mortality.

Kidney attack must be prevented

Hsu et al. report a progressive increase in the incidence of dialysis-requiring acute kidney injury (AKI) and associated deaths in the USA between 2000 and 2009. As with chronic kidney disease, a concerted campaign to increase awareness and alertness of AKI is urgently required. We must prevent “kidney attack”.

Five-year risk of end-stage renal disease among intensive care patients surviving dialysis-requiring acute kidney injury: a nationwide cohort study

IntroductionDialysis-requiring acute kidney injury (D-AKI) is common among intensive care unit (ICU) patients. However, follow-up data on the risk of end-stage renal disease (ESRD) among these patients remain sparse. We assessed the short-term and long-term risk of ESRD after D-AKI, compared it with the risk in other ICU patients, and examined the risk within subgroups of ICU patients.MethodsWe used population-based medical registries to identify all adult patients admitted to an ICU in Denmark from 2005 through 2010, who survived for 90 days after ICU admission. D-AKI was defined as needing acute dialysis at or after ICU admission. Subsequent ESRD was defined as a need for chronic dialysis for more than 90 days or a kidney transplant. We computed the cumulative ESRD risk for patients with D-AKI and for other ICU patients, taking into account death as a competing risk, and computed hazard ratios (HRs) using a Cox model adjusted for potential confounders.ResultsWe identified 107,937 patients who survived for 90 days after ICU admission. Of these, 3,062 (2.8%) had an episode of D-AKI following ICU admission. The subsequent risk of ESRD up to 180 days after ICU admission was 8.5% for patients with D-AKI, compared with 0.1% for other ICU patients. This corresponds to an adjusted HR of 105.6 (95% confidence interval (CI): 78.1 to 142.9). Among patients who survived 180 days after ICU admission without developing ESRD (n = 103,996), the 181-day to 5-year ESRD risk was 3.8% for patients with D-AKI, compared with 0.3% for other ICU patients, corresponding to an adjusted HR of 6.2 (95% CI: 4.7 to 8.1). During the latter period, the impact of AKI was most pronounced in the youngest patients, aged 15 to 49 years (adjusted HR = 12.8, 95% CI: 6.5 to 25.4) and among patients without preexisting chronic kidney disease (adjusted HR = 11.9, 95% CI: 8.5 to 16.8).ConclusionD-AKI is an important risk factor for ESRD for up to five years after ICU admission.

Risk of developing severe sepsis after acute kidney injury: a population-based cohort study

IntroductionSepsis has been a factor of acute kidney injury (AKI); however, little is known about dialysis-requiring AKI and the risk of severe sepsis after survival to discharge.MethodsWe conducted a population-based cohort study based on the Taiwan National Health Insurance Research Database from 1999 to 2009. We identified patients with AKI requiring dialysis during hospitalization and survived for at least 90 days after discharge, and matched them with those without AKI according to age, sex, and concurrent diabetes. The primary outcome was severe sepsis, defined as sepsis with a diagnosis of acute organ dysfunction. Individuals who recovered enough to survive without acute dialysis were further analyzed.ResultsWe identified 2983 individuals (mean age, 62 years; median follow-up, 3.96 years) with dialysis-requiring AKI and 11,932 matched controls. The incidence rate of severe sepsis was 6.84 and 2.32 per 100 person-years among individuals with dialysis-requiring AKI and without AKI in the index hospitalization, respectively. Dialysis-requiring AKI patients had a higher risk of developing de novo severe sepsis than the non-AKI group. In subgroup analysis, even individuals with recovery from dialysis-requiring AKI were at high risk of developing severe sepsis.ConclusionsAKI is an independent risk factor for severe sepsis. Even patients who recovered from AKI had a high risk of long-term severe sepsis.

Trends in Acute Kidney Injury, Associated Use of Dialysis, and Mortality After Cardiac Surgery, 1999 to 2008

The development of acute kidney injury (AKI) after cardiac surgery is associated with significant mortality, morbidity, and cost. The last decade has seen major changes in the complexity of cardiac surgical candidates and in the number and type of cardiac surgical procedures being performed. Using data from the Nationwide Inpatient Sample, we determined the annual rates of AKI, AKI requiring dialysis (AKI-D), and inpatient mortality after cardiac surgery in the United States in the years 1999 through 2008. Inpatient mortality with AKI and AKI-D decreased from 27.9% and 45.9%, respectively, in 1999 to 12.8% and 35.3%, respectively, in 2008. Compared with 1999, the odds of AKI and AKI-D in 2008, adjusted for demographic and clinical factors, were 3.30 (95% confidence interval [CI]: 2.89 to 3.77) and 2.23 (95% CI: 1.78 to 2.80), respectively. Corresponding adjusted odds of death associated with AKI and AKI-D were 0.31 (95% CI: 0.26 to 0.36) and 0.47 (95% CI: 0.34 to 0.65.) Taken together, the attributable risks for death after cardiac surgery associated with AKI and AKI-D increased from 30% and 5%, respectively, in 1999 to 47% and 14%, respectively, in 2008. In sum, despite improvements in individual patient outcomes over the decade 1999 to 2008, the population contribution of AKI and AKI-D to inpatient mortality after surgery increased over the same period.

The Impact of Dialysis-Requiring Acute Kidney Injury on Long-Term Prognosis of Patients Requiring Prolonged Mechanical Ventilation: Nationwide Population-Based Study

BackgroundProlonged mechanical ventilation (PMV) is increasingly common worldwide, consuming enormous healthcare resources. Factors that modify PMV outcome are still obscure.MethodsWe selected patients without preceding mechanical ventilation within the one past year and who developed PMV during index admission in Taiwan's National Health Insurance (NHI) system during 1998–2007 for comparison of mortality and resource use. They were divided into three groups: (1) patients with end-stage renal diseases (ESRD) before the index admission for PMV onset; (2) patients with dialysis-requiring acute kidney injury (AKI-dialysis) during the hospitalization course; and (3) patients without AKI or with non dialysis-requiring AKI during the hospitalization course (non-AKI). We used a random-effects logistic regression model to identify factors associated with mortality.ResultsCompared with the other two groups, patients with AKI-dialysis had significantly longer mechanical ventilation, more frequent use of vasopressors, longer intensive care unit/hospital stay and higher inpatient expenditures during the index admission. Relative to non-AKI patients, patients with AKI-dialysis had an elevated mortality hazard; the adjusted relative risk ratios were 1.51 (95% confidence interval [CI]:1.46–1.56), 1.27 (95% CI: 1.23–1.32), and 1.10 (95% CI: 1.08–1.12) for mortality rates at discharge, 3 months, and 4 years after PMV, respectively. Patients with AKI-dialysis also consumed significantly higher total in-patient expenditure than the other two patient groups (p<0.001).ConclusionsAmong patients that need PMV care during an admission, the presence of de novo AKI requiring dialysis significantly increased short and long term mortality, and demand for health care resources.