The incidence and prevalence of diabetes mellitus have grown significantly throughout the world, due primarily to the increase in type 2 diabetes. This overall increase in the number of people with ...diabetes has had a major impact on development of diabetic kidney disease (DKD), one of the most frequent complications of both types of diabetes. DKD is the leading cause of end-stage renal disease (ESRD), accounting for approximately 50% of cases in the developed world. Although incidence rates for ESRD attributable to DKD have recently stabilized, these rates continue to rise in high-risk groups such as middle-aged African Americans, Native Americans, and Hispanics. The costs of care for people with DKD are extraordinarily high. In the Medicare population alone, DKD-related expenditures among this mostly older group were nearly $25 billion in 2011. Due to the high human and societal costs, the Consensus Conference on Chronic Kidney Disease and Diabetes was convened by the American Diabetes Association in collaboration with the American Society of Nephrology and the National Kidney Foundation to appraise issues regarding patient management, highlighting current practices and new directions. Major topic areas in DKD included (1) identification and monitoring, (2) cardiovascular disease and management of dyslipidemia, (3) hypertension and use of renin-angiotensin-aldosterone system blockade and mineralocorticoid receptor blockade, (4) glycemia measurement, hypoglycemia, and drug therapies, (5) nutrition and general care in advanced-stage chronic kidney disease, (6) children and adolescents, and (7) multidisciplinary approaches and medical home models for health care delivery. This current state summary and research recommendations are designed to guide advances in care and the generation of new knowledge that will meaningfully improve life for people with DKD.
Objectives This study sought to examine the contemporary incidence, predictors and outcomes of acute kidney injury in patients undergoing percutaneous coronary interventions. Background Acute kidney ...injury (AKI) is a serious and potentially preventable complication of percutaneous coronary interventions (PCIs) that is associated with adverse outcomes. The contemporary incidence, predictors, and outcomes of AKI are not well defined, and clarifying these can help identify high-risk patients for proactive prevention. Methods A total of 985,737 consecutive patients underwent PCIs at 1,253 sites participating in the National Cardiovascular Data Registry Cath-PCI registry from June 2009 through June 2011. AKI was defined on the basis of changes in serum creatinine level in the hospital according to the Acute Kidney Injury Network (AKIN) criteria. Using multivariable regression analyses with generalized estimating equations, we identified patient characteristics associated with AKI. Results Overall, 69,658 (7.1%) patients experienced AKI, with 3,005 (0.3%) requiring new dialysis. On multivariable analyses, the factors most strongly associated with development of AKI included ST-segment elevation myocardial infarction (STEMI) presentation (odds ratio OR: 2.60; 95% confidence interval CI: 2.53 to 2.67), severe chronic kidney disease (OR: 3.59; 95% CI: 3.47 to 3.71), and cardiogenic shock (OR: 2.92; 95% CI: 2.80 to 3.04). The in-hospital mortality rate was 9.7% for patients with AKI and 34% for those requiring dialysis compared with 0.5% for patients without AKI (p < 0.001). After multivariable adjustment, AKI (OR: 7.8; 95% CI: 7.4 to 8.1, p < 0.001) and dialysis (OR: 21.7; 95% CI: 19.6 to 24.1; p < 0.001) remained independent predictors of in-hospital mortality. Conclusions Approximately 7% of patients undergoing a PCI experience AKI, which is strongly associated with in-hospital mortality. Defining strategies to minimize the risk of AKI in patients undergoing PCI are needed to improve the safety and outcomes of the procedure.
Summary Background Amid rapid urbanisation, the HIV epidemic, and increasing rates of non-communicable diseases, people in sub-Saharan Africa are especially vulnerable to kidney disease. Little is ...known about the epidemiology of chronic kidney disease (CKD) in sub-Saharan Africa, so we did a systematic review and meta-analysis examining the epidemiology of the disease. Methods We searched Medline, Embase, and WHO Global Health Library databases for all articles published through March 29, 2012, and searched the reference lists of retrieved articles. We independently reviewed each study for quality. We used the inverse-variance random-effects method for meta-analyses of the medium-quality and high-quality data and explored heterogeneity by comparing CKD burdens across countries, settings (urban or rural), comorbid disorders (hypertension, diabetes, HIV), CKD definitions, and time. Findings Overall, we included 90 studies from 96 sites in the review. Study quality was low, with only 18 (20%) medium-quality studies and three (3%) high-quality studies. We noted moderate heterogeneity between the medium-quality and high-quality studies (n=21; I2 =47·11%, p<0·0009). Measurement of urine protein was the most common method of determining the presence of kidney disease (62 69% studies), but the Cockcroft-Gault formula (22 24% studies) and Modification of Diet in Renal Disease formula (17 19% studies) were also used. Most of the studies were done in urban settings (83 93% studies) and after the year 2000 (57 63% studies), and we detected no significant difference in the prevalence of CKD between urban (12·4%, 95% CI 11–14) and rural (16·5%, 13·8–19·6) settings (p=0·474). The overall prevalence of CKD from the 21 medium-quality and high-quality studies was 13·9% (95% CI 12·2–15·7). Interpretation In sub-Saharan Africa, CKD is a substantial health burden with risk factors that include communicable and non-communicable diseases. However, poor data quality limits inferences and draws attention to the need for more information and validated measures of kidney function especially in the context of the growing burden of non-communicable diseases. Funding Duke University.
Background Well-designed trials are of paramount importance in improving the delivery of care to patients with kidney disease. However, it remains unknown whether contemporary clinical trials within ...nephrology are of sufficient quality and quantity to meet this need. Study Design Systematic review. Setting & Population Studies registered with ClinicalTrials.gov. Selection Criteria for Studies Interventional (ie, nonobservational) studies (both randomized and nonrandomized) registered between October 2007 and September 2010 were included for analysis. Studies were reviewed independently by physicians and classified by clinical specialty. Predictor Nephrology versus cardiology versus other trials. Outcomes Select clinical trial characteristics. Results Of 40,970 trials overall, 1,054 (2.6%) were classified as nephrology. Most nephrology trials were for treatment (75.4%) or prevention (15.7%), with very few diagnostic, screening, or health services research studies. Most nephrology trials were randomized (72.3%). Study designs included 24.9% with a single study group, 64.0% that included parallel groups, and 9.4% that were crossover trials. Nephrology trials, compared with 2,264 cardiology trials (5.5% overall), were more likely to be smaller (64.5% vs 48.0% enrolling ≤ 100 patients), phases 1-2 (29.0% vs 19.7%), and unblinded (66.2% vs 53.3%; P < 0.05 for all). Nephrology trials also were more likely than cardiology trials to include a drug intervention (72.4% vs 41.9%) and less likely to report having a data monitoring committee (40.3% vs 48.5%; P < 0.05 for all). Finally, there were few trials funded by the National Institutes of Health (NIH; 3.3%, nephrology; 4.2%, cardiology). Limitations Does not include all trials performed worldwide, and frequent categorization of funding source as university may underestimate NIH support. Conclusions Critical differences remain between clinical trials in nephrology and other specialties. Improving care for patients with kidney disease will require a concerted effort to increase the scope, quality, and quantity of clinical trials within nephrology.
Background The primary aim of this study was to compare the sensitivity and rapidity of acute kidney injury (AKI) detection by cystatin C level relative to creatinine level after cardiac surgery. ...Study Design Prospective cohort study. Settings & Participants 1,150 high-risk adult cardiac surgery patients in the TRIBE-AKI (Translational Research Investigating Biomarker Endpoints for Acute Kidney Injury) Consortium. Predictor Changes in serum creatinine and cystatin C levels. Outcome Postsurgical incidence of AKI. Measurements Serum creatinine and cystatin C were measured at the preoperative visit and daily on postoperative days 1-5. To allow comparisons between changes in creatinine and cystatin C levels, AKI end points were defined by the relative increases in each marker from baseline (25%, 50%, and 100%) and the incidence of AKI was compared based on each marker. Secondary aims were to compare clinical outcomes among patients defined as having AKI by cystatin C and/or creatinine levels. Results Overall, serum creatinine level detected more cases of AKI than cystatin C level: 35% developed a ≥25% increase in serum creatinine level, whereas only 23% had a ≥25% increase in cystatin C level ( P < 0.001). Creatinine level also had higher proportions meeting the 50% (14% and 8%; P < 0.001) and 100% (4% and 2%; P = 0.005) thresholds for AKI diagnosis. Clinical outcomes generally were not statistically different for AKI cases detected by creatinine or cystatin C level. However, for each AKI threshold, patients with AKI confirmed by both markers had a significantly higher risk of the combined mortality/dialysis outcome compared with patients with AKI detected by creatinine level alone ( P = 0.002). Limitations There were few adverse clinical outcomes, limiting our ability to detect differences in outcomes between subgroups of patients based on their definitions of AKI. Conclusions In this large multicenter study, we found that cystatin C level was less sensitive for AKI detection than creatinine level. However, confirmation by cystatin C level appeared to identify a subset of patients with AKI with a substantially higher risk of adverse outcomes.
Background Elderly patients with advanced kidney disease experience considerable disability, morbidity, and mortality. Little is known about the impact of physician-patient interactions on patient ...preparation for the illness trajectory. We sought to describe how nephrologists and older patients discuss and understand the prognosis and course of kidney disease leading to renal replacement therapy. Methods We conducted focus groups and interviews with 11 nephrologists and 29 patients older than 65 years with advanced chronic kidney disease or receiving hemodialysis. Interviews were audiorecorded and transcribed. We used qualitative analytic methods to identify common and recurrent themes related to the primary research question. Results We identified 6 themes that describe how the kidney disease trajectory is discussed and understood: (1) patients are shocked by their diagnosis, (2) patients are uncertain how their disease will progress, (3) patients lack preparation for living with dialysis, (4) nephrologists struggle to explain illness complexity, (5) nephrologists manage a disease over which they have little control, and (6) nephrologists tend to avoid discussions of the future. Patients and nephrologists acknowledged that prognosis discussions are rare. Patients tended to cope with thoughts of the future through avoidance by focusing on their present clinical status. Nephrologists reported uncertainty and concern for evoking negative reactions as barriers to these conversations. Conclusions Patients and nephrologists face challenges in understanding and preparing for the kidney disease trajectory. Communication interventions that acknowledge the role of patient emotion and address uncertainty may improve how nephrologists discuss disease trajectory with patients and thereby enhance their understanding and preparation for the future.
Objective Cardiac surgery is a major cause of acute kidney injury. In this setting, receipt of blood transfusions seems to be associated with a higher risk of acute kidney injury, as measured using ...serum creatinine values. We examined this association further by using urinary biomarkers of kidney injury. Methods A total of 1210 adults underwent cardiac surgery and were divided into 3 groups on the basis of the receipt of intraoperative packed red blood cell units: no blood (n = 894), 2 or less packed red blood cell units (n = 206), and more than 2 packed red blood cell units (n = 110). Acute kidney injury was defined as (1) doubling of serum creatinine from the preoperative value; (2) first postoperative urinary interleukin-18 in the fifth quintile; and (3) first postoperative urinary neutrophil gelatinase-associated lipocalin in the fifth quintile. We determined the relative risk for acute kidney injury outcome according to packed red blood cell units group after adjusting for 12 preoperative and surgical variables. By using the Sobel test for mediation analysis, we also evaluated the role of biomarkers in causing acute kidney injury through alternative pathways. Results Acute kidney injury was more common in those who received more than 2 packed red blood cell units. In patients receiving more than 2 packed red blood cell units, the adjusted relative risks were 2.3 (95% confidence interval, 1.2-4.4, P .01), 1.36 (95% confidence interval, 1.0-1.9, P .05), and 1.34 (95% confidence interval, 1.0-1.8, P .06) for doubling of serum creatinine, urinary interleukin-18 in the fifth quintile (>60 pg/mL), and urinary neutrophil gelatinase-associated lipocalin in the fifth quintile (>102 ng/mL), respectively. Furthermore, the effect of packed red blood cell units transfusion on acute kidney injury was partially mediated by interleukin-18. Conclusions Receipt of 2 or more packed red blood cell units during cardiac surgery is associated with a greater risk of acute kidney injury defined by serum creatinine and kidney injury biomarkers.
Background Among patients presenting with ST-segment elevation myocardial infarction (STEMI) for primary percutaneous coronary intervention (PCI), the associations between clinical outcomes and both ...baseline renal function and the development of acute kidney injury (AKI) have not been reported in a trial population with unselected baseline renal function. Methods Patients enrolled in the APEX-AMI trial who underwent primary PCI for the treatment of STEMI were categorized according to ( a ) baseline renal function and ( b ) the development of AKI. Patient characteristics, clinical outcomes, and treatment patterns were analyzed according to baseline renal function and the development of AKI. A prediction model for AKI after primary PCI for STEMI was also developed. Results A total of 5,244 patients were included in this analysis and stratified according to baseline estimated glomerular filtration rate (eGFR) (milliliters per minute per 1.73 m2 ) of >90, 60 to 90, 30 to 59, or <30 or as dialysis dependent. Patients with lower eGFR were older, more often female, and less often treated with evidence-based medicines and had worse angiographic outcomes and higher mortality. The rates of AKI for patients with a baseline eGFR of >90, 60 to 90, 30 to 59, and <30 were 2.5%, 4.1%, 8.1%, and 1.6%, respectively ( P < .0001). The strongest predictors of AKI were age and presenting in Killip class III or IV. Conclusions Among patients undergoing primary PCI for STEMI, impaired renal function at presentation and development of post-PCI AKI were highly associated with worse clinical and angiographic outcomes, including death. The risk of developing AKI was low and only modestly associated with baseline renal function.
Background Intradialytic increases in blood pressure (BP) can complicate the management of hypertension in hemodialysis (HD) patients. However, the long-term consequences are uncertain. Thus, we ...sought to determine whether BP increases during HD were associated with greater 2-year mortality in incident HD patients. Study Design Secondary analysis of a prospective dialysis cohort. Setting & Participants Incident HD patients in the Dialysis Morbidity and Mortality Wave 2 Study. Predictors Changes in systolic BP (SBP) during HD (ie, postdialysis SBP − predialysis SBP), averaged from 3 HD sessions before enrollment. Outcome Time to 2-year all-cause mortality. Measurements Cox regression was used to model hazard ratios for mortality associated with changes in SBP during HD while adjusting for demographics, comorbid conditions, interdialytic weight gain, laboratory variables, and antihypertensive agents. Results Of 1,748 patients, 12.2% showed greater than 10–mm Hg increases in SBP during HD. In adjusted analyses, every 10–mm Hg increase in SBP during HD was associated independently with a 6% increased hazard of death (hazard ratio, 1.06; 95% confidence interval, 1.01 to 1.11). When also adjusted for diastolic BP and postdialysis SBP, the adjusted hazard of death associated with increasing SBP during HD remained significant (hazard ratio, 1.12; 95% confidence interval, 1.05 to 1.21 per 10–mm Hg increase in SBP during HD). However, in analyses adjusted for predialysis SBP, there was a significant interaction between change in SBP and predialysis SBP. In analyses stratified by predialysis SBP, trends for increased mortality associated with increasing SBP during dialysis were present in patients with predialysis SBP less than 160 mm Hg. However, this relationship was significant only in patients with predialysis SBP less than 120 mm Hg. Limitations Secondary analysis with a limited number of baseline BP measurements and limited information about dialysis prescription. Conclusions Increasing SBP by more than 10 mm Hg during HD occurs in approximately 10% of incident patients, and although increasing SBP during HD was associated with decreased 2-year survival, these findings were limited to patients with predialysis SBP less than 120 mm Hg.
Background Acute kidney injury (AKI) after cardiac surgery is associated with poor outcomes, but is challenging to predict from information available before surgery. Study Design Prospective cohort ...study. Setting & Participants The TRIBE-AKI (Translational Research Investigating Biomarker Endpoints in Acute Kidney Injury) Consortium enrolled 1,147 adults undergoing cardiac surgery at 6 hospitals from 2007-2009; participants were selected for high AKI risk. Predictors Presurgical values for cystatin C, creatinine, and creatinine-based estimated glomerular filtration rate (eGFR) were categorized into quintiles and grouped as “best” (quintiles 1-2), “intermediate” (quintiles 3-4), and “worst” (quintile 5) kidney function. Outcomes The primary outcome was AKI Network (AKIN) stage 1 or higher; ≥0.3 mg/dL or 50% increase in creatinine level. Measurements Analyses were adjusted for characteristics used clinically for presurgical risk stratification. Results Average age was 71 ± 10 years (mean ± standard deviation); serum creatinine, 1.1 ± 0.3 mg/dL; eGFR-Cr, 74 ± 9 mL/min/1.73 m2 ; and cystatin C, 0.9 ± 0.3 mg/L. 407 (36%) participants developed AKI during hospitalization. Adjusted odds ratios for intermediate and worst kidney function by cystatin C were 1.9 (95% CI, 1.4-2.7) and 4.8 (95% CI, 2.9-7.7) compared with 1.2 (95% CI, 0.9-1.7) and 1.8 (95% CI, 1.2-2.6) for creatinine and 1.0 (95% CI, 0.7-1.4) and 1.7 (95% CI, 1.1-2.3) for eGFR-Cr categories, respectively. After adjustment for clinical predictors, the C statistic to predict AKI was 0.70 without kidney markers, 0.69 with creatinine, and 0.72 with cystatin C. Cystatin C also substantially improved AKI risk classification compared with creatinine, based on a net reclassification index of 0.21 ( P < 0.001). Limitations The ability of these kidney biomarkers to predict risk of dialysis-requiring AKI or death could not be assessed reliably in our study because of a small number of patients with either outcome. Conclusions Presurgical cystatin C is better than creatinine or creatinine-based eGFR at forecasting the risk of AKI after cardiac surgery.
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