Contributor disclosures are reviewed for conflicts of interest by the editorial group. When found, these are addressed by vetting through a multi-level review process, and through requirements for references to be provided to support the content. Appropriately referenced content is required of all authors and must conform to UpToDate standards of evidence.
The following represent additions to UpToDate from the past six months that were considered by the editors and authors to be of particular interest. The most recent What's New entries are at the top of each subsection.
ACUTE AND CHRONIC KIDNEY DISEASE
Metformin use and reduced kidney function (April 2016)
The use of metformin is contraindicated in patients with factors predisposing to lactic acidosis, including impaired renal function. The precise renal thresholds for the safe use of metformin remain uncertain. Improved clinical outcomes with metformin have been reported in observational studies of patients with diabetes and renal impairment (estimated glomerular filtration rate [eGFR] 45 to 60 mL/min). On the basis of these studies, the US Food and Drug Administration (FDA) revised its labeling of metformin, which previously had identified metformin as contraindicated in women and men with serum creatinine levels ≥1.4 mg/dL (124 micromol/L) and ≥1.5 mg/dL (133 micromol/L), respectively . The use of metformin is contraindicated in patients with an eGFR <30 mL/min, and the initiation of metformin is not recommended in patients with an eGFR between 30 and 45 mL/min. For patients taking metformin whose eGFR falls below 45 mL/min, the benefits and risks of continuing treatment should be assessed, whereas metformin should be discontinued if the eGFR falls below 30 mL/min. For patients with eGFR between 30 and 60 mL/min, we typically reduce the metformin dose by half (no more than 1000 mg per day), although there are no data to support this approach. (See "Metformin in the treatment of adults with type 2 diabetes mellitus", section on 'Contraindications'.)
Increased body weight and chronic kidney disease (March 2016)
Increased body weight is known to be associated with a higher risk of chronic kidney disease (CKD), which has been attributed to its association with conditions that cause CKD. A prospective cohort study from Korea now suggests that, compared with those of normal weight, even metabolically healthy overweight or obese individuals who are free from diabetes, hypertension, hypertriglyceridemia, and insulin resistance at baseline have a higher five-year cumulative incidence of CKD . (See "Screening for chronic kidney disease", section on 'Risk factors for chronic kidney disease'.)
Medication to prevent contrast nephropathy (March 2016)
A meta-analysis evaluated the effectiveness of multiple interventions to reduce the risk of contrast nephropathy. Compared with saline alone or saline plus placebo, both low- and high-dose N-acetylcysteine given with saline reduced the risk of contrast nephropathy . In addition, analysis of five studies (n = 1477) revealed that statins given with N-acetylcysteine and intravenous saline reduced the risk of contrast nephropathy compared with N-acetylcysteine and intravenous saline alone. The strength of the evidence in the meta-analysis was considered low, however, and we do not believe that there are sufficient data to support the use of statins solely for the prevention of contrast nephropathy. For at-risk patients, we suggest administration of acetylcysteine based upon its potential for benefit and low toxicity and cost. (See "Prevention of contrast-induced nephropathy", section on 'Acetylcysteine'.)
Choice of contrast agent to prevent contrast nephropathy (March 2016)
The type of contrast agent affects the risk of contrast nephropathy. Nonionic agents tend to be safer with respect to contrast nephropathy compared with ionic contrast agents. It is not known, however, whether nonionic iso-osmolal agents are safer than nonionic low-osmolal agents. A meta-analysis that included 25 randomized trials comparing the nonionic iso-osmolal agent iodixanol with a diverse group of nonionic low-osmolal agents reported a slight reduction in the risk of nephropathy with iodixanol that did not meet study criteria for clinical importance . There was no difference between groups in the risk for renal replacement therapy, cardiovascular outcomes, or death, and the strength of the evidence was only moderate. These findings are consistent with our recommendation to use either iodixanol or nonionic low-osmolal contrast agents. (See "Prevention of contrast-induced nephropathy", section on 'Nonionic iso-osmolal agents'.)
Erythropoiesis-stimulating agents may not improve quality of life in chronic kidney disease (February 2016)
While many clinicians believe that maintaining hemoglobin levels above 10 to 12 g/dL with erythropoiesis-stimulating agents (ESAs) in patients with chronic kidney disease (CKD) improves quality of life, particularly in younger individuals with active lifestyles, a meta-analysis calls this into question. The meta-analysis included studies that examined the effect of ESAs on changes in health-related quality of life using validated instruments including the 36-item Short Form Health Survey (SF-36; 13 studies) and the Kidney Disease Questionnaire (KDQ; four studies) . The achieved hemoglobin was 7.4 to 12 g/L in the placebo-treated and/or lower hemoglobin target group and 10.2 to 13.6 g/L in the higher hemoglobin target group. Overall, there were no significant differences between groups in any SF-36 or KDQ domains. These data suggest that the use of ESAs to treat anemia may not result in significant changes in health-related quality of life among CKD patients. (See "Anemia of chronic kidney disease: Target hemoglobin/hematocrit for patients treated with erythropoietic agents", section on 'Quality of life'.)
suPAR and decreased eGFR after cardiac catheterization (November 2015)
The soluble urokinase-type plasminogen activator receptor (suPAR) is a membrane protein that has been implicated in the pathogenesis of glomerular diseases including focal and segmental glomerulosclerosis (FSGS) and diabetic nephropathy. Plasma suPAR concentrations were measured in individuals enrolled in a prospective registry of patients undergoing cardiac catheterization . Patients were excluded who had congenital heart disease, severe valvular heart disease, severe anemia, a recent blood transfusion, myocarditis or an active inflammatory condition, or cancer. A higher suPAR concentration at baseline was associated with a greater annual decline in eGFR among patients with baseline eGFR <60 mL/min/1.73 m2. A role for suPAR as a biomarker of chronic kidney disease requires further study in other cohorts . (See "Screening for chronic kidney disease", section on 'Other biomarkers'.)
Cool-temperature dialysis and hemodynamic stability (April 2016)
Using cool-temperature dialysate may increase the hemodynamic stability of selected patients during hemodialysis. A recent meta-analysis showed that, compared with standard dialysis, cool-temperature dialysis reduced the risk of intradialytic hypotension by 68 percent . Patients on cool-temperature dialysis were more likely to have uncomfortable symptoms during dialysis, such as chills, shivering, or cramps, although there was no effect on overall quality of life or dialysis adequacy, as assessed by the 36-question health survey assessment form. Cool-temperature dialysis is an effective strategy to increase hemodynamic stability in patients with intradialytic hypotension. (See "Intradialytic hypotension in an otherwise stable patient", section on 'Second-line approach'.)
Venous thromboembolism risk with central versus peripheral insertion of central venous catheters (January 2016)
There is accumulating evidence that peripherally-inserted central venous catheters (PICCs) are associated with a greater risk for upper extremity deep vein thrombosis (UEDVT) compared with centrally-inserted central venous catheters (CICCs). The Medical Inpatients and Thrombosis (MITH) Study evaluated catheter use in 299 venous thromboembolism cases compared with controls without venous thromboembolism at a single institution . Central catheter use was associated with a 14-fold increased risk for UEDVT, without a significantly increased risk for pulmonary embolism. PICCs were associated with a higher cumulative risk compared with CICCs (8.1 versus 4.8 per 1000 admissions). Given the higher risk for UEDVT with PICCs, we generally avoid them in patients for whom maintaining vascular patency and integrity for long-term vascular access options (eg, future hemodialysis access) is essential. (See "Catheter-related upper extremity venous thrombosis", section on 'Peripheral versus central insertion' and "Overview of central venous access".)
GLOMERULAR DISEASE AND VASCULITIS
Immunosuppressive therapy in IgA nephropathy (December 2015)
Glucocorticoid monotherapy may be beneficial in patients with IgA nephropathy who have persistent proteinuria >1 g/day despite nonimmunosuppressive therapy, provided that such patients do not have extensive chronic fibrosis on kidney biopsy. In the STOP-IgA trial, 162 patients with IgA nephropathy and persistent proteinuria >0.75 g/day despite six months of nonimmunosuppressive therapy were assigned to continue nonimmunosuppressive therapy alone or to receive immunosuppressive therapy (glucocorticoids alone or combined with cyclophosphamide and azathioprine, depending upon the level of kidney function) . At three years, the protein-to-creatinine ratio decreased to <0.2 g/g in 11 percent of patients who received nonimmunosuppressive therapy alone, 31 percent of those who received glucocorticoid monotherapy, and 11 percent of those who received combination immunosuppression. However, the change in estimated glomerular filtration rate (GFR) was not different between the groups, and immunosuppression led to more adverse events. Various trial limitations may have impacted these results and thus, UpToDate has not altered its recommendation to use immunosuppressive therapy in selected patients with IgA nephropathy and persistent proteinuria despite nonimmunosuppressive therapy. (See "Treatment and prognosis of IgA nephropathy", section on 'Glucocorticoids as sole immunosuppressive/anti-inflammatory therapy'.)
Antihypertensive therapy in patients not at high cardiovascular risk (April 2016)
The benefit of antihypertensive therapy in patients at low or moderate cardiovascular risk, including those who are normotensive, is unclear. The Third Heart Outcomes Prevention Evaluation trial (HOPE-3) randomly assigned 12,705 patients at moderate risk for cardiovascular disease (only 38 percent were hypertensive at baseline) to receive a fixed-dose combination of candesartan plus hydrochlorothiazide or placebo . At 5.6 years, there was no significant difference in cardiovascular events. However, among a hypertensive subgroup (ie, those whose initial systolic pressure was in the highest tertile, or greater than 143 mmHg), antihypertensive therapy significantly reduced the incidence of major cardiovascular events (5.7 versus 7.5 percent, absolute benefit of 1.8 percent). Thus, antihypertensive therapy reduced cardiovascular events in patients with mild hypertension and low overall cardiovascular risk. (See "What is goal blood pressure in the treatment of hypertension?", section on 'Benefit in those with mild hypertension'.)
Meta-analysis of goal blood pressure trials (March 2016)
A meta-analysis of goal blood pressure trials (ie, comparing a more intensive versus a less intensive goal) included 16 studies (including the SPRINT trial) and 52,235 patients . A standardized 10/5 mmHg reduction in systolic/diastolic pressure resulted in reductions in the relative risks of stroke, coronary heart disease, and cardiovascular death. A trend, that did not reach statistical significance, was also seen for reduction in heart failure and all-cause mortality. The absolute (as opposed to relative) risk reductions varied according to baseline cardiovascular risk. The absolute benefit from blood pressure reduction was substantially greater among patients who, at baseline, were considered high-risk for having a cardiovascular event over the subsequent 5 to 10 years. (See "What is goal blood pressure in the treatment of hypertension?", section on 'Evidence of benefit from treating hypertension'.)
Cardiovascular benefits from blood pressure lowering (February 2016)
A meta-analysis of 123 randomized trials of antihypertensive therapy including 613,815 patients found that a standardized 10 mmHg reduction in achieved systolic pressure reduced the risk of death (relative risk [RR] 0.87, 95% CI 0.84-0.91), as well as risk of coronary heart disease, stroke, or heart failure . The benefit was consistent regardless of the baseline blood pressure (including in patients whose initial systolic pressure was less than 130 mmHg). In addition, patients with both low initial systolic pressure and preexisting cardiovascular disease benefited from lower blood pressure. (See "What is goal blood pressure in the treatment of hypertension?", section on 'Evidence of benefit from treating hypertension'.)
New guidelines on screening and diagnosis of hypertension (October 2015)
New guidelines from the United States Preventive Services Task Force (USPSTF) and the Canadian Hypertension Education Program (CHEP) have been released and suggest that, in nearly all patients who have an elevated blood pressure measured in the office, out-of-office blood pressure readings should be obtained to confirm the diagnosis [14,15]. For out-of-office blood pressure measurement, 24-hour ambulatory blood pressure monitoring (ABPM) is preferred, and home blood pressure monitoring is an acceptable alternative if ABPM is not possible. These guidelines are consistent with our recommendations for confirming elevated blood pressure readings. (See "Overview of hypertension in adults", section on 'Diagnosis'.)
Early volume expansion in STEC-hemolytic uremic syndrome (January 2016)
Fluid management of patients with Shiga toxin-producing Escherichia coli hemolytic uremic syndrome (STEC-HUS) has been based on assessment of intravascular volume, which can be increased or decreased. However, a prospective Italian study of 38 children with STEC-HUS from 2012 and 2014 compared with historical controls from 2006 to 2009 reported that routine early volume expansion targeted to increase body weight by 10 percent improved outcome (lower rate of renal replacement therapy, shorter hospital course, and shorter duration of intensive care) . Although these results are promising, further investigation is needed due to the potential bias from the use of historical controls and the relatively small number of patients and adverse events in the study. Until confirmatory data are available, we recommend assessment of intravascular volume status and renal function, with administration of fluids to rapidly correct documented volume depletion. We recommend not routinely providing volume expansion, especially if there is evidence of increased intravascular volume. (See "Treatment and prognosis of Shiga toxin-producing Escherichia coli (STEC) hemolytic uremic syndrome (HUS) in children", section on 'Fluid management'.)
Survival of recipients of HLA-mismatched kidneys (March 2016)
The success of human leukocyte antigen (HLA)-mismatched kidney transplantation is reduced compared with HLA-matched kidneys. However, a multicenter study suggests higher survival rates for recipients of HLA-incompatible living-donor kidneys compared with waitlisted controls who either never receive a kidney or who receive an HLA-compatible deceased-donor kidney after a prolonged time on the waiting list . The observed survival benefit persisted despite the presence of high donor-specific antibody (DSA) levels and independent of the desensitization protocol utilized. However, a few factors may have influenced these findings: data were reported from highly effective transplant centers and may not be generalizable to all centers, and the comparator group came from all patients on the waiting list rather than just active patients who would be considered suitable for transplantation, which may overestimate the apparent benefit of transplantation. (See "HLA matching and graft survival in kidney transplantation", section on 'Survival compared with waiting list'.)
Zika virus and tissue/gamete donation (March 2016)
Zika virus has been detected in a number of tissues and body fluids. To avoid possible transmission of Zika virus infection, the US Food and Drug Administration (FDA) has issued donor deferral recommendations for hematopoietic stem cells, tissues, and donor sperm or eggs; the recommendations do not apply to solid organs . Living donors with Zika virus infection or relevant epidemiologic exposure (residence in or travel to an area where mosquito-borne transmission of Zika virus infection has been reported, or unprotected sexual contact with a person who meets these criteria) should be considered ineligible for donation for six months. Deceased donors with Zika virus infection in the preceding six months should also be considered ineligible. The deferral period recommended by the FDA for blood donors with risk factors for Zika virus infection remains at four weeks. (See "Zika virus infection: An overview", section on 'Blood/tissue donation'.)
BENEFIT trial comparing belatacept and cyclosporine in kidney transplant patients (February 2016)
The final results of the Belatacept Evaluation of Nephroprotection and Efficacy as First-line Immunosuppression Trial (BENEFIT) have been published . BENEFIT was a phase III trial that compared a more intensive (MI) or less intensive (LI) regimen of a T cell inhibitor, belatacept, versus cyclosporine in adults receiving a kidney transplant from living or standard criteria deceased donors. Of the 660 patients initially treated, only 128 (MI group), 136 (LI group), and 92 (cyclosporine group) completed the 84-month study. Patients who dropped out of the trial were ineligible to continue, declined the extension study, withdrew consent, had an adverse effect, or died; others were lost to follow-up, or were nonadherent and not included in the analysis. Of the patients who were evaluated, at 84 months, the risks of death or graft loss and the development of donor-specific antibodies were lower among patients treated with belatacept compared with cyclosporine. However confidence in these data are limited because of the large number of patients who were excluded from the final analysis. (See "Maintenance immunosuppressive therapy in renal transplantation in adults", section on 'Belatacept'.)
Estimation of ESRD risk for kidney donor candidates (December 2015)
To improve the evaluation and selection of living kidney donors, a Kidney Disease Improving Global Outcomes (KDIGO) work group and the Chronic Kidney Disease-Prognosis Consortium (CKD-PC) developed a risk prediction model for end stage renal disease (ESRD) in the absence of donation . The model was based on a meta-analysis of seven general population cohorts combined with an analysis of the incidence of ESRD in a low-risk segment of the United States (US) population. The observed incidence of ESRD at 15 years among US kidney donors was 3.5 to 5.3 times the projected risks for healthy persons in the absence of donation, and varied according to sex and race. An online risk tool was developed to project ESRD risk (in the absence of donation) for donor candidates. Further research is needed to validate these results, and to extend the models to non-US populations and other racial groups. (See "Risk of live kidney donation", section on 'End-stage renal disease'.)
Elbasvir-grazoprevir for chronic HCV infection (February 2016)
Despite the proliferation of interferon-free regimens for the treatment of chronic hepatitis C (HCV) infection, safety concerns have limited options for patients with severe renal impairment, who have been excluded from trials of most available regimens. In January 2016, the US Food and Drug Administration approved the new combination regimen elbasvir-grazoprevir for the treatment of patients with genotypes 1 and 4 HCV infection, including those with any degree of renal impairment (including dialysis dependence) . In a randomized, placebo-controlled trial of genotype 1-infected patients with estimated glomerular filtration rate (eGFR) <30 mL/min per 1.73 m2, the sustained virologic response (SVR) rate was 94 percent among the 122 patients who received elbasvir-grazoprevir for 12 weeks, and adverse event rates were similar between treatment and placebo groups . These results were comparable to those among patients with normal renal function. Elbasvir-grazoprevir is given for 12 to 16 weeks with or without ribavirin, depending on the presence of pre-existing resistance-associated variants in the NS5A protein and prior exposure to HCV protease inhibitors. (See "Treatment of chronic hepatitis C infection in adults with renal impairment", section on 'Regimens with direct-acting antivirals'.)
Tenofovir alafenamide as part of a coformulated antiretroviral regimen (November 2015)
Tenofovir is a preferred nucleoside to use in a combination antiretroviral regimen for the treatment of HIV infection. Until recently, tenofovir was available only as tenofovir-disoproxil fumarate (TDF), which has been associated with renal toxicity and decreased bone mineral density. In November 2015, a newer formulation, tenofovir alafenamide (TAF) became available in the United States as part of a single tablet coformulation, elvitegravir-cobicistat-emtricitabine-TAF (ECF-TAF) . This combination agent is as effective as elvitegravir-cobicistat-emtricitabine-TDF (ECF-TDF) in suppressing HIV RNA with fewer adverse renal and bone effects . ECF-TAF can be used for patients with reduced kidney function (estimated glomerular filtration rate [eGFR] ≥30 mL/min/m2), unlike ECF-TDF, which should only be used in patients with an eGFR >70 mL/min/m2. ECF-TAF is considered a recommended regimen by the United States Department of Health and Human Services . In March 2016, TAF also became available as part of the coformulated tablet rilpivirine-emtricitabine-tenofovir alafenamide. (See "Selecting antiretroviral regimens for the treatment-naïve HIV-infected patient", section on 'Preferred regimens'.)
- http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm494829.htm?source=govdelivery&utm_medium=email&utm_source=govdelivery (Accessed on April 11, 2016).
- Chang Y, Ryu S, Choi Y, et al. Metabolically Healthy Obesity and Development of Chronic Kidney Disease: A Cohort Study. Ann Intern Med 2016; 164:305.
- Subramaniam RM, Suarez-Cuervo C, Wilson RF, et al. Effectiveness of Prevention Strategies for Contrast-Induced Nephropathy: A Systematic Review and Meta-analysis. Ann Intern Med 2016; 164:406.
- Eng J, Wilson RF, Subramaniam RM, et al. Comparative Effect of Contrast Media Type on the Incidence of Contrast-Induced Nephropathy: A Systematic Review and Meta-analysis. Ann Intern Med 2016; 164:417.
- Collister D, Komenda P, Hiebert B, et al. The Effect of Erythropoietin-Stimulating Agents on Health-Related Quality of Life in Anemia of Chronic Kidney Disease: A Systematic Review and Meta-analysis. Ann Intern Med 2016; 164:472.
- Hayek SS, Sever S, Ko YA, et al. Soluble Urokinase Receptor and Chronic Kidney Disease. N Engl J Med 2015; 373:1916.
- Skorecki KL, Freedman BI. A suPAR Biomarker for Chronic Kidney Disease. N Engl J Med 2015; 373:1971.
- Mustafa RA, Bdair F, Akl EA, et al. Effect of Lowering the Dialysate Temperature in Chronic Hemodialysis: A Systematic Review and Meta-Analysis. Clin J Am Soc Nephrol 2016; 11:442.
- Winters JP, Callas PW, Cushman M, et al. Central venous catheters and upper extremity deep vein thrombosis in medical inpatients: the Medical Inpatients and Thrombosis (MITH) Study. J Thromb Haemost 2015; 13:2155.
- Rauen T, Eitner F, Fitzner C, et al. Intensive Supportive Care plus Immunosuppression in IgA Nephropathy. N Engl J Med 2015; 373:2225.
- Lonn EM, Bosch J, López-Jaramillo P, et al. Blood-Pressure Lowering in Intermediate-Risk Persons without Cardiovascular Disease. N Engl J Med 2016.
- Thomopoulos C, Parati G, Zanchetti A. Effects of blood pressure lowering on outcome incidence in hypertension: 7. Effects of more vs. less intensive blood pressure lowering and different achieved blood pressure levels - updated overview and meta-analyses of randomized trials. J Hypertens 2016; 34:613.
- Ettehad D, Emdin CA, Kiran A, et al. Blood pressure lowering for prevention of cardiovascular disease and death: a systematic review and meta-analysis. Lancet 2016; 387:957.
- Siu AL, U.S. Preventive Services Task Force. Screening for high blood pressure in adults: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med 2015; 163:778.
- Daskalopoulou SS, Rabi DM, Zarnke KB, et al. The 2015 Canadian Hypertension Education Program recommendations for blood pressure measurement, diagnosis, assessment of risk, prevention, and treatment of hypertension. Can J Cardiol 2015; 31:549.
- Ardissino G, Tel F, Possenti I, et al. Early Volume Expansion and Outcomes of Hemolytic Uremic Syndrome. Pediatrics 2016; 137.
- Orandi BJ, Luo X, Massie AB, et al. Survival Benefit with Kidney Transplants from HLA-Incompatible Live Donors. N Engl J Med 2016; 374:940.
- US Food and Drug Administration. Donor Screening Recommendations to Reduce the Risk of Transmission of Zika Virus by Human Cells, Tissues, and Cellular and Tissue-Based Products: Guidance for Industry, March 2016. http://www.fda.gov/downloads/BiologicsBloodVaccines/GuidanceComplianceRegulatoryInformation/Guidances/Tissue/UCM488582.pdf (Accessed on March 07, 2016).
- Vincenti F, Charpentier B, Vanrenterghem Y, et al. A phase III study of belatacept-based immunosuppression regimens versus cyclosporine in renal transplant recipients (BENEFIT study). Am J Transplant 2010; 10:535.
- Grams ME, Sang Y, Levey AS, et al. Kidney-Failure Risk Projection for the Living Kidney-Donor Candidate. N Engl J Med 2016; 374:411.
- Zepatier (elbasvir and grazoprevir). US FDA approved product information; Whitehouse Station, NJ: Merck and Co, Inc; January 2016.
- Roth D, Nelson DR, Bruchfeld A, et al. Grazoprevir plus elbasvir in treatment-naive and treatment-experienced patients with hepatitis C virus genotype 1 infection and stage 4-5 chronic kidney disease (the C-SURFER study): a combination phase 3 study. Lancet 2015; 386:1537.
- United States Food and Drug Administration. FDA approves new treatment for HIV. http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm471300.htm (Accessed on November 16, 2015).
- Sax PE, Wohl D, Yin MT, et al. Tenofovir alafenamide versus tenofovir disoproxil fumarate, coformulated with elvitegravir, cobicistat, and emtricitabine, for initial treatment of HIV-1 infection: two randomised, double-blind, phase 3, non-inferiority trials. Lancet 2015; 385:2606.
- HHS Panel on antiretroviral guidelines for adults and adolescents includes a fixed-dose combination of elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide among the recommended regimens for antiretroviral treatment-naive individuals with HIV-1 infection. https://aidsinfo.nih.gov/news/1621/evg-c-ftc-taf-statement-from-adult-arv-guideline-panel (Accessed on November 20, 2015).