Hypoxia signaling in renal pericytes-is it safe to activate?

While excitement has grown for the use of hypoxia-inducible factor (HIF) prolyl hydroxylase inhibitors for treating renal anemia, multiple preclinical studies have shown the complex and cell-type-dependent roles of HIFs in kidney disease pathogenesis, including renal fibrosis. Pan et al. now clearly show that activating the HIF signaling in the Gli1-lineage myofibroblasts restores erythropoietin production while not adversely affecting matrix production, mitigating the concerns of exacerbated fibrosis by HIF prolyl hydroxylase inhibitors.

Design and Rationale of HiLo: A Pragmatic, Randomized Trial of Phosphate Management for Patients Receiving Maintenance Hemodialysis.

RATIONALE & OBJECTIVE: Hyperphosphatemia is a risk factor for poor clinical outcomes in patients with kidney failure receiving maintenance dialysis. Opinion-based clinical practice guidelines recommend the use of phosphate binders and dietary phosphate restriction to lower serum phosphate levels toward the normal range in patients receiving maintenance dialysis, but the benefits of these approaches and the optimal serum phosphate target have not been tested in randomized trials. It is also unknown if aggressive treatment that achieves unnecessarily low serum phosphate levels worsens outcomes. STUDY DESIGN: Multicenter, pragmatic, cluster-randomized clinical trial. SETTING & PARTICIPANTS: HiLo will randomize 80-120 dialysis facilities operated by DaVita Inc and the University of Utah to enroll 4,400 patients undergoing 3-times-weekly, in-center hemodialysis. INTERVENTION: Phosphate binder prescriptions and dietary recommendations to achieve the "Hi" serum phosphate target (≥6.5 mg/dL) or the "Lo" serum phosphate target (<5.5 mg/dL). OUTCOMES: Primary outcome: Hierarchical composite outcome of all-cause mortality and all-cause hospitalization. Main secondary outcomes: Individual components of the primary outcome. RESULTS: The trial is currently enrolling. LIMITATIONS: HiLo will not adjudicate causes of hospitalizations or mortality and does not protocolize use of specific phosphate binder classes. CONCLUSIONS: HiLo aims to address an important clinical question while more generally advancing methods for pragmatic clinical trials in nephrology by introducing multiple innovative features including stakeholder engagement in the study design, liberal eligibility criteria, use of electronic informed consent, engagement of dietitians to implement the interventions in real-world practice, leveraging electronic health records to eliminate dedicated study visits, remote monitoring of serum phosphate separation between trial arms, and use of a novel hierarchical composite outcome. TRIAL REGISTRATION: Registered at ClinicalTrials.gov with study number NCT04095039.

Therapeutic options for chronic kidney disease-associated pulmonary hypertension.

PURPOSE OF REVIEW: Pulmonary hypertension is a common and devastating complication of chronic kidney disease (CKD). Traditionally considered a consequence of volume overload, recent findings now expand this paradigm. These novel mechanisms herald new treatment options. This review summarizes the current evidence to provide a theoretical model of the contributing factors for CKD-associated pulmonary hypertension. Along this framework, we highlight current and emerging therapeutic strategies for each putative factor. RECENT FINDINGS: A series of retrospective studies of right heart catheterization data provide insights into the potential hemodynamic profile of CKD-associated pulmonary hypertension. These studies suggest that elevated pulmonary vascular resistance may commonly contribute to pulmonary hypertension. In addition, preclinical models implicate an increasing array of CKD-associated factors which influence pulmonary vascular biology. Many of these factors also adversely affect kidney function and CKD progression. Clinical trial and other prospective data for treatments of CKD-associated pulmonary hypertension remain limited. SUMMARY: Volume overload and left-ventricular dysfunction are the predominant focus of CKD-associated pulmonary hypertension treatment for most patients. However, new findings suggest that treatments targeting pulmonary vascular vasoconstriction and remodeling may be promising treatment options for select patients. Clinical trials are needed for all therapeutic strategies for CKD-associated pulmonary hypertension.

Pulmonary Hypertension Subtypes and Mortality in CKD.

RATIONALE & OBJECTIVE: Pulmonary hypertension (PH) contributes to cardiovascular disease and mortality in patients with chronic kidney disease (CKD), but the pathophysiology is mostly unknown. This study sought to estimate the prevalence and consequences of PH subtypes in the setting of CKD. STUDY DESIGN: Observational retrospective cohort study. SETTING & PARTICIPANTS: We examined 12,618 patients with a right heart catheterization in the Duke Databank for Cardiovascular Disease from January 1, 2000, to December 31, 2014. EXPOSURES: Baseline kidney function stratified by CKD glomerular filtration rate category and PH subtype. OUTCOMES: All-cause mortality. ANALYTICAL APPROACH: Multivariable Cox proportional hazards analysis. RESULTS: In this cohort, 73.4% of patients with CKD had PH, compared with 56.9% of patients without CKD. Isolated postcapillary PH (39.0%) and combined pre- and postcapillary PH (38.3%) were the most common PH subtypes in CKD. Conversely, precapillary PH was the most common subtype in the non-CKD cohort (35.9%). The relationships between mean pulmonary artery pressure, pulmonary capillary wedge pressure, and right atrial pressure with mortality were similar in both the CKD and non-CKD cohorts. Compared with those without PH, precapillary PH conferred the highest mortality risk among patients without CKD (HR, 2.27; 95% CI, 2.00-2.57). By contrast, in those with CKD, combined pre- and postcapillary PH was associated with the highest risk for mortality in CKD in adjusted analyses (compared with no PH, HRs of 1.89 [95% CI, 1.57-2.28], 1.87 [95% CI, 1.52-2.31], 2.13 [95% CI, 1.52-2.97], and 1.63 [95% CI, 1.12-2.36] for glomerular filtration rate categories G3a, G3b, G4, and G5/G5D). LIMITATIONS: The cohort referred for right heart catheterization may not be generalizable to the general population. Serum creatinine data in the 6 months preceding catheterization may not reflect true baseline CKD. Observational design precludes assumptions of causality. CONCLUSIONS: In patients with CKD referred for right heart catheterization, PH is common and associated with poor survival. Combined pre- and postcapillary PH was common and portended the worst survival for patients with CKD.

Drug Development in Kidney Disease: Proceedings From a Multistakeholder Conference.

Occasional bursts of discovery and innovation have appeared during the otherwise stagnant past several decades of drug development in nephrology. Among other recent drug discoveries, the unexpected kidney benefits observed with sodium/glucose cotransporter 2 inhibitors may herald a renaissance of drug development in kidney disease. This recent progress highlights the need to further promote and stimulate research and development of promising therapies that may ameliorate the morbidity and mortality associated with kidney disease. To help identify and address barriers to drug development in nephrology, the Duke Clinical Research Institute convened a conference in April 2019 that included stakeholders from academia, industry, government agencies, and patient advocacy. From these discussions, several opportunities were identified to improve every stage of drug development for kidney disease from early discovery to implementation into practice. Key topics reviewed in this article are the utility of interconnected data and site research networks, surrogate end points, pragmatic and adaptive trial designs, the promising uses of real-world data, and methods to improve the generalizability of trial results and uptake of approved drugs for kidney-related diseases.

Association of post-discharge specialty outpatient visits with readmissions and mortality in high-risk heart failure patients.

Heart failure (HF) outcomes are especially poor in high-risk patients with certain comorbidities including diabetes mellitus (DM), chronic kidney disease (CKD), and chronic obstructive pulmonary disease (COPD). Whether early specialty or primary care provider (PCP) follow-up after HF discharge affects outcomes in high-risk patients is unknown. METHODS: We analyzed patients discharged from a Get With The Guidelines HF-participating hospital from 2007-2012 with linked Medicare claims to investigate the association of medical specialist visit within 14 days of discharge stratified by comorbidity with the primary outcome of 90-day HF readmission. Secondary outcomes included 90-day and 1-year all-cause mortality. RESULTS: Out of 33,243 patients, 39.4% had DM, 19.8% had CKD, 30.0% had COPD, and 36.3% had no key comorbidity. Nephrologist visit in patients with CKD was associated with a 35% reduction in 90-day HF readmission (hazard ratio [HR] 0.65, 95% confidence interval [CI] 0.49-0.85). Pulmonologist visit in patients with COPD was associated with a 29% reduction in 90-day HF readmission (HR 0.71, 95% CI 0.55-0.91). In patients with no key comorbidity, PCP and Cardiologist visits were associated with decreased 90-day mortality (HR for PCP 0.79, 95% CI 0.66-0.94; HR for Cardiologist 0.78, 95% CI 0.63-0.96). In patients with DM, Endocrinologist visit was associated with a 42% reduction of 90-day mortality (HR 0.58, 95% CI 0.34-0.99). CONCLUSIONS: Specialist and PCP visit in the immediate post-discharge period may improve 90-day HF readmission and mortality in certain high-risk groups of patients with HF.

Association of Chronic Renal Insufficiency with Inhospital Outcomes in Primary Heart Failure Hospitalizations (Insights from the National Inpatient Sample 2004 to 2018).

Chronic kidney disease (CKD) is a major co-morbidity in patients with heart failure (HF). There are limited contemporary data characterizing the clinical profile, inhospital outcomes, and resource use in patients hospitalized for HF with co-morbid CKD. We utilized a nationally representative population to address the knowledge gap. We examined the National Inpatient Sample 2004 to 2018 database to study the co-morbid profile, in-hospital mortality, clinical resource utilization, healthcare cost, and length of stay (LOS) in primary adult HF hospitalizations stratified by presence versus absence of a diagnosis codes of CKD. There were a total of 16,050,301 adult hospitalizations with a primary HF diagnosis from January 1, 2004, to December 31, 2018. Of these, 428,175 (33.81%) had CKD; 1,110,778 (6.92%) had end-stage kidney disease (ESKD); and 9,511,348 (59.25%) had no diagnosis of CKD. Patients with hospitalizations for HF with ESKD were younger (mean age 65.4 years) compared with those without ESKD. In multivariable analysis, those with CKD had higher odds of inhospital mortality (2.82% vs 3.57%, adjusted odds ratio [aOR] 1.30, confidence interval [CI] 1.28 to 1.26, p <0.001), cardiogenic shock (1.01% vs 1.79% aOR 2.00, CI 1.95 to 2.05, p <0.001), and the need for mechanical circulatory support (0.4% vs 0.5%, aOR 1.51, 1.44 to 1.57, p <0.001) compared with those without CKD. In multivariable analysis, those with ESKD had higher odds of inhospital mortality (2.82% vs 3.84%, aOR 2.07, CI 2.01 to 2.12, p <0.001), need for invasive mechanical ventilation use (2.04% vs 3.94%, aOR 1.79, CI 1.75 to 1.84, p <0.001), cardiac arrest (0.72% vs 1.54%, aOR 2.09, CI 2.00 to 2.17, p <0.001), longer LOS (Adjusted mean difference 1.48, 1.44 to 1.53, p <0.001) and higher inflation-adjusted cost (Adjusted mean difference 3,411.63, CI 3,238.35 to 3,584.91, p <0.001) compared with those without CKD. CKD and ESKD affected about 40.7% of all primary HF hospitalizations from 2004 to 2018. The inhospital mortality, clinical complications, LOS, and inflation-adjusted cost were higher in hospitalized patients with ESKD compared with patients with and without CKD. In addition, compared with those without CKD, hospitalized patients with CKD had higher inhospital mortality, clinical complications, LOS, and inflation-adjusted cost compared with patients with no diagnosis of CKD.

Noninvasive Risk Score to Screen for Pulmonary Hypertension With Elevated Pulmonary Vascular Resistance in Diseases of Chronic Volume Overload.

Volume overload promotes pulmonary hypertension (PH) through pulmonary venous hypertension. However, PH with elevated pulmonary vascular resistance (hereafter PH-PVR) may develop in patients with diseases of volume overload, such as heart failure or chronic kidney disease (CKD). In such cases, volume management alone may be insufficient to slow PH progression. An accurate, noninvasive method to screen for PH-PVR in these diseases would facilitate early targeted therapy. We integrated invasive hemodynamic and echocardiography data collected from a single-center clinical cohort and identified patients with CKD or heart failure at the time of assessment. We applied penalized regression to derive a risk score of clinical parameters and echocardiography data associated with PH-PVR and categorized patients into low- (≤5 points), intermediate- (6-10 points), or high-risk (>10 points) groups. Using an internal validation strategy, we evaluated the ability of this risk score to predict PH-PVR and determined the association of this risk classification with 3-year all-cause mortality. Of 2422 patients, 42.4% had PH-PVR. In adjusted analyses, tricuspid regurgitant velocity, right ventricular function, BMI, heart rate, and hemoglobin most strongly associated with PH-PVR. The risk score significantly associated with PH-PVR (age-adjusted odds ratio 11.69 for the highest-risk group, 95% confidence interval [CI] 6.54-20.92). The high-risk group also associated with a significantly higher risk of 3-year all-cause mortality in adjusted analyses (hazard ratio 1.85, 95% CI 1.50-2.27). In conclusion, a noninvasive risk score derived from echocardiography and clinical parameters significantly associated with PH-PVR and all-cause mortality in a cohort of patients with CKD and heart failure.

Continuation versus discontinuation of renin-angiotensin system inhibitors in patients admitted to hospital with COVID-19: a prospective, randomised, open-label trial.

BACKGROUND: Biological considerations suggest that renin-angiotensin system inhibitors might influence the severity of COVID-19. We aimed to evaluate whether continuing versus discontinuing renin-angiotensin system inhibitors (angiotensin-converting enzyme inhibitors or angiotensin receptor blockers) affects outcomes in patients admitted to hospital with COVID-19. METHODS: The REPLACE COVID trial was a prospective, randomised, open-label trial done at 20 large referral hospitals in seven countries worldwide. Eligible participants were aged 18 years and older who were admitted to hospital with COVID-19 and were receiving a renin-angiotensin system inhibitor before admission. Individuals with contraindications to continuation or discontinuation of renin-angiotensin system inhibitor therapy were excluded. Participants were randomly assigned (1:1) to continuation or discontinuation of their renin-angiotensin system inhibitor using permuted block randomisation, with allocation concealed using a secure web-based randomisation system. The primary outcome was a global rank score in which participants were ranked across four hierarchical tiers incorporating time to death, duration of mechanical ventilation, time on renal replacement or vasopressor therapy, and multiorgan dysfunction during the hospitalisation. Primary analyses were done in the intention-to-treat population. The REPLACE COVID trial is registered with ClinicalTrials.gov, NCT04338009. FINDINGS: Between March 31 and Aug 20, 2020, 152 participants were enrolled and randomly assigned to either continue or discontinue renin-angiotensin system inhibitor therapy (continuation group n=75; discontinuation group n=77). Mean age of participants was 62 years (SD 12), 68 (45%) were female, mean body-mass index was 33 kg/m2 (SD 8), and 79 (52%) had diabetes. Compared with discontinuation of renin-angiotensin system inhibitors, continuation had no effect on the global rank score (median rank 73 [IQR 40-110] for continuation vs 81 [38-117] for discontinuation; ß-coefficient 8 [95% CI -13 to 29]). There were 16 (21%) of 75 participants in the continuation arm versus 14 (18%) of 77 in the discontinuation arm who required intensive care unit admission or invasive mechanical ventilation, and 11 (15%) of 75 participants in the continuation group versus ten (13%) of 77 in the discontinuation group died. 29 (39%) participants in the continuation group and 28 (36%) participants in the discontinuation group had at least one adverse event (χ2 test of adverse events between treatment groups p=0·77). There was no difference in blood pressure, serum potassium, or creatinine during follow-up across the two groups. INTERPRETATION: Consistent with international society recommendations, renin-angiotensin system inhibitors can be safely continued in patients admitted to hospital with COVID-19. FUNDING: REPLACE COVID Investigators, REPLACE COVID Trial Social Fundraising Campaign, and FastGrants.

Infection rate and risk factor analysis in an orthopaedic ambulatory surgical center.

Surgical site infections (SSI) are a costly problem. The purpose of this study was to determine the rate of infection and identify patient and technical risk factors for SSI in an orthopaedic ambulatory surgical center. Over 11,000 consecutive orthopaedic surgeries over 5 years were reviewed for SSI as well as demographic, medical, and surgical risk factors. Nearly 400 noninfected patients served as statistical controls. The overall infection rate was 0.33%, which compares favorably to previous studies of outpatient surgery and appears to be substantially lower than SSI rates previously reported for inpatient orthopaedic surgery. Male sex, smoking, and diabetes demonstrated significantly higher risk for infection. Surgery time and duration of anesthesia administration were also associated statistically with SSI. A history of cancer, hypertension, or thyroid problems were all associated with higher but statistically insignificant risk of SSI. Patient age and number of past surgeries were equal in the SSI and control groups.

Echocardiography to Screen for Pulmonary Hypertension in CKD.

INTRODUCTION: Pulmonary hypertension (PH) is a common yet incompletely understood complication of chronic kidney disease (CKD). Although transthoracic echocardiogram is commonly used to noninvasively estimate PH, it has not been validated in a CKD population. We investigated the utility of this diagnostic tool for CKD-associated PH in a large right heart catheterization (RHC) cohort. METHODS: We reviewed RHC and echocardiography data in 4036 patients (1714 with CKD) obtained between 2011 and 2014 at a single center. We used multivariate regression to determine the associations of echocardiography measurements with PH, and evaluated whether estimated glomerular filtration rate (eGFR) modified these associations. Using internal validation, we sequentially added measurements to predictive models and analyzed the incremental predictive performance using the change in the area under the receiver operating characteristic curve (ΔAUC) and net reclassification improvement. RESULTS: The echocardiography measurements most strongly associated with the diagnosis of PH included tricuspid regurgitant velocity (TRV), tricuspid annular plane systolic excursion (TAPSE), right atrial pressure, diastolic dysfunction, and right ventricular function. Among these measurements, eGFR significantly modified the associations of TAPSE and diastolic dysfunction with the diagnosis of PH. The model consisting of a combination of TRV, right atrial pressure, and TAPSE most accurately predicted the diagnosis of PH in a CKD population (AUC 0.82). CONCLUSIONS: The optimal model to predict PH diagnosis included TRV, right atrial pressure, and TAPSE. Since TAPSE more strongly associated with PH in the CKD population, these findings support a CKD-specific approach to the development of noninvasive screening algorithms for PH.

Coronavirus Disease 2019 and Hypertension: The Role of Angiotensin-Converting Enzyme 2 and the Renin-Angiotensin System.

Hypertension emerged from early reports as a potential risk factor for worse outcomes for persons with coronavirus disease 2019 (COVID-19). Among the putative links between hypertension and COVID-19 is a key counter-regulatory component of the renin-angiotensin system (RAS): angiotensin-converting enzyme 2 (ACE2). ACE2 facilitates entry of severe acute respiratory syndrome coronavirus 2, the virus responsible for COVID-19, into host cells. Because RAS inhibitors have been suggested to increase ACE2 expression, health-care providers and patients have grappled with the decision of whether to discontinue these medications during the COVID-19 pandemic. However, experimental models of analogous viral pneumonias suggest RAS inhibitors may exert protective effects against acute lung injury. We review how RAS and ACE2 biology may affect outcomes in COVID-19 through pulmonary and other systemic effects. In addition, we briefly detail the data for and against continuation of RAS inhibitors in persons with COVID-19 and summarize the current consensus recommendations from select specialty organizations.

Randomized elimination and prolongation of ACE inhibitors and ARBs in coronavirus 2019 (REPLACE COVID) Trial Protocol.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for coronavirus disease 2019 (COVID-19), is associated with high incidence of multiorgan dysfunction and death. Angiotensin-converting enzyme 2 (ACE2), which facilitates SARS-CoV-2 host cell entry, may be impacted by angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), two commonly used antihypertensive classes. In a multicenter, international randomized controlled trial that began enrollment on March 31, 2020, participants are randomized to continuation vs withdrawal of their long-term outpatient ACEI or ARB upon hospitalization with COVID-19. The primary outcome is a hierarchical global rank score incorporating time to death, duration of mechanical ventilation, duration of renal replacement or vasopressor therapy, and multiorgan dysfunction severity. Approval for the study has been obtained from the Institutional Review Board of each participating institution, and all participants will provide informed consent. A data safety monitoring board has been assembled to provide independent oversight of the project.