Empagliflozin in Heart Failure: Regional Nephron Sodium Handling Effects.

SIGNIFICANCE STATEMENT: The effect of sodium-glucose cotransporter-2 inhibitors (SGLT2i) on regional tubular sodium handling is poorly understood in humans. In this study, empagliflozin substantially decreased lithium reabsorption in the proximal tubule (PT) (a marker of proximal tubular sodium reabsorption), a magnitude out of proportion to that expected with only inhibition of sodium-glucose cotransporter-2. This finding was not driven by an "osmotic diuretic" effect; however, several parameters changed in a manner consistent with inhibition of the sodium-hydrogen exchanger 3. The large changes in proximal tubular handling were acutely buffered by increased reabsorption in both the loop of Henle and the distal nephron, resulting in the observed modest acute natriuresis with these agents. After 14 days of empagliflozin, natriuresis waned due to increased reabsorption in the PT and/or loop of Henle. These findings confirm in humans that SGLT2i have complex and important effects on renal tubular solute handling. BACKGROUND: The effect of SGLT2i on regional tubular sodium handling is poorly understood in humans but may be important for the cardiorenal benefits. METHODS: This study used a previously reported randomized, placebo-controlled crossover study of empagliflozin 10 mg daily in patients with diabetes and heart failure. Sodium handling in the PT, loop of Henle (loop), and distal nephron was assessed at baseline and day 14 using fractional excretion of lithium (FELi), capturing PT/loop sodium reabsorption. Assessments were made with and without antagonism of sodium reabsorption through the loop using bumetanide. RESULTS: Empagliflozin resulted in a large decrease in sodium reabsorption in the PT (increase in FELi=7.5%±10.6%, P = 0.001), with several observations suggesting inhibition of PT sodium hydrogen exchanger 3. In the absence of renal compensation, this would be expected to result in approximately 40 g of sodium excretion/24 hours with normal kidney function. However, rapid tubular compensation occurred with increased sodium reabsorption both in the loop ( P < 0.001) and distal nephron ( P < 0.001). Inhibition of sodium-glucose cotransporter-2 did not attenuate over 14 days of empagliflozin ( P = 0.14). However, there were significant reductions in FELi ( P = 0.009), fractional excretion of sodium ( P = 0.004), and absolute fractional distal sodium reabsorption ( P = 0.036), indicating that chronic adaptation to SGLT2i results primarily from increased reabsorption in the loop and/or PT. CONCLUSIONS: Empagliflozin caused substantial redistribution of intrarenal sodium delivery and reabsorption, providing mechanistic substrate to explain some of the benefits of this class. Importantly, the large increase in sodium exit from the PT was balanced by distal compensation, consistent with SGLT2i excellent safety profile. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: ClinicalTrials.gov ( NCT03027960 ).

In the "Plant-Based" Era, Patients With Chronic Kidney Disease Should Focus on Eating Healthy.

In the era of plant-based diets, it is important for Nephrology providers to know the evidence regarding their healthfulness in patients with chronic kidney disease (CKD). A whole food, plant-based diet, which emphasizes fresh, minimally processed or refined plant-based foods and limits animal products, has shown benefits for patients with CKD. These include reduced dietary acid load, lower bioavailability of potassium and phosphorus, increased dietary fiber intake, nutritional adequacy, and cardiovascular and mortality benefits. Potential drawbacks include the need for specific knowledge, skills, and cost involved in preparing varied, healthy, and appetizing plant-based meals, leading to lower acceptability and accessibility to certain populations. Liberalization of the standard CKD diet to include healthy, minimally processed foods such as fruits, vegetables, nuts, legumes, and whole grains is likely beneficial, though more research is needed to determine whether a plant-based-only diet is the optimal way to achieve healthier eating in patients with CKD.

Current and Developing Technologies for BP Monitoring.

PURPOSE OF REVIEW: To discuss new and emerging technologies for blood pressure measurement and monitoring, including the limitations of current blood pressure measurement techniques, hopes for new device technologies, and the current barriers impeding change in this space. RECENT FINDINGS: A number of new cuffless devices are being developed and poised to emerge on the marketplace in coming years. There are several different types of technologies and sensors currently under study. New guidelines for validation of cuffless blood pressure devices have recently been developed in anticipation of this change. The current standards for blood pressure device validation are specific to cuff-based technology and are insufficient for validating devices with cuffless-based technologies. In anticipation of a number of new cuffless technologies coming to market in the coming years, three sets of standards have been developed and published in recent years to address this gap.

Compensatory post-diuretic renal sodium reabsorption is not a dominant mechanism of diuretic resistance in acute heart failure.

AIMS: In healthy volunteers, the kidney deploys compensatory post-diuretic sodium reabsorption (CPDSR) following loop diuretic-induced natriuresis, minimizing sodium excretion and producing a neutral sodium balance. CPDSR is extrapolated to non-euvolemic populations as a diuretic resistance mechanism; however, its importance in acute decompensated heart failure (ADHF) is unknown. METHODS AND RESULTS: Patients with ADHF in the Mechanisms of Diuretic Resistance cohort receiving intravenous loop diuretics (462 administrations in 285 patients) underwent supervised urine collections entailing an immediate pre-diuretic spot urine sample, then 6-h (diuretic-induced natriuresis period) and 18-h (post-diuretic period) urine collections. The average spot urine sodium concentration immediately prior to diuretic administration [median 15 h (13-17) after last diuretic] was 64 ± 33 mmol/L with only 4% of patients having low (<20 mmol/L) urine sodium consistent with CPDSR. Paradoxically, greater 6-h diuretic-induced natriuresis was associated with larger 18-h post-diuretic spontaneous natriuresis (r = 0.7, P < 0.001). Higher pre-diuretic urine sodium to creatinine ratio (r = 0.37, P < 0.001) was the strongest predictor of post-diuretic spontaneous natriuresis. In a subgroup of patients (n = 43) randomized to protocol-driven intensified diuretic therapies, the mean diuretic-induced natriuresis increased three-fold. In contrast to the substantial decrease in spontaneous natriuresis predicted by CPDSR, no change in post-diuretic spontaneous natriuresis was observed (P = 0.47). CONCLUSION: On a population level, CPDSR was not an important driver of diuretic resistance in hypervolemic ADHF. Contrary to CPDSR, a greater diuretic-induced natriuresis predicted a larger post-diuretic spontaneous natriuresis. Basal sodium avidity, rather than diuretic-induced CPDSR, appears to be the predominant determinate of both diuretic-induced and post-diuretic natriuresis in hypervolemic ADHF.

First-in-Human Experience With Peritoneal Direct Sodium Removal Using a Zero-Sodium Solution: A New Candidate Therapy for Volume Overload.

BACKGROUND: Loop diuretics have well-described toxicities, and loss of response to these agents is common. Alternative strategies are needed for the maintenance of euvolemia in heart failure (HF). Nonrenal removal of sodium directly across the peritoneal membrane (direct sodium removal [DSR]) with a sodium-free osmotic solution should result in extraction of large quantities of sodium with limited off-target solute removal. METHODS: This article describes the preclinical development and first-in-human proof of concept for DSR. Sodium-free 10% dextrose was used as the DSR solution. Porcine experiments were conducted to investigate the optimal dwell time, safety, and scalability and to determine the effect of experimental heart failure. In the human study, participants with end-stage renal disease on peritoneal dialysis (PD) underwent randomization and crossover to either a 2-hour dwell with 1 L DSR solution or standard PD solution (Dianeal 4.25% dextrose, Baxter). The primary end point was completion of the 2-hour dwell without significant discomfort or adverse events, and the secondary end point was difference in sodium removal between DSR and standard PD solution. RESULTS: Porcine experiments revealed that 1 L DSR solution removed 4.1±0.4 g sodium in 2 hours with negligible off-target solute removal and overall stable serum electrolytes. Increasing the volume of DSR solution cycled across the peritoneum increased sodium removal and substantially decreased plasma volume (P=0.005). In the setting of experimental heart failure with elevated right atrial pressure, sodium removal was ≈4 times greater than in healthy animals (P<0.001). In the human proof-of-concept study, DSR solution was well tolerated and not associated with significant discomfort or adverse events. Plasma electrolyte concentrations were stable, and off-target solute removal was negligible. Sodium removal was substantially higher with DSR (4.5±0.4 g) compared with standard PD solution (1.0±0.3 g; P<0.0001). CONCLUSIONS: DSR was well tolerated in both animals and human subjects and produced substantially greater sodium removal than standard PD solution. Additional research evaluating the use of DSR as a method to prevent and treat hypervolemia in heart failure is warranted. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03801226.

Empagliflozin in Heart Failure: Diuretic and Cardiorenal Effects.

BACKGROUND: Sodium-glucose cotransporter-2 inhibitors improve heart failure-related outcomes. The mechanisms underlying these benefits are not well understood, but diuretic properties may contribute. Traditional diuretics such as furosemide induce substantial neurohormonal activation, contributing to the limited improvement in intravascular volume often seen with these agents. However, the proximal tubular site of action of the sodium-glucose cotransporter-2 inhibitors may help circumvent these limitations. METHODS: Twenty patients with type 2 diabetes mellitus and chronic, stable heart failure completed a randomized, placebo-controlled crossover study of empagliflozin 10 mg daily versus placebo. Patients underwent an intensive 6-hour biospecimen collection and cardiorenal phenotyping at baseline and again after 14 days of study drug. After a 2-week washout, patients crossed over to the alternate therapy with the above protocol repeated. RESULTS: Oral empagliflozin was rapidly absorbed as evidenced by a 27-fold increase in urinary glucose excretion by 3 hours (P<0.0001). Fractional excretion of sodium increased significantly with empagliflozin monotherapy versus placebo (fractional excretion of sodium, 1.2±0.7% versus 0.7±0.4%; P=0.001), and there was a synergistic effect in combination with bumetanide (fractional excretion of sodium, 5.8±2.5% versus 3.9±1.9%; P=0.001). At 14 days, the natriuretic effect of empagliflozin persisted, resulting in a reduction in blood volume (-208 mL [interquartile range, -536 to 153 mL] versus -14 mL [interquartile range, -282 to 335 mL]; P=0.035) and plasma volume (-138 mL, interquartile range, -379 to 154±453 mL; P=0.04). This natriuresis was not, however, associated with evidence of neurohormonal activation because the change in norepinephrine was superior (P=0.02) and all other neurohormones were similar (P<0.34) during the empagliflozin versus placebo period. Furthermore, there was no evidence of potassium wasting (P=0.20) or renal dysfunction (P>0.11 for all biomarkers), whereas both serum magnesium (P<0.001) and uric acid levels (P=0.008) improved. CONCLUSIONS: Empagliflozin causes significant natriuresis, particularly when combined with loop diuretics, resulting in an improvement in blood volume. However, off-target electrolyte wasting, renal dysfunction, and neurohormonal activation were not observed. This favorable diuretic profile may offer significant advantage in the management of volume status in patients with heart failure and may represent a mechanism contributing to the superior long-term heart failure outcomes observed with these agents. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03027960.

Renal negative pressure treatment as a novel therapy for heart failure-induced renal dysfunction.

Congestion is the primary pathophysiological lesion in most heart failure (HF) hospitalizations. Renal congestion increases renal tubular pressure, reducing glomerular filtration rate (GFR) and diuresis. Because each nephron is a fluid-filled column, renal negative pressure therapy (rNPT) applied to the urinary collecting system should reduce tubular pressure, potentially improving kidney function. We evaluated the renal response to rNPT in congestive HF. Ten anesthetized ∼80-kg pigs underwent instrumentation with bilateral renal pelvic JuxtaFlow catheters. GFR was determined by iothalamate clearance (mGFR) and renal plasma flow (RPF) by para-aminohippurate clearance. Each animal served as its own control with randomization of left versus right kidney to -30 mmHg rNPT or no rNPT. mGFR and RPF were measured simultaneously from the rNPT and no rNPT kidney. Congestive HF was induced via cardiac tamponade maintaining central venous pressure at 20-22.5 mmHg throughout the experiment. Before HF induction, rNPT increased natriuresis, diuresis, and mGFR compared with the control kidney (P < 0.001 for all). Natriuresis, diuresis, and mGFR decreased following HF (P < 0.001 for all) but were higher in rNPT kidney versus control (P < 0.001 for all). RPF decreased during HF (P < 0.001) without significant differences between rNPT treatments. During HF, the rNPT kidney had similar diuresis and natriuresis (P > 0.5 for both) and higher fractional excretion of sodium (P = 0.001) compared with the non-rNPT kidney in the no HF period. In conclusion, rNPT resulted in significantly increased diuresis, natriuresis, and mGFR, with or without experimental HF. rNPT improved key renal parameters of the congested cardiorenal phenotype.

Cystatin C and Muscle Mass in Patients With Heart Failure.

BACKGROUND: The estimated glomerular filtration rate (eGFR) from cystatin C (eGFRcys) is often considered a more accurate method to assess GFR compared with an eGFR from creatinine (eGFRcr) in the setting of heart failure (HF) and sarcopenia, because cystatin C is hypothesized to be less affected by muscle mass than creatinine. We evaluated (1) the association of muscle mass with cystatin C, (2) the accuracy of eGFRcys, and (3) the association of eGFRcys with mortality given muscle mass. METHODS AND RESULTS: We included 293 patients admitted with HF. Muscle mass was estimated with a validated creatinine excretion-based equation. Accuracy of eGFRcys and eGFRcr was compared with measured creatinine clearance. Cystatin C and creatinine were 31.7% and 59.9% higher per 14 kg higher muscle mass at multivariable analysis (both P < .001). At lower muscle mass, eGFRcys and eGFRcr overestimated the measured creatinine clearance. At higher muscle mass, eGFRcys underestimated the measured creatinine clearance, but eGFRcr did not. After adjusting for muscle mass, neither eGFRcys nor eGFRcr were associated with mortality (both P > .19). CONCLUSIONS: Cystatin C levels were associated with muscle mass in patients with HF, which could potentially decrease the accuracy of eGFRcys. In HF where aberrations in body composition are common, eGFRcys, like eGFRcr, may not provide accurate GFR estimations and results should be interpreted cautiously.

Should Angiotensin-Converting Enzyme Inhibitors ever Be Used for the Management of Hypertension?

PURPOSE OF REVIEW: Angiotensin-converting enzyme inhibitors and angiotensin receptor blockers are commonly used anti-hypertensive medications in a number of clinical settings. They are often used interchangeably, but we pose the provocative question as to whether they should be. We review the literature to evaluate for any differences in efficacy between the two classes in order to determine if the greater side effects associated with angiotensin-converting enzyme inhibitors are offset by any advantageous effects on outcomes to warrant their use over angiotensin receptor blockers. RECENT FINDINGS: In many clinical scenarios, the data supports similar efficacy between ACE inhibitors and ARBs, while in a minority of others, there are murky signals from previous trials that suggest ACE inhibitors may be better. However, when reviewing the literature in its entirety, and taking into account recently published pooled analysis and head to head trials, it is reasonable to conclude that ACE inhibitors and ARBs have similar efficacy. This is in contrast to data on adverse effects, which consistently favors the use of ARBs. From the available data, it is reasonable to conclude that ACE inhibitors and ARBs have equal efficacy yet unequal adverse effects. It is in this context that we take the provocative stance that ACE inhibitors should not be used to treat hypertension.

Blood pressure targets for hemodialysis patients.

The association between blood pressure (BP) and mortality is unique in hemodialysis patients compared with that in the general population. This is because of an altered benefit-risk balance associated with BP reduction in these patients. An adequately designed study comparing BP targets in hemodialysis patients remains to be conducted. The current evidence available to guide dialysis providers regarding treatment strategies for managing hypertension in this population is limited to large observational studies and small randomized controlled trials. In this opinion article, we review these data and discuss the key points regarding BP management for hemodialysis patients. Our aim is to provide a practical opinion regarding BP targets that nephrologists can incorporate into clinical practice, with a focus on moving away from dialysis unit BPs and focusing on out-of-dialysis unit BPs.

We Avoid RAAS Inhibitors in PD Patients with Residual Renal Function.

Preserving residual renal function in patients on peritoneal dialysis (PD) positively impacts mortality. While it is important to avoid nephrotoxic agents in this setting, clinicians should appreciate that inhibitors of the renin-angiotensin-aldosterone system (RAAS), including angiotensin converting enzyme inhibitors, and angiotensin receptor blockers are likely to preserve glomerular filtration rate and prolong the time until patients on PD reach anuria, and this may improve mortality in these patients. In addition, RAAS blockade favorably affects the peritoneal membrane by reducing morphologic changes that can lead to ultrafiltration failure. This in turn may delay or prevent modality failure in patients on PD. Thus, clinicians should avoid the impulse to stop RAAS inhibitors in the PD population.

Nutritional Supplements for the Treatment of Hypertension: A Practical Guide for Clinicians.

Nutraceuticals are dietary components with pharmacologic properties that can be used to treat various disease states. There is growing interest among patients in the use of nutraceuticals for the management of hypertension; as such, it is important that clinicians are prepared to engage in meaningful discussions with their patients about these substances. Flavonoids, beetroot, garlic, and unsaturated fats have garnered significant attention for their blood pressure lowering properties. We review the clinical evidence and reported mechanisms of action for these substances in an attempt to offer a practical guide for clinicians to engage with patients who are highly motivated to seek out nutraceutical therapies to manage their hypertension.

Serial direct sodium removal in patients with heart failure and diuretic resistance.

AIMS: Loop diuretics may exacerbate cardiorenal syndrome (CRS) in heart failure (HF). Direct sodium removal (DSR) using the peritoneal membrane, in conjunction with complete diuretic withdrawal, may improve CRS and diuretic resistance. METHODS AND RESULTS: Patients with HF requiring high-dose loop diuretics were enrolled in two prospective, single-arm studies: RED DESERT (n = 8 euvolaemic patients), and SAHARA (n = 10 hypervolaemic patients). Loop diuretics were withdrawn, and serial DSR was utilized to achieve and maintain euvolaemia. At baseline, participants required a median 240 mg (interquartile range [IQR] 200-400) oral furosemide equivalents/day, which was withdrawn in all participants during DSR (median time of DSR 4 weeks [IQR 4-6]). Diuretic response (queried by formal 40 mg intravenous furosemide challenge and 6 h urine sodium quantification) increased substantially from baseline (81 ± 37 mmol) to end of DSR (223 ± 71 mmol, p < 0.001). Median time to re-initiate diuretics was 87 days, and the median re-initiation dose was 8% (IQR 6-10%) of baseline. At 1 year, diuretic dose remained substantially below baseline (30 [IQR 7.5-40] mg furosemide equivalents/day). Multiple dimensions of kidney function such as filtration, uraemic toxin excretion, kidney injury, and electrolyte handling improved (p < 0.05 for all). HF-related biomarkers including N-terminal pro-B-type natriuretic peptide, carbohydrate antigen-125, soluble ST2, interleukin-6, and growth differentiation factor-15 (p < 0.003 for all) also improved. CONCLUSIONS: In patients with HF and diuretic resistance, serial DSR therapy with loop diuretic withdrawal was feasible and associated with substantial and persistent improvement in diuretic resistance and several cardiorenal parameters. If replicated in randomized controlled studies, DSR may represent a novel therapy for diuretic resistance and CRS. CLINICAL TRIAL REGISTRATION: RED DESERT (NCT04116034), SAHARA (NCT04882358).

Secondary Hypertension Overview and Workup for the Primary Care Physician.

Secondary hypertension occurs in 5% to 10% of all patients with hypertension. Given the majority of patients with hypertension will not have a secondary cause, only select patients with specific characteristics should be screened. The causes include a range of abnormalities, some are quite rare, such as pheochromocytoma, while others are much more common, such as chronic kidney disease. When considering which disorders to test for, it is important to incorporate the clinical history, family history, and prevalence of each disease. Treatment is specific to the underlying cause and includes medications, procedures, surgery, and device therapies.

In-Hospital Observation on Oral Diuretics After Treatment for Acute Decompensated Heart Failure: Evaluating the Utility.

BACKGROUND: Following treatment for acute decompensated heart failure, in-hospital observation on oral diuretics (OOD) is recommended, assuming it provides actionable information on discharge diuretic dosing and thus reduces readmissions. METHODS: In the Mechanisms of Diuretic Resistance (MDR) cohort, we analyzed in-hospital measures of diuretic response, provider's decisions, and diuretic response ≈30 days postdischarge. In a Yale multicenter cohort, we assessed if in-hospital OOD was associated with 30-day readmission risk. The main objective of this study was to evaluate the utility of in-hospital OOD. RESULTS: Of the 468 patients in the MDR cohort, 57% (N=265) underwent in-hospital OOD. During the OOD, weight change and net fluid balance correlated poorly with each other (r=0.36). Discharge diuretic dosing was similar between patients who had increased, stable, or decreased weight (decreased discharge dose from OOD dose in 77% versus 72% versus 70%, respectively), net fluid status (decreased discharge dose from OOD dose in 100% versus 69% versus 74%, respectively), and urine output (decreased discharge dose from OOD dose in 69% versus 79% versus 72%, respectively) during the 24-hour OOD period (P>0.27 for all). In participants returning at 30 days for formal quantification of outpatient diuretic response (n=98), outpatient and inpatient OOD natriuresis was poorly correlated (r=0.26). In the Yale multicenter cohort (n=18 454 hospitalizations), OOD occurred in 55% and was not associated with 30-day hospital readmission (hazard ratio, 0.98 [95% CI, 0.93-1.05]; P=0.51). CONCLUSIONS: In-hospital OOD did not provide actionable information on diuretic response, was not associated with outpatient dose selection, did not predict subsequent outpatient diuretic response, and was not associated with lower readmission rate. Additional research is needed to replicate these findings and understand if these resources could be better allocated elsewhere. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02546583.

Treatment of chronic kidney disease.

Treatment of chronic kidney disease (CKD) can slow its progression to end-stage renal disease (ESRD). However, the therapies remain limited. Blood pressure control using angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs) has the greatest weight of evidence. Glycemic control in diabetes seems likely to retard progression. Several metabolic disturbances of CKD may prove to be useful therapeutic targets but have been insufficiently tested. These include acidosis, hyperphosphatemia, and vitamin D deficiency. Drugs aimed at other potentially damaging systems and processes, including endothelin, fibrosis, oxidation, and advanced glycation end products, are at various stages of development. In addition to the paucity of proven effective therapies, the incomplete application of existing treatments, the education of patients about their disease, and the transition to ESRD care remain major practical barriers to better outcomes.

Hemoconcentration of Creatinine Minimally Contributes to Changes in Creatinine during the Treatment of Decompensated Heart Failure.

Background: Worsening serum creatinine is common during treatment of acute decompensated heart failure (ADHF). A possible contributor to creatinine increase is diuresis-induced changes in volume of distribution (VD) of creatinine as total body water (TBW) contracts around a fixed mass of creatinine. Our objective was to better understand the filtration and nonfiltration factors driving change in creatinine during ADHF. Methods: Participants in the ROSE-AHF trial with baseline to 72-hour serum creatinine; net fluid output; and urinary KIM-1, NGAL, and NAG were included (n=270). Changes in VD were calculated by accounting for measured input and outputs from weight-based calculated TBW. Changes in observed creatinine (Crobserved) were compared with predicted changes in creatinine after accounting for alterations in VD and non-steady state conditions using a kinetic GFR equation (Cr72HR Kinetic). Results: When considering only change in VD, the median diuresis to elicit a ≥0.3 mg/dl rise in creatinine was -7526 ml (IQR, -5932 to -9149). After accounting for stable creatinine filtration during diuresis, a change in VD alone was insufficient to elicit a ≥0.3 mg/dl rise in creatinine. Larger estimated decreases in VD were paradoxically associated with improvement in Crobserved (r=-0.18, P=0.003). Overall, -3% of the change in eCr72HR Kinetic was attributable to the change in VD. A ≥0.3 mg/dl rise in eCr72HR Kinetic was not associated with worsening of KIM-1, NGAL, NAG, or postdischarge survival (P>0.05 for all). Conclusions: During ADHF therapy, increases in serum creatinine are driven predominantly by changes in filtration, with minimal contribution from change in VD.

Barriers and Motivators to Opioid Treatment Among Suburban Women Who Are Pregnant and Mothers in Caregiver Roles.

Women of childbearing age who misuse opioids are a particularly vulnerable population, and their barriers to treatment are unique because of their caregiver roles. Research on treatment for opioid use generally draws from urban and rural areas. This study fills a gap in research that focuses on barriers and motivators to opioid treatment in suburban areas. The aim of this study was to give voice to suburban pregnant women and mothers caring for children while using opioids. Ethnographic methods were used for recruitment, and 58 in-depth interviews were analyzed using a modified grounded theory approach. Barriers to medication-assisted treatment (MAT) included stigma, staff attitudes, and perceptions the women had about MAT treatment. Barriers associated with all types of treatment included structural factors and access difficulties. Relationships with partners, friends, family, and providers could be barriers as well as motivators, depending on the social context of the women's situation. Our findings suggest increasing treatment-seeking motivators for mothers and pregnant women by identifying lack of resources, more empathetic consideration of social environments, and implementing structural changes to overcome barriers. Findings provide a contemporary understanding of how suburban landscapes affect mothers' treatment-seeking for opioid dependence and suggest the need for more focus on emotional and structural resources rather than strict surveillance of women with opioid dependence who are pregnant or caring for children.

FGF-23 (Fibroblast Growth Factor-23) and Cardiorenal Interactions.

BACKGROUND: Animal models implicate FGF-23 (fibroblast growth factor-23) as a direct contributor to adverse cardiorenal interactions such as sodium avidity, diuretic resistance, and neurohormonal activation, but this has not been conclusively demonstrated in humans. Therefore, we aimed to evaluate whether FGF-23 is associated with parameters of cardiorenal dysfunction in humans with heart failure, independent of confounding factors. METHODS: One hundred ninety-nine outpatients with heart failure undergoing diuretic treatment at the Yale Transitional Care Center were enrolled and underwent blood collection, and urine sampling before and after diuretics. RESULTS: FGF-23 was associated with several metrics of disease severity such as higher home loop diuretic dose and NT-proBNP (N-terminal pro-B-type natriuretic peptide), and lower estimated glomerular filtration rate, serum chloride, and serum albumin. Multivariable analysis demonstrated no statistically significant association between FGF-23 and sodium avidity measured by fractional excretion of sodium, or proximal or distal tubular sodium reabsorption, either before diuretic administration or at peak diuresis (P≥0.11 for all). Likewise, FGF-23 was not independently associated with parameters of diuretic resistance (diuretic excretion, cumulative urine and sodium output, and loop diuretic efficiency [P≥0.33 for all]) or neurohormonal activation (plasma or urine renin [P≥0.36 for all]). Moreover, the upper boundary of the 95% CI of all the partial correlations were ≤0.30, supporting the lack of meaningful correlations. FGF-23 was not associated with mortality in multivariable analysis (P=0.44). CONCLUSIONS: FGF-23 was not meaningfully associated with any cardiorenal parameter in patients with heart failure. While our methods cannot rule out a small effect, FGF-23 is unlikely to be a primary driver of cardiorenal interactions.