Trends in Automated Peritoneal Dialysis Prescriptions in a Large Dialysis Organization in the United States

Key Points

Background

Changes in health care policies and recognition of patient benefit have contributed to increases in home-based dialysis, including peritoneal dialysis (PD). Frequent monitoring and early individualization of PD prescriptions are key prerequisites for the delivery of high-quality PD. The present analysis aimed to assess variations in PD prescriptions among incident automated PD (APD) patients who remain on PD for 120+ days.

Methods

This retrospective analysis examined data from patients within a large dialysis organization that initiated PD with APD between 2015 and 2019. PD prescription data were described by calendar year, timing of PD, and residual renal function categories. Changes in prescriptions from PD initiation (day 1) to day 120 were assessed descriptively.

Results

The cohort included 11,659 patients. The mean age at PD initiation increased from 2015 (56 [15] years) through 2019 (58 [15] years), whereas most other variables demonstrated no clear temporal change. Most patients (86%) had nighttime PD prescribed, with an average of 4.9 (1.3) cycles per day, a mean total treatment volume of 9.3 (2.5) L, and a median daily total dwell time of 7 (6–9.5) hours. Relative to day 1 nighttime prescriptions, there were (1) small increases in the proportion of patients receiving three or fewer cycles per day and those receiving 6+ cycles per day, (2) a 100 ml mean increase in fill volume per exchange, and (3) a mean 0.5 L increase in total nighttime treatment volume at day 120. When changes in nighttime APD prescriptions were examined at the patient level, 49% of patients had day 120 prescriptions that were unchanged from their initial prescription.

Conclusions

In the largest analysis of incident APD prescriptions conducted in the United States to date, most patients were prescribed nocturnal PD only with limited variability across the first 4 months of therapy.

Serum Phosphorus Management with Sucroferric Oxyhydroxide as a First-Line Phosphate Binder within the First Year of Hemodialysis

INTRODUCTION

Sucroferric oxyhydroxide (SO), a non-calcium, chewable, iron-based phosphate binder (PB), effectively lowers serum phosphorus (sP) concentrations while reducing pill burden relative to other PBs. To date, SO studies have largely examined treatment-experienced, prevalent hemodialysis populations. We aimed to explore the role of first-line SO initiated during the first year of dialysis.

METHODS

We retrospectively analyzed deidentified data from adults receiving in-center hemodialysis who were prescribed SO monotherapy within the first year of hemodialysis as part of routine clinical care. All patients continuing SO monotherapy for 12 months were included. Changes from baseline in sP, achievement of sP ≤5.5 and ≤4.5 mg/dL, and other laboratory parameters were analyzed quarterly for 1 year.

RESULTS

The overall cohort included 596 patients, 286 of whom had a dialysis vintage ≤3 months. In the 3 months preceding SO initiation, sP rapidly increased (mean increases of 1.02 and 1.65 mg/dL in the overall cohort and incident cohort, respectively). SO treatment was associated with significant decreases in quarterly sP (mean decreases of 0.26-0.36; p < 0.0001 for each quarter and overall). While receiving SO, 55-60% of patients achieved sP ≤5.5 mg/dL and 21-24% achieved sP ≤4.5 mg/dL (p < 0.0001 for each quarter and overall vs. baseline). Daily PB pill burden was approximately 4 pills. Serum calcium concentrations increased and intact parathyroid hormone concentrations decreased during SO treatment (p < 0.0001 vs. baseline).

CONCLUSIONS

Among patients on hemodialysis, initiating SO as a first-line PB resulted in significant reductions in sP while maintaining a relatively low PB pill burden.

A real-world analysis of the influence of age on maintenance hemodialysis patients: managing serum phosphorus with sucroferric oxyhydroxide as part of routine clinical care

OBJECTIVE

Despite the growing number of elderly hemodialysis patients, the influence of age on nutritional parameters, serum phosphorus (sP), and use of phosphate-binder (PB) medications has not been well characterized. We aimed to describe age-related differences in patient characteristics in a large, real-world cohort of maintenance hemodialysis patients, and to examine the impact of age on sP management with sucroferric oxyhydroxide (SO).

METHODS

We retrospectively analyzed de-identified data from 2017 adult, in-center hemodialysis patients who switched from another PB to SO monotherapy as part of routine clinical care. Changes in baseline PB pill burden, sP levels, and nutritional and dialytic clearance parameters were assessed across varying age groups through 6 months.

RESULTS

At baseline, older patients had lower mean sP, serum albumin, and pre-dialysis weights compared with younger patients. Prescription of SO was associated with a 62% increase in the proportion of patients achieving sP ≤ 5.5 mg/dl and a 42% reduction in daily pill burden. The proportion of patients achieving sP ≤ 5.5 mg/dl after transitioning to SO increased by 113, 96, 68, 77, 61, 37 and 40% among those aged 19-29, 30-39, 40-49, 50-59, 60-69, 70-79, and ≥ 80 years, respectively.

CONCLUSIONS

Older patients had worse nutritional parameters, lower pill burden, and lower sP at baseline versus younger counterparts. Prescription of SO was associated with improved sP control and reduced pill burden across all ages.

Serum Phosphorus and Pill Burden Among Hemodialysis Patients Prescribed Sucroferric Oxyhydroxide: One-Year Follow-Up on a Contemporary Cohort

Purpose

In prior analyses of real-world cohorts of hemodialysis patients switched from one phosphate binder (PB) to sucroferric oxyhydroxide (SO), SO therapy has been associated with improvements in serum phosphorus (sP) and reductions in daily PB pill burden. To characterize how SO initiation patterns have changed over time, we examined the long-term effectiveness of SO in a contemporary (2018–2019) cohort.

Patients and Methods

Adult Fresenius Kidney Care hemodialysis patients first prescribed SO monotherapy as part of routine care between May 2018 and May 2019 (N = 1792) were followed for 1 year. All patients received a non-SO PB during a 91-day baseline period before SO prescription. Mean PB pills/day and laboratory parameters were compared before and during SO treatment. Results were divided into consecutive 91-day intervals (Q1–Q4) and analyzed using linear mixed-effects regression and Cochran’s Q test. These results were contrasted with findings from a historical (2014–2015) cohort (N = 530).

Results

The proportion of patients achieving sP ≤5.5 mg/dl increased after switching to SO (from 27.0% at baseline to 37.8%, 45.1%, 44.7%, and 44.0% at Q1, Q2, Q3, and Q4, respectively; P < 0.0001 for all). The mean daily PB pill burden decreased from a baseline of 7.7 to 4.4, 4.6, 4.8, and 4.9, respectively, across quarters (P < 0.0001 for all). Patients in the contemporary cohort had improved sP control (27.0% achieving sP ≤5.5 mg/dl vs 17.7%) and lower daily PB pill burden (mean 7.7 vs 8.5 pills/day) at baseline than those in the historical cohort. Overall use of active vitamin D was similar between cohorts, although higher use of oral active vitamin D (63.9% vs 15.7%) and lower use of IV active vitamin D lower (23.4% vs 74.2%) was observed in the contemporary cohort.

Conclusion

Despite evolving treatment patterns, switching to SO resulted in improved sP control with fewer pills per day in this contemporary hemodialysis cohort.

Effect of Citrate-Acidified Dialysate on Intact Parathyroid Hormone in Prevalent Hemodialysis Patients: A Matched Retrospective Cohort Study

Background

It has been proposed that substituting citrate-acidified dialysate (CAD) solutions for acetate-acidified dialysate (AAD) could improve hemodynamics and dialysis tolerance and reduce the requirement for systemic anticoagulation. Citrate chelates ionized calcium, but long-term effects of CAD use during maintenance hemodialysis have not been well studied. While many studies of the effects of CAD on serum calcium and intact parathyroid hormone (iPTH) have been short-term or have been limited by sample size, we aimed to determine if there are any long-term (i.e., 6-month) changes from pre-dialysis iPTH levels when patients are switched from AAD to CAD.

Methods

This retrospective cohort study compared various clinical parameters, including pre-dialysis iPTH and serum calcium as well as single pool Kt/V, from eligible patients who received in-center hemodialysis thrice-weekly in geographically matched CAD (n=3) or AAD clinics (n=12). CAD clinics were defined as clinics converting from AAD to CAD if >85% of the patients were prescribed CAD after implementation of CAD within the clinic.

Results

Pre-dialysis iPTH was not significantly different from baseline to 6-month follow-up within either CAD or AAD clinics. Moreover, the mean change from baseline to month 6 in iPTH between patients (n=142) in CAD clinics (−17 pg/mL) and patients (n=671) in AAD clinics (13 pg/mL) was similar (p = 0.24). Likewise, the differences in the mean change in serum calcium concentrations and dialysis adequacy (single pool Kt/V) were not significant between CAD and AAD clinics. For subgroups of patients who were never prescribed cinacalcet or calcium-based phosphate binders, there were no significantly different categorical shifts in iPTH between CAD and AAD clinics.

Conclusion

Similar trends in single pool Kt/V, iPTH, and serum calcium levels were observed in clinics that switched from AAD to CAD versus the geographically matched AAD clinics. These results support CAD as a potential alternative to AAD in hemodialysis.

Real-World Performance of High-Flux Dialyzers in Patients With Hypoalbuminemia

There is little research on factors that influence the choice of dialyzer in patients undergoing hemodialysis. In patients at risk for poorer outcomes, including those with hypoalbuminemia, understanding how this choice impacts clinical parameters could inform patient management. The objective of this real-world analysis was to evaluate the use and performance of four single-use (i.e., nonreuse [NR]), high-flux Optiflux dialyzers with varying surface areas (F160NR [1.5 m2], F180NR [1.7 m2], F200NR [1.9 m2], and F250NR [2.5 m2]) in patients (N = 271) with baseline hypoalbuminemia (≤3.5 g/dl) receiving hemodialysis at a medium-sized dialysis organization. Thrice weekly, in-center dialysis was delivered for 6 months without adjustments to the hemodialysis prescription. Larger dialyzers were more frequently used in men, patients with higher body mass indices, and those with diabetes. Increases in serum albumin from baseline (month 1) to month 6 (p < 0.05) were observed with all dialyzer sizes. A mean increase in hemoglobin of 0.31 g/dl was also observed (p < 0.001). Among patients exhibiting increased serum albumin levels (n = 177), reductions in the neutrophil-to-lymphocyte ratio, a marker of inflammation, were observed (mean: 0.90; p < 0.001). These results support the use of high-flux dialyzers in patients with hypoalbuminemia.

Slipping Through the Pores: Hypoalbuminemia and Albumin Loss During Hemodialysis

Hypoalbuminemia results when compensatory mechanisms are unable to keep pace with derangements in catabolism/loss and/or decreased synthesis of albumin. Across many disease states, including chronic kidney disease (CKD), hypoalbuminemia is a well-established, independent risk factor for adverse outcomes, including mortality. In the setting of CKD, reduced serum albumin concentrations are often a manifestation of protein-energy wasting, a state of metabolic and nutritional alterations resulting in reduced protein and energy stores. The progression of CKD to kidney failure and the initiation of maintenance hemodialysis (HD) further predisposes an already at-risk population toward hypoalbuminemia such that approximately 60% of HD patients have albumin concentrations <4.0 g/dl. Albumin loss into the dialysate through the dialyzer appears to be a potentially modifiable cause of hypoalbuminemia in some patients. A group of newer dialyzers for maintenance HD-sometimes termed protein-leaking or medium cut-off membranes-aim to improve clearance of middle molecules (vs high flux dialyzers) but are associated with increased albumin losses. In this article, we will examine the impact of dialyzer selection on albumin losses during conventional HD, including the clinical relevance of such losses on serum albumin levels. Data on the clinical relevance of albumin losses during dialysis and current gaps in the evidence base are also discussed.

A multicenter, prospective, randomized, comparative evaluation of dual- versus triple-lumen catheters for hemodialysis and apheresis in 485 patients

BACKGROUND

The purpose of this study is to compare a new temporary triple-lumen catheter (TLC) for dialysis that has a third lumen devoted to fluid and medication administration or blood sampling with a marketed dual-lumen catheter (DLC).

METHODS

Four hundred eighty-five patients referred for acute hemodialysis or apheresis were randomly assigned to either a TLC or DLC in a multicenter, prospective, randomized trial.

RESULTS

Analysis of blood flow rates was completed on 464 patients (228 patients, DLC; 236 patients, TLC) with a total of 1,681 hemodialysis (808 treatments, DLC; 873 treatments, TLC) and 82 apheresis treatments (37 treatments, DLC; 45 treatments, TLC). During hemodialysis, a median achieved flow rate (AFR) of 267 mL/min was realized for both groups (P = 0.58). During apheresis, a median AFR of 72.5 mL/min (range, 50 to 150 mL/min) was achieved in the DLC group, and 87 mL/min (range, 60 to 150 mL/min), in the TLC group (P = 0.14). Three hundred ninety-three patients (193 patients, DLC; 200 patients, TLC) had blood and catheter tip cultures performed on removal, and catheter-related bloodstream infection (CRBSI) status was determined. Thirty-one patients (7.9%) had a CRBSI: 16 patients (8.3%), DLC; and 15 patients (7.5%), TLC (P= 0.77). Incidence densities of CRBSI were 12.4/1,000 DLC-days and 10.2/1,000 TLC-days (P = 0.59). The CRBSI incidence of 18.2/1,000 catheter-days for femoral sites was significantly greater than the 7/1,000 catheter-days for jugular sites (P = 0.02) and 6.6/1,000 catheter-days for combined jugular and subclavian sites (P = 0.01). In multivariate analysis, antibiotic use was the only factor related to CRBSI (odds ratio, 0.30; 95% confidence interval, 0.12 to 0.76). There were no statistically significant differences in rates of other complications between the 2 catheters.

CONCLUSION

Results show that the new TLC is similar to the marketed DLC.

Effect of cyclical therapy with phosphorus and etidronate on axial bone mineral density in postmenopausal osteoporotic women

Forty seven women with postmenopausal osteoporosis and at least one but no more than four vertebral compression fractures received sequential and cyclical therapy with phosphorus and etidronate (p/etid). During the same 2-year period of observation, three other groups of patients received either sodium fluoride (n = 12), estrogen replacement therapy (n = 12), or vitamin D and calcium (Ca++) alone (n = 15). Axial bone mineral density (BMD) was measured by means of dual-photon absorptiometry. Lateral thoracic and lumbar spine radiographs were taken to assess fractures. Bone mineral density increased from baseline during p/etid therapy: Mean 15.7 +/- 1.6% (SD) (P less than 0.001). During the same time, the patients in the sodium fluoride group showed a comparable increase in their BMD from baseline: mean 15.7 +/- 1.1% (P less than 0.001). During the first year of therapy, patients in the estrogen replacement group had an increase in their BMD from baseline: mean: 4.6% +/- 1.1% (P less than 0.05). No change in BMD was seen in the control group that received vitamin D and Ca++ alone. No patient who received p/etid, sodium fluoride, or estrogen replacement therapy had any new vertebral compression fractures or height loss, whereas in the control group that received vitamin D and Ca++ alone 6 out of 15 had height loss and at least one new vertebral fracture (P less than 0.01). p/etid therapy increases BMD in women with postmenopausal osteoporosis comparable to sodium fluoride but without side effects or toxicity and stabilizes vertebral compression fractures.

Effects of lithium on cAMP generation in cultured rat inner medullary collecting tubule cells

The effects of lithium (Li) on the cAMP system in rat inner medullary collecting tubule cells were studied. While acute exposure to 5 mM Li was without effect, 10 mM, 25 mM and 50 mM Li significantly decreased AVP-stimulated cAMP formation. In contrast, cells grown in 5 mM Li for 72 hours which caused no morphologic changes enhanced cAMP formation (fmol/microgram protein) in response to both 10 nM AVP (114.5 +/- 9.2 vs. 71.6 +/- 7.4, P less than 0.005) and 100 nM AVP (182 +/- 14 vs. 120 +/- 8.3, P less than 0.001), N = 16. A similar enhancement was observed when cAMP formation was stimulated by a post-receptor agonist, cholera toxin. The role of eicosanoids was examined with 5 microM meclofenamate which reversed Li-enhanced cAMP formation in response to both AVP and cholera toxin. To define the eicosanoid responsible, cyclooxygenase products were measured. Prostaglandin E2 and thromboxane B2 synthesis were unchanged by Li, but the production of prostacyclin was significantly (P less than 0.02) increased. Prostacyclin (3 microM) mimicked the effect of Li to enhance the response to 10 nM AVP as cAMP levels increased from 100 +/- 11 to 173 +/- 13, P less than 0.05. The experiments suggest that acute exposure of Li at concentrations of 10 mM or greater inhibit cAMP formation but prolonged Li exposure enhances cAMP formation by increasing the formation of prostacyclin.

Eosinophiluria--a new method of detection and definition of the clinical spectrum

Eosinophiluria is considered a useful marker of drug-induced acute interstitial nephritis. However, recognition of eosinophiluria by Wright's staining is technically difficult, and the spectrum of disorders causing eosinophiluria is not completely defined. We have adapted Hansel's stain for the examination of urinary sediment. Whereas there was a variable uptake of Wright's stain by eosinophils in the urine, such eosinophils were readily recognized with Hansel's stain by the presence of bright red granules. The prevalence of eosinophiluria in acute interstitial nephritis was 10 of 11 patients, in acute tubular necrosis none of 30, in acute pyelonephritis none of 10, in acute cystitis 1 of 15, in postinfectious glomerulonephritis 1 of 6, in rapidly progressive glomerulonephritis 4 of 10, and in acute prostatitis 6 of 10. Eosinophiluria in acute interstitial nephritis was demonstrated by Hansel's stain in 10 of 11 patients but by Wright's stain in only 2 of 11 patients. We conclude that Hansel's stain substantially improves the recognition of eosinophiluria as compared with Wright's stain. Eosinophiluria is useful in distinguishing acute interstitial nephritis from acute tubular necrosis. The clinical spectrum of eosinophiluria also includes rapidly progressive glomerulonephritis, acute prostatitis, and occasionally, acute cystitis or postinfectious glomerulonephritis.

Vasopressin and the concentrating mechanism

The role of vasopressin in the kidney has classically been considered to result from its ability to increase water permeability in the collecting duct. Recent data, however, suggest that the hormone may also promote urinary concentration by increasing interstitial tonicity. The mechanisms whereby vasopressin could enhance interstitial tonicity include increasing urea permeability in the inner medullary collecting tubule, stimulation of solute reabsorption in the thick ascending limb of the loop of Henle, increasing the glomerular filtration rate of juxtamedullary nephrons, and decreasing vasa recta blood flow. We review experiments directed at assessing the role of vasopressin in these four processes. The multitude of effects of vasopressin appears to be well integrated and contributes to the tightly regulated urinary concentration mechanisms.