Decreasing end-stage renal disease (ESRD) is a national priority formalized by the Advancing American Kidney Health Initiative. Increased attention to dialysis-requiring acute kidney injury (AKI-D) may be an important step toward this goal, since more than 15% of modern patients who start dialysis at outpatient hemodialysis units have AKI-D as the proximal cause of their dialysis dependency.
Even though AKI-D patients are not rare in outpatient hemodialysis units (about one in six), most patients in these units are there for ESRD — a condition that has no potential for recovery without kidney transplantation. But treatment goals differ between AKI-D patients and ESRD patients. For the former, avoiding recurrent kidney injury that can occur when blood pressure drops during dialysis and monitoring closely for kidney recovery should be priorities. For the latter, more aggressive fluid removal for long-term control of blood pressure and volume status, obtaining permanent dialysis access, and completing transplant work-up are more appropriate. But in real-life clinical practice, it is unclear whether management actually differs between AKI-D and ESRD patients.
What Do We Know About How to Manage AKI-D?
Most research on AKI-D has focused on when to start dialysis for AKI and how much dialysis to provide. After patients leave the hospital, we know that about 30-40% of AKI-D patients who survive to hospital discharge will recover enough kidney function to discontinue dialysis (as determined by their physicians), though this figure fluctuates widely based largely on the pre-AKI kidney function. But little is known about how kidney doctors typically monitor AKI-D patients for recovery and tailor their dialysis prescriptions to the specific treatment goals of AKI-D mentioned above.
Descriptions of outpatient AKI-D management have been limited to case series from single academic centers that focus on outcomes rather than process measures like laboratory testing or dialysis orders. A survey of the American Society of Nephrology AKI Community found that only 35% of respondents had AKI-D protocols in their dialysis units.
My colleagues and I recently published a description of the management of more than 1,700 AKI-D patients who started outpatient dialysis in 2017-2022. Our findings identified several areas where opportunities to improve care may exist.
How Can We Monitor for Recovery of Kidney Function?
Monitoring for kidney function recovery is challenging in an AKI-D patient because ongoing dialysis treatments artificially clean the blood, so blood tests cannot be used to estimate kidney function the way they are in patients who are not on dialysis. Timed urine collections are the most common way to estimate a patient’s own kidney function when they are being treated with dialysis. Trials evaluating how much dialysis to give AKI-D patients in the hospital have used timed urine collections to protocolize dialysis discontinuation. But in our study, only about a quarter of patients completed a timed urine collection in the first 30 days at the dialysis unit. While there are no clinical practice guidelines on how often recovery should be assessed, multiple expert groups suggest weekly urine collections. Timed urine collections may allow us to recognize recovery earlier and to recognize subtle recovery (i.e., recovery to a kidney function level that remains severely decreased but sufficient to discontinue dialysis), which may otherwise go undetected.
How Should We Deprescribe Dialysis as a Patient Recovers?
When recovery is suspected, it is unclear how dialysis should be deprescribed. Should dialysis be stopped directly (thrice-weekly to zero times per week), deprescribed by frequency (e.g., thrice- to twice-weekly), or deprescribed by session duration (e.g., progressively reducing the duration of the thrice-weekly dialysis sessions)?
In our study, we found that most patients were stopped directly from three times to zero times per week. This finding suggests there may be substantial opportunity to wean dialysis (e.g., thrice- to twice-weekly) sooner and more often, likely resulting in cost savings and quality-of-life improvement. This practice can be compared with the nephrology community’s interest in promoting “incremental dialysis,” in which patients with advancing chronic kidney disease are started on chronic dialysis at a frequency of twice-weekly instead of thrice-weekly.
Systemic Barriers to Deprescribing Dialysis
While our study found potential opportunities to deprescribe dialysis among AKI-D patients after hospital discharge, there are numerous systemic disincentives to recognizing recovery and deprescribing dialysis. For example, discontinuing or deprescribing dialysis when recovery occurs will benefit patients and should result in cost savings. But the cost savings will be accrued by the healthcare system, not by the dialysis provider, who will receive less payment if dialysis is performed only two times per week rather than three times per week and will have an empty dialysis chair in the middle of the week that is not easy to fill. Meanwhile, the extra resources and attention required to monitor AKI-D patients for recovery are borne by the dialysis provider.
Similarly, nephrologists lose a valuable multidisciplinary clinical support team provided by outpatient dialysis units (nurses, dietitians, social workers) when a patient recovers enough to discontinue dialysis. And nephrologists are paid less for non-dialysis care than for dialysis care, even though managing a patient with borderline kidney function is more time consuming and risky than managing a patient on thrice-weekly dialysis, which assures electrolyte and volume control.
Liberating a patient from the need for dialysis can be one of the most rewarding experiences a physician can have. For now, we can monitor our AKI-D patients more closely for recovery with frequent timed urine collections. We can attempt to wean patients from three times to two times per week with close laboratory monitoring in patients who recover to borderline levels of kidney function. In the future, after additional research clarifies optimal dialysis deprescribing and recovery monitoring strategies, we hope to have evidence-based protocols for detecting kidney recovery to better ensure that no patient is left on dialysis longer than necessary.
Ian McCoy, MD, MS, is an assistant professor of nephrology at University of California San Francisco, who conducts clinical research on acute kidney injury.
McCoy has received research funding from Satellite Healthcare, Inc (a not-for-profit dialysis provider).