Deprescribing the Kt/V Target for Peritoneal Dialysis in the United States: The Path Toward Adopting International Standards for Dialysis Adequacy

The United States aims to sharply increase the use of home dialysis through the Advancing American Kidney Health initiative; increasing use will likely require leading with peritoneal dialysis (PD). However, as 44% of graduating nephrologists report being ill-prepared to prescribe PD, we must simultaneously ensure that quality metrics are updated to help patients initiated on PD receive high-quality care.1 To facilitate this goal, the Centers for Medicare and Medicaid Services (CMS) recently requested public input on strategies to monitor and assess quality of care for patients receiving dialysis at home.2 New measures for infection (e.g., peritonitis) and patient experience (e.g., patient activation measure survey) may improve quality. However, existing measures, such as the Kt/V target of 1.7 for PD, need to be revisited. This Kt/V target no longer reflects the 2020 guidelines from the International Society for PD (ISPD)3 or the views of US home dialysis leaders.4,5 This target also risks causing harm by resulting in additional PD exchanges or a transition to hemodialysis in some patients who have no other clinical indications to adjust their prescription. In this perspective, we summarize the evidence for a Kt/V target of 1.7 for PD, review current CMS policies that require Kt/V targets, and suggest an immediate, practical path that CMS can take to guide the United States toward increased adoption of high-quality, goal-directed PD. What is Kt/V, and What is the Evidence for a Kt/V Target of 1.7 for PD? Kt/V is a measure of dialysis adequacy that accounts for dialyzer clearance (K) of urea—one of the smallest and easiest to remove perceived uremic toxins—dialysis time (t), and volume (V, total body water). A Kt/V target of 1.7—which includes both residual kidney function and PD clearance—was recommended by the Kidney Disease Outcomes Quality Initiative's (KDOQI) 2006 guidelines,6 which reviewed evidence from three prospective studies: CANUSA, ADEMEX, and a study in Hong Kong. CANUSA initially suggested a mortality benefit for patients with higher Kt/V and partly formed the basis for the 1996 and 2000 National Kidney Foundation-Dialysis Outcomes Quality Initiative guidelines recommending a Kt/V target of 2.0.7–9 However, reanalysis showed that this mortality benefit reflected residual kidney function of patients, rather than the dialysis Kt/V.10 ADEMEX, which compared a Kt/V of 2.27 and 1.80, revealed no difference in mortality between targets.11 Finally, a Hong Kong trial randomized patients to Kt/V of 1.5–1.7, 1.7–2.0, and >2.0 and found no mortality difference among groups.12 However, 14% of patients in the low-target group withdrew because of inadequate dialysis or ultrafiltration, and this group required higher doses of erythropoietin to achieve similar hemoglobin targets.12 This dropout led KDOQI to recommend a total PD Kt/V target of 1.7.3 However, since the 2006 KDOQI guidelines were published, observational studies have failed to show a benefit for a Kt/V target of 1.7, and no additional trials have been published.4,13 Unfortunately, the focus on achieving a specific number—without the context of other clinical variables—may lead dialysis centers and clinicians to divert resources away from other valuable goals. Nurses and patients spend several hours each month measuring Kt/V, and when the value is below 1.7, many patients return to clinic to remeasure Kt/V, often with temporary or permanent changes to their prescription just to improve Kt/V. Some asymptomatic patients whose Kt/V persist below 1.7 might be forced to switch to hemodialysis. Conversely, achieving the number can provide false security when other parameters suggest inadequate dialysis. Given the weak evidence and potential harm of a Kt/V target of 1.7, the ISPD announced new guidelines that de-emphasize this Kt/V target, instead favoring a more holistic approach to providing high-quality, goal-directed PD.3 Which Policies Prevent the United States From Moving Beyond Kt/V of 1.7? The United States has yet to adopt these new ISPD guidelines because CMS—influenced by the national KDOQI guidelines—enforces the use of Kt/V through three federal rules and guidance documents. First, the Conditions for Coverage (CfC) provides standards that dialysis facilities must follow. These regulations require the interdisciplinary team to target a PD Kt/V of 1.714 or risk losing Medicare certification. Second, the ESRD Quality Incentive Program (QIP) penalizes centers that fail to meet certain quality metrics thresholds, one of which is Kt/V (for both PD and hemodialysis). However, according to Medicare Dialysis Facility Report data, dialysis facilities are 13 times more likely to miss the Kt/V target for PD, relative to HD, in at least 10% of their patients; this may suggest that some PD programs have already deprioritized near-universal achievement of the Kt/V target (Formally, we found that among 7037 Medicare-certified dialysis facilities with ≥5 adult hemodialysis patient-years in 2019, only 1.1% of facilities had ≥10% of patient-months with single-pool Kt/V <1.2. In contrast, among 2209 facilities with ≥5 adult PD patient-years, 14.1% of facilities had ≥10% of patient-months with weekly Kt/V <1.7. Data available at: https://data.cms.gov/quality-of-care/medicare-dialysis-facilities, [last accessed on December 29, 2022]). Third, the Medicare Claims Processing Manual provides guidance on how dialysis claims should be processed. Although formally the manual cannot alter legal obligations, functionally it can be a forum for Medicare to announce how it is implementing a program. For PD, the manual specifies that facilities must measure PD Kt/V at least every four months (although the manual does not specify that facilities must achieve a target Kt/V of 1.7). How Can the United States Move beyond Kt/V for PD? Ultimately, the existing CfC, QIP, and Claims Processing Manual hinder the US’ ability to de-emphasize a PD Kt/V target. However, there is a path forward (Table 1). Table 1. - Summary of problems and solutions related to Medicare documents that influence the Kt/V target of 1.7 Medicare Document/Policy Purpose of the Document/Policy Relevance to Kt/V a Solution to Adopt an Alternative Pathway to Move Toward the 2020 ISPD Guidelines CfC Establishes standards that all dialysis facilities must follow to receive Medicare certification and payment b The interdisciplinary team must meet a weekly Kt/V target of 1.7 for PD or an alternative, professionally accepted measure of dialysis adequacy CMS must provide written guidance that recognizes the ISPD 2020 guidelines, which call for a de-emphasis of a Kt/V target, as a professionally accepted alternative for dialysis adequacyThis written guidance could be provided through annual rulemaking or on their website ESRD QIP Provides quality metrics that are used to provide financial penalties to facilities that do not meet these quality metrics. Kt/V target of 1.7 for PD is a clinical measure of quality in the QIPThe Kt/V clinical measure has been paused because of the effect of the COVID-19 pandemic CMS must move the PD Kt/V target of 1.7 from a clinical measure to a reporting measure to allow nephrologists to follow an alternative pathway of the ISPD guidelinesThis change can be made through annual rulemaking Medicare claims processing manual Provides guidance on how claims should be structured Kt/V measurement is required every 4 mo for PD patients CMS must establish a billing code to prespecify patients in the alternative pathway, allowing for a rigorous evaluation of the alternative pathway ISPD, International Society for Peritoneal Dialysis; CfC, conditions for coverage; PD, peritoneal dialysis; CMS, Centers for Medicare and Medicaid Services; QIP, quality incentive program; COVID-19, coronavirus disease 2019.aKt/V is a measure of dialysis adequacy that accounts for dialyzer clearance (K), dialysis time (t), and volume (V, total body water).bMedicare certification status is a universal standard for dialysis facilities and thus nephrologists who care for patients with non-Medicare insurance are still held to these guidelines. We propose an alternative pathway for dialysis adequacy that CMS could implement to allow nephrologists to follow the ISPD guidelines. Specifically, we propose that nephrologists interested in the alternative pathway could prespecify, through a condition code, a subset of their patients for whom their multidisciplinary team would follow the ISPD guidelines for dialysis adequacy instead of the Kt/V target of 1.7. Nephrologists following the ISPD guidelines would still be required to measure Kt/V at least every 4 months, but they would be allowed to prescribe PD without fear of losing Medicare certification status or having their facility penalized by the QIP. There are three steps CMS must take to allow nephrologists to adopt this alternative pathway and practice within the ISPD guidelines (Table 1). First, they must address Kt/V in the CfC. Fortunately, when CMS adopted the 2006 KDOQI guidelines, it recognized that the PD Kt/V target of 1.7 was imperfect. In its rule implementing the CfC, CMS created a pathway for future updates by stating that, instead of achieving a Kt/V target of 1.7, care teams can meet an alternative equivalent professionally accepted clinical practice standard for adequacy of dialysis.14 We believe that the ISPD guidelines meet this equivalent standard. However, because failure to abide by the CfC could result in Medicare decertification, CMS should confirm that the ISPD guidelines meet these criteria by providing written commentary during their annual rulemaking or on their website. Second, CMS should address Kt/V in the QIP. Specifically, CMS should change Kt/V for PD from a clinical measure to a reporting measure, such that facilities must continue to measure Kt/V at least every 4 months, without adhering to a strict target of 1.7. There is ample precedent for this approach. First, despite a Congressional mandate to develop measures of bone mineral metabolism in the QIP, CMS recently moved the hypercalcemia measure in the QIP from a clinical measure to a reporting measure, in part because of concerns that hypercalcemia has limited evidence for being an adequate measure of bone mineral metabolism.2 Second, because of the effect of coronavirus disease 2019, CMS has already suppressed the Kt/V dialysis adequacy clinical measure for 2023. In light of the new ISPD guidelines and the fact that CMS has already suppressed Kt/V, we recommend that CMS move Kt/V to a reporting measure in the QIP so that nephrologists can follow the ISPD guidelines without fear of having their facilities receive penalties through the QIP. Third, the Claims Processing Manual should be changed to allow providers to list a condition code for patients who are placed on the alternative pathway. Again, this is feasible as CMS previously used the manual to announce implementation changes to benefits, such as payment for certain injectable drugs. Creating this code for the alternative pathway is critical to allow rigorous research on how the ISPD guidelines change care delivery within the US. If CMS takes these three steps to create this alternative pathway, US nephrologists will have the option to adopt the ISPD guidelines. We acknowledge that the Kt/V target of 1.7 is controversial and that we must consider the unintended consequences of removing this target. However, similar to the National Kidney Foundation's 2021 statement,5 we do not argue for the total abandonment of Kt/V. Rather, even in the alternative pathway, nephrologists must measure Kt/V at least every 4 months to guide decision making. Furthermore, by creating a condition code to document which patients receive care in the alternative pathway, CMS will allow for research to compare outcomes between patients in the traditional (i.e., Kt/V target of 1.7) and the alternative pathway (i.e., 2020 ISPD guidelines) using Medicare claims data to assess differences in technique failure, hospitalization, and mortality between the two pathways. In summary, the Kt/V target of 1.7 for PD needs to evolve given the dearth of supporting evidence and potentially undue burden on patients, nurses, and nephrologists. CMS can de-emphasize a Kt/V target of 1.7 and can ensure patient-centered PD if they take three steps: (1) clarify through written guidance that the 2020 ISPD guidelines are an acceptable alternative clinical practice standard for PD adequacy (creating an alternative pathway for PD), (2) move PD Kt/V from a clinical measure to a reporting measure in the QIP, and (3) adjust the claims processing manual to create a condition code to allow researchers to identify patients receiving care in this alternative pathway. Once CMS adopts these changes, professional societies and patient organizations—such as the American Society of Nephrology, the National Kidney Foundation, the Renal Physicians Association, and the American Association of Kidney Patients—could promote the implementation of the 2020 ISPD guidelines such that nephrologists and patients have the option to prescribe and receive high-quality, goal-directed PD that aligns with the Advancing American Kidney Health initiative.