How To: Acute Kidney Injury | Medisolv

The Hospital Harm – Acute Kidney Injury (HH-AKI) eCQM is one of five hospital harm measures that CMS has added in quick succession to the Inpatient Quality Reporting (IQR) program in its efforts to shine a glaring, no-excuses spotlight on patient safety.

And—just like the other four hospital harm measures—the HH-AKI eCQM is being rolled out first as a voluntary measure (in 2025), before quickly transitioning to a mandatory one (in 2027). That means you have a brief window of time to master the Acute Kidney Injury measure before your payment determination and your public reporting depends on it.

To help you beat the clock, we’ve assembled this complete HH-AKI-for-beginners guide. We’ll walk you through the “why” behind the measure, what patient populations you need to track, and how to track them in your workflows. Let’s dive in.

[Editor’s Note: As always, be sure to review the measure’s official specifications. And for a full schedule of your upcoming Hospital Harm requirements, be sure to check out our 2025 IPPS Proposed Rule slideshow.]

What does the Acute Kidney Injury eCQM measure?

The HH-AKI eCQM measures the proportion of inpatient hospitalizations for patients ages 18 and older who develop an acute kidney injury (stage 2 or greater) while under your care.

This is an inverse measure, so the lower your rate, the better.

CMS defines a stage 2 or greater AKI as either “a substantial increase in serum creatinine value” or “the initiation of kidney dialysis.” In this measure, dialysis is defined as either CRRT, hemodialysis, or peritoneal dialysis.

The HH-AKI measure is also risk adjusted to account for the patient’s sex, age, vital signs, baseline estimated Glomerular Filtration Rate (eGFR), and certain comorbidities that are present on admission, as well as the patient’s length of stay. More on that in a little bit.

Why is CMS adding an Acute Kidney Injury eCQM now?

Acute kidney injury (AKI) is still an all-too-common part of the U.S. inpatient experience. CMS cites that up to 20% of all general patients will experience it during their hospital stay. For cardiac surgery patients and critically ill patients that number is even higher – up to 50%.

And while AKI itself can be a relatively short-term condition, the associated risks and after-effects that it can trigger are alarming. A 2017 meta-analysis of more than 25 studies and over 500,000 adults revealed that AKI is associated with an increased risk of heart failure (58% increase), acute myocardial infarction (40%), and stroke (15%), as well as—not surprising—an 86% increased risk of cardiovascular mortality. A second study showed that, even when AKI is caught and course-corrected during hospitalization, more than one-third of AKI patients relapse, often within 72 hours. Those that do relapse have a 5 times greater risk for death within one year as compared to patients for whom AKI is permanently reversed.

In other words, AKI is a dangerous beast—and CMS has declared that it’s time we tame it. The HH-AKI eCQM forces hospitals to take control of their AKI rate or risk losing out on payment dollars and star ratings.

Acute Kidney Injury eCQM Populations

So how does a patient make his or her way into the HH-AKI measure population? Let’s break it down.

Initial Patient Population

Layman’s description:

The Initial Patient Population (IPP) for the HH-AKI eCQM is all patients ages 18 and older who were inpatient hospitalizations for at least 48 hours and who had at least one serum creatinine value after 48 hours from the start of their hospitalization.

Patients who had an obstetrical or pregnancy related condition should NOT be included in your IPP.

Simplified logic:

• Inpatient encounter
• Age > or = 18 years
• Length of stay > or = 48 hours
• At least 1 serum creatine value after 48 hours
• No OB or OBE VTE encounter diagnosis

Workflow:

Denominator

Layman’s description:

The denominator is the same as the IPP.

Simplified logic:

• Inpatient encounter
• Age > or = 18 years
• Length of stay > or = 48 hours
• At least 1 serum creatine value after 48 hours
• No OB or OBE VTE encounter diagnosis

Workflow:

Denominator Exclusions

Layman’s description:

The acute kidney injury eCQM includes a number of denominator exclusions to account for the fact that, even in the best clinical care scenarios. some cases of AKI are typically non-preventable.

This includes four things to look for in the first 48 hours: a 0.3 spike or higher in the patient’s serum creatine level over the baseline value; an estimated glomerular filtration rate (eGFR) index value of less than 60 ml/min; less than 2 creatine results; and/or the initiation of kidney dialysis.

CMS is also asking you to exclude patients with a diagnosis or procedure that puts them at high risk for developing AKI.

Simplified logic:

Patients that demonstrate the following within 48 hours of the encounter start:

• Increase of serum creatine over patient’s index value > or = 0.3 mg dL
• eGFR index value < than 60 ml/min
• Number of creatine results < 2
• Kidney dialysis initiated

Also exclude patients with:

• Encounter with High-Risk Diagnosis for AKI present on admission or clinically undetermined
  • Hemolytic uremic syndrome (HUS)
  • Large body surface area (BSA) burns
  • Traumatic avulsion of kidney
  • Rapidly progressive nephritic syndrome
  • Thrombotic Thrombocytopenic Purpura
  • Out-of-hospital cardiac arrest (OHCA)
• Encounter with High-Risk Procedures for AKI
  • Extracorporeal membrane oxygenation (ECMO)
  • Intra-aortic balloon pump
  • Resuscitative endovascular balloon occlusion of the aorta (REBOA)
  • Nephrectomy

Workflow:

Numerator

Laymen’s description:

The numerator is any patient from your denominator who is not excluded and develops stage 2 AKI or greater during the encounter. CMS defines “develops stage 2 AKI” in two ways.

The first way is pretty simple: kidney dialysis was initiated more than 48 hours after the start of the encounter. In these cases, evidence of an increase in creatinine is not required.

The second requires a little math: the patient has a serum creatinine value at least two times higher than his or her lowest recorded value. This increased value must also be greater than the highest normal value for the patient’s sex.

Only one of these two scenarios needs to be counted per encounter.

Simplified logic:

• 2x serum creatinine increase

OR

• Kidney dialysis initiated more than 48 hours after the encounter start

Workflow:

Risk Adjustment

Laymen’s description:

CMS evaluated a large number of factors that can put patients at a higher risk for kidney injury as it was developing the risk-adjustment model for HH-AKI. For the initial rollout of the measure, however, it has decided to include just the variables listed in the Simplified Logic section below. These variables should be submitted in your QRDA file, and then CMS will handle the adjustment calculations for you.

On a related note, CMS has released a complete report on how it arrived at its risk-adjusted methodology for this measure. If you love doing deep dives into your quality measures, it’s an interesting read.

Simplified logic:

• Sex and age
• First vital signs in encounter:
  • Temperature
  • Heart rate
  • Respiratory rate
  • Systolic blood pressure
• eGFR rate calculated using the index serum creatinine, patient sex, and age-based formula
• ALL encounter diagnoses with present on admission indicators (collected for development of baseline risk adjustment model)
• Targeted diagnoses at the time of development:
  • Cancer (leukemia, lymphoma, or metastatic cancer)
  • Diabetes
  • Heart failure
  • Hypertension
  • Obesity
• Encounter length of stay

Workflow:

Tips for Getting Started with the Acute Kidney Injury eCQM

• CMS relies heavily on the Kidney Disease: Improving Global Outcomes (KDIGO) best practices in the measure specification's Clinical Recommendation Statement. Review these with your quality team and your clinical stakeholders to make sure they are being implemented, can be implemented in the next 12 months, or there is a good reason why they can’t be implemented.
• Recording dates and times accurately is critical for multiple data elements in this measure. Make sure your EHR is set up to make capturing this data dummy-proof. Educate your frontline clinicians and lab staff on the importance of the measure’s time windows.
• Wondering how you’ll map eGFR rates in your workflow? You don’t have to worry. Per the specification’s logic, eGFR is calculated during the data evaluation process. No mapping required!
• Schedule a time to talk to Medisolv. The HH-AKI eCQM is available now in our ENCOR for Electronic Hospital Measures software, so you can be up and running on the measure in record time. Click here to send us a message.

More “How To” Guides from Medisolv

Need help getting started with CMS’s other new measures? Check out these latest “how to implement” guides from Medisolv:

• Excessive Radiation Dose (ExRad) eCQM
• Hospital Harm – Opioid Related Adverse Events eCQM
• Hospital Harm – Hypoglycemic and Hyperglycemic eCQMs
• Hospital Harm - Pressure Injury eCQM
• 2024 eCQM Logic (Webinar Series)