---
title: "CKD Stage"
slug: "ckd-key-concepts-ckd-stage"
updated: 2023-05-16T21:45:41Z
published: 2023-05-16T21:45:41Z
canonical: "docs.ursahealth.com/ckd-key-concepts-ckd-stage"
stale: true
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ursahealth.com/llms.txt
> Use this file to discover all available pages before exploring further.

# CKD Stage

## **Definition**

The stage of a patient’s chronic kidney disease (CKD), for stage 1 through stage 5 and ESRD. Stage is calculated only for patients already meeting the criteria for CKD. Stage is determined by a combination of the following: (1) ICD-10-CM codes specific to a particular stage; (2) estimated glomerular filtration rate (eGFR) lab results within certain bands associated with a stage; (3) identification of the patient in a CMS Monthly Membership Report as an ESRD beneficiary; (4) documentation of a prior kidney transplantation surgery; and/or (5) status as a chronic dialysis patient. The patient’s CKD stage can change over time, so a patient timeline data structure is appropriate.

## **Purpose**

Used in the URSA-CKD module to risk stratify and to identify later-stage CKD patients for certain measure inclusion / exclusion criteria.

## **Related objects**

- [**Document Aggregator for URSA-CKD Concepts**](/v1/docs/ckd-objects-document-aggregator-for-ursa-ckd-concepts)
- [**Chronic Dialysis Episodes**](/v1/docs/ckd-objects-chronic-dialysis-episodes)
- [**Kidney Transplantation Surgery Encounter**](/v1/docs/ckd-objects-kidney-transplantation-surgery-encounter)
- [**Patient Timelines for CCW Conditions**](/v1/docs/ckd-objects-patient-timelines-master-for-ursa-ckd-concepts)
- [**Patient Timelines of Any Plan Membership**](/v1/docs/ckd-objects-patient-timelines-master-for-ursa-ckd-concepts)
- [**Patient Timelines for CKD Stage**](/v1/docs/ckd-objects-patient-timelines-master-for-ursa-ckd-concepts)
- [**Patient Timelines Master for URSA-CKD Concepts**](/v1/docs/ckd-objects-patient-timelines-master-for-ursa-ckd-concepts)

## **Detailed narrative of logic**

1. At a high level, the CKD staging logic, as implemented primarily in **Patient Timelines for CKD Stage**, uses an attribution framework to reconcile potentially competing evidence to generate a dynamic longitudinal picture of a patient’s CKD stage. In this framework, each stage represents an exclusive result for each CKD patient — that is, the patient can be assigned only one stage — and the logic is seeking to find the “best” stage given the evidence available.
2. As implemented in **Patient Timelines for CKD Stage**, the logic restricts results to patient-periods during which the patient met the criteria for CKD, as obtained from **Patient Timelines for CCW Conditions** using a restriction of Is CCW CKD = 1, or was identified on a CMS Monthly Membership Report as an ESRD beneficiary, as obtained from **Patient Timelines of Any Plan Membership** using a restriction of Is CMS ESRD Status = 1.
3. Continuing in **Patient Timelines for CKD Stage**, patients are considered to have ESRD if any of the following criteria are met: the patient is in a chronic dialysis episode (obtained from **Chronic Dialysis Episodes**); the patient has a history of kidney transplant (obtained from **Kidney Transplantation Surgery Encounter**); or the patient is identified as an ESRD beneficiary in the CMS MMR as described above (obtained from **Patient Timelines of Any Plan Membership**).
4. Finally, CKD patients that do not meet the criteria for ESRD are assigned a stage, if possible, based on their history of stage-specific ICD-10-CM diagnosis codes (see value set cluster CKD STAGE) or eGFR lab results (see value set cluster GFR TESTS BY PATIENT RACE) with the following staging bands: eGFR ≥ 90 indicates stage 1, 60 ≤ eGFR < 90 indicates stage 2, 30 ≤ eGFR < 60 indicates stage 3; 15 ≤ eGFR < 30 indicates stage 4; and eGFR < 15 indicates stage 5. When identified on the patient’s record, the appropriate race-specific eGFR lab is used; patients without race documented use the non-black or non-race-specific labs. The identification of documents with qualifying ICD-10-CM codes or eGFR lab codes, and their translation to CKD stage values, is implemented in **Document Aggregator for URSA-CKD Concepts**; the integration of this information with other evidence of staging described above occurs in **Patient Timelines for CKD Stage**.