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
  
• Chronic Dialysis Episodes
• Kidney Transplantation Surgery Encounter
• Patient Timelines for CCW Conditions
  
• Patient Timelines of Any Plan Membership
  
• Patient Timelines for CKD Stage
  
• 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.