# Presentation: 745820

## Chronic Kidney Disease:Proposed Revisions to the ICD-9-CM Classification

- Lesley Stevens MD
- Tufts-New England Medical Center
- National Kidney Foundation

## Objectives

- Kidney Failure
- Stages of Chronic Kidney Disease
- Definition and Classification of CKD
- GFR
- Proteinuria
- Etiology
- Current use of ICD-9-CM codes for CKD
- Proposed changes to ICD-9-CM

## Incidence and Prevalence of End-Stage Renal Disease in the US

## Cardiovascular Mortality in the General Population and in ESRD Treated by Dialysis

**0.01**

**100**

**10**

**1**

**0.1**

**Annual mortality (%)**

**25–34**

**45–54**

**65–74**

******85**

**35–44**

**55–64**

**75–84**

**Male**

**Female**

**Black**

**White**

**Dialysis**

**General population**

**Age (years)**

## Costs of Associated with Initiation of Dialysis

- St Peters, Khan, Ebben. Li,  Xue, Pereira, Collins. Kidney Int. 200.

## Stages in Progression of Chronic Kidney Disease and Therapeutic Strategies

**Stages in Progression of Chronic Kidney Disease and Therapeutic Strategies**

**Complications**

**Screening ****for CKD****risk factors**

**CKD risk****reduction;****Screening for****CKD**

**Diagnosis****& treatment;****Treat ****comorbid****conditions;****Slow ****progression**

**Estimate****progression;****Treat****complications;****Prepare for****replacement**

**Replacement****by dialysis****& transplant**

**Normal**

**Increased****risk**

**Kidney****failure**

**Damage**

****** ****GFR**

## Definition of CKD

- Structural or functional abnormalities of the kidneys for _>_3 months, as manifested by either:
- 1. Kidney damage, with or without decreased GFR, as defined by
- pathologic abnormalities
- markers of kidney damage, including abnormalities in the composition of the blood or urine or abnormalities in imaging tests
- 2. GFR <60 ml/min/1.73 m2, with or without kidney damage

## Prevalence of CKD and Estimated Number of Adults with CKD in the US (NHANES 88-94)

| Stage | Description | GFR 
(ml/min/1.73 m2) | Prevalence* |  |
| --- | --- | --- | --- | --- |
|  |  |  | N (1000s) | % |
| 1 | Kidney Damage with Normal or  GFR |  90 | 5,900 | 3.3 |
| 2 | Kidney Damage with Mild  GFR | 60-89 | 5,300 | 3.0 |
| 3 | Moderate  GFR | 30-59 | 7,600 | 4.3 |
| 4 | Severe  GFR | 15-29 | 400 | 0.2 |
| 5 | Kidney Failure | < 15 or Dialysis | 300 | 0.1 |

- *Stages 1-4 from NHANES III (1988-1994).  Population of 177 million with age 20.  Stage 5 from USRDS (1998), includes approximately 230,000 patients treated by dialysis, and assuming 70,000 additional patients not on dialysis.  GFR estimated from serum creatinine using MDRD Study equation based on age, gender, race and calibration for serum creatinine.  For Stage 1 and 2, kidney damage estimated by spot albumin-to-creatinine ratio 17 mg/g in men or 25 mg/g in women in two measurements.

## Prevalence of Abnormalities at each level of GFR

- *>140/90 or antihypertensive medication

- p-trend < 0.001 for each abnormality

## Age-Standardized Rates of Death from Any Cause (Panel A) and Cardiovascular Events (Panel B), According to the Estimated GFR among 1,120,295 Ambulatory Adults

- Go, A, et al. NEJM 351: 1296

## Clinical Practice Guidelines for the Detection, Evaluation and Management of CKD

## Definition of ESRD vs Kidney Failure

- ESRD is a federal government defined term that indicates chronic treatment by dialysis or transplantation
- Kidney Failure: GFR < 15 ml/min/1.73 m2 or on dialysis.

## Importance of Proteinuria in CKD

## Albuminuria as a Risk Factor for CVD in PREVEND

- Hillege HL et al. Circulation 2002: 106: 1777-1782

## Progression of Kidney Disease related to level of proteinuria and blood pressure lowering in MDRD Study

- Petersen. Annals of Internal Medicine. 1995

## Clinical Practice Guidelines for Management of Hypertension in CKD

| Type of Kidney Disease | Blood Pressure Target 
(mm Hg) | Preferred Agents for CKD, with or without Hypertension | Other Agents to Reduce CVD Risk and Reach Blood Pressure Target |
| --- | --- | --- | --- |
| Diabetic Kidney Disease | <130/80 | ACE inhibitor or ARB | Diuretic preferred, then BB or CCB |
| Nondiabetic Kidney Disease with Urine Total Protein-to-Creatinine Ratio 200 mg/g |  |  |  |
| Nondiabetic Kidney Disease with Spot Urine Total Protein-to-Creatinine ratio <200 mg/g |  | None preferred | Diuretic preferred, then ACE inhibitor, ARB, BB or CCB |
| Kidney Disease in Kidney Transplant Recipient |  |  | CCB, diuretic, BB, ACE inhibitor, ARB |

## Classification of CKD by Diagnosis

**Diabetic Kidney Disease**
**Glomerular diseases**  (autoimmune diseases, systemic infections, drugs, neoplasia)
**Vascular diseases**  (renal artery disease, hypertension, microangiopathy)
**Tubulointerstitial diseases** (urinary tract infection, stones, obstruction, drug toxicity)
**Cystic diseases** (polycystic kidney disease)
**Diseases in the transplant**** ****(**Allograft nephropathy, drug toxicity, recurrent diseases, transplant glomerulopathy)

## Current use of ICD-9-CM codes for Kidney Disease

- ICD-9-CM codes for kidney disease were used in 1% of all patients.

- * GFR in ml/min/1.72 m2

## Current use of ‘585’ (chronic  renal failure) in 277, 262 adults visiting an outpatient commercial clinical laboratory

|  | GFR (ml/min/1.73 m2)* |  |  |  |  |
| --- | --- | --- | --- | --- | --- |
|  | >90 | 60-89 | 30-59 | 15-29 | <15 |
| No 585 code** | 13 | 60 | 27 | 3 | <1 |
| 585 code | 10 | 62 | 23 | 2 | <1 |

- * GFR in ml/min/1.72 m2
- **Row Percentages

## Proposed Classification: ESRD code

- 585 		End Stage Renal Disease;
- 			on dialysis
- 585.1		End Stage Renal Disease;
- 			transplanted
- 			Use additional code to identify
- 			chronic kidney disease (586.1-586.9)

## Proposed Classification: CKD code

- 586.1	Stage I CKD: Kidney damage with normal or 			increased glomerular filtration rate (GFR), greater than 	or equal to 90 ml/min/1.73m2
- 586.2	Stage II CKD: Kidney damage with mild decrease in 		GFR 60-89 ml/min/1.73m2
- 586.3	Stage III CKD: Kidney damage with moderate 			decrease in GFR 30-59 ml/min/1.73m2
- 586.4	Stage IV CKD: Kidney damage with severe decrease 		in GFR 15-29 ml/min/1.73m2
- 586.5	Stage V CKD: Kidney damage with GFR of less than 		15 ml/min/1.73m2 Kidney failure with GFR less than 15 	ml/min/1.73m2 and not on dialysis
- Note: 	Codes apply only to patients diagnosed kidney disease > 3 mo

## Proposed Classification: CKD code 5th digit

- Each 586 (CKD) code requires a 5th digit to indicate evidence of proteinuria or albuminuria
- 586.X0 for those without evidence of proteinuria or albuminuria
- 586.X1 for those with evidence of proteinuria or albuminuria

## Proposed Classification: Etiology

- Instructions to code for CKD stage along with disease specific codes
- 250.4 Diabetes with renal manifestations
- Use additional code to identify manifestation, as: Add chronic kidney disease (585.1-585.9)
- 582.81 Chronic glomerulonephritis in diseases 			classified elsewhere: amyloidosis, SLE
- Use additional code to identify manifestation, as: Add chronic kidney disease (585.1-585.9)

## Benefits of Revised ICD-9-CM codes

- Distinguish between ESRD and CKD; between dialysis and transplantation
- Assess risk for adverse outcomes, expected complications and comorbid disease by the combination of severity of CKD (stages), proteinuria and diagnosis
- Determine which patients require specific treatments based on severity of CKD, and in particular proteinuria
- Examine of health care utilization and costs. Assess rural and urban settings and racial disparities
- Assess quality of care delivered
- Progress toward achievement of Healthy People 2010 goals
- Allow CMS and USRDS to develop specific research files to investigators to enhance our knowledge of CKD by the major risk groups