Definition of Renal Failure

Renal failure is the loss of the kidneys ability to remove wastes, concentrate urine, and maintain electrolytes levels in the blood. At MCHP, our definition of renal failure includes both acute and chronic renal failure. Renal disease associated with some other conditions, along with renal failure due to trauma, pregnancy and labour have typically not been included in our definition.

Renal Failure can be identified from the hospital abstracts data using ICD codes, or from the medical services (physician claims) data using ICD codes or tariff codes.

Identification Using Diagnoses Codes

In Fransoo et al. (2005), renal failure was identified using the following ICD codes from hospital discharge abstract and medical services/physician claims data:


• Acute renal failure (ICD-9-CM: 584; ICD-10: N17)
  
• Chronic renal failure (ICD-9-CM: 585; ICD-10: N18), or
  
• Renal failure unspecified (ICD-9-CM: 586; ICD-10: N19)

Renal failure is often a complication of diabetes, but can have other causes as well. It is expressed as a percentage because each resident is defined either as having been treated for renal failure, or not, in a period of time. Values are typically age-adjusted to reflect the Manitoba population age 20 and older (males and females combined).

The following diagnoses codes were excluded from the definition:


• renal failure following labour and delivery, trauma, post procedure, and hypertension associated renal disease (ICD-9-CM codes: 403.x1, 404.x2 and ICD-10-CA codes: I12 or I13),
  
• congenital renal failure (ICD-10: P96.0)

Other renal disease codes referenced in the literature, but not used in our definition included:


• unspecified disorder of kidney and ureter (ICD-9-CM: 593.9; ICD-10-CA: N28.9);
  
• Diabetes with renal malfunctions (ICD-9-CM: 250.4);
  
• Diabetes mellitus with renal complications (ICD-10-CA: E10.2);
  
• Gouty nephropathy (ICD-9-CM: 274.1); and
  
• Disorders of calcium metabolism (ICD-9-CM: 275.4; ICD-10-CA: E83.5)

Kidney transplant and/or death has been identified as an endpoint through surgical physician tariff codes or from hospital procedure codes:


• Renal Transplant: tariff code: 5883;
  
• Transplant of Kidney (ICD-9-CM: 55.6; CCI code: 1.PC.85.^^);
  
• Procurement, pancreas with duodenum and kidney (CCI code: 1.OK.85.^^)

Lix et al. (2006) looked at renal failure as a possible chronic disease but it was not included in the final report as there was no data source for validation.

Identification Using Physician Tariff Codes

Dialysis has also been looked as a possibility to identify individuals with renal failure using medical services/physician claims data. In Martens et al. (2010), , the following tariff codes were used to identify initiation and subsequent dialysis. Follow-up dialysis may not be billed consistently in the medical services data across all years. Dialysis (ICD-9-CM diagnosis V56, procedure 39.95, ICD-10-CA Z49.1) generally will not be found in Manitoba hospital discharge abstracts data unless it is part of an inpatient stay.



Manitoba Tariff Code	Tariff Code Description
9798	ACUTE RENAL FAILURE Initial hemodialysis - See Rules 44 and 45
9799	ACUTE RENAL FAILURE subsequent hemodialysis, each
9801	CHRONIC RENAL FAILURE Initial hemodialysis - See Rules 44 and 45
9802	CHRONIC RENAL FAILURE subsequent hemodialysis, each
9805	ACUTE RENAL FAILURE Initial peritoneal dialysis, complete medical management, up to two (2) weeks
9807	ACUTE RENAL FAILURE subsequent (peritoneal) dialysis, after two (2) weeks
9806	CHRONIC RENAL FAILURE Initial peritoneal dialysis, first twenty-four (24) hours
9819	CHRONIC RENAL FAILURE Intermittent subsequent (peritoneal) dialysis (maximum $180.00 per week)
9821	CHRONIC RENAL FAILURE Home dialysis and self-care dialysis and self-care dialysis weekly retainer
9610	Chronic ambulatory peritoneal dialysis, in hospital, per day
9820	Home (peritoneal) dialysis and self-care dialysis weekly retainer for administration, routine visits, and supervision Note: The above fee is not applicable if the patient is admitted to hospital as an in-patient.

In a study of adult obesity in Manitoba, Fransoo et al. (2011) also used the tariff codes listed above to identify participants who began dialysis treatment.

In Hilderman et al. (2011), they investigated chronic renal failure using the following MB tariff codes: 9801, 9802, 9806, 9819, 9821, 9610 or 9820.

In Chartier et al. (2012) the tariff codes listed in the table above were used to identify residents aged 19 and older who began dialysis treatment in a five-year period.

Cautions / Limitations

This concept and the associated SAS code should be considered a starting point for any study looking at renal failure. Issues around the use of acute and chronic conditions as well as additional codes should be reviewed and discussed prior to starting any analyes.