Chronic Dialysis Episode

Definition

A period during which the patient can be considered to be receiving frequent, ongoing dialysis for a chronic condition. New episodes begin with an initial dialysis encounter with at least 60 days of prior negative history for dialysis and continue as long as the patient receives their next documented dialysis encounter within 60 days of the previous encounter. (The episode ends 60 days after the last dialysis encounter.) A dialysis episode qualifies as “chronic” if it contains at least one dialysis encounter performed in a dialysis facility or at home. The same dialysis episode can contain dialysis encounters in different settings, and with different dialysis modalities and vascular access types.

Purpose

Used in the URSA-CKD module to identify ESRD patients and inform clinical performance measures related to dialysis.

Related objects

• Dialysis Encounters
• Chronic Dialysis Episodes
  • Chronic Dialysis Episodes, Precursor 1 (Dialysis Encounters with Episode Metadata)
• Patient Timelines for CKD Stage
• Patient Timelines Master for URSA-CKD Concepts

Detailed narrative of logic

1. As implemented in Chronic Dialysis Episodes, Precursor 1 (Dialysis Encounters with Episode Metadata), all dialysis encounters, obtained from Dialysis Encounters without an earlier dialysis encounter in the prior 60 days are considered to represent the start of a new dialysis episode. All subsequent dialysis encounters, as long as they fall within 60 days of the prior dialysis encounter, extend the episode. Dialysis episodes are considered to end 60 days after the last dialysis encounter in the episode. 
2. Note that Chronic Dialysis Episodes, Precursor 1 (Dialysis Encounters with Episode Metadata) generates episode-level characteristics such as the Episode ID but retains the original grain size of the components — i.e., one record per dialysis encounter.
3. Next, as implemented in Chronic Dialysis Episodes, any dialysis episode without at least one dialysis encounter with a home or outpatient dialysis facility setting is excluded (as not chronic). That is, to be considered a “chronic” dialysis episode, the episode must contain at least one encounter in which dialysis was performed at a dialysis facility or at home.
4. Finally, Chronic Dialysis Episodes collapses the grain to one record per episode. At this point, certain episode-level fields — e.g., related to dialysis setting and modality — are generated based on the characteristics of individual encounters. Not infrequently, episodes contain dialysis encounters with a mix of settings and modalities, and these fields can be used to more easily implement rules to characterize the entire episode one way or another, if desired.