Table 1. ICD-9-CM coding definitions.

	ICD-9 codes used
Cirrhosis	Two of the following: 571.2, 571.5, 456.0–456.21, 567.23, 572.2, 572.4
Esophageal varices with bleeding	456.0, 456.20
Spontaneous bacterial peritonitis	567.23
Hepatic encephalopathy	572.2
Hepatorenal syndrome	572.4
Hepatocellular carcinoma	155.00
Charlson Comorbidity Score	410–410.9 (myocardial infarction, Charlson score 1); 428–428.9 (congestive heart failure, Charlson score 1); 433.9, 441–441.9, 785.4, V43.4 (peripheral vascular disease, Charlson score 1); 430–438 (Cerebrovascular Disease, Charlson score 1); 290–290.9 (Dementia, Charlson score 1); 490–496, 500–505, 506.4 (Chronic Pulmonary Disease, Charlson score 1); 710.0, 710.1, 710.4, 714.0–714.2, 714.81, 725 (Rheumatologic Disease, Charlson score 1); 531–534.9 (Peptic Ulcer Disease, Charlson score 1); 571.2, 571.5, 571.6, 571.4–571.49 (Mild Liver Disease, Charlson score 1); 250–250.3, 250.7 (Diabetes, Charlson score 1); 250.4–250.6 (Diabetes with Chronic Complications, Charlson score 2); 344.1, 342–342.9 (Hemiplegia or Paraplegia, Charlson score 2); 582–582.9, 583–583.7, 585, 586, 588–588.9 (Renal Disease, Charlson score 2); 572.2–572.8 (Moderate or Severe Liver Disease, Charlson score 3); 042–044.9 (AIDS, Charlson score 6)
ESRD/hemodialysis	V45.1, V56.0, V56.1, CPT 39.95
Depression	296.20–25, 296.30–35, 300.4, 311
Anxiety	300.00–300.02
Substance abuse/dependence	305.00–305.95, 304.40–304.93

ICD-9-CM: International Classification of Diseases, 9th revision, clinical modification; AIDS: acquired immune deficiency syndrome; ESRD: end stage renal disease; CPT: Current Procedural Terminology