Table 6. Principal readmission diagnosis within 30 days by modified condition categories among patients with an index hospitalization for heart failure.

Description	Age Group (Years)
	18–39		40–54		55–64		≥65
	n	%	n	%	n	%	n	%
Heart failure	578	49.6	2489	45.2	2918	42.2	11569	36.0
Acute myocardial infarction	5	0.4	80	1.5	134	1.9	783	2.4
Unstable angina and other acute ischemic heart disease	2	0.2	19	0.4	15	0.2	39	0.1
Chronic angina and coronary artery disease	3	0.3	52	0.9	105	1.5	323	1.0
Valvular/rheumatic heart disease	3	0.3	26	0.5	42	0.6	385	1.2
Other cardiac disease including congenital heart and hypertensive disease	24	2.1	60	1.1	62	0.9	216	0.7
Arrhythmias and conduction disorders	16	1.4	121	2.2	195	2.8	1001	3.1
Pleural effusion/pneumothorax	5	0.4	19	0.4	37	0.5	222	0.7
Chest pain	50	4.3	220	4.0	156	2.3	383	1.2
Syncope	4	0.3	12	0.2	30	0.4	210	0.7
Acute stroke/transient ischemic attack	11	0.9	80	1.5	101	1.5	768	2.4
Pulmonary embolism/deep venous thrombosis	15	1.3	38	0.7	41	0.6	159	0.5
Other peripheral vascular disease	5	0.4	65	1.2	93	1.4	631	1.9
Cardio-respiratory failure	32	2.8	183	3.3	255	3.7	1219	3.8
Chronic obstructive pulmonary disease	11	0.9	198	3.6	236	3.4	941	2.9
Pneumonia including aspiration pneumonia	36	3.1	196	3.6	223	3.2	1750	5.4
Septicemia/shock	17	1.5	120	2.2	209	3.0	1619	5.0
Urinary tract infection	3	0.3	18	0.3	44	0.6	587	1.8
Cellulitis	6	0.5	69	1.3	75	1.1	255	0.8
Clostridium difficile-associated infection	1	0.1	7	0.1	24	0.4	292	0.9
Renal disorders including renal failure	103	8.8	403	7.3	547	7.9	2676	8.2
Anemia	4	0.3	15	0.3	34	0.5	274	0.8
Gastrointestinal hemorrhage	4	0.3	37	0.7	81	1.2	632	1.9
Diabetes and its complications	27	2.3	119	2.2	169	2.5	559	1.7
Fibrosis of lung and other chronic lung disorders	2	0.2	10	0.2	14	0.2	91	0.3
Hip fracture	0	0.0	6	0.1	22	0.3	287	0.9
Complications of care	39	3.4	203	3.7	258	3.7	834	2.6
Other lung disorders including acute, congenital, and unspecified lung abnormalities	4	0.3	19	0.4	21	0.3	89	0.3
Primary cancer of the trachea, bronchus, lung, and pleura	0	0.0	3	0.1	3	0.0	58	0.2
Othera	155	13.3	619	11.2	767	11.1	3659	11.3

^aAmong patients aged 18–64 years, the “other” modified CC consisted of 508 distinct ICD-9-CM diagnoses. In comparison, among patients aged ≥65, the “other” modified CC consisted of 794 distinct ICD-9-CM diagnoses.