Prediction of Length of Stay Following Elective Percutaneous Coronary Intervention

Table 2

Distribution of covariates by data set.

Covariate	Learning (%); (N = 67766)	Testing (%); (N = 79545)
Age (Years)	64.1 (11.8)*	64.7 (11.8)
Body mass index	28.7 (5.4)*	28.9 (5.6)
Women	32.1%	32.6%
White	86.9%	83.2%
Black	6.5%	7.3%
Other	6.6%	9.6%
Hispanic	6.5%	7.3%
Current smoker	16.7%	16.9%
Diabetes mellitus	25.8%	28.6%
Hypertension	71.0%	76.2%
Heart failure	5.5%	5.5%
Vascular disease	8.9%	9.4%
Renal failure; (including dialysis)	2.3%	2.8%
Chronic lung disease	5.3%	6.1%
Malignant ventricular arrhythmias	1.4%	0.8%
Prior myocardial infarction	6.9%	6.9%
Prior percutaneous coronary intervention	30.6%	35.3%
Prior open heart surgery	18.0%	19.7%
Previous stroke	4.0%	4.3%
Left Main disease	2.7%	2.9%
Multivessel coronary disease	46.0%	47.0%

*Age and body mass index are presented as mean (SD).