Exploring relationships between in-hospital mortality and hospital case volume using random forest: results of a cohort study based on a nationwide sample of German hospitals, 2016–2018

Table 3 Number of hospital-years and cases by indication and volume group

Indication	Stroke		Myocardial infarction		Colorectal resection		Ventilation > 24 h		COPD		Pneumonia
Volume group	Hospital-years	Cases	Hospital-years	Cases	Hospital-years	Cases	Hospital-years	Cases	Hospital-years	Cases	Hospital-years	Cases
1–9	91	430	48	221	74	369	29	101	13	37	23	75
10–19	60	873	53	750	91	1274	13	177	5	76	4	63
20–49	112	3783	129	4199	205	6848	82	3064	54	1949	35	1261
50–99	78	5465	75	5107	167	11,353	134	10,052	120	9055	78	5943
100–199	56	7989	74	10,957	39	4860	162	24,106	245	36,001	218	32,230
200–499	104	34,418	206	62,815	2	455	146	41,630	175	49,806	288	86,355
500–999	118	83,143	60	39,532	–	–	60	43,885	38	24,113	25	15,710
1000-1999	40	51,498	8	10,174	–	–	26	34,090	9	9750	–	–
2000+	3	6313	–	–	–	–	3	14,352	–	–	–	–
Total	662	193,912	653	133,755	578	25,159	655	171,457	659	130,787	671	141,637

Hospital-years: each year in which a hospital treated patients was counted as one hospital-year of the corresponding volume-group

ISSN: 1472-6963