Table 2. Association of external quality assurance and covariates – including stroke unit treatment – with adjusted overall mortality risk*¹ of stroke patients.

Control group	Variable/Covariate	HR*2 [95% CI]
Federal states without external QA	Quality Assurance Office Hess (GQH)	0.93 [0.92; 0.95]
	External quality assurance without GQH	0.96 [0.95; 0.97]
No stroke unit	Stroke unit	0.86 [0.85; 0.87]
Age <50 years	Age 50–59	1.31 [1.24; 1.38]
	Age 60–69	1.81 [1.72; 1.90]
	Age 70–79	2.85 [2.71; 3.00]
	Age 80–89	5.13 [4.88; 5.39]
	Age >89	8.35 [7.93; 8.79]
Male	Female	0.82 [0.81; 0.83]
ICD-10-G45 (transient [cerebral] ischemic attacks and related syndromes)	ICD-10-I60 (subarachnoid hemorrhage)	2.72 [2.60; 2.85]
	ICD-10-I61 (intracerebral hemorrhage)	3.03 [2.97; 3.09]
	ICD-10-I63 (cerebral infarction)	1.58 [1.56; 1.60]
	ICD-10-I64 (other type of stroke)	1.26 [1.19; 1.34]
Years 2007–10	Years 2011–13	0.95 [0.94; 0.96]
	Years 2014–17	0.89 [0.88; 0.91]
Elixhauser index <4 (comorbidity score)	Elixhauser 4–6	1.48 [1.46; 1.49]
	Elixhauser >6	2.09 [2.05; 2.13]
No nursing care level before cerebral insult	Nursing care level 1 before cerebral insult	1.90 [1.87; 1.92]
	Nursing care level 2 before cerebral insult	2.42 [2.38; 2.46]
	Nursing care level 3 before cerebral insult	2.92 [2.83; 3.00]
GISD <6	GISD >5 (higher socioeconomic deprivation of the patients‘ home region)	0.99 [0.98; 1.00]

*¹ overall mortality risk adjusted for type of stroke, age, sex, comorbidity, nursing care level, patients‘ regional social deprivation

*² all HRs statistically significant apart from GISD (p <10 ^–5)

GISD, German Index of Socioeconomic Deprivation; HR, hazard ratio; QA, quality assurance;

95% CI, 95% confidence interval