Mortality following acute medical admission in Denmark: a feasibility study

Figures & data

Figure 1 Relative frequency of primary admission conditions according to major ICD-10 groups (corresponding disease categories are shown in Table 2).

Table 1 Characteristics of patients with a first-ever admission to the medical admission unit at Aarhus University Hospital, Nørrebrogade, during 2008

	Patients
	n	%
Overall	3,727	100.0
Gender
Female	1,997	53.6
Male	1,730	46.4
Age group (y)
18–64	2,045	54.9
65–80	886	23.8
>80	796	21.4
Charlson comorbiditiesa
Myocardial infarction	263	7.1
Congestive heart failure	358	9.6
Peripheral vascular disease	279	7.5
Cerebrovascular disease	559	15.0
Dementia	86	2.3
Chronic pulmonary disease	661	17.7
Connective tissue disease	195	5.2
Ulcer disease	335	9.0
Mild liver disease	176	4.7
Diabetes mellitus	531	14.2
Hemiplegia	29	0.8
Moderate to severe renal disease	137	3.7
Diabetes with end-organ damage	319	8.6
Any tumor	472	12.7
Leukemia	4	0.1
Lymphoma	26	0.7
Moderate to severe liver disease	59	1.6
Metastatic solid tumor	72	1.9
AIDS	3	0.1
Comorbidity levelb
Low	1,624	43.6
Moderate	1,241	33.3
High	862	23.1

a Notes: Any hospital discharge diagnosis recorded in the Danish National Patients Registry between 1977 and the index date;

b Three levels of comorbidity were defined based on Charlson index scores of 0 (low), 1–2 (moderate), and 3 or more (high).

Table 2 Frequency and proportion of primary admission conditions according to major ICD-10 groups

ICD-10 groups	Disease categories	n	%
A00–B99	Certain infectious and parasitic diseases	126	3.4
C00–D48	Neoplasms	19	0.5
D50–D89	Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism	51	1.4
E00–E90	Endocrine, nutritional, and metabolic diseases	299	8.0
F00–F99	Mental and behavioral disorders	265	7.1
G00–G99	Diseases of the nervous system	80	2.1
H00–H59	Diseases of the eye and adnexa	3	0.1
H60–H95	Diseases of the ear and mastoid process	5	0.1
I00–I99	Diseases of the circulatory system	245	6.6
J00–J99	Diseases of the respiratory system	575	15.4
K00–K93	Diseases of the digestive system	76	2.0
L00–L99	Diseases of the skin and subcutaneous tissue	33	0.9
M00–M99	Diseases of the musculoskeletal system and connective tissue	117	3.1
N00–N99	Diseases of the genitourinary system	114	3.1
O00–O99	Pregnancy, childbirth, and the puerperium	–	–
P00–P96	Certain conditions originating in the perinatal period	–	–
Q00–Q99	Congenital malformations, deformations, and chromosomal abnormalities	–	–
R00–R99	Symptoms, signs, and abnormal clinical and laboratory findings, not elsewhere classified	522	14.0
S00–T98	Injury, poisoning, and certain other consequences of external causes	528	14.2
V01–Y98	External causes of morbidity and mortality	1	0.0
Z00–Z99	Factors influencing health status and contact with health servicesa	668	17.9

a Note: Among z-categories, 567 (84.9%) were admitted as “medical observation and evaluation for suspected diseases and conditions” (Z03).

Figure 2 Mortality for all patients.

Figure 3 Mortality according to gender. A) Unadjusted; B) adjusted.

Figure 4 Mortality according to age groups. A) Unadjusted; B) adjusted.

Figure 5 Mortality according to comorbidity level. A) Unadjusted; B) adjusted.

Table 3 Cumulative mortality risk after 1, 3, and 6 months, overall and according to gender, age, and comorbidity groups

	Cumulative mortality (%)
	Unadjusted			Adjusteda
	1 mo	3 mo	6 mo	1 mo	3 mo	6 mo
Overall	5.7	9.5	12.8	3.1	5.3	7.4
Gender
Female	5.4	9.5	12.9	2.8	5.1	7.1
Male	6.0	9.4	12.7	3.4	5.5	7.7
Age group (y)
18–64	1.7	3.1	4.4	0.9	1.6	2.3
65–80	7.3	11.6	17.2	6.8	10.7	16.1
>80	13.9	23.4	29.4	13.2	22.3	28.4
Comorbidity levelb
Low	2.0	3.0	4.2	1.0	1.5	2.1
Moderate	6.3	10.6	14.5	4.2	7.2	10.1
High	11.7	20.1	26.5	10.8	18.6	24.8

a Notes: Adjusted for gender, age as continuous variable, and comorbidity level (2 in each analysis);

b Three levels of comorbidity were defined based on Charlson index scores of 0 (low), 1–2 (moderate), and 3 or more (high).

Table 4 Mortality hazard ratios within gender, age, and comorbidity groups

	Hazard ratios (95% confidence intervals)
	Unadjusted	Adjusteda
Gender
Female	1.00 (reference)	1.00 (reference)
Male	0.99 (0.82–1.18)	1.16 (0.97–1.39)
Age group (y)
18–64	1.00 (reference)	1.00 (reference)
65–80	4.16 (3.20–5.39)	2.77 (2.11–3.64)
>80	7.76 (6.08–9.90)	5.25 (4.06–6.80)
Comorbidity levelb
Low	1.00 (reference)	1.00 (reference)
Moderate	3.65 (2.76–4.83)	2.43 (1.82–3.24)
High	7.15 (5.45–9.37)	3.87 (2.91–5.15)

a Notes: Adjusted for gender, age as a continuous variable, and comorbidity level (2 in each analysis).

b Three levels of comorbidity were defined based on Charlson index scores of 0 (low), 1–2 (moderate), and 3 or more (high).

Table 5 Mortality hazard ratios stratified on gender, age, and comorbidity groups

	Hazard ratios (95% confidence intervals)
	Unadjusted	Adjusteda
Female patients
Age 65–80	4.74 (3.20–7.03)	2.93 (1.95–4.41)
Age >80	8.73 (6.08–12.53)	5.26 (3.60–7.68)
Moderate comorbidity	4.38 (2.94–6.51)	2.79 (1.86–4.21)
High comorbidity	8.98 (6.09–13.25)	4.74 (3.15–7.13)
Male patients
Age 65–80	3.77 (2.65–5.34)	2.68 (1.86–3.86)
Age >80	7.56 (5.38–10.63)	5.35 (3.74–7.65)
Moderate comorbidity	3.02 (2.03–4.47)	2.11 (1.41–3.16)
High comorbidity	5.61 (3.84–8.20)	3.11 (2.08–4.65)
Patients aged 18–64 y
Male	1.18 (0.78–1.80)	1.12 (0.74–1.71)
Moderate comorbidity	2.12 (1.22–3.67)	2.10 (1.21–3.65)
High comorbidity	4.65 (2.68–8.09)	4.62 (2.66–8.03)
Patients aged 65–80 y
Male	1.16 (0.84–1.59)	1.09 (0.79–1.50)
Moderate comorbidity	1.59 (0.95–2.68)	1.58 (0.94–2.66)
High comorbidity	2.79 (1.71–4.56)	2.76 (1.69–4.52)
Patients aged ≥80 y
Male	1.27 (0.98–1.66)	1.24 (0.95–1.61)
Moderate comorbidity	2.19 (1.42–3.37)	2.20 (1.43–3.39)
High comorbidity	2.89 (1.88–4.43)	2.85 (1.86–4.37)
Patients with low comorbidityb
Male	1.35 (0.84–2.18)	1.70 (1.05–2.74)
Age 65–80	5.38 (2.93–9.85)	5.55 (3.03–10.18)
Age >80	9.05 (5.13–15.96)	9.83 (5.54–17.44)
Patients with moderate comorbidityb
Male	0.94 (0.70–1.26)	1.24 (0.92–1.68)
Age 65–80	2.81 (1.81–4.37)	2.83 (1.82–4.40)
Age >80	6.22 (4.17–9.28)	6.54 (4.36–9.81)
Patients with high comorbidityb
Male	0.85 (0.66–1.10)	0.98 (0.75–1.27)
Age 65–80	1.70 (1.15–2.51)	1.69 (1.14–2.51)
Age >80	2.82 (1.94–4.11)	2.81 (1.92–4.11)

Notes: The reference groups (not shown) were female patients, patients aged 18–64 years, and patients with low comorbidity.

a The adjustments differed between strata and included only the nonstratifying variable (either gender, age as a continuous variable, or comorbidity level). As an exception for age strata, additional adjustment for age as a continuous variable was made;

b Three levels of comorbidity were defined based on Charlson index scores of 0 (low), 1–2 (moderate), and 3 or more (high).