Study participants and outcome
A total number of 2,601 patients fulfilled inclusion criteria (Figure 1). The study population comprised patients 18 to 99 years of age (mean=65.7, SD 16.8), of which 44.3% were female. Fewer than half the patients (42.5%) were transferred to the ICU. Overall 30-day mortality was 29.0%. Patients with palliative decisions and LOMT demonstrated a significantly higher 30-day mortality (65.5%), in comparison to patients without any treatment restrictions (21.2%). There were, however, no significant differences in 30-day mortality with regards to gender or level of care (age-adjusted p=0.37 and 0.31, respectively) (Additional file 4).
Type of ward
Most of the patients assessed by the MET were admitted to general medicine wards, followed by general surgery and neurological wards. The highest 30-day mortality was found in geriatric wards, followed by respiratory medicine and oncology wards. Overall, there was a similar number of patients from any medical and any surgical wards. MET assessed patients on surgical wards had significantly lower 30-day mortality (Table 1).
Table 1 – Outcome in relation to the type of ward for patients where MET was activated while hospitalised in 2010-2015 at Sahlgrenska University Hospital
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DEATH WITHIN 30 DAYS
Yes No
TYPE OF WARD (n=755) (n=1,846) p#
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MEDICAL WARDS 423 (56.0) 718 (38.9) <0.0001
General medicine 234 (31.0) 451 (24.4)
Oncology 68 ( 9.0) 99 ( 5.4)
Respiratory medicine 61 ( 8.1) 66 ( 3.6)
Cardiology 31 ( 4.1) 60 ( 3.3)
Rheumatology 15 ( 2.0) 29 ( 1.6)
Geriatric 13 ( 1.7) 10 ( 0.5)
Dermatology 1 ( 0.1) 3 ( 0.2)
SURGICAL WARDS 230 (30.5) 929 (50.3) <0.0001
General surgery 131 (17.4) 403 (21.8)
Urology 27 ( 3.6) 194 (10.5)
Transplantation 21 ( 2.8) 107 ( 5.8)
Orthopaedics 11 ( 1.5) 64 ( 3.5)
Gynaecology 14 ( 1.9) 54 ( 2.9)
Vascular surgery 18 ( 2.4) 51 ( 2.8)
Plastic surgery 2 ( 0.3) 25 ( 1.4)
Ear, nose and throat 6 ( 0.8) 25 ( 1.4)
Hand surgery 0 ( 0.0) 6 ( 0.3)
NEUROLOGICAL WARDS* 101 (13.4) 183 ( 9.9) 0.004
PSYCHIATRIC WARDS 1 ( 0.1) 16 ( 0.9) 0.20
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Results presented as number (percent)
* Neurological wards include neurology, spinal injury and neurosurgery patients
# Age-adjusted p-value for association with 30-day mortality
Previous medical history
The most frequently reported conditions in the patients' previous history were hypertension, cancer and lung diseases. Previous conditions associated with the highest 30-day mortality were cardiac failure, followed by haematological disease, angina pectoris and pulmonary disease. The following previous conditions were significantly associated with increased age-adjusted mortality during the subsequent 30 days: cancer, haematological disease, pulmonary disease, and liver disease. (Table 2).
Table 2 – Outcome in relation to previous medical history for patients where MET was activated while hospitalised in 2010-2015 at Sahlgrenska University Hospital
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DEATH WITHIN 30 DAYS
PREVIOUS Yes No
MEDICAL HISTORY* (n=755) (n=1,846) p#
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Cancer 276 (36.6) 502 (27.2) 0.0007
Hypertension 264 (35.0) 562 (30.4) 0.06
Angina pectoris 131 (17.4) 211 (11.4) 0.34
Myocardial infarction 93 (12.3) 163 ( 8.8) 0.80
Cardiac failure 120 (15.9) 171 ( 9.3) 0.04
Cardiac arrest 6 ( 0.8) 15 ( 0.8) 0.48
Other cardiac diseases** 199 (26.4) 349 (18.9) 0.95
Peripheral arterial disease 30 ( 4.0) 75 ( 4.1) 0.11
Stroke 82 (10.9) 167 ( 9.0) 0.36
Neurological disease 146 (19.4) 342 (18.5) 0.96
Haematological disease 69 ( 9.2) 110 ( 6.0) <0.0001
Diabetes 128 (17.0) 297 (16.1) 0.77
Endocrine disease 11 ( 1.5) 36 ( 2.0) 0.35
Rheumatic disease 53 ( 7.0) 134 ( 7.3) 0.60
Pulmonary disease 228 (30.2) 389 (21.1) 0.001
Respiratory insufficiency 39 ( 5.2) 80 ( 4.3) 0.98
Gastrointestinal disease 95 (12.6) 262 (14.2) 0.36
Liver disease 81 (10.7) 175 ( 9.5) 0.001
Pancreatic disease 20 ( 2.7) 46 ( 2.5) 0.60
Renal disease 78 (10.3) 183 ( 9.9) 0.79
Skeletal disease 100 (13.3) 187 (10.1) 0.27
Psychiatric disease 18 ( 2.4) 96 ( 5.2) 0.04
Addiction 56 ( 7.4) 192 (10.4) 1.00
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Results presented as number (percent)
* Information on previous medical history was missing for one patient who died within 30 days
** Including; cardiac arrhythmias, valvular heart diseases, pericardial disorders, cardiogenetic disorders or congenital heart defects, among others
# Age-adjusted p-value for association with 30-day mortality
Acute medical condition
The acute conditions most frequently associated with MET activation were sepsis and pneumonia. Acute conditions associated with the highest 30-day mortality were gastroenteritis, acute coronary syndrome, cardiac failure and renal failure. The following acute medical conditions were associated with increased age-adjusted mortality during the subsequent 30 days: cardiac failure, pneumonia and renal failure. Other infections (exemplified in the footnote), postoperative infection and other postoperative complications (exemplified in the footnote) were associated with a decreased mortality (Table 3).
Table 3 – Outcome in relation to acute medical condition for patients where MET was activated while hospitalised in 2010-2015 at Sahlgrenska University Hospital
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DEATH WITHIN 30 DAYS
ACUTE Yes No
MEDICAL CONDITION* (n=755) (n=1,846) p#
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Acute coronary syndrome 43 ( 5.7) 57 ( 3.1) 0.07
Cardiac failure 137 (18.2) 196 (10.8) 0.002
Pulmonary disease 73 ( 9.7) 110 ( 6.1) 0.03
Pulmonary embolism 35 ( 4.6) 75 ( 4.1) 0.67
Pneumonia 232 (30.8) 375 (20.7) <0.0001
Sepsis 254 (33.7) 592 (32.7) 0.32
Other infection** 110 (14.6) 454 (25.0) <0.0001
Gastroenteritis 10 ( 1.3) 10 ( 0.6) 0.10
Renal failure 82 (10.9) 121 ( 6.7) 0.0003
Clinically relevant haemorrhage 103 (13.7) 258 (14.2) 0.32
Postoperative infection 33 ( 4.4) 176 ( 9.7) <0.0001
Other postoperative complications*** 41 ( 5.4) 206 (11.4) <0.0001
Allergic reaction/anaphylaxis 0 ( 0.0) 34 ( 1.9) 0.04##
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Results presented as number (percent)
* Information on acute medical condition was missing for 1 and 33 patients in the two groups, respectively
** Including pancreatitis, cholecystitis, pyelonephritis, diverticulitis, peritonitis, pancytopenia, neutropenic fever, cerebral abscess or meningitis, among others
*** Including respiratory insufficiency, pneumothorax, deep vein thrombosis, postoperative cerebral insult, hypovolemia, intestinal perforation or anastomotic leakage, among others
# Age-adjusted p-value for association with 30-day mortality
## Firth bias correction used for likelihood penalty
Laboratory findings
The most frequent laboratory alteration was hyperglycaemia, followed by low haemoglobin, hypoxaemia and elevated serum creatinine. Laboratory findings associated with the highest 30-day mortality were hypoglycaemia, hypernatraemia, hyperkalaemia, acidosis and hyperlactatemia. The same laboratory findings were also associated with significantly increased age-adjusted mortality, along with elevated serum creatinine and hypoxaemia (Table 4).
Table 4 – Outcome in relation to laboratory findings for patients where MET was activated while hospitalised in 2010-2015 at Sahlgrenska University Hospital
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DEATH WITHIN 30 DAYS
LABORATORY Yes No
FINDINGS (n=755) (n=1,846) p#
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pH (224/596)*
<7.35 222 (41.8) 341 (27.3) <0.0001
>7.45 95 (17.9) 247 (19.8) 0.74
pCO2; kPa (221/591)
<4.6 149 (27.9) 316 (25.2) 0.18
>6.0 201 (37.6) 402 (32.0) 0.07
pO2; kPa (275/753)
<10.0 291 (60.6) 541 (49.5) 0.002
Haemoglobin (Hb); g/l (94/169)
<134 ♂ / <117 ♀ 484 (73.2) 1,260 (75.1) 0.40
Sodium (Na); mmol/l (73/173)
<137 302 (44.3) 744 (44.5) 0.53
>145 52 ( 7.6) 66 ( 3.9) 0.002
Potassium (K); mmol/l (78/177)
<3.6 121 (17.9) 327 (19.6) 0.53
>4.6 177 (26.1) 257 (15.4) <0.0001
Calcium (Ca); mmol/l (281/681)
<1.12 129 (27.2) 289 (24.8) 0.14
>1.32 29 ( 6.1) 51 ( 4.4) 0.14
Glucose; mmol/l (281/673)
<4.2 24 ( 5.1) 18 ( 1.5) <0.0001
>6.3 378 (79.7) 899 (76.6) 0.84
Creatinine; μmol/l (79/187)
>105 ♂ / >90 ♀ 387 (57.2) 718 (43.3) <0.0001
Lactate; mmol/l (288/701)
>2.2 222 (47.5) 345 (30.1) <0.0001
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Results presented as number (percent)
* Number of patients for whom information was missing in the two groups, respectively
# Age-adjusted p-value for association with 30-day mortality
Status on arrival of MET
The most frequent abnormalities in terms of vital parameters were hypoxia and tachypnoea. Patients who presented with these findings also had the highest 30-day mortality. The following vital parameters were associated with a significantly higher age-adjusted mortality risk during the subsequent 30 days: hypoxia, tachypnoea, tachycardia and unconsciousness (Table 5).
Table 5 – Outcome in relation to status on arrival of MET for patients where MET was activated while hospitalised in 2010-2015 at Sahlgrenska University Hospital
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DEATH WITHIN 30 DAYS
Yes No
VITAL PARAMETERS (n=755) (n=1,846) p#
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POX; % (15/40)*
<90 338 (45.7) 409 (22.6) <0.0001
RR; breaths/min (127/434)
<8 5 ( 0.8) 17 ( 1.2) 0.59
<30 237 (37.7) 303 (21.5) <0.0001
SBP; mmHg (43/63)
<90 164 (23.0) 336 (18.8) 0.06
HR; beats/min (22/36)
<40 3 ( 0.4) 9 ( 0.5) 0.92
>130 104 (14.2) 206 (11.4) 0.001
Consciousness; RLS (160/260)
≥4 48 ( 8.1) 73 ( 4.6) 0.0007
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Results presented as number (percent)
* Number of patients for whom information was missing in the two groups, respectively
# Age-adjusted p-value for association with 30-day mortality
POX, pulse oximetry; RR, respiratory rate; HR, heart rate; SBP, systolic blood pressure; RLS, reaction level scale
Independent factors associated with mortality
No important collinearity was found among candidate variables for association with 30-day mortality in the multivariable analysis. When using multiple imputations, age, type of ward, vital parameters, laboratory findings, previous medical history, and acute medical condition all contributed to the prediction of death. Apart from age, the factors with the highest odds ratio for death within 30 days were hypoglycaemia, haematological disease and hypoxia (Table 6).
Table 6 – Multivariable analysis of factors associated with 30-day mortality for patients where MET was activated while hospitalised in 2010-2015 at Sahlgrenska University Hospital, using multiple imputations
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OR (95% CI) p
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AGE (per year) 1.045 (1.038,1.053) <0.0001
TYPE OF WARD
Surgical wards 0.42 (0.34,0.51) <0.0001
VITAL PARAMETERS
POX <90 % 2.12 (1.72,2.61) <0.0001
RR >30 breaths/min 1.69 (1.34,2.13) <0.0001
RLS ≥4 1.92 (1.25,2.93) 0.003
LABORATORY FINDINGS
Sodium >145 mmol/l 1.91 (1.23,2.96) 0.004
Potassium >4.6 mmol/l 1.50 (1.17,1.92) 0.001
Glucose <4.2 mmol/l 4.30 (2.10,8.81) <0.0001
Lactate >2.2 mmol/l 1.71 (1.32,2.22) <0.0001
PREVIOUS MEDICAL HISTORY
Cancer 1.73 (1.40,2.13) <0.0001
Haematological disease 2.45 (1.71,3.50) 0.0001
Liver disease 1.89 (1.36,2.61) 0.0001
ACUTE MEDICAL CONDITION
Renal failure 1.71 (1.22,2.38) 0.002
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755 (29.0%) endpoints of 2,601 patients
OR, odds ratio; CI, confidence interval; POX, pulse oximetry; RR, respiratory rate; RLS, reaction level scale
The timing of death in relation to days after MET assessment
In order to illustrate in more detail the time of death after MET assessment, cumulative mortality curves for the thirteen factors independently associated with 30-day mortality (Table 6) are presented (Additional file 5). Overall, approximately half of the deaths occurred within the first four days after MET assessment (Figure 2).