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Table 2 Mortality rates and involuntary early retirement in patients admitted to the stroke unit

From: The impact of a physician-staffed helicopter on outcome in patients admitted to a stroke unit: a prospective observational study

 

Number of persons under observation in each group (GEMS/HEMS)

Number of events

Total PYR

GEMS IR (per 100 PYR)

HEMS IR (per 100 PYR)

Unadjusted IRR (95% CI)

P value

Adjusteda, b, cIRR (95% CI)

P value

Mortality rates ( n=1068)

916/152

258/46

2854/474

9.04 (7.94–10.14)

9.71 (6.91–12.52)

1.09 (0.79–1.49)

0.60

1.09 (0.79–1.49)a

0.60

 Patients diagnosed with stroke (n = 702)

587/115

187/40

1773/341

10.55 (9.04–12.06)

11.73 (8.10–15.37)

1.12 (0.79–1.57)

0.53

1.07 (0.75–1.53)b

0.72

 Patients who underwent thrombolysis (n = 388)

330/58

96/16

1031/189

9.31 (7.45–11.17)

8.48 (4.33–12.64)

0.92 (0.54–1.57)

0.92

0.89 (0.50–1.56)c

0.68

Mortality rates with transport distance >63 km ( n=539)

441/98

114/36

1375/289

8.29 (6.77–9.81)

12.44 (8.37–16.50)

1.49 (1.02–2.16)

0.04

1.36 (0.93–1.98)a

0.11

 Patients diagnosed with stroke (n = 362)

287/75

88/32

864/206

10.18 (8.06–12.31)

15.51 (10.13–20.88)

1.49 (0.99–2.24)

0.05

1.29 (0.84–1.99)b

0.25

 Patients who underwent thrombolysis (n = 202)

167/35

43/12

541/113

7.95 (5.57–10.33)

10.64 (4.62–16.66)

1.33 (0.70–2.52)

0.39

1.03 (0.51–2.07)c

0.94

Mortality rates in directly referred patients

 Patients who underwent thrombolysis (n = 332)

277/55

79/16

871/174

9.07 (7.07–11.07)

9.19 (4.69–13.70)

1.02 (0.60–1.75)

0.94

0.97 (0.55–1.73)c

0.92

Involuntary early retirement

 Patients diagnosed with stroke (n = 101)

89/12

20/3

287/40

6.97 (3.92–10.03)

7.58 (0.00–16.16)

1.12 (0.33–3.77)

0.85

1.19 (0.27–5.26)b

0.81

 Directly referred patients who underwent thrombolysis (n = 44)

37/7

8/0

123/26

6.48 (1.99–10.98)

0.00 (−)

  1. GEMS ground emergency medical services, HEMS helicopter emergency medical services, PYR person-years at risk, IR incidence rate, IRR incidence rate ratio, CI confidence interval, NIHSS National Institute of Health Stroke Scale. Co-morbidity was defined as having at least one of the following conditions: diabetes, atrial fibrillation, hypertension, previous myocardial infarction, previous stroke
  2. aAdjusted for sex (male/female) and age (quadratic)
  3. bAdjusted for sex (male/female), age (quadratic), and co-morbidity (yes/no)
  4. cAdjusted for sex (male/female), age (quadratic), co-morbidity (yes/no), and NIHSS (continuous)