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Table 1 Study population, incidence rates and adjusted rate ratios of patients who developed HA-VTE and associated case fatality

From: Incidences and variations of hospital acquired venous thromboembolism in Australian hospitals: a population-based study

Characteristics All Patients HA-VTE HA-VTE case fatality
N (%) n (%) IR IRR (95 % CI)   n (%) % IRR (95 % CI)  
Admission typea
 Medical 573,042 (17.20 %) 2,565 (6.72 %) 4.5 1.00    245 (6.59 %) 9.6 % 1.00   
 Surgical 2,758,635 (82.80 %) 35,596 (93.28 %) 12.9 2.28 (2.19–2.38) d 3,471 (93.41 %) 9.8 % 1.05 (0.91–1.20)  
Sex
 Female 1,693,109 (50.82 %) 19,805 (51.90 %) 11.7 1.00    1,730 (46.56 %) 8.7 % 1.00   
 Male 1,638,568 (49.18 %) 18,356 (48.10 %) 11.2 0.93 (0.91–0.95) d 1,986 (53.44 %) 10.8 % 1.25 (1.17–1.33) d
Age
  > =75 years & <90 1,074,206 (32.24 %) 15,350 (40.22 %) 14.3 1.00    1,832 (49.30 %) 11.9 % 1.00   
  > =18 years & <35 years 396,444 (11.90 %) 1,742 (4.56 %) 4.4 0.53 (0.50–0.56) d 55 (1.48 %) 3.2 % 0.23 (0.17–0.30) d
  > =35 years & <55 years 707,274 (21.23 %) 5,612 (14.71 %) 7.9 0.83 (0.81–0.86) d 354 (9.53 %) 6.3 % 0.47 (0.41–0.52) d
  > =55 years & <75 years 1,153,753 (34.63 %) 15,457 (40.50 %) 13.4 1.13 (1.10–1.15) d 1,475 (39.69 %) 9.5 % 0.77 (0.72–0.83) d
Marital status
 Married 1,803,208 (54.12 %) 20,814 (54.54 %) 11.5 1.00    2,089 (56.22 %) 10.0 % 1.00   
 Single 1,372,496 (41.20 %) 15,730 (41.22 %) 11.5 0.90 (0.89–0.92) d 1,447 (38.94 %) 9.2 % 0.91 (0.85–0.98) c
 Unknown 155,973 (4.68 %) 1,617 (4.24 %) 10.4 0.83 (0.79–0.88) d 180 (4.84 %) 11.1 % 1.12 (0.96–1.31)  
Country of birth
 Australia and New Zealand 2,411,315 (72.38 %) 26,794 (70.21 %) 11.1 1.00    2,575 (69.29 %) 9.6 % 1.00   
 UK, US & Canada 223,710 (6.71 %) 2,873 (7.53 %) 12.8 1.01 (0.97–1.05)   271 (7.29 %) 9.4 % 0.90 (0.79–1.02)  
 Non-English Europe 317,973 (9.54 %) 4,546 (11.91 %) 14.3 0.98 (0.95–1.02)   493 (13.27 %) 10.8 % 0.98 (0.88–1.08)  
 North Africa 61,595 (1.85 %) 487 (1.28 %) 7.9 0.67 (0.61–0.73) d 47 (1.26 %) 9.7 % 1.09 (0.82–1.46)  
 Asia 101,485 (3.05 %) 996 (2.61 %) 9.8 0.76 (0.71–0.81) d 98 (2.64 %) 9.8 % 1.11 (0.90–1.36)  
 Others 215,599 (6.47 %) 2,465 (6.46 %) 11.4 0.94 (0.90–0.98) d 232 (6.24 %) 9.4 % 1.01 (0.88–1.16)  
Quartiles of SEIFA
 1st quartile (most disadvantaged) 913,712 (27.42 %) 9,482 (24.85 %) 10.4 1.00    939 (25.27 %) 9.9 % 1.00   
 2nd quartile (disadvantaged) 862,580 (25.89 %) 8,843 (23.17 %) 10.3 1.00 (0.97–1.03)   900 (24.22 %) 10.2 % 1.05 (0.95–1.16)  
 3rd quartile (advantaged) 827,343 (24.83 %) 9,701 (25.42 %) 11.7 0.98 (0.95–1.01)   1,011 (27.21 %) 10.4 % 1.12 (1.01–1.23) c
 4th quartile (most advantaged) 728,042 (21.85 %) 10,135 (26.56 %) 13.9 0.99 (0.95–1.03)   866 (23.30 %) 8.5 % 1.13 (1–1.27) c
Length of stay
 2–4 days 1,495,477 (44.89 %) 4,803 (12.59 %) 3.2 1.00    567 (15.26 %) 11.8 % 1.00   
 4–9 days 1,056,167 (31.70 %) 10,724 (28.10 %) 10.2 2.78 (2.69–2.88) d 816 (21.96 %) 7.6 % 0.69 (0.62–0.76) d
 Over 10 days 780,033 (23.41 %) 22,634 (59.31 %) 29.0 7.91 (7.65–8.17) d 2,333 (62.78 %) 10.3 % 0.82 (0.74–0.90) d
Major principal diagnostic diseasesb
 Cardiac arrhythmias 74,686 (2.24 %) 657 (1.72 %) 8.8 -    22 (0.59 %) 3.3 % -   
 Chronic pulmonary disease 129,030 (3.87 %) 853 (2.24 %) 6.6 -    92 (2.48 %) 10.8 % -   
 Coagulopathy 5,455 (0.16 %) 211 (0.55 %) 38.7 -    15 (0.40 %) 7.1 % -   
 Congestive heart failure 71,705 (2.15 %) 971 (2.54 %) 13.5 -    130 (3.50 %) 13.4 % -   
 Diabetes with chronic complication 41,956 (1.26 %) 464 (1.22 %) 11.1 -    58 (1.56 %) 12.5 % -   
 Malignancies 206,407 (6.20 %) 3,796 (9.95 %) 18.4 -    860 (23.14 %) 22.7 % -   
 Metastatic solid tumour 49,332 (1.48 %) 1,427 (3.74 %) 28.9 -    368 (9.90 %) 25.8 % -   
 Peripheral vascular disease 26,225 (0.79 %) 425 (1.11 %) 16.2 -    61 (1.64 %) 14.4 % -   
 Pulmonary circulation disorders 1,520 (0.05 %) 73 (0.19 %) 48.0 -    10 (0.27 %) 13.7 % -   
 Renal disease 8,736 (0.26 %) 103 (0.27 %) 11.8 -    14 (0.38 %) 13.6 % -   
 Rheumatic disease 9,811 (0.29 %) 176 (0.46 %) 17.9 -    9 (0.24 %) 5.1 % -   
Hospital type
 Public 2,704,301 (81.17 %) 31,160 (81.65 %) 11.5 1.00    3,362 (90.47 %) 10.8 % 1.00   
 Private 627,376 (18.83 %) 7,001 (18.35 %) 11.2 1.03 (0.85–1.25)   354 (9.53 %) 5.1 % 0.55 (0.43–0.71) d
Peer hospital groups-Public
 Principal referral (A1) 1,315,038 (48.63 %) 19,134 (61.41 %) 14.6 1.00    2,069 (61.54 %) 10.8 % 1.00   
 Ungrouped acute (A3) 73,569 (2.72 %) 765 (2.46 %) 10.4 0.67 (0.46–0.95) c 132 (3.93 %) 17.3 % 2.71 (1.48–4.97) d
 Major metro- & non-metropolitan (B) 839,827 (31.06 %) 7,958 (25.54 %) 9.5 0.73 (0.60–0.89) d 817 (24.30 %) 10.3 % 1.22 (0.91–1.64)  
 District group 1 (C1) 245,005 (9.06 %) 1,933 (6.20 %) 7.9 0.64 (0.51–0.81) d 198 (5.89 %) 10.2 % 1.75 (1.22–2.50) d
 District group 2 (C2) 230,862 (8.54 %) 1,370 (4.40 %) 5.9 0.48 (0.39–0.60) d 146 (4.34 %) 10.7 % 2.06 (1.44–2.95) d
Peer hospital groups-Private
 Major m 409,555 (65.28 %) 4,961 (70.86 %) 12.1 1.00    213 (60.17 %) 4.3 % 1.00   
 District (22) 217,821 (34.72 %) 2,040 (29.14 %) 9.4 1.03 (0.64–1.64)   141 (39.83 %) 6.9 % 1.36 (0.79–2.34)  
Local health district
 Metropolitan 2,300,073 (69.04 %) 29,779 (78.04 %) 12.9 1.00    2,814 (75.73 %) 9.4 % 1.00   
 Rural & Regional NSW 1,031,604 (30.96 %) 8,382 (21.96 %) 8.1 0.69 (0.59–0.81) d 902 (24.27 %) 10.8 % 1.18 (0.95–1.45)  
Total 3,331,677   38,161   11.4     3,716   9.7 %    
  1. 111,493 (3.2 %) cases were excluded due to missing items
  2. Incidence rates (IR) are crude and reported per 1000 patients
  3. Incidence rate ratios (IRR) and related confident intervals (CI) were obtained using a Poisson mixed model and adjusted for patient and hospital characteristics
  4. aIRRs were not adjusted for length of stay due to highly unbalanced distributions for medical versus surgical admissions
  5. bNo RR is reported since this characteristic has not been included in the Poisson mixed model
  6. cSignificant at 5 %; dsignificant at 1 %