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Internal Medicine Journal 45 (2015)
B R I E F C O M M U N I C AT I O N S
Incidence of pulmonary embolism: a comparison of two Australian hospitals T. P. Shiraev,1,2 A. Omari3 and R. L. Rushworth1 1
Public Health, The University of Notre Dame, 2Department of Surgery, St George Hospital and 3Vascular Medicine, St Vincent’s Hospital, Sydney,
New South Wales, Australia
Key words Australia, deep venous thrombosis, private hospital, admission, venous thromboembolism. Correspondence Timothy P. Shiraev, Department of Surgery, St George Hospital, Gray Street, Kogarah, Sydney, NSW 2217, Australia. Email: [email protected]
Abstract In this retrospective observational study, we noted that there were significantly more admissions at the public than the private hospital due to both a principal (1.87 vs 0.83 per 1000, P < 0.001) and secondary diagnosis of pulmonary embolism (PE) (3.10 vs 2.01 per 1000, P = 0.002), with no difference in mortality. There was a highly significant increase in secondary PE diagnoses at the private hospital (R2 = 0.68, β = 0.14, P = 0.003) over the study period. Despite disparate rates of PE between the two hospitals, there was no difference in mortality, suggesting there may be an element of overdiagnosis.
Received 10 July 2014; accepted 11 December 2014. doi:10.1111/imj.12681
Venous thromboembolism (VTE), is a substantial cause of mortality in the community and in the hospital,1,2 with pulmonary embolism (PE) estimated to be responsible for the death of up to 5–10% of inpatients.3 Mortality from PE is preventable in over 50% of cases,4 making it the most common preventable cause of in-hospital mortality.5 While there are several preventive strategies that can be used by hospital staff to minimise the likelihood of a patient developing VTE,6 implementation of these remains poor.7 Hospital admissions due to PE have increased markedly in the USA, Europe, the United Kingdom and China,8–11 with a simultaneous decrease in mortality in these countries,11–13 the reasons for which remain unclear.8 We sought to assess patterns of distribution of PE within and between two hospitals (one public, one private) in Sydney, Australia, examining trends over time. We also sought to identify the burden of disease due to PE between different patient subgroups. We obtained data through the NSW Health ‘Admitted Patients Data Collection’ from two co-located hospitals in
Funding: None. Conflict of interest: None.
Sydney, one public and one private. Using the International Classification of Diseases (10th revision) codes I26.0 (pulmonary embolism with acute cor pulmonale) and I26.9 (pulmonary embolism without acute cor pulmonale), we extracted data on all separations (with the assumption that one separation, or discharge, equals one admission – and henceforth the word ‘admission’ will be used for ‘separation’) for PE between 2001/2002 and 2010/2011, and standardised them into a rate per 1000 admissions. Methods and statistical analyses have been described previously.12 Ethics approval for the study was obtained from the Human Research Ethics Committee of the University of Notre Dame, Australia. There were 822 admissions for principal diagnosis of PE in the two hospitals (644 at the public hospital and 168 at the private), and 1501 admissions (1092 at the public and 409 at the private hospital) for secondary diagnosis of PE. Of the public admissions for principal diagnosis of PE, 87.7% (565) were through the emergency department. Over the study period, there were significantly more admissions at the public than the private hospital due to both principal (1.87 ± 0.06 vs 0.83 ± 0.09 per 1000 admissions, P < 0.001) and secondary diagnosis of PE (3.10 ± 0.98 vs 2.01 ± 0.64 per 1000 admissions, © 2015 Royal Australasian College of Physicians
344
Brief Communications
Table 1 Admissions with a principal diagnosis of pulmonary embolism, 2001/2002–2010/2011 Total (%)
Figure 1 Admission rates for secondary diagnosis of pulmonary embolism (PE) between 2000/2001 and 2010/2011 in the public and private hospital, per 1000 admissions. Public hospital admissions are indicated by filled circles, and private hospital admissions by filled squares. ( ), Public; (■), private.
•
P = 0.002). The rate of principal diagnosis of PE did not change at the public or private hospital after linear regression (R2 = 0.20, β = −0.04, P = 0.20; R2 = 0.13, β = 3.24, P = 0.30 respectively). In contrast, while there was no significant increase in rate of admissions with a secondary diagnosis of PE in the public hospital (R2 = 0.03, β = 0.05, P = 0.96), there was a highly significant increase at the private hospital (R2 = 0.68, β = 0.14, P = 0.003; Fig. 1). Proportions of males and females were not significantly different (53.3 vs 46.7%, P = 0.064). Median age was significantly higher at the private hospital (63 vs 59 years, P = 0.009). The age range for all patients was 19–95 years (Table 1). Patients admitted to the public hospital through the emergency department were significantly less likely to have an inferior vena cava (IVC) filter inserted than elective admissions (3.1 vs 15.5%, P < 0.001). Patients at the private hospital were three times more likely to have an underlying diagnosis of deep venous thrombosis (DVT). In-hospital mortality occurred in 2.1% of all patients with a principal diagnosis of PE. The effect of hospital type on mortality was not significant on logistic regression controlling for age, sex, mode of admission, underlying comorbidities and surgical procedures (P = 0.139). Public hospital admission was a significant predictor of IVC filter insertion (P < 0.001) after logistic regression controlled for confounders. Patients had a median age of 66 years (range 13–99) and a median length of stay of 8 days. Of the patients, 33.2% were also diagnosed with a DVT (Table 2). For patients with a secondary diagnosis of PE, the median length of stay was significantly longer (7 vs 9
Total PE admissions In-hospital mortality† Sex Male Female Age group (years)
Internal Medicine Journal 45 (2015)
B R I E F C O M M U N I C AT I O N S
Incidence of pulmonary embolism: a comparison of two Australian hospitals T. P. Shiraev,1,2 A. Omari3 and R. L. Rushworth1 1
Public Health, The University of Notre Dame, 2Department of Surgery, St George Hospital and 3Vascular Medicine, St Vincent’s Hospital, Sydney,
New South Wales, Australia
Key words Australia, deep venous thrombosis, private hospital, admission, venous thromboembolism. Correspondence Timothy P. Shiraev, Department of Surgery, St George Hospital, Gray Street, Kogarah, Sydney, NSW 2217, Australia. Email: [email protected]
Abstract In this retrospective observational study, we noted that there were significantly more admissions at the public than the private hospital due to both a principal (1.87 vs 0.83 per 1000, P < 0.001) and secondary diagnosis of pulmonary embolism (PE) (3.10 vs 2.01 per 1000, P = 0.002), with no difference in mortality. There was a highly significant increase in secondary PE diagnoses at the private hospital (R2 = 0.68, β = 0.14, P = 0.003) over the study period. Despite disparate rates of PE between the two hospitals, there was no difference in mortality, suggesting there may be an element of overdiagnosis.
Received 10 July 2014; accepted 11 December 2014. doi:10.1111/imj.12681
Venous thromboembolism (VTE), is a substantial cause of mortality in the community and in the hospital,1,2 with pulmonary embolism (PE) estimated to be responsible for the death of up to 5–10% of inpatients.3 Mortality from PE is preventable in over 50% of cases,4 making it the most common preventable cause of in-hospital mortality.5 While there are several preventive strategies that can be used by hospital staff to minimise the likelihood of a patient developing VTE,6 implementation of these remains poor.7 Hospital admissions due to PE have increased markedly in the USA, Europe, the United Kingdom and China,8–11 with a simultaneous decrease in mortality in these countries,11–13 the reasons for which remain unclear.8 We sought to assess patterns of distribution of PE within and between two hospitals (one public, one private) in Sydney, Australia, examining trends over time. We also sought to identify the burden of disease due to PE between different patient subgroups. We obtained data through the NSW Health ‘Admitted Patients Data Collection’ from two co-located hospitals in
Funding: None. Conflict of interest: None.
Sydney, one public and one private. Using the International Classification of Diseases (10th revision) codes I26.0 (pulmonary embolism with acute cor pulmonale) and I26.9 (pulmonary embolism without acute cor pulmonale), we extracted data on all separations (with the assumption that one separation, or discharge, equals one admission – and henceforth the word ‘admission’ will be used for ‘separation’) for PE between 2001/2002 and 2010/2011, and standardised them into a rate per 1000 admissions. Methods and statistical analyses have been described previously.12 Ethics approval for the study was obtained from the Human Research Ethics Committee of the University of Notre Dame, Australia. There were 822 admissions for principal diagnosis of PE in the two hospitals (644 at the public hospital and 168 at the private), and 1501 admissions (1092 at the public and 409 at the private hospital) for secondary diagnosis of PE. Of the public admissions for principal diagnosis of PE, 87.7% (565) were through the emergency department. Over the study period, there were significantly more admissions at the public than the private hospital due to both principal (1.87 ± 0.06 vs 0.83 ± 0.09 per 1000 admissions, P < 0.001) and secondary diagnosis of PE (3.10 ± 0.98 vs 2.01 ± 0.64 per 1000 admissions, © 2015 Royal Australasian College of Physicians
344
Brief Communications
Table 1 Admissions with a principal diagnosis of pulmonary embolism, 2001/2002–2010/2011 Total (%)
Figure 1 Admission rates for secondary diagnosis of pulmonary embolism (PE) between 2000/2001 and 2010/2011 in the public and private hospital, per 1000 admissions. Public hospital admissions are indicated by filled circles, and private hospital admissions by filled squares. ( ), Public; (■), private.
•
P = 0.002). The rate of principal diagnosis of PE did not change at the public or private hospital after linear regression (R2 = 0.20, β = −0.04, P = 0.20; R2 = 0.13, β = 3.24, P = 0.30 respectively). In contrast, while there was no significant increase in rate of admissions with a secondary diagnosis of PE in the public hospital (R2 = 0.03, β = 0.05, P = 0.96), there was a highly significant increase at the private hospital (R2 = 0.68, β = 0.14, P = 0.003; Fig. 1). Proportions of males and females were not significantly different (53.3 vs 46.7%, P = 0.064). Median age was significantly higher at the private hospital (63 vs 59 years, P = 0.009). The age range for all patients was 19–95 years (Table 1). Patients admitted to the public hospital through the emergency department were significantly less likely to have an inferior vena cava (IVC) filter inserted than elective admissions (3.1 vs 15.5%, P < 0.001). Patients at the private hospital were three times more likely to have an underlying diagnosis of deep venous thrombosis (DVT). In-hospital mortality occurred in 2.1% of all patients with a principal diagnosis of PE. The effect of hospital type on mortality was not significant on logistic regression controlling for age, sex, mode of admission, underlying comorbidities and surgical procedures (P = 0.139). Public hospital admission was a significant predictor of IVC filter insertion (P < 0.001) after logistic regression controlled for confounders. Patients had a median age of 66 years (range 13–99) and a median length of stay of 8 days. Of the patients, 33.2% were also diagnosed with a DVT (Table 2). For patients with a secondary diagnosis of PE, the median length of stay was significantly longer (7 vs 9
Total PE admissions In-hospital mortality† Sex Male Female Age group (years)
