Adult-population incidence of severe sepsis in Australian and New Zealand intensive care units

Objective. To determine the population incidence and outcome of severe sepsis occurring in adult patients treated in Australian and New Zealand intensive care units (ICUs), and compare with recent retrospective estimates from the USA and UK. Design. Inception cohort study. Setting. Twenty-three closed multi-disciplinary ICUs of 21 hospitals (16 tertiary and 5 university affiliated) in Australia and New Zealand. Patients. A total of 5878 consecutive ICU admission episodes. Measurements and results. Main outcome measures were population-based incidence of severe sepsis, mortality at ICU discharge, mortality at 28 days after onset of severe sepsis, and mortality at hospital discharge. A total of 691 patients, 11.8 (95% confidence intervals 10.9-12.6) per 100 ICU admissions, were diagnosed with 752 episodes of severe sepsis. Site of infection was pulmonary in 50.3% of episodes and abdominal in 19.3% of episodes. The calculated incidence of severe sepsis in adults treated in Australian and New Zealand ICUs is 0.77 (0.76-0.79) per 1000 of population. 26.5% of patients with severe sepsis died in ICU, 32.4% died within 28 days of the diagnosis of severe sepsis and 37.5% died in hospital. Conclusion. In this prospective study, 11.8 patients per 100 ICU admissions were diagnosed with severe sepsis and the calculated annual incidence of severe sepsis in adult patients treated in Australian and New Zealand ICUs is 0.77 per 1000 of population. This figure for the population incidence falls in the lower range of recent estimates from retrospective studies in the U.S. and the U.K.

Differences in prevalence of pre-existing morbility between injured and non-injured populations

Objectives To identify and examine differences in pre-existing morbidity between injured and non-injured population-based cohorts. Methods Administrative health data from Manitoba, Canada, were used to select a population-based cohort of injured people and a sample of non-injured people matched on age, gender, aboriginal status and geographical location of residence at the date of injury. All individuals aged 18-64 years who had been hospitalized between 1988 and 1991 for injury (International Classification of Diseases, Ninth Edition, Clinical Modification (ICD-9-CM) code 800-995) (n = 21032), were identified from the Manitoba discharge database. The matched non-injured comparison group comprised individuals randomly selected 1: 1 from the Manitoba population registry. Morbidity data for the 12 months prior to the date of the injury were obtained by linking the two cohorts with all hospital discharge records and physician claims. Results Compared to the non-injured group, injured people had higher Charlson Comorbidity Index scores, 1.9 times higher rates of hospital admissions and 1.7 times higher rates of physician claims in the year prior to the injury. Injured people had a rate of admissions to hospital for a mental health disorder 9.3 times higher, and physician claims for a mental health disorder 3.5 times higher, than that of non-injured people. These differences were all statistically significant (P < 0.001). Conclusion Injured people were shown to differ from the general non-injured population in terms of pre-existing morbidity. Existing population estimates of the attributable burden of injury that are obtained by extrapolating from observed outcomes in samples of injured cases may overestimate the magnitude of the problem.