Clinical outcomes, costs, knowledge and awareness of invasive meningococcal disease in South Australia.

Introduction: Despite appropriate antibiotic therapy, invasive meningococcal disease (IMD) still remains a leading infectious cause of death in childhood in developed countries. We aimed to 1. describe the clinical burden of sequelae following IMD and identify predictors of sequelae in South Australian children; 2. estimate and compare the inpatient costs and hospital service use associated with IMD by serogroup, age, sequelae, gender, previous medical diagnosis and clinical type in South Australian children; 3. assess community, parent and adolescent knowledge and awareness of IMD in South Australia. Methods: 1. Clinical details were collected from medical records of children admitted to a tertiary paediatric hospital in South Australia with a diagnosis of IMD from 2000 to 2011. Logistic regression was used to identify predictors of sequelae. 2. Inpatient costs were provided by the Health Informatics, Performance, Planning and Outcomes Unit at the Women’s and Children’s Hospital (WCH) in South Australia and inflated to 2011 Australian dollars using the medical and hospital services component of the Australian Consumer Price Index. Multivariate regression was used to determine predictors of higher inpatient costs, longer hospital stay and increased hospital service use. 3. A cross-sectional survey was conducted through face to face interviews, with 5200 households randomly selected in metropolitan and rural South Australia in 2012. 3055 interviews were conducted with questions regarding IMD knowledge and concern asked in the survey. The survey was developed by the staff members of Vaccinology and Immunology Research Trials Unit (VIRTU) at the WCH. Logistic regression analyses were performed with the survey data weighted to reflect 2011 Census figures. Results: 1. Of 109 children hospitalised with IMD, 54.1% were female and 11.9% Aboriginal. The majority of cases were caused by serogroup B (70.6%) with 9.2% caused by serogroup C, 2.7% caused by serogroup Y or W135. The serogroup of the remaining patients (17.4%) was unknown including 12 patients (11.0%) who had the undermined or ungroupable serogroup and 7 patients (6.4%) who were only clinically diagnosed. 37.6% (n=41) had sequelae with 41.3% (31/75) occurring following serogroup B disease and 22.2% (2/9) following serogroup C disease (p=0.280). Sequelae were defined as any complications related to IMD that were not resolved at hospital discharge or occurred after discharge. Children who developed sequelae, were followed up for 5 – 659 days (mean [95% CI]: 645.8 [403.3 to 939.3]) from the acute admission day to the discharge day of the acute hospitalisation if they were not followed up at the WCH OR to the day of their last IMD related outpatient visit. For children aged less than one year (n=31), sequelae occurred in 100% (4/4) of children with a history of prematurity compared to 44.4% (12/27) of full term infants (p=0.038). Fever ≥ 39°C on presentation to the hospital (OR [95% CI]: 4.5 [1.4 to 14.3]; p=0.012), a diagnosis of septicaemia with meningitis compared to septicaemia alone (OR [95% CI]: 15.5 [4.4 to 54.4]; p<0.001) and meningitis alone (OR [95% CI]: 7.8 [2.2 to 28.3]; p=0.002), and antibiotics given prior to admission (OR [95% CI]: 12.0 [2.0 to 71.6]; p=0.007), are independent predictors of developing sequelae following IMD. 2. Presence of sequelae, serogroup B infection, male gender, infants less than one year of age, and previous medical diagnosis were associated with higher inpatient costs and length of stay (LOS) in hospital (p<0.001) during the acute admission. Serogroup B cases incurred a significantly higher risk of IMD related readmissions (IRR [95% CI]: 21.1 [2.2 to 199.6], p=0.008). During the IMD related readmissions, children with serogroup B infection, male gender, diagnosis of septicaemia, infants less than one year of age, and no previous medical diagnosis were more likely to have higher inpatient costs and LOS (p<0.05). 3. Of 3055 participants in the community survey, 64.9% correctly answered at least two of three questions regarding severity, incidence and susceptibility of IMD and 33.7% expressed high concern about IMD. Age, country of birth, marital status, educational level, household income, residential area and socioeconomic status were associated with levels of IMD knowledge (p<0.05). Female gender, married/De Facto, low educational attainment, low household income, parents living in the rural area and low socioeconomic status were predicators of higher concern about IMD (p