Use of a Victorian statewide surveillance programme to evaluate the burden of healthcare-associated Staphylococcus aureus bacteraemia and Clostridioides difficile infection in patients with cancer.

BACKGROUND: Patients with cancer are at high risk for infection, but the epidemiology of healthcare-associated Staphylococcus aureus bacteraemia (HA-SAB) and Clostridioides difficile infection (HA-CDI) in Australian cancer patients has not previously been reported. AIMS: To compare the cumulative aggregate incidence and time trends of HA-SAB and HA-CDI in a predefined cancer cohort with a mixed statewide patient population in Victoria, Australia. METHODS: All SAB and CDI events in patients admitted to Victorian healthcare facilities between 1 July 2010 and 31 December 2018 were submitted to the Victorian Healthcare Associated Infection Surveillance System Coordinating Centre. Descriptive analyses and multilevel mixed-effects Poisson regression modelling were applied to a standardised data extract. RESULTS: In total, 10 608 and 13 118 SAB and CDI events were reported across 139 Victorian healthcare facilities, respectively. Of these, 89 (85%) and 279 (88%) were healthcare-associated in the cancer cohort compared with 34% (3561/10 503) and 66% (8403/12 802) in the statewide cohort. The aggregate incidence was more than twofold higher in the cancer cohort compared with the statewide cohort for HA-SAB (2.25 (95% confidence interval (CI): 1.74-2.77) vs 1.11 (95% CI: 1.07-1.15) HA-SAB/10 000 occupied bed-days) and threefold higher for HA-CDI (6.26 (95% CI: 5.12-7.41) vs 2.31 (95% CI: 2.21-2.42) HA-CDI/10 000 occupied bed-days). Higher quarterly diminishing rates were observed in the cancer cohort than the statewide data for both infections. CONCLUSIONS: Our findings demonstrate a higher burden of HA-SAB and HA-CDI in a cancer cohort when compared with state data and highlight the need for cancer-specific targets and benchmarks to meaningfully support quality improvement.

Burden and clinical outcomes of hospital-coded infections in patients with cancer: an 11-year longitudinal cohort study at an Australian cancer centre.

PURPOSE: Patients with cancer are at increased risk for infection, but the relative morbidity and mortality of all infections is not well understood. The objectives of this study were to determine the prevalence, incidence, time-trends and risk of mortality of infections associated with hospital admissions in patients with haematological- and solid-tumour malignancies over 11 years. METHODS: A retrospective, longitudinal cohort study of inpatient admissions between 1 January 2007 and 31 December 2017 at the Peter MacCallum Cancer Centre was conducted using administratively coded and patient demographics data. Descriptive analyses, autoregressive integrated moving average, Kaplan-Meier and Cox regression modelling were applied. RESULTS: Of 45,116 inpatient hospitalisations consisting of 3033 haematological malignancy (HM), 18,372 solid tumour neoplasm (STN) patients and 953 autologous haematopoietic stem cell transplantation recipients, 67%, 29% and 88% were coded with ≥ 1 infection, respectively. Gastrointestinal tract and bloodstream infections were observed with the highest incidence, and bloodstream infection rates increased significantly over time in both HM- and STN-cohorts. Inpatient length of stay was significantly higher in exposed patients with coded infection compared to unexposed in HM- and STN-cohorts (22 versus 4 days [p < 0.001] and 15 versus 4 days [p < 0.001], respectively). Risk of in-hospital mortality was higher in exposed than unexposed patients in the STN-cohort (adjusted hazard ratio [aHR] 1.61 [95% CI 1.41-1.83]; p < 0.001)) and HM-cohort (aHR 1.30 [95% CI 0.90-1.90]; p = 0.166). CONCLUSION: Infection burden among cancer patients is substantial and findings reflect the need for targeted surveillance in high-risk patient groups (e.g. haematological malignancy), in whom enhanced monitoring may be required to support infection prevention strategies.

A population-based analysis of attributable hospitalisation costs of invasive fungal diseases in haematological malignancy patients using data linkage of state-wide registry and costing databases: 2009-2015.

BACKGROUND: Invasive fungal diseases (IFD) are associated with significant treatment-related costs in patients with haematological malignancies (HM). OBJECTIVES: The objectives of this study were to characterise the gross and attributable hospitalisation costs of a variety of IFD in patients with HM by linking state-wide hospital administrative and costing datasets. PATIENTS/METHODS: We linked the Victorian Admitted Episodes Dataset, Victorian Cancer Registry and the Victorian Cost Data Collection from 1 July 2009 to 30 June 2015. IFD cases and uninfected controls were matched 1:1 based on age within ten years, same underlying HM and length of stay prior to IFD diagnosis. The cost difference between surviving cases and controls, indexed to 2019 Australian dollars (AUD) calculated twelve months from IFD diagnosis, was determined using Poisson and negative binomial regression (NBR). RESULTS: From 334 matched pairs, the gross hospitalisation cost of cases was AUD$67 277 compared to AUD$51 158 among uninfected controls, associated with an excess median hospitalisation cost of AUD$16 119 (P < .001) attributable to IFD, approximating to USD$11 362 and €10 154 at purchasing power parity. Median attributable costs were highest for patients with invasive aspergillosis (AUD$55 642; P < .001) and mucormycosis (AUD$51 272; P = .043) followed by invasive candidiasis AUD$24 572 (P < .001). No change in median excess attributable costs was observed over the study period (P = .90) Analyses by NBR revealed a 1.36-fold increase (P < .001) in total hospitalisation costs among cases as compared to controls twelve months from IFD diagnosis. CONCLUSION: Invasive aspergillosis and mucormycosis have high attributable hospitalisation costs but the overall excess IFD cost of AUD$16 119 is modest, potentially reflecting missed or miscoded fungal episodes arguing for better quality surveillance data at hospital level.

A population-based analysis of invasive fungal disease in haematology-oncology patients using data linkage of state-wide registries and administrative databases: 2005 - 2016.

BACKGROUND: Little is known about the morbidity and mortality of invasive fungal disease (IFD) at a population level. The aim of this study was to determine the incidence, trends and outcomes of IFD in all haematology-oncology patients by linking Victorian hospital data to state-based registries. METHODS: Episodes of IFD complicating adult haematological malignancy (HM) and haematopoietic stem cell transplantation (HSCT) patients admitted to Victorian hospitals from 1st July 2005 to 30th June 2016 were extracted from the Victorian Admitted Episodes Dataset and linked to the date of HM diagnosis from the Victorian Cancer Registry and mortality from the Victorian Death Index. Descriptive analyses and regression modelling were used. RESULTS: There were 619,702 inpatient-episodes among 32,815 HM and 1,765 HSCT-patients. IFD occurring twelve-months from HM-diagnosis was detected in 669 (2.04%) HM-patients and 111 (6.29%) HSCT-recipients, respectively. Median time to IFD-diagnosis was 3, 5, 15 and 22 months in acute myeloid leukaemia, acute lymphoblastic leukaemia, Hodgkin lymphoma and multiple myeloma, respectively. Median survival from IFD-diagnosis was 7, 7 and 3 months for invasive aspergillosis, invasive candidiasis and mucormycosis, respectively. From 2005-2016, IFD incidence decreased 0.28% per 1,000 bed-days. Fungal incidence coincided with spring peaks on time-series analysis. CONCLUSIONS: Data linkage is an efficient means of evaluating the epidemiology of a rare disease, however the burden of IFD is likely underestimated, arguing for better quality hospital level surveillance data to improve management strategies.

Disease and economic burden of infections in hospitalised children in New South Wales, Australia.

Objectives To describe the burden of disease and hospitalisation costs in children with common infections using statewide administrative data. Methods We analysed hospitalisation prevalence and costs for 10 infections: appendicitis, cellulitis, cervical lymphadenitis, meningitis, osteomyelitis, pneumonia, pyelonephritis, sepsis, septic arthritis, and urinary tract infections in children aged <18 years admitted to hospital within New South Wales, Australia, using an activity-based management administrative dataset over three financial years (1 July 2016-30 June 2019). Results Among 339 077 admissions, 28 748 (8.48%) were coded with one of the 10 infections, associated with a total hospitalisation cost of AUD230 905 190 and a per episode median length-of-stay of 3 bed-days. Pneumonia was the most prevalent coded infection (3.1% [n = 10 524] of all admissions), followed by appendicitis (1.61%; n = 5460), cellulitis (1.22%; n = 4126) and urinary tract infections (0.94%; n = 3193). Eighty per cent of children (n = 22 529) were admitted to a non-paediatric hospital. Mean costs were increased 1.18-fold per additional bed-day, 2.14-fold with paediatric hospital admissions, and 5.49-fold with intensive care unit admissions, which were both also associated with greater total bed-day occupancy. Indigenous children comprised 9.7% of children admitted with these infections, and mean per episode costs, and median bed-days were reduced compared with non-Indigenous children (0.84 [95% CI 0.78, 0.89] and 3 (IQR: 2,5) vs 2 (IQR: 2,4), respectively. Conclusions Infections in children requiring hospitalisation contributea substantial burden of disease and cost to the community. This varies by infection, facility type, and patient demographics, and this information should be used to inform and prioritise programs to improve care for children.

Performance of ICD-10-AM codes for quality improvement monitoring of hospital-acquired pneumonia in a haematology-oncology casemix in Victoria, Australia.

BACKGROUND: The Australian hospital-acquired complication (HAC) policy was introduced to facilitate negative funding adjustments in Australian hospitals using ICD-10-AM codes. OBJECTIVE: The aim of this study was to determine the positive predictive value (PPV) of the ICD-10-AM codes in the HAC framework to detect hospital-acquired pneumonia in patients with cancer and to describe any change in PPV before and after implementation of an electronic medical record (EMR) at our centre. METHOD: A retrospective case review of all coded pneumonia episodes at the Peter MacCallum Cancer Centre in Melbourne, Australia spanning two time periods (01 July 2015 to 30 June 2017 [pre-EMR period] and 01 September 2020 to 28 February 2021 [EMR period]) was performed to determine the proportion of events satisfying standardised surveillance definitions. RESULTS: HAC-coded pneumonia occurred in 3.66% (n = 151) of 41,260 separations during the study period. Of the 151 coded pneumonia separations, 27 satisfied consensus surveillance criteria, corresponding to an overall PPV of 0.18 (95% CI: 0.12, 0.25). The PPV was approximately three times higher following EMR implementation (0.34 [95% CI: 0.19, 0.53] versus 0.13 [95% CI: 0.08, 0.21]; p = .013). CONCLUSION: The current HAC definition is a poor-to-moderate classifier for hospital-acquired pneumonia in patients with cancer and, therefore, may not accurately reflect hospital-level quality improvement. Implementation of an EMR did enhance case detection, and future refinements to administratively coded data in support of robust monitoring frameworks should focus on EMR systems. IMPLICATIONS: Although ICD-10-AM data are readily available in Australian healthcare settings, these data are not sufficient for monitoring and reporting of hospital-acquired pneumonia in haematology-oncology patients.

Classification performance of administrative coding data for detection of invasive fungal infection in paediatric cancer patients.

BACKGROUND: Invasive fungal infection (IFI) detection requires application of complex case definitions by trained staff. Administrative coding data (ICD-10-AM) may provide a simplified method for IFI surveillance, but accuracy of case ascertainment in children with cancer is unknown. OBJECTIVE: To determine the classification performance of ICD-10-AM codes for detecting IFI using a gold-standard dataset (r-TERIFIC) of confirmed IFIs in paediatric cancer patients at a quaternary referral centre (Royal Children's Hospital) in Victoria, Australia from 1st April 2004 to 31st December 2013. METHODS: ICD-10-AM codes denoting IFI in paediatric patients (<18-years) with haematologic or solid tumour malignancies were extracted from the Victorian Admitted Episodes Dataset and linked to the r-TERIFIC dataset. Sensitivity, positive predictive value (PPV) and the F1 scores of the ICD-10-AM codes were calculated. RESULTS: Of 1,671 evaluable patients, 113 (6.76%) had confirmed IFI diagnoses according to gold-standard criteria, while 114 (6.82%) cases were identified using the codes. Of the clinical IFI cases, 68 were in receipt of ≥1 ICD-10-AM code(s) for IFI, corresponding to an overall sensitivity, PPV and F1 score of 60%, respectively. Sensitivity was highest for proven IFI (77% [95% CI: 58-90]; F1 = 47%) and invasive candidiasis (83% [95% CI: 61-95]; F1 = 76%) and lowest for other/unspecified IFI (20% [95% CI: 5.05-72%]; F1 = 5.00%). The most frequent misclassification was coding of invasive aspergillosis as invasive candidiasis. CONCLUSION: ICD-10-AM codes demonstrate moderate sensitivity and PPV to detect IFI in children with cancer. However, specific subsets of proven IFI and invasive candidiasis (codes B37.x) are more accurately coded.

The current scope of healthcare-associated infection surveillance activities in hospitalized immunocompromised patients: a systematic review.

BACKGROUND: Immunocompromised patients are at increased risk of acquiring healthcare-associated infections (HAIs) and often require specialized models of care. Surveillance of HAIs is essential for effective infection-prevention programmes. However, little is known regarding standardized or specific surveillance methods currently employed for high-risk hospitalized patients. METHODS: A systematic review adopting a narrative synthesis approach of published material between 1 January 2000 and 31 March 2018 was conducted. Publications describing the application of traditional and/or electronic surveillance of HAIs in immunocompromised patient settings were identified from the Ovid MEDLINE®, Ovid Embase® and Elsevier Scopus® search engines [PROSPERO international prospective register of systematic reviews (registration ID: CRD42018093651)]. RESULTS: In total, 2708 studies were screened, of whom 17 fulfilled inclusion criteria. Inpatients diagnosed with haematological malignancies were the most-represented immunosuppressed population. The majority of studies described manual HAI surveillance utilizing internationally accepted definitions for infection. Chart review of diagnostic and pathology reports was most commonly employed for case ascertainment. Data linkage of disparate datasets was performed in two studies. The most frequently monitored infections were bloodstream infections and invasive fungal disease. No surveillance programmes applied risk adjustment for reporting surveillance outcomes. CONCLUSIONS: Targeted, tailored monitoring of HAIs in high-risk immunocompromised settings is infrequently reported in current hospital surveillance programmes. Standardized surveillance frameworks, including risk adjustment and timely data dissemination, are required to adequately support infection-prevention programmes in these populations.