Surgery (RMH) - Theses
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ItemUse of administrative data to create a colorectal cancer database( 2018)Background: Research into Colorectal cancer (CRC) require maintenance of clinical cancer databases with complex datasets. These are resource intensive, region specific, and compromised by reporting bias [1]. Administrative data are routinely captured for each hospital admission and may serve as an alternative source for populating databases. However, the accuracy of administrative data has not been fully explored and may vary by data item. The aims of this study included identifying a cohort of new CRC patients from administrative data, measuring its accuracy, and deriving coding algorithms to improve the accuracy of diagnoses, procedures and short-term outcomes. There has been much debate that major surgery, in particular for cancer patients, should be concentrated in tertiary centres, based on the premise that high volume centres achieve better outcomes. In this study, we investigated two hypotheses: that the majority of complex colorectal cancer resections are performed in major city hospitals and that the short-term outcomes are better in CSSANZ (Colorectal Surgical Society of Australia and New Zealand) hospitals. Large Inpatient administrative databases are a common source used to identify comorbidities recorded with International Classification of Disease (ICD) diagnostic codes. These data sources may be used to assess the effect of baseline comorbidity status on surgical care outcomes. In this study, we hypothesized that the ASA PS (American Society of Anaesthesiologists physical status) classification can predict short-term outcomes after a colorectal cancer resection when compared to the Elixhauser comorbidity index (ECI). Methods: A retrospective study was conducted to identify all new colorectal cancer resections at The Royal Melbourne Hospital from 1st of January 2008 to 31st of December 2013, using administrative data. Code combinations and algorithms were used to improve the accuracy of administrative data. These algorithms were utilized to identify an accurate cohort of colorectal cancer resection cases from the Victorian Admitted Episodes Dataset (VAED), between July 2008 to June 2013. The short-term outcomes and workloads were compared in public hospitals across the state of Victoria. The algorithms constructed were also utilised to identify an accurate cohort of CRC resection cases from Dr Foster Global Comparators Victorian dataset. ASA PS classification scores were identified from these cases. Multiple linear regression models were constructed to study the association between comorbidity indices and short-term outcomes. Results: It is possible to use administrative data to identify new colorectal cancer patients who have had a surgical resection, using specific coding algorithms. Administrative data has an accuracy of 80-100% for most data fields, and this accuracy can be improved using coding algorithms. An accurate cohort of colorectal cancer resection cases was identified from the VAED dataset. Seventy-three percent of CRC resections in the state were performed in metropolitan city hospitals. There was no significant difference in LOS (length of stay), mortality and reoperation rates between CSSANZ and non-CSSANZ hospitals. This study demonstrates that administrative data is both cost-effective and informative. The ASA PS model was indeed shown to be a strong predictor of the primary outcome: length of stay (LOS). The significant predictors of LOS were emergency operations, rectal cancer resections, ASA3 and patients age. The Elixhauser model was a better predictor than the ASA PS model. However, the full model adjusted for both the ECI and ASA PS grade was the best predictor of outcome. The study indeed showed the ability of the ASA PS classification to identify short-term clinical outcomes. Conclusion: These studies make the possibility of a Victorian CRC registry containing all surgical CRC patients a real possibility. Such a registry would enable outcomes research across the whole state with the possibility of data linkage to international administrative data sets.
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ItemAn international comparison of outcomes in acute diverticulitis( 2016)Acute diverticulitis is an increasingly common disease but the rate of emergency operative intervention for this condition is decreasing. Despite this decrease, there has been no obvious detriment in outcomes, which suggests that emergency operative intervention may not always improve outcomes. Operative intervention represents higher resource use compared with non-operative intervention. Excessive utilisation of healthcare resources without improvement of outcomes threatens the sustainability of healthcare. Value in healthcare has become a global priority in the developed world. The term ‘value’ represents the optimum use of healthcare resources for quality in outcomes. International variation in surgical practice and outcomes can highlight differences in the value of healthcare systems around the world. The drivers of resource utilisation in healthcare are complex and include financial incentives for surgical activity. The surgical community can improve the value of surgical care by reducing variation through use of the most efficient surgical practices. Administrative data are routinely collected for every inpatient admission in most countries. They are stored as alphanumeric codes for diagnoses and procedures that occur during each inpatient episode. Advances in computing have unlocked the ‘big data’ era and administrative data are currently the only feasible method for international comparisons. Their optimum use as a measurement tool remains undefined. This thesis aimed to explore the limits of administrative data in the context of acute diverticulitis. Specifically, it explored the use of administrative data in performing an international comparison of the emergency operative intervention rate between USA, England and Australia. It also examined their ability to provide meaningful outcomes data about acute diverticulitis admissions in each country. This sets a foundation for their use in surgical audit. Differences in international coding systems require the use of logic algorithms to more clearly define cohorts of uncomplicated and complicated diverticulitis in each country. These algorithms represent combinations of codes that could account for international differences in coding systems as well as predict variations in coding. These logic algorithms were developed after a chart review of Australian coding for diverticular disease. This focussed on how cases that were missed by only searching for diverticular codes, were actually coded. This novel method can be applied to outcomes research in other diseases. Outcomes for unplanned admissions for acute diverticulitis were explored in several hospitals in each of the three countries. The Dr Foster Global Comparators international dataset containing administrative data from hospitals in these countries was used. In addition to providing meaningful outcomes data for a patient with acute diverticulitis in each of these countries, we showed that Hartmann’s procedure remains the most common emergency operation for acute complicated diverticulitis in these countries. Multivariable logistic regression analysis found that Australia had the lowest propensity for emergency operation and that England had the highest inpatient mortality risk for acute diverticulitis. This demonstration of international variation suggests differences in international resource utilisation, their outcomes and therefore healthcare value. This thesis shows how administrative data can be used to measure international variation in the management and outcomes of surgical disease, which is a critical process in addressing healthcare resource utilisation and value.