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Economic analysis of malnutrition and pressure ulcers in Queensland hospitals and residential aged care facilities

Banks, Merrilyn Dell (2008) Economic analysis of malnutrition and pressure ulcers in Queensland hospitals and residential aged care facilities. PhD thesis, Queensland University of Technology.

Abstract

Malnutrition is reported to be common in hospitals (10-60%), residential aged care facilities (up to 50% or more) and in free living individuals with severe or multiple disease (>10%) (Stratton et al., 2003). Published Australian studies indicate similar results (Beck et al., 2001, Ferguson et al., 1997, Lazarus and Hamlyn, 2005, Middleton et al., 2001, Visvanathan et al., 2003), but are generally limited in number, with none conducted across multiple centres or in residential aged care facilities. In Australia, there is a general lack of awareness and recognition of the problem of malnutrition, with currently no policy, standards or guidelines related to the identification, prevention and treatment of malnutrition. Malnutrition has been found to be associated with the development of pressure ulcers, but studies are limited. The consequences of the development of pressure ulcers include pain and discomfort for the patient, and considerable costs associated with treatment and increased length of stay. Pressure ulcers are considered largely preventable, and the demand for the establishment of appropriate policy, standards and guidelines regarding pressure ulcers has recently become important because the incidence and prevalence of pressure ulcers is increasingly being considered a parameter of quality of care. The aims of this study program were to firstly determine the prevalence of malnutrition and its association with pressure ulcers in Queensland Health hospitals and residential aged care facilities; and secondly to estimate the potential economic consequences of malnutrition by determining the costs arising from pressure ulcer attributable to malnutrition; and the economic outcomes of an intervention to address malnutrition in the prevention of pressure ulcers. The study program was conducted in two phases: an epidemiological study phase and an economic modelling study phase. In phase one, a multi centre, cross sectional audit of a convenience sample of subjects was carried out as part of a larger audit of pressure ulcers in Queensland public acute and residential aged care facilities in 2002 and again in 2003. Dietitians in 20 hospitals and six aged care facilities conducted single day nutritional status audits of 2208 acute and 839 aged care subjects using the Subjective Global Assessment, in either or both audits. Subjects excluded were obstetric, same day, paediatric and mental health patients. Weighted average proportions of nutritional status categories for acute and residential aged care facilities across the two audits were determined and compared. The effects of gender, age, facility location and medical specialty on malnutrition were determined via logistic regression. The effect of nutritional status on the presence of pressure ulcer was also determined via logistic regression. Logistic regression analyses were carried out using an analysis of correlated data approach with SUDAAN statistical package (Research Triangle Institute, USA) to account for the potential clustering effect of different facilities in the model. In phase two, an exploratory economic modelling framework was used to estimate the number of cases of pressure ulcer, total bed days lost to pressure ulcer and the economic cost of these lost bed days which could be attributed to malnutrition in Queensland public hospitals in 2002/2003. Data was obtained on the number of relevant separations, the incidence rate of pressure ulcer, the independent effect of pressure ulcers on length of stay, the cost of a bed day, and the attributable fraction of malnutrition in the development of pressure ulcers determined using the prevalence of malnutrition, the incidence rate of developing a pressure ulcer and the odds risk of developing a pressure ulcer when malnourished (as determined previously). A probabilistic sensitivity analysis approach was undertaken whereby probability distributions to the specified ranges for the key input parameters were assigned and 1000 Monte Carlo samples made from the input parameters. In an extension of the above model, an economic modelling framework was also used to predict the number of cases of pressure ulcer avoided, number of bed days not lost to pressure ulcer and economic costs if an intensive nutrition support intervention was provided to all nutritionally at risk patients in Queensland public hospitals in 2002/2003 compared to standard care. In addition to the above input parameters, data was obtained on the change in risk in developing a pressure ulcer associated with an intensive nutrition support intervention compared to standard care. The annual monetary cost of the provision of an intensive nutrition support intervention to at risk patients was modelled at a cost of AU$ 3.8-$5.4 million for additional food and nutritional supplements and staffing resources to assist patients with nutritional intake. A probabilistic sensitivity analysis approach was again taken. A mean of 34.7 + 4.0% and 31.4 + 9.5% of acute subjects and a median of 50.0% and 49.2% of residents of aged care facilities were found to be malnourished in Audits 1 and 2, respectively. Variables found to be significantly associated with an increased odds risk of malnutrition included: older age groups, metropolitan location of facility and medical specialty, in particular oncology and critical care. Malnutrition was found to be significantly associated with an increased odds risk of having a pressure ulcer, with the odds risk increasing with severity of malnutrition. In acute facilities moderate malnutrition had an odds risk of 2.2 (95% CI 1.6-3.0, p<0.001) and severe malnutrition had an odds risk of 4.8 (95% CI 3.2-7.2, p<0.001) of having a pressure ulcer. The overall adjusted odds risk of having a pressure ulcer when malnourished (total malnutrition) in an acute facility was 2.6 (95% CI 1.8-3.5, p<0.001). In residential facilities, where the audit results were presented separately, the same pattern applied with moderate malnutrition having an odds risk of 1.7 (95% CI 1.2-2.2, p<0.001) and 2.0 (95% CI 1.5-2.8, p<0.001); and severe malnutrition having an odds risk of 2.8 (95% CI1.2-6.6, p=0.02) and 2.2 (95% CI 1.5-3.1, p<0.001), for Audits 1 and 2 respectively. There was no statistical difference between these odds risk ratios between the audits. The overall adjusted odds risk of having a pressure ulcer when malnourished (total malnutrition) in a residential aged care facility was 1.9 (95% CI 1.3-2.7, p<0.001) and 2.0 (95% CI 1.5-2.7, p<0.001) for Audits 1 and 2 respectively. Being malnourished was also found to be significantly associated with an increased odds risk of having a higher stage and higher number of pressure ulcers, with the odds risk increasing with severity of malnutrition. The economic model predicted a mean of 3666 (Standard deviation 555) cases of pressure ulcer attributable to malnutrition out of a total mean of 11162 (Standard deviation 1210), or approximately 33%, in Queensland public acute hospitals in 2002/2003. The mean number of bed days lost to pressure ulcer that were attributable to malnutrition was predicted to be 16050, which represents approximately 0.67% of total patient bed days in Queensland public hospitals in 2002/2003. The corresponding mean economic costs of pressure ulcer attributable to malnutrition in Queensland public acute hospitals in 2002/2003 were estimated to be almost AU$13 million, out of a total mean estimated cost of pressure ulcer of AU$ 38 526 601. In the extension of the economic model, the mean economic cost of the implementation of an intensive nutrition support intervention was predicted to be a negative value ( -AU$ 5.4 million) with a standard deviation of $AU3.9 million, and interquartile range of –AU$ 7.7 million to –AU$ 2.5 million. Overall there were 951 of the 1000 re-samples where the economic cost is a negative value. This means there was a 95% chance that implementing an intensive nutrition support intervention was overall cost saving, due to reducing the cases of pressure ulcer and hospital bed days lost to pressure ulcer. This research program has demonstrated an independent association between malnutrition and pressure ulcers, on a background of a high prevalence of malnutrition, providing evidence to justify the elevation of malnutrition to a safety and quality issue for Australian healthcare organisations, similarly to pressure ulcers. In addition this research provides preliminary economic evidence to justify the requirement for consideration of healthcare policy, standards and guidelines regarding systems to identify, prevent and treat malnutrition, at least in the case of pressure ulcers in Australia.

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ID Code: 16966
Item Type: QUT Thesis (PhD)
Supervisor: Ash, Susan& Graves, Nicholas
Keywords: malnutrition, pressure ulcers, nutritional status, economic analysis, nutrition intervention
Divisions: Current > Institutes > Institute of Health and Biomedical Innovation
Institution: Queensland University of Technology
Deposited On: 16 Dec 2008 15:33
Last Modified: 29 Oct 2011 05:51

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