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Nicholas Graves

Publications and source records attributed to Nicholas Graves.

15 recordsLinked to original sources
PubMed2006

Cost-effectiveness analyses and modelling the lifetime costs and benefits of health-behaviour interventions.

BACKGROUND: We describe an approach to estimating the cost-effectiveness of an intervention that changes health behaviour. The method captures the lifetime costs and benefits incurred by participants in an ongoing cluster-randomized controlled trial of an intervention that aims to change health behaviour. The existing literature only captures short-term economic and health outcomes. METHODS: We develop a state-transition Markov model of how individuals move between different health behaviour states over time. We simulate hypothetical data to describe the costs and health benefits of the intervention, illustrate how the data collected in the ongoing randomized controlled trial can be used and demonstrate how incremental cost-effectiveness ratios are estimated. RESULTS: On the basis of the simulated (i.e. hypothetical) data, we estimate the cost per quality-adjusted life year. The estimate reflects the lifetime health and economic consequences of the intervention. DISCUSSION: The method used for the cost-effectiveness analysis described in this paper is appropriate for investigating whether interventions that change health behaviour in relation to chronic diseases represent good value for money as compared to alternative uses of scarce healthcare resources.

Adult↗
PubMed2006

Costs of surgical site infections that appear after hospital discharge.

Data were collected from surgical patients in the hospital and on 4 occasions postdischarge. The incidence of postdischarge surgical site infection was 8.46%. Strong evidence showed that these infections caused minor additional costs, which contradicts existing literature. We discuss why previous studies might have overstated costs.

Australia↗
PubMed2005

Re-interpreting the data on the cost and effectiveness of population screening for colorectal cancer in Australia.

Three studies report estimates of the cost and effectiveness of alternate strategies for screening the average-risk Australian population for colorectal cancer. The options considered are faecal occult blood testing, double contrast barium enema, sigmoidoscopy and colonoscopy. At present, there is no consensus over which screening method is optimal by the economic criterion. Also, the existing studies report a mixture of average and incremental cost-effectiveness ratios derived from data collected between 1994 and 2002. We suggest average cost-effectiveness ratios are not useful for decision-making and illustrate how they differ from the preferred incremental cost-effectiveness ratio. We then update the cost data reported in the three studies to 2002 prices and calculate incremental cost-effectiveness ratios where not previously available. Our re-analysis of one study contradicts the conclusions drawn by the authors, who had only calculated average cost-effectiveness ratios. In particular, we find their recommendation of population screening with colonoscopy would cause, annually, between 33 and 1,322 years of life to be lost and between M17 dollars and M87 dollars to be wasted. Based on updated cost data and the incremental analysis, our findings indicate that population screening using biennial faecal occult blood testing (39,459 dollars per life-year gained), annual faecal occult blood testing (30,556 dollars per life-year gained) and colonoscopy (26,587 dollars per life-year gained) are cost-effective. Hence, the decision over which method of screening is optimal remains ambiguous across the three studies. We recommend policy-makers choose the study they believe produces the most accurate estimates of cost and health effect, identify their willingness to pay for health benefits and consider other issues relevant to the decision.

Editorial↗
PubMed2005

Correcting for bias when estimating the cost of hospital-acquired infection: an analysis of lower respiratory tract infections in non-surgical patients.

Hospital acquired infections (HAI) are costly but many are avoidable. Evaluating prevention programmes requires data on their costs and benefits. Estimating the actual costs of HAI (a measure of the cost savings due to prevention) is difficult as HAI changes cost by extending patient length of stay, yet, length of stay is a major risk factor for HAI. This endogeneity bias can confound attempts to measure accurately the cost of HAI. We propose a two-stage instrumental variables estimation strategy that explicitly controls for the endogeneity between risk of HAI and length of stay. We find that a 10% reduction in ex ante risk of HAI results in an expected savings of pound 693 ($ US 984).

Bias↗
PubMed2005

Effect of pressure ulcers on length of hospital stay.

OBJECTIVE: To identify the independent effect of pressure ulcers on excess length of stay and control for all observable factors that may also contribute to excess length of stay. Hospitalized patients who develop a pressure ulcer during their hospital stay are at a greater risk for increased length of stay as compared with patients who do not. DESIGN: Cross-sectional, observational study. SETTING: Tertiary-care referral and teaching hospital in Australia. PATIENTS: Two thousand hospitalized patients 18 years and older who had a minimum stay in the hospital of 1 night and admission to selected clinical units. METHODS: Two thousand participants were randomly selected from 4,500 patients enrolled in a prospective survey conducted between October 2002 and January 2003. Quantile median robust regression was used to assess risk factors for excess length of hospital stay. RESULTS: Having a pressure ulcer resulted in a median excess length of stay of 4.31 days. Twenty other variables were statistically significant at the 5% level in the final model. CONCLUSIONS: Pressure ulcers make a significant independent contribution to excess length of hospitalization beyond what might be expected based on admission diagnosis. However, our estimates were substantially lower than those currently used to make predictions of the economic costs of pressure ulcers; existing estimates may overstate the true economic cost.

Adult↗
PubMed2004

Would universal antenatal screening for HIV infection be cost-effective in a setting of very low prevalence? Modelling the data for Australia.

BACKGROUND: The economics of universal antenatal human immunodeficiency virus (HIV) screening should be explored if mother-to-child transmission of HIV occurs, the health-service infrastructure for universal screening exists, and optimal risk-reducing treatments can be supplied. METHODS: We evaluated a hypothetical cohort of the antenatal population of Australia during 2001-2002, to examine whether universal antenatal HIV screening is cost-effective in this setting. A quasi-societal perspective was adopted, secondary data sources were used, and sensitivity analyses were undertaken. Costs and benefits incurred in the future were discounted to their present value. RESULTS: The intervention would be cost-effective if the prevalence of undiagnosed HIV in the currently unscreened Australian antenatal population was >or=0.004372%. We predict 6.95 new diagnoses of HIV, 1.73 infections avoided, and 46.97 discounted-life-years gained. Applying favorable and unfavorable values for key variables suggests that the prevalence at which the intervention would be cost-effective is 0.0016%-0.0106%. CONCLUSIONS: Universal antenatal HIV screening would be cost-effective at a very low prevalence and would generate net benefits under many scenarios; accurate statistics on the true prevalence of HIV in the currently unscreened antenatal population are required.

Australia↗
PubMed2004

Economics and preventing hospital-acquired infection.

The economics of preventing hospital-acquired infections is most often described in general terms. The underlying concepts and mechanisms are rarely made explicit but should be understood for research and policy-making. We define the key economic concepts and specify an illustrative model that uses hypothetical data to identify how two related questions might be addressed: 1) how much should be invested for infection control, and 2) what are the most appropriate infection-control programs? We aim to make explicit the economics of preventing hospital-acquired infections.

Cost-Benefit Analysis↗
PubMed2003

The cost effectiveness of universal antenatal screening for HIV in New Zealand.

OBJECTIVE: To model the incremental costs and benefits of a universal antenatal HIV screening programme in New Zealand (NZ). DESIGN: Cost effectiveness analysis, including only health service costs, using secondary data sources and expert opinion. Uncertainty assessed in multi-way sensitivity analyses. SETTING: The NZ Health Care System. SUBJECTS: Antenatal population of NZ. INTERVENTION: Universal antenatal HIV screening programme. MAIN OUTCOME MEASURES: Incremental cost per true-positive HIV case detected in mothers; incremental cost per HIV case avoided in babies; and incremental cost per discounted life-year gained, for mothers and babies, due to screening. RESULTS: Using base case values the application of universal screening would cost an additional $NZ 723 607 ($US 307 917) and would lead to the identification of an additional 6.25 true-positive women. After terminations have been excluded, the screening programme would detect five HIV exposed babies. There would be 1.15 avoided cases of HIV infection in babies and a net gain of 41.97 discounted life-years, for mothers and babies combined. The cost per incremental HIV-positive woman detected was $NZ 115 859 ($US 49 301), HIV infected baby avoided $NZ 629 669 ($US 267 944) and discounted life-year gained $NZ 17 241 ($US 7336). CONCLUSION: The discounted cost per life gained in NZ compares favourably to estimates reported in studies of similar interventions in other developed countries and other health care interventions in NZ. The decision of whether to implement universal screening in NZ would be clarified if the prevalence of antenatal HIV infection was known and policy makers identified their willingness to pay for an additional life-year gained.

Cost-Benefit Analysis↗
PubMed2003

The prevalence and estimates of the cumulative incidence of hospital-acquired infections among patients admitted to Auckland District Health Board Hospitals in New Zealand.

OBJECTIVES: To report the pooled results of seven prevalence surveys of hospital-acquired infections conducted between November 1996 and November 1999, and to use the data to predict the cumulative incidence of hospital-acquired infections in the same patient group. DESIGN: The summary and modeling of data gathered from the routine surveillance of the point prevalence of hospital-acquired infections. SETTING: Auckland District Health Board Hospitals (Auckland DHBH), the largest publicly funded hospital group in New Zealand supplying secondary and tertiary services. PATIENTS: All inpatients. METHOD: Point-prevalence surveys were conducted including all patients in Auckland DHBH. Standard definitions of hospital-acquired infection were used. The data from the seven surveys were pooled and used in a modeling exercise to predict the cumulative incidence of hospital-acquired infection. An existing method for the conversion of prevalence to cumulative incidence was applied. Results are presented for all patients and stratified by clinical service and site of hospital-acquired infection. RESULTS: The underlying patterns of hospital-acquired infection by site and service were stable during the seven time periods. The prevalence rate for all patients was 9.5%, with 553 patients identified with one or more hospital-acquired infections from a population of 5,819. The predicted cumulative incidence for all patients was 6.33% (95% confidence interval, 6.20% to 6.46%). CONCLUSIONS: The prevalence and the predicted cumulative incidence are similar to rates reported in the international literature. The validity of the predicted cumulative incidence derived here is not known. If it were accurate, then the application of this method would represent a cost-effective alternative to incidence studies.

Cross Infection↗
PubMed2003

Modeling the costs of hospital-acquired infections in New Zealand.

OBJECTIVE: To model the economic costs of hospital-acquired infections (HAIs) in New Zealand, by type of HAI. DESIGN: Monte Carlo simulation model. SETTING: Auckland District Health Board Hospitals (DHBH), the largest publicly funded hospital group in New Zealand supplying secondary and tertiary services. Costs are also estimated for predicted HAIs in admissions to all hospitals in New Zealand. PATIENTS: All adults admitted to general medical and general surgical services. METHOD: Data on the number of cases of HAI were combined with data on the estimated prolongation of hospital stay due to HAI to produce an estimate of the number of bed days attributable to HAI. A cost per bed day value was applied to provide an estimate of the economic cost. Costs were estimated for predicted infections of the urinary tract, surgical wounds, the lower and upper respiratory tracts, the bloodstream, and other sites, and for cases of multiple sites of infection. Sensitivity analyses were undertaken for input variables. RESULTS: The estimated costs of predicted HAIs in medical and surgical admissions to Auckland DHBH were dollar 10.12 (US dollar 4.56) million and dollar 8.64 (US dollar 3.90) million, respectively. They were dollar 51.35 (US dollar 23.16) million and dollar 85.26 (US dollar 38.47) million, respectively, for medical and surgical admissions to all hospitals in New Zealand. CONCLUSIONS: The method used produces results that are less precise than those of a specifically designed study using primary data collection, but has been applied at a lower cost The estimated cost of HAIs is substantial but only a proportion of infections can be avoided. Further work is required to identify the most cost-effective strategies for the prevention of HAI.

Costs and Cost Analysis↗
PubMed2002

Cost data for individual patients included in clinical studies: no amount of statistical analysis can compensate for inadequate costing methods.

This work examines the quality of the cost methods used to derive patient level costs in 45 economic evaluations conducted alongside randomised controlled trials. The perspective of the cost analysis, the methods used to determine quantities and values of resources and how the cost data were reported are examined. The reported costing methods were found to be of poor quality, highlighting the need for greater rigour. Researchers to date appear more concerned with whether cost data have been subjected to the appropriate statistical analysis. For the results of clinical studies to be valid both cost methods and the methods used for the statistical analysis of cost data should be of a high quality.

Cost-Benefit Analysis↗
PubMedDate not supplied

Modeling the economic losses from pressure ulcers among hospitalized patients in Australia.

The objective of this study was to predict the number of cases of pressure ulcer, the bed days lost, and the economic value of these losses at Australian public hospitals. All adults (>or= 18 years of age) with a minimum stay of 1 night and discharged from selected clinical units from all Australian public hospitals in 2001-02 were included in the study. The main outcome measures were the number of cases of pressure ulcer, bed days lost to pressure ulcer, and economic value of these losses. We predict a median of 95,695 cases of pressure ulcer with a median of 398,432 bed days lost, incurring median opportunity costs of AU$285 M. The number of cases, and so costs, were greatest in New South Wales and lowest in Australian Capitol Territory. We conclude that pressure ulcers represent a serious clinical and economic problem for a resource-constrained public hospital system. The most cost-effective, risk-reducing interventions should be pursued up to a point where the marginal benefit of prevention is equalized with marginal cost. By preventing pressure ulcers, public hospitals can improve efficiency and the quality of the patient's experience and health outcome.

Adult↗