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Biomedical subjects

Alastair M Gray

Publications and source records attributed to Alastair M Gray.

7 recordsLinked to original sources
PubMed2006

Population-based study of determinants of initial secondary care costs of acute stroke in the United Kingdom.

BACKGROUND AND PURPOSE: To determine the cost-effectiveness of specific interventions to prevent or treat acute stroke, it is necessary to know the costs of stroke according to patient characteristics and stroke subtype and etiology. However, very few such data are available and none from population-based studies. We determined the predictors of resource use and acute care costs of stroke using data from a population-based study. METHODS: Data were obtained from the Oxford Vascular study, a population-based cohort of all individuals in nine general practices in Oxfordshire, UK, which identified 346 patients with a first or recurrent stroke during April 1, 2002, to March 31, 2004. Univariate and multivariate analyses were performed to identify the main predictors of resource use and costs. RESULTS: Acute care costs ranged from 326 pounds sterling (lower decile) to 19,901 pounds sterling (upper decile). There were multiple important univariate interrelations of patient characteristics, stroke subtype, and stroke etiology with hospital admission, length of stay, and 30-day case-fatality. For example, patients with primary intracerebral hemorrhage were more likely to be admitted than patients with partial anterior circulation ischemic stroke and less likely to survive without disability, but length of stay was reduced as a result of high early case-fatality such that cost was substantially less. However, the majority of univariate predictors of resource use, cost, and outcome were confounded by initial stroke severity as measured by the National Institutes of Health Stroke Scale score, which accounted for approximately half of the predicted variance in cost. Cost increased approximately linearly up to an National Institutes of Health Stroke Scale score of 18 and then fell steeply at higher scores as a result of rising early case-fatality. CONCLUSIONS: Several patient and event-related characteristics explained the wide range of initial secondary care costs of acute stroke, but stroke severity was by far the most important independent predictor.

Acute Disease↗
PubMed2006

Cost-effectiveness analyses alongside randomised clinical trials.

BACKGROUND: Many health economists increasingly advocate the use of model-based evaluations rather than trial-based evaluations. PURPOSE: The purpose of this paper is to review the merits and limitations of RCT-based evaluations of cost-effectiveness. RESULTS: The paper draws on the examples of large studies such as the United Kingdom Prospective Diabetes Study and the Heart Protection Study to suggest that large randomised trials offer a number of advantages to health economists wishing to estimate cost-effectiveness, including access to patient-level data, unbiased estimates of resource use as well as effects, the estimation of cost-effectiveness in sub-groups of patients, and an enhanced ability to build and validate extrapolation models. CONCLUSIONS: While many methodological issues remain to be resolved, the use of patient-level data derived from clinical trials as a basis for economic evaluations is likely to remain an important part of the health economics evidence base, and will also continue to provide the data required for methodological research.

Cost-Benefit Analysis↗
PubMed2005

Screening for cervical cancer in India: How much will it cost? A trial based analysis of the cost per case detected.

The cost and cost effectiveness of screening previously unscreened women by VIA, cytology or HPV testing was investigated within a large cluster randomised trial involving 131,178 women in rural India. All resources involved in implementation, training, management, recruitment, screening and diagnosis were identified and costed. We estimated the total costs and detection rates for each cluster and used these data to calculate an average cluster cost and detection rate for each screening approach. These estimates were combined to estimate a cost per case of cervical intraepithelial neoplasia grade 2/3 or invasive cancer (CIN 2/3+) detected. The average total costs per 1,000 women eligible for screening were US dollar 3,917, US dollar 6,609 and US dollar 11,779 with VIA, cytology and HPV respectively. The cost of detecting a case of CIN2/3+ using VIA was dollar 522 (95% CI dollar 429- dollar 652). Our results suggest that more CIN2/3+ cases would be detected in the same population if cytology were used instead of VIA and each additional case would cost US dollar 1065 (95% CI dollar 713- dollar2175). Delivering cervical cancer screening is potentially expensive in a low-income country although costs might be lower outside a trial setting. We found screening with VIA to be the least expensive option, but it also detected fewer cases of CIN2/3+ than other methods; its long-term cost-effectiveness will depend on the long-term benefits of early detection. Cytology was more effective at detecting cases than VIA but was also more expensive. Our findings indicate that HPV may not be a cost effective screening strategy in India at current consumable prices.

Adult↗
PubMed2004

A longitudinal study of the effects of age and time to death on hospital costs.

Recent studies indicate that approaching death, rather than age, may be the main demographic driver of health care costs. Using a 29-year longitudinal English dataset, this paper uses more robust methods to examine the effects of age and proximity to death on hospital costs. A random effects panel data two-part model shows that approaching death affects costs up to 15 years prior to death. The large tenfold increase in costs from 5 years prior to death to the last year of life overshadows the 30% increase in costs from age 65 to 85. Hence, expenditure projections must consider remaining life expectancy in the populations.

Age Distribution↗
PubMed2002

The cost-effectiveness of residential radon remediation programmes: assumptions about benefits stream profiles over time.

A recent cost-effectiveness analysis of a residential radon remediation programme considered and highlighted many areas of uncertainty in the parameters chosen for the analysis. One assumption not challenged in the study was the benefits stream profile adopted. There are several different ways of loading the benefits in terms of life years into the cost-effectiveness model and several of these are explored and the results are reported in this study. The benefits profile depends upon the lead-time to cancer manifestation post environmental carcinogen (radon) exposure. The literature reviewed suggests that there are many options for loading benefits to radon-induced lung cancer prevention programmes. In this study, the alternative benefits stream profiles are explored and their implications for the cost-effectiveness ratio are examined. Adopting different benefits stream profiles to the model results in a range of cost-effectiveness ratios from 14912.90 pounds per life year gained to 52416.27 pounds per life year gained. The preferred model is reported where the life years gained are assumed to be equally distributed over the last 15 years of the 40-year time horizon of the analysis (Y25-40) and the corresponding cost-effectiveness ratio is 37,943 pounds per life year gained.

Aged↗
PubMedDate not supplied

Estimating the association between SF-12 responses and EQ-5D utility values by response mapping.

BACKGROUND: Reliably mapping from generic or disease-specific health status measures into health state utilities would assist health economists. Existing studies mainly use ordinary least squares (OLS) regression equations to predict utility values for particular health states. The authors examine an alternative approach to map between 2 generic health status instruments, the SF-12 and the EQ-5D. METHODS: Multinomial logit regression is used to estimate the probability that a respondent will select a particular level of response to questions in the EQ-5D, using individual question responses and summary scores from the SF-12 as predictors. Monte Carlo simulation methods are used to generate predicted EQ-5D responses, and utility scores (tariffs) are then attached. Results are compared with an alternative approach based on direct mapping to utility scores using OLS. DATA: The authors estimate equations using 12,967 adult survey responses-from the 2000 US Medical Expenditure Panel Survey. They report mean squared error (MSE) and mean absolute error (MAE) of their predicted utilities within this sample, and out-of-sample using 13,304 adults from the 1996 Health Survey for England. RESULTS: The authors obtain an in-sample and out-of-sample MSE of 0.03, compared with 0.02 for the OLS approach. Their MAE of 0.11 is similar to OLS results. The authors' method predicts group mean utility scores and differentiates between groups with or without known existing illness. CONCLUSIONS: The authors' approach has higher MSE than the direct OLS approach but gives more descriptive data on domains of health effects. Further out of sample prediction work will help test the validity of these methods.

Activities of Daily Living↗