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Biomedical subjects

John Cairns

Publications and source records attributed to John Cairns.

At least 19 recordsLinked to original sources
PubMed2007

Multilevel models for estimating incremental net benefits in multinational studies.

Multilevel models (MLMs) have been recommended for estimating incremental net benefits (INBs) in multicentre cost-effectiveness analysis (CEA). However, these models have assumed that the INBs are exchangeable and that there is a common variance across all centres. This paper examines the plausibility of these assumptions by comparing various MLMs for estimating the mean INB in a multinational CEA. The results showed that the MLMs that assumed the INBs were exchangeable and had a common variance led to incorrect inferences. The MLMs that included covariates to allow for systematic differences across the centres, and estimated different variances in each centre, made more plausible assumptions, fitted the data better and led to more appropriate inferences. We conclude that the validity of assumptions underlying MLMs used in CEA need to be critically evaluated before reliable conclusions can be drawn.

Cost-Benefit Analysis↗
PubMed2007

Time preferences for health in northern Tanzania: an empirical analysis of alternative discounting models.

AIM: The discounted utility (DU) model has dominated economic evaluation for almost 7 decades, despite the fact that important assumptions of the model are commonly found to be violated. This paper formally explores whether the key assumption of stationarity is violated in a sample of the general population of Northern Tanzania. Furthermore, three hyperbolic discounting models are fitted to the data, and whether they perform better than the DU model in predicting individuals' time preferences is tested using nonlinear least squares regression. METHOD: The data were collected from 450 households by trained enumerators. The individual data on time preferences were collected by structured interviews using an open-ended stated preference methodology. Respondents marked a rating scale to indicate the maximum number of days they would be willing to suffer a nonfatal disease if the outbreak of the disease could be delayed to a point further into the future. Households were randomised to answer questions framed to elicit either a private or social time preference. RESULTS: Hypothesis testing confirmed decreasing time aversion and a magnitude effect, suggesting that the DU model is inappropriate as a descriptive tool. When the DU model was compared with the three hyperbolic discounting models by analysing the discount factor using nonlinear least squares regression, the most important findings were that a variable for starting point was nonsignificant only for the Loewenstein and Prelec (L&P) and the Mazur models, and that people in this setting generally discounted future health far more than suggested by current discounting practice in economic evaluations. CONCLUSION: The time preferences of our sample are better represented by the L&P and the Mazur models (which allow relaxation of the stationarity assumption through a modification of the expression for the discount factor) and less well reflected by the Harvey (a modification of the L&P model that assigns more importance to the future than standard utility discounting) and DU models. This implies that, from the point of view of a consumer sovereignty-friendly economist, the Mazur and the L&P models are preferable for discounting of future health in economic evaluations. However, from the point of view of other value bases for discounting the choice of discounting model is of less importance.

Aged↗
PubMed2006

Comparison of urokinase and video-assisted thoracoscopic surgery for treatment of childhood empyema.

BACKGROUND: Despite increasing incidence and morbidity, little evidence exists to inform the best management approach in childhood empyema. AIM: To compare chest drain with intrapleural urokinase and primary video-assisted thoracoscopic surgery (VATS) for the treatment of childhood empyema. METHODS: Children were prospectively randomized to receive either percutaneous chest drain with intrapleural urokinase or primary VATS. The primary outcome was the number of hospital days after intervention. Secondary end points were number of chest drain days, total hospital stay, failure rate, radiologic outcome at 6 mo, and total treatment costs. RESULTS: Sixty children were recruited. The two groups were well matched for demographics; baseline characteristics; and hematologic, biochemical, and bacteriologic parameters. No significant difference was found in length of hospital stay after intervention between the two groups: VATS (median [range], 6 [3-16] d) versus urokinase (6 [4-25] d) (p = 0.311; 95% confidence interval, -2 to 1). No difference was demonstrated in total hospital stay: VATS versus urokinase (8 [4-17] d and 7 [4-25] d) (p = 0.645); failure rate: 5 (16.6%); and radiologic outcome at 6 mo after intervention in both groups. The mean (median) treatment costs of patients in the urokinase arm US dollars 9,127 (US dollars 6,914) were significantly lower than those for the VATS arm US dollars 11,379 (US dollars 10,146) (p < 0.001). CONCLUSIONS: There is no difference in clinical outcome between intrapleural urokinase and VATS for the treatment of childhood empyema. Urokinase is a more economic treatment option compared with VATS and should be the primary treatment of choice. This study provides an evidence base to guide the management of childhood empyema.

Child↗
PubMed2006

Geography, private costs and uptake of screening for abdominal aortic aneurysm in a remote rural area.

BACKGROUND: The relationship between geographical location, private costs, health provider costs and uptake of health screening is unclear. This paper examines these relationships in a screening programme for abdominal aortic aneurysm in the Highlands and Western Isles of Scotland, a rural and remote area of over 10,000 square miles. METHODS: Men aged 65-74 (n = 9323) were invited to attend screening at 51 locations in 50 settlements. Effects of geography, deprivation and age on uptake were examined. Among 8,355 attendees, 8,292 completed a questionnaire detailing mode of travel and costs incurred, time travelled, whether accompanied, whether dependants were cared for, and what they would have been doing if not attending screening, thus allowing private costs to be calculated. Health provider (NHS) costs were also determined. Data were analysed by deprivation categories, using the Scottish Indices of Deprivation (2003), and by settlement type ranging from urban to very remote rural. RESULTS: Uptake of screening was high in all settlement types (mean 89.6%, range 87.4-92.6%). Non-attendees were more deprived in terms of income, employment, education and health but there was no significant difference between non-attendees and attendees in terms of geographical access to services. Age was similar in both groups. The highest private costs (median 7.29 pound sterling per man) and NHS screening costs (18.27 pound sterling per man invited) were observed in very remote rural areas. Corresponding values for all subjects were: private cost 4.34 pound sterling and NHS cost 15.72 pound sterling per man invited. CONCLUSION: Uptake of screening for abdominal aortic aneurysm in is remote and rural setting was high in comparison with previous studies, and this applied across all settlement types. Geographical location did not affect uptake, most likely due to the outreach approach adopted. Private and NHS costs were highest in very remote settings but still compared favourably with other published studies.

Aged↗
PubMed2006

Preferences over dental restorative materials among young patients and dental professionals.

Knowledge of the patient's view is necessary, as patients' rights are an issue of increasing importance in dental practice. This study aimed to examine how dentists (n = 42), dental assistants (n = 65), and young dental patients (n = 306) in Norway and Denmark valued three attributes of dental restorations, namely, expected longevity, the appearance, and the risk of an adverse reaction. According to the discrete choice method, participants were presented with several scenarios, describing different levels of the attributes, for comparison of two restorations (A and B). The differences among patients, dentists, and dental assistants were examined by logistic regression analyses. The likelihood of a dentist favoring one restoration over another was very sensitive to the difference in the expected longevity of the restorations, and much less to differences in visibility. The patients had considerable sensitivity to differences in visibility and much less to differences in duration. Danish teenagers attach less importance to visibility of the restoration and greater importance to the risk of an adverse reaction than Norwegian teenagers. All differences were statistically significant. Preferences associated with properties of dental restorations differ between teenage patients and dental professionals and this should be addressed in clinical decision-making.

Adolescent↗
PubMed2005

Providing guidance to the NHS: The Scottish Medicines Consortium and the National Institute for Clinical Excellence compared.

There is wide acceptance that cost-effectiveness is a relevant consideration when deciding which treatments to make available in publicly funded health services. An unresolved issue concerns the timing and the extent of such evaluations. The United Kingdom provides examples of two distinct approaches. The Scottish Medicines Consortium (SMC) provides guidance to the NHS in Scotland based on a rapid early review of the evidence. The National Institute for Health and Clinical Excellence (NICE) provides guidance to the NHS in England and Wales based on a later, more extensive review of the evidence. This paper explores how the difference in approach affects the role of the pharmaceutical industry, clinical experts and other stakeholders. It compares the guidance produced when both bodies have evaluated the same medicines. It addresses the general question of when to assess the cost-effectiveness of medicines. It concludes that there are important differences between the approaches of SMC and NICE, relating primarily to the timing of the review of evidence on clinical and cost-effectiveness. The difference in timing means that the activities of the two bodies are to a large extent complementary.

Cost-Benefit Analysis↗
PubMed2005

Inequality in willingness-to-pay for community-based health insurance.

The purpose was to provide information for devising community-based health insurance (CBI) policies that reduce inequality in enrolment and further inequality in access to health services. A two-stage cluster sampling was used in the household survey. Inequalities in willingness-to-pay (WTP) for CBI are examined by expenditure quintile using data collected from a household survey. Interviews were conducted with 2414 individuals, 705 of whom were household heads. A bidding game method was used to elicit WTP. Individuals and households were assigned to 6-month expenditure quintiles. We found that mean and median individual WTP for CBI was significantly higher for higher spending quintiles, as was mean and median household WTP. The curves of cumulative percentage of individual and household WTP shifted rightwards for higher quintiles, implying that at any given premium the lower the quintile the lower the uptake of CBI. The Gini coefficient for individual WTP and household WTP was 0.15 and 0.08, respectively, and for individual 6-month expenditure and household 6-month expenditure is 0.68 and 0.63, respectively. The results imply that the premium needs to be adjusted for income; otherwise, a lower proportion of poor people will enrol in CBI and without exemptions or subsidies the poor will have less access to health services than the rich. Thus, exemptions and subsidies for the poor for enrolling in CBI are an important issue for decision-makers with an objective of improving equity of health and helping the poor to break out of the cycle of poverty. Since the distribution of WTP by household is less unequal than the distribution of WTP by individuals, the household might be a better unit of enrolment in terms of equity than the individual.

Adult↗
PubMed2005

Prospective epidemiologic study of the outcome and cost-effectiveness of antenatal screening to detect neonatal alloimmune thrombocytopenia due to anti-HPA-1a.

BACKGROUND: To assess the value of antenatal screening to detect neonatal alloimmune thrombocytopenia (NAIT) due to anti-HPA-1a, a prospective study was carried out to quantify the potential clinical benefits and determine whether screening would be cost-effective. STUDY DESIGN AND METHODS: An observational prospective controlled study was carried out on 26,506 pregnant women over 2 years. HPA-1a phenotyping was performed in the first trimester and women confirmed HPA-1a-negative were tested for anti-HPA-1a during pregnancy, at delivery, and 10 to 14 days after birth. Babies of HPA-1a-negative women were tested at delivery for thrombocytopenia and examined for signs of bleeding. Economic evaluation was undertaken on the basis of the data collected during the study. RESULTS: Twenty-five of 318 women (7.9%) had anti-HPA-1a detected for the first time. Eight women (43 per 100,000) gave birth to babies with NAIT, and 5 (27 per 100,000) had severe thrombocytopenia. Three babies had mild signs of bleeding, and no cases of intracranial hemorrhage (ICH) or fetal loss were detected. It is estimated that it would cost 60,596 pounds (98,771 US dollars) to detect a case of severe NAIT, where anti-HPA-1a has been identified for the first time, and 1,151,323 pounds (1,876,656 US dollars) to prevent a case of ICH, assuming that detection allowed successful intervention. CONCLUSIONS: Our data suggest that severe HPA-1a NAIT is underdiagnosed in the absence of routine antenatal screening. Serious bleeding complications and ICH, however, occur less frequently in first cases of NAIT than suspected from the literature, and the costs of screening and possible intervention must be balanced against the procedural risks.

Antigens, Human Platelet↗
PubMed2004

Immediate computed tomography scanning of acute stroke is cost-effective and improves quality of life.

BACKGROUND AND PURPOSE: Stroke is very common, but computed tomography (CT) scanning, an expensive and finite resource, is required to differentiate cerebral infarction, hemorrhage, and stroke mimics. We determined whether, and in what circumstances, CT is cost-effective in acute stroke. METHODS: We developed a decision tree representing acute stroke care pathways populated with data from multiple sources. We determined the effect of diagnostic information from CT scanning on functional outcome, length of stay, costs, and quality of life during 5 years for 13 alternative CT strategies (varying proportions and types of patients and rapidity of scanning). RESULTS: For 1000 patients aged 70 to 74 years, the policy "scan all strokes within 48 hours" cost 10,279,728 pounds sterling and achieved 1982.3 quality-adjusted life years (QALYs). The most cost-effective strategy was "scan all immediately" (9,993,676 pounds sterling and 1982.4 QALYs). The least cost-effective was "scan patients on anticoagulants and those in a life-threatening condition immediately and the rest within 14 days" (12,592,666 pounds sterling and 1931.8 QALYs). "Scan no patients" reduced QALYs (1904.2) and increased cost (10,544,000 pounds sterling). CONCLUSIONS: Immediate CT scanning is the most cost-effective strategy. For the majority of acute stroke patients, increasing independent survival by correct early diagnosis, ensuring appropriate subsequent treatment and management decisions, reduced costs of stroke and increased QALYs.

Aged↗
PubMed2004

Repeated follow-up as a method for reducing non-trading behaviour in discrete choice experiments.

Eliciting individuals' preferences using discrete choice experiments is becoming increasingly popular. An emerging issue is that some people do not trade, that is, their choices are consistent with them having a dominant preference. However, it may be the case that these individuals have not been presented with the 'right' trade-offs. This experiment presents individuals with trade-offs that are systematically varied in response to their previous answer. It is thus assessed whether individuals have truly dominant preferences or whether they will trade given the 'right' choices. The preferences studied are time preferences over future health states. After being presented with an initial discrete choice, 203 university students were asked a series of follow-up questions using a web-based questionnaire. Very little evidence of any dominant preferences was found in this sample of respondents. Only one subject did not trade duration and timing following repeated follow-up questions. This finding suggests that non-trading behaviour could be virtually eliminated by asking the 'right' questions.

Adult↗
PubMed2004

Annual review of patients with sleep apnea/hypopnea syndrome--a pragmatic randomised trial of nurse home visit versus consultant clinic review.

BACKGROUND: This pragmatic randomised, controlled trial investigated annual review of patients with sleep apnea/hypopnea syndrome (SAHS). Clinical outcomes and costs were compared for consultant clinic review versus specialist nurse home visit. METHOD: One hundred and seventy-four patients were randomised to annual review by consultant clinic appointment or by specialist nurse home visit. SAHS symptoms, Epworth score, hospital anxiety and depression scale (HADS), Short Form-36 (SF-36) and hours of use of constant positive airway pressure (CPAP) were measured before and 3 months after review. The costs and patient preference for review were determined. RESULTS: After review, both groups significantly increased CPAP use (mean (SD) increase: nurse, 0.66 (1.71) h; consultant, 0.45 (1.69) h) and reduced symptom scores (nurse, -2 (7); consultant, -3 (9)), compared to baseline. There were no differences between groups in these improvements, or in HADS or SF-36 scores. Average duration of a nurse home visit, excluding travel time, was 26 (6) min. Total NHS cost per visit was 52.26 UK pounds (49.85) ($83.62 (79.76)), of which 6.57 UK pounds (1.43) ($10.51 (2.29)) reflected time spent with the patient and the remainder was travel cost. Average duration of consultant review was 10 (6) min, total NHS cost 6.21 UK pounds (3.99) ($9.94 (6.38)). However, the cost to the patient of attending the clinic was 23.63 UK pounds (23.21) ($37.81 (37.13)). Patient preference for review was nurse 16%, consultant 19%, and no preference 65%. CONCLUSION: Following annual review, use of CPAP increased and symptoms improved. Outcomes were similar for consultant and nurse led review. Home visits were expensive for the healthcare provider, whereas clinic attendance incurred substantial costs to the patient. The majority of patients would accept nurse review for their sleep apnea management.

Annual Reports as Topic↗
PubMed2004

Differential willingness of household heads to pay community-based health insurance premia for themselves and other household members.

OBJECTIVE: This study compares household heads' willingness-to-pay (WTP) for community-based health insurance (CBI) for themselves with their WTP for other household members, in order to provide information for policy makers on setting the premium and choosing the enrollment unit. METHOD: A random sample of 698 heads of households was interviewed in the northwest of Burkina Faso and a bidding game approach was used to elicit WTP. Factors associated with differences in WTP were identified, including characteristics of the household head and of the household. RESULTS: Mean WTP by the heads of households for insurance for themselves (3575 CFA) was twice their mean WTP per capita for the household as a whole (1759 CFA). The old have a lower WTP than the young, females have lower WTP than males, the poor have a lower WTP than the rich, and that those with less schooling have a lower WTP than those with more years of schooling. CONCLUSION: The differences in household heads' WTP for insurance for themselves and their WTP to insure their households as a whole need to be considered when setting the insurance premium. WTP information can assist decision makers with the complex problem of choosing the enrollment unit and setting the premium.

Burkina Faso↗
PubMed2003

Willingness-to-pay for community-based insurance in Burkina Faso.

PURPOSE: To study the willingness-to-pay (WTP) for a proposed community-based health insurance (CBI) scheme in order to provide information about the relationship between the premium that is required to cover the costs of the scheme and expected insurance enrollment levels. In addition, factors that influence WTP were to be identified. METHODS: Data were collected from a household survey using a two-stage cluster sampling approach, with each household having the same probability of being selected. Interviews were conducted with 2414 individuals and 705 household heads. The take-it-or-leave-it (TIOLI) and the bidding game were used to elicit WTP. RESULTS: The average individual was willing to pay 2384 (elicited by the TIOLI) or 3191 (elicited by the bidding game) CFA (3.17 US dollars or 4.25 US dollars) to join CBI for him/herself. The head of household agreed to pay from 6448 (elicited by the TIOLI) or 9769 (elicited by the bidding game) CFA (8.6 US dollars or 13.03 US dollars) to join the health insurance scheme for his/her household. These results were influenced by household and individual ability-to-pay, household and individual characteristics, such as age, sex and education. The two methods yielded similar patterns of estimated WTP, in that higher WTP was obtained for higher income level, higher previous medical expenditure, higher education, younger people and males. A starting point bias was found in the case of the bidding game. CONCLUSIONS: Both TIOLI and bidding game methods can elicit a value of WTP for CBI. The value elicited by the bidding game is higher than by the TIOLI, but the two approaches yielded similar patterns of estimated WTP. WTP information can be used for setting insurance premium. When setting the premiums, it is important to consider differences between the real market and the theoretical one, and between the WTP and the cost of benefits package. The beneficiaries of CBI should be enrolled at the level of households or villages in order to protect vulnerable groups such as women, elders and the poor.

Adult↗
PubMed2003

A comparison of the reliability of the take-it-or-leave-it and the bidding game approaches to estimating willingness-to-pay in a rural population in West Africa.

The test-retest reliability of the bidding game and the take-it-or-leave-it (TIOLI) approaches to eliciting willingness-to-pay (WTP) are compared. A random sample of households in the Nouna area of Burkina Faso were interviewed twice with an interval of around 4-5 weeks. One thousand one hundred and eight individuals were asked their individual WTP for community-based health insurance. Three hundred and forty eight of these individuals were household heads who were in addition asked about their WTP for health insurance for the whole household. Median and the mean WTP were higher in the test than in the retest. Despite these differences both methods displayed moderate to good reliability (kappa values ranged from 0.467 to 0.621, Spearman correlations ranged from 0.653 to 0.701 and Pearson correlations ranged from 0.593 to 0.675). There was some evidence that the bidding game was more reliable than the TIOLI method. This study is based on larger sample size than previous studies and also is one of the first studies of the reliability of WTP in a developing country.

Adult↗
PubMed2003

Predicting attendance for breast screening using routinely collected data.

The aim of this paper is to predict attendance if the age range for routine invitation to breast screening were to be extended. The response to the most recent screening invitation is modelled for women eligible for screening if the age range were extended. The independent variables include (i) the woman's characteristics: her screening history; the deprivation score of the area she lives in and (ii) the characteristics of the screening: whether the screening took place in a mobile van or at a static site; and time of the year. The predictive ability of the regression model is tested by goodness of fit measures and by predicting attendance for a holdout sample of the data and for women who participated in a demonstration project. The modelling of attendance is quite successful in that most hypothesised variables have the expected sign. Moreover, the predictive ability of the model is satisfactory in terms of goodness of fit statistics and in terms of accuracy of predictions for a holdout sample. The model predicts less well for the demonstration project possibly because it is less representative of usual screening practice.

Aged↗