Biomedical subjects

David K Whynes

Publications and source records attributed to David K Whynes.

At least 19 recordsLinked to original sources

PubMed2006

Why do women participate in the English cervical cancer screening programme?

The vast majority of women in England attend for cervical cancer screening. Conventional economic theorising fails to explain why and its predictions are inconsistent with the evidence. Using questionnaire data, we analyse directly motivations for screening attendance. We conclude that regular attendance at screening is driven primarily by a search for reassurance, a sense of duty and herd signalling. It is evident that recognisable sub-groups of attenders exist, in which the configurations of motivational factors differ. Being motivated to attend by physicians is less significant that is widely supposed and is more frequently associated with irregular attendance.

Adult↗

PubMed2006

Accounting for the increase in NSAID expenditure: substitution or leakage?

BACKGROUND: National Institute of Health and Clinical Excellence (NICE) guidance stated that a new form of non-steroidal anti-inflammatory drug (NSAID) (selective COX-2 inhibitors) should only be an option for arthritis patients at high risk of a gastro-intestinal (GI) event. Total expenditure on NSAIDs has risen by 57% over five years, to 247 pounds sterling million in 2004. We assess whether this expenditure increase can be accounted for by substitution--an increased prescribing of two (more expensive) selective COX-2 inhibitors (celecoxib and rofecoxib) and a simultaneous equivalent reduction in the prescribing volume of three (cheaper) older NSAIDs (diclofenac, ibuprofen and naproxen). METHODS: Quarterly prescription data was collated from January 1999 to September 2004. Over this period, the level of correlation between the total prescribing volumes for i) celecoxib and rofecoxib, and ii) diclofenac, ibuprofen, and naproxen were compared, the change in total expenditure on the five NSAIDs was also estimated. The latter was apportioned into that which was estimated to have arisen due to i) substitution, and ii) increased NSAID prescription volume. RESULTS: Total prescription volumes for the two NSAID groups were negatively correlated (r = -0.97, p < 0.001). In the last quarter there were 1.23 million prescriptions for celecoxib and rofecoxib, and 0.46 million fewer prescriptions for naproxen, diclofenac, and ibuprofen (than in the first quarter, when celecoxib and rofecoxib were not prescribed). Total expenditure for the five NSAIDs was 32.7 pounds sterling million higher in the last quarter, than the first, 12.2 pounds sterling million of which was estimated to be due to substitution, and 20.4 pounds sterling million due to increased volume. CONCLUSION: The introduction of celecoxib and rofecoxib was associated with a reduction in the prescription volume for naproxen, diclofenac, and ibuprofen. However, overall quarterly prescription volume for these five NSAIDs increased by 0.76 million, and we estimate that quarterly expenditure increased by 20.4 pounds sterling million more than would have been expected if overall NSAID volume had remained constant. This suggests that the prescription of both celecoxib and rofecoxib may have 'leaked' to population groups who would not previously have received an older NSAID.

Journal Article↗

PubMed2006

Testing the construct validity of willingness to pay valuations using objective information about risk and health benefit.

This paper describes an experiment to test the construct validity of contingent valuation, by eliciting women's valuations for the NHS cervical cancer screening programme. It is known that, owing to low levels of knowledge of cancer and screening in the general population, women both over-estimate the risk of disease and the efficacy of screening. The study is constructed as a randomised experiment, in which one group is provided with accurate information about cervical cancer screening, whilst the other is not. The first hypothesis supporting construct validity, that controls who perceive greater benefits from screening will offer higher valuations, is substantiated. Both groups are then provided with objective information on an improvement to the screening programme, and are asked to value the improvement as an increment to their original valuations. The second hypothesis supporting construct validity, that controls who perceive the benefits of the programme to be high already will offer lower incremental valuations, is also substantiated.

Adult↗

PubMed2006

Introducing HPV triage into the English cervical cancer screening program: consequences for participation.

OBJECTIVE: To predict the likely impact of adding human papillomavirus (HPV) triage for minor abnormalities on participation in the English cervical cancer screening program. METHOD: Contingent valuations of the existing Pap program and a possible HPV-augmented screening program, obtained from questionnaires completed by 1141 women in east-central England. RESULTS: The value of participating in Pap screening was negatively associated with age, positively associated with educational level, and positively associated with the level of household income. Higher levels of worry about cervical cancer were associated with higher valuations of screening. Adding HPV-based triage to the Pap program lowered the value of screening participation for only two women, whereas for the sample as a whole, it increased the average valuation by about 47 percent. Supposedly-negative characteristics of HPV testing, when described, were expected to trigger psychosocial concerns in respondents and thereby give rise to significant decreases in valuations of participating in a Pap-plus-HPV program. For most women, however, such information changed their valuations of participation in screening little, if at all. CONCLUSIONS: Accepting the proposition that higher contingent valuations indicate stronger behavioural preferences, our results offer insubstantial grounds for believing that the inclusion of HPV triage would detrimentally affect participation in Pap screening for cervical cancer.

Adult↗

PubMed2005

Think of a number... any number?

An examination of the willingness to pay values elicited from more than 3000 persons involved in three independent studies revealed that the majority had offered one of a limited number of values from the ranges available to them. These values were 'prominent numbers', the use of which has been observed previously in circumstances where subjects feel that precise estimates of value are either difficult to make, or are not worth making. The existence of widespread prominence in response is suggestive of hypothetical bias in contingent valuation.

Choice Behavior↗

PubMed2005

Willingness-to-pay and demand curves: a comparison of results obtained using different elicitation formats.

Health economists use "willingness-to-pay" to assess the prospective value of novel interventions. The technique remains controversial, not least with respect to the formats under which values are elicited. The paper analyses the results of a series of studies of the same intervention valued by the same population, in which different elicitation formats were employed. The findings support the hypothesis that data collected using different formats give rise to different demand curves, from which different inferences about demand elasticity, profitability and consumer surplus will be derived. Judgements as to the relative merits of rival interventions depend crucially upon whichever format has been used to evaluate each intervention.

Fees and Charges↗

PubMed2005

Paediatric cochlear implantation: the views of parents.

The purpose of this study was to understand the parental perspective on paediatric cochlear implantation over time. Face-to-face semi-structured interviews were conducted with 216 families of children who were implanted at the Nottingham Paediatric Cochlear Implant Programme between 1989 and 2002, and who were attending an appointment during the study period (July 2001 August 2002). The qualitative data revealed that time played an important role in family experiences of paediatric cochlear implantation. Expectations were continually revised throughout the process, as a result of new knowledge and new technological developments. The results show that outcomes are highly individualistic although parents had a shared hope of the implant enabling the child to function in a "hearing world"; that the biggest area of contention is in respect of their child's education; and that parents talked openly about constraints imposed on them by implantation. The vast majority of parents did not regret their decision to proceed with implantation.

Adult↗

PubMed2004

Cost effectiveness analysis of intensive versus conventional follow up after curative resection for colorectal cancer.

OBJECTIVE: To determine the cost effectiveness of intensive follow up compared with conventional follow up in patients with colorectal cancer. DESIGN: Incremental cost effectiveness analysis recognising differences in follow up strategies, based on effectiveness data from a meta-analysis of five randomised trials. SETTING: United Kingdom. MAIN OUTCOME MEASURES: Taking a health service perspective, estimated incremental costs effectiveness ratios for each life year gained for five trials and four trials designed for early detection of extramural recurrences (targeted surveillance). RESULTS: Based on five year follow up, the numbers of life years gained by intensive follow up were 0.73 for the five trial model and 0.82 for the four trial model. For the five trials, the adjusted net (extra) cost for each patient was 2479 pounds sterling (3550 euros; 4288 dollars) and for each life year gained was 3402 pounds sterling, substantially lower than the current threshold of NHS cost acceptability (30 000 pounds sterling). The corresponding values for the four trial model were 2529 pounds sterling and 3077 pounds sterling, suggesting that targeted surveillance is more cost effective. The main predictor of incremental cost effectiveness ratios was surveillance costs rather than treatment costs. Judged against the NHS threshold of cost acceptability, the predicted incremental cost threshold was ninefold and the effectiveness threshold was 3%. CONCLUSIONS: Based on the available data and current costs, intensive follow up after curative resection for colorectal cancer is economically justified and should be normal practice. There is a continuing need to evaluate the efficacy of specific surveillance tools: this study forms the basis for economic evaluations in such trials.

Colorectal Neoplasms↗

PubMed2004

Evidence of range bias in contingent valuation payment scales.

The payment scale format has been widely used in willingness-to-pay studies in health care. Concerns have been expressed that the format is, in theory, prone to range bias, although this proposition has not been tested directly. We report the findings of a contingent valuation questionnaire study of colorectal cancer screening, wherein different subjects were provided with payment scales of two different lengths. Whilst the long-scale instrument included scale values up to pound 1000, the short-scale version extended only to pound 100. After controlling for inter-sample differences in, for example, income, education and health behaviour, it emerged that the long-scale instrument produced a mean willingness to pay more than 30% higher than that resulting from the short-scale version. We believe our findings to be strongly supportive of the likelihood of range bias in payment-scale instruments, with important consequences for the estimation of both average valuation and consumer surplus.

Aged↗

PubMed2004

Comparing willingness-to-pay: bidding game format versus open-ended and payment scale formats.

The willingness-to-pay technique is being used increasingly in the economic evaluation of new health care technologies. Clinical trials of two methods of screening for colorectal cancer are currently being conducted in the UK and willingness-to-pay for screening has already been estimated by means of a questionnaire survey, using open-ended (OE) and payment scale (PS) formats. This paper addresses the same medical issue, although it elicits willingness-to-pay values by means of a bidding game in an interview setting. Interviews were conducted with 106 subjects in Nottingham. The bidding game format produced considerably higher valuations than had either of the previous questionnaire formats, whilst the significant differences between agreed valuations obtained using different initial bids supported the existence of starting-point bias in the bidding game. As with the questionnaire study, the majority of interview subjects offered relative valuations of tests at variance with their expressed preferences over the same tests. Given the significant difference in valuations generated by different formats, it follows that the economic case for preferring any one technology over others will depend considerably upon whichever format happens to have been used to generate the valuations.

Adult↗

PubMed2004

Cost-effectiveness of screening for colorectal cancer: evidence from the Nottingham faecal occult blood trial.

OBJECTIVES: To estimate the cost-effectiveness of faecal occult blood (FOB) screening for colorectal cancer within the Nottingham trial. SETTING: A randomised controlled trial (1981-present) of 153,000 subjects, of whom approximately half were offered biennial FOB testing over up to five screening rounds. METHODS: The additional costs of participation in screening relative to symptomatic presentation were calculated by combining the results of (i) a comprehensive audit of resource use on the part of subjects within the trial, (ii) previously-established unit costs for each of the procedures involved. Life expectancy gains were estimated from a survival analysis of those trial subjects who had been diagnosed with cancer (screening participants vs controls). RESULTS: The cost of screening under the Nottingham trial protocol was pound 5290 per cancer detected (at 2002 prices). Under conservative assumptions, the incremental cost per life year gained as a result of screening was pound 1584 (Confidence Interval [CI]:717 to 8612).

Colorectal Neoplasms↗

PubMed2003

A comparison of two methods for eliciting contingent valuations of colorectal cancer screening.

Willingness-to-pay (WTP) is being used increasingly in health technology assessment, although a number of methodological issues remain unresolved. Using data obtained from a randomised questionnaire survey, we investigated the metrical properties of two WTP formats, the open-ended question versus the payment scale, in the context of screening for colorectal cancer. Approximately, 2800 responses were analysed. Household income, attitudes toward health promotion and personal risk perceptions were the principal determinants of the nature and value of response. In comparison with the open-ended format, the payment scale achieved a higher completion rate and generated higher valuations. We believe that a framing effect is the most plausible explanation for these differences in performance. In contrast to previous findings, we do not find subjects' perceptions of the resource cost of interventions to be a convincing explanation for either their WTP values or inconsistencies between values and preferences. Although a proportion of respondents protested at the notion of valuation, the majority offer positive valuations, although typically of a lower value that non-protesters.

Adult↗

PubMed2003

Costs of flexible sigmoidoscopy screening for colorectal cancer in the United Kingdom.

OBJECTIVES: Colorectal cancer is one of the most commonly occurring cancers in industrialized countries, yet appears to be amenable to screening. Amongst the many possible protocols is once-only screening by means of flexible sigmoidoscopy. This protocol is currently being investigated in a UK multicenter trial and the study provides estimates of the expected resource costs. METHODS: The direct health care costs of sigmoidoscopy and of all subsequent procedures were estimated from an audit of resource use of approximately 40,000 patients at thirteen centers. Patient-borne costs were estimated from the results of surveys conducted at twelve of these centers. RESULTS: The health service costs of a flexible sigmoidoscopy was estimated at pounds 56. The total costs of screening (including private costs) averaged pounds 82 per person screened, although costs varied by center. The total health service costs of screening and subsequent management averaged approximately pounds 91 per person screened, again with variations between centers. CONCLUSIONS: Even within a strict trial protocol, intercenter variation in costs can be detected, ascribable to variability in local management practices, local yield, and local patient-borne costs. Other recent estimates of flexible sigmoidoscopy costs vary widely. As these costs form the basis of technology assessment simulation models which, in turn, inform policy obtaining realistic cost estimates within the appropriate health care setting is of paramount importance.

Colorectal Neoplasms↗

PubMed2003

Human papillomavirus and the value of screening: young women's knowledge of cervical cancer.

The study reports a questionnaire survey of female university students intended (1) to delineate their knowledge of cervical cancer and screening, and (2) to impute their valuation of the introduction of human papillomavirus (HPV) testing. It was found that almost 80% of respondents thought cervical cancer was a leading cause of cancer death amongst women. Most subjects consistently over-estimated the incidence of cervical cancer, consistent with the social amplification hypothesis. The major risk factors were accurately identified by the majority, although family history was emphasized to a degree unwarranted by epidemiological evidence. Subjects' knowledge of the screening programme was accurate in some respects, but not in others, e.g. the majority under-estimated the abnormality rate and over-estimated the age at which abnormalities typically occurred. Subjects placed a premium on the increased accuracy which HPV testing might potentially offer, predictable from their beliefs about the performance of the existing screening programme. Policy makers can be reassured that female university students appear unconcerned about undergoing a test for a sexually transmitted disease, although their beliefs about cervical cancer and the power of screening are distorted, and their enthusiasm for HPV testing relates to an, as yet, unconfirmed belief in its accuracy.

Adolescent↗

PubMed2003

Measuring indirect costs: is there a problem?

It is generally accepted that, in order to appraise from a societal perspective, indirect costs should be included in economic evaluations. What is less generally accepted, however, is the method by which such indirect costs should be calculated. Different methods and assumptions can, in theory, produce different results. Previous studies have commented on this variability, and most suggest a need for consensus. This having been said, no previous study appears to have demonstrated that variability in method is actually a practical problem, in the sense that the use of different costing methods would lead to different policy conclusions. In this paper, we examine this issue with respect to a specific intervention, namely, paediatric cochlear implantation (PCI). Based on questionnaire data, we estimate the indirect costs of PCI using a variety of methods. Thereafter, we integrate these indirect costs into a cost-utility analysis of PCI, and demonstrate that the variability in methods can significantly affect the outcome of a cost-effectiveness study. Therefore, in this case at least, the measurement of indirect cost is indeed a problem.

Child↗

PubMed2002

The boundaries of cellular pathology: how pathologists see their clinical role.

There has been much recent public attention on the effects of the practices of cellular pathology on patients and their relatives. It is important to establish clearly pathologists' views about their professional relationships to clinicians and patients. A national postal questionnaire survey was performed to investigate how cellular pathologists perceive their role in clinical practice and whether there are important differences between different groups of pathologists. Responses were received from 773 pathologists, of whom 167 were trainees. On the basis of responses to 25 attitude statements, it appears that the profession shares a core belief that pathologists are clinicians rather than scientists and sees diagnosis as its main clinical responsibility. However, the role that each pathologist feels clear about differs significantly between pathologists, with a stronger consensus over function, responsibility, and professional image than on the clinical practice of pathology, job satisfaction, and the impact of technological change. Academic activities are a minority interest, although academic pathologists express better job satisfaction and more radical views of professional practice. Young trainees are more likely to work in teaching hospitals, to be female, to have trained outside the UK, and to have had experience in other specialties. They have, however, a more restricted view of the clinical role of pathology than accredited pathologists. Most cellular pathologists see themselves as clinicians with a special role in diagnosis, but how this is interpreted and the extent to which pathologists involve themselves in clinical decision-making is inconsistent. This professional dilemma should be addressed by research to obtain more systematic knowledge of the clinical impact of cellular pathology and especially the ill-defined links between diagnosis and clinical decision-making.

Adult↗

PubMed2002

Professional attitudes to Changing Childbirth in Nottingham, UK.

Changing Childbirth has been a central focus of maternity care policy in England. The objective of this study was to determine whether different professional groups involved in maternity care-hospital and community midwives, general practitioners and obstetricians-had different professional attitudes to a local implementation scheme. Data were obtained using a postal questionnaire, based on an agenda developed from focus groups. Whilst general practitioners appeared to be somewhat less optimistic than were midwives, there existed clear differences of opinion within the midwifery profession itself, depending upon whether the midwife worked in the community or in hospital. All professionals appeared conscious of the gap between the service ideals and the limited resources available to achieve them, and expressed uncertainty over future directions and ways of working.

Attitude of Health Personnel↗

PubMed2002

Primary care physicians' attitudes to health care reform in England.

Primary care organisation in England has been subject to particularly extensive and far-reaching reform in recent years. In 1991, a quasi-market was introduced into the National Health Service and general practitioners were offered the opportunity to manage independent budgets from which to purchase and deliver care services. Practitioners joined the scheme in increasing numbers, although it was eventually abandoned following a change of government in 1997. This paper reports the results of two surveys of primary care physicians' opinions on the English health care reforms, conducted in 1997 and 2000. It concludes that, first, those opting for discretionary budgets were significantly more supportive of the policy than those not joining the scheme and this support continued long after the scheme had been abolished. Second, professional attitudes, with respect to other terms of service in primary care, remained homogenous to a considerable degree over time. Finally, physicians in favour of imposing user charges tend to be those with responsibility for more patients, suggesting a perceived need to manage patient demand.

Attitude of Health Personnel↗