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M Johannesson

Publications and source records attributed to M Johannesson.

At least 37 records · Page 2Linked to original sources
PubMed2000

Modelling asymmetric similarity with prominence.

This paper introduces and discusses a geometrically based model, the relative prominence model, which is inspired by Tversky's finding that a factor behind asymmetric similarity seems to be 'relative prominence'. The model proposes that the experienced directed similarity from I to J is proportional to some symmetric similarity measure between I and J, and the quotient between the 'prominences' for J and I. Analysis of several empirical data sets shows that it is possible for a procedure to estimate the parameters of the model quite well. The differences between the relative prominence model and related models that handle asymmetry in terms of 'stimulus bias' are discussed.

Color Perception↗
PubMed1999

A comparison of patient and social tariff values derived from the time trade-off method.

A social tariff of EuroQol time trade-off (TTO) values was recently presented. We compared the social tariff and patient TTO values among 104 women with mild and severe menopausal symptoms. The social tariff and patient TTO values were elicited both after and before hormone replacement therapy (HRT). There was a close correspondence between social-tariff values and patient TTO values for relatively good health states, whereas the social tariff TTO values were lower than the patient TTO values for severe health states.

Cost-Benefit Analysis↗
PubMed1999

Probability Weighting and Utility Curvature in QALY-Based Decision Making.

Quality-Adjusted Life-Years (QALYs) are currently the most important utility model in medical decision making. QALYs are calculated by adjusting years of life for the utility of the health state in which these years are spent. For normative reasons the standard gamble is the preferred method to measure health state utilities, but concern exists about its descriptive properties. Recent theoretical work has suggested that probability weighting can explain anomalies in standard gamble measurement. This paper shows that applying probability weighting in standard gamble measurement increases the consistency of QALYs with individual preferences. The consistency of QALYs with individual preferences is not significantly increased further if utility curvature is also taken into account. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Use of contingent valuation to place a monetary value on pharmacy services: an overview and review of the literature.

An important goal for the pharmacy profession is to quantify the economic value of pharmacy services. The contingent valuation (CV), or willingness-to-pay method, offers one approach to valuing the benefits of pharmacy services. The potential advantage CV offers is that it reflects, in a single monetary amount, the entire range of attributes (both benefits and "nonbenefits") offered by the good or service being valued. This paper provides a brief overview of the CV method and reviews 10 published studies that used a willingness-to-pay question to place a monetary value on pharmacy services. Suggestions for other researchers wishing to use this method are provided.

Cost-Benefit Analysis↗
PubMed1999

A note on validating Wagstaff and van Doorslaer's health measure in the analysis of inequalities in health.

The aim of this note is to validate Wagstaff and van Doorslaer's approach of constructing a continuous health measure to be used in the analysis of inequalities in health. We calculate health concentration indices for Uppsala County in Sweden based on three different health status measures: health measured according to the WvD approach based on a self-assessed categorical health measure, health measured by the rating scale method, and health measured by the time trade-off method. The concentration index does not differ significantly for the three health status measures, and our results thus support the validity of the WvD method.

Developed Countries↗
PubMed1999

On aggregating QALYs: a comment on Dolan.

Dolan [Dolan, P., 1998, The measurement of individual utility and social welfare. Journal of Health Economics, Vol. 17, pp. 39-52] in a recent paper suggested an empirical method for estimating the shape of the social welfare function. Using a simple theoretical model it is shown that Dolan's proposed empirical method has no theoretical foundation. The main problem with the approach is that it measures only the altruistic values that individuals attach to other peoples' health status and ignores the utility that individuals attach to their own health status.

Altruism↗
PubMed1999

New estimates of the demand for health: results based on a categorical health measure and Swedish micro data.

In this paper we estimate a "Grossman" model of demand for health based on Swedish micro data. The data set consists of a random sample of over 5000 individuals taken from the Swedish adult population. Health capital is measured by a categorical measure of overall health status, and an ordered probit model is used to econometrically estimate the demand for health equation. The results are consistent with the theoretical predictions and show that the demand for health increases with income and education and decreases with age, male gender, overweight, living in big cities and being single.

Adult↗
PubMed1999

Three common CFTR mutations should be included in a neonatal screening programme for cystic fibrosis in Sweden.

Children with cystic fibrosis (CF) diagnosed by neonatal screening have a better nutritional development and other advantages compared with those in a nonscreened group. The two-tier immunoreactive trypsinogen (IRT)/DNA screening protocol has been found superior to the single-tier IRT approach, improving the positive predictive value and thus reducing the false-positive rate. However, variations of the DNA test are required for different populations. In this study we examined CFTR (cystic fibrosis transmembrane conductance regulator) mutations in 331 CF patients attending the centres in Stockholm, Lund and Uppsala, comprising about 75% of the CF population in Sweden. The frequency of deltaF508 among CF alleles was 68.3%. There were two other mutations, 394delTT and 3659delC, found to be fairly frequent, amounting to 8.5 and 7.9%, respectively. Other mutations were comparatively rare. A simple and effective method of analysing the three mutations from Guthrie cards has been developed. Assuming Hardy-Weinberg equilibrium, 90% of our CF patients will be expected to carry at least one deltaF508 allele and 97.6% to carry at least one deltaF508, 394delTT or 3659delC copy. Including the latter two in a screening programme would thus substantially reduce the risk of a false-negative outcome.

Cystic Fibrosis↗
PubMed1999

Quality of life, health-state utilities and willingness to pay in patients with psoriasis and atopic eczema.

Skin diseases have been shown to have a significant adverse impact on the health-related quality of life of patients that may be underestimated by objective assessments of clinical severity. The main aim of this study was to measure the health-state utilities on a scale between 0 (dead) and 1 (full health) of patients with psoriasis and atopic eczema, and to measure the willingness to pay for a cure for psoriasis and atopic eczema. A second aim was to analyse how these measures are related to different dimensions of health-related quality of life, as measured by general and disease-specific quality of life instruments and a subjective measure of disability activity. This study was based on data from a questionnaire administered to, and interviews conducted with, 366 patients with psoriasis and atopic eczema aged 17-73 years, attending the dermatology outpatient clinic in Uppsala, Sweden from November 1996 to December 1997. The survey included: a rating scale question, a time trade-off question, a standard gamble question, a dichotomous choice willingness to pay question, a bidding-game willingness to pay question, a generic quality of life instrument (SF-36), a disease-specific quality of life instrument (the Dermatology Life Quality Index) and a subjective measure of disease activity (on a visual analogue scale). The mean health-state utility was 0.69 (rating scale), 0.88 (time trade-off) and 0.97 (standard gamble) for patients with psoriasis. The corresponding health-state utilities for patients with atopic eczema were 0.73, 0.93 and 0.98. On average, patients were willing to pay between 1253 and 1956 Swedish crowns (SEK) per month for a psoriasis cure and between SEK 960 and 1083 per month for an atopic eczema cure ($1 = SEK 8.25 and pound1 = SEK 13.23). The health-state utilities were related to SF-36, the Dermatology Life Quality Index and disease activity in the expected direction and the correlations were strongest for rating scale and weakest for standard gamble. The willingness to pay was correlated with the Dermatology Life Quality Index and disease activity, but not with SF-36. The study indicates that it is feasible to measure health-state utilities and willingness to pay in this patient population, and the sizeable willingness to pay suggests that skin diseases are associated with substantial reductions in quality of life.

Adolescent↗
PubMed1999

A computer model to analyze the cost-effectiveness of hormone replacement therapy.

This paper gives a detailed presentation of a computer model for evaluating the cost-effectiveness (CE) of hormone replacement therapy (HRT), describing the model's design, structure, and data requirements. The model needs data specified for costs, quality of life, risks, and mortality rates. As an illustration, the CE of HRT in Sweden is calculated. Two treatment strategies are evaluated for asymptomatic women: estrogen-only therapy and estrogen combined with a progestin. The model produces similar results compared with earlier studies. The CE ratios improve with the size of the risk reduction and generally with age. Further, estrogen-only therapy is associated with a lower cost per gained effectiveness unit compared with combined therapy. Uncertainty surrounding the long-term effects of HRT means that the CE estimates should be interpreted carefully. The model permits the inclusion of indirect costs and costs in added life-years, allowing the analysis to be made from a societal perspective, which is an improvement relative to previous studies.

Aged↗
PubMed1998

Time spent on waiting lists for medical care: an insurance approach.

In this paper, we develop a simple model of the benefits and costs of being on a waiting list. The model shows that complex factors are in operation, implying that a shorter waiting time need not necessarily be preferred to a longer waiting time. We also present an empirical study, where a sample of Swedes are offered the possibility of purchasing private insurance, thus reducing waiting time for surgery beyond the three-month guarantee offered by the public sector health care system. Respondents could choose between two insurance contracts. A 'spike' model, where the probability of a zero WTP is strictly positive, was developed and estimated to obtain demand functions for private insurance.

Cost-Benefit Analysis↗
PubMed1998

Effects of user charges on the use of prescription medicines in different socio-economic groups.

This study examined the sensitivity towards increases in user charges for different types of drugs and among different socio-economic groups. It was based on responses by 2008 consumers of prescription drugs to a self-administered postal questionnaire sent to a random sample of 8000 inhabitants in Uppsala County in Sweden. The questionnaire included a question about whether the respondents would use fewer prescription drugs if the user charges increased by a specific amount. The increase in user charges was varied between 9 and 150% in five different subsamples. Logistic regression analysis was used to estimate the probability that a respondent would reduce consumption of prescription drugs as a function of the size of the user charges increase, socio-economic characteristics and the type of drug used. Results showed that the price sensitivity decreased with increasing age, income, education and self-rated health status. Price sensitivity was highest for antitussives and lowest for climacteric drugs. If the user charges doubled, 40% of antitussives users would reduce their consumption whereas only 11% of climacteric drugs users would reduce their consumption. It is concluded that sensitivity to increases in user charges varied greatly between different types of drugs and between socio-economic groups. The young, those with poor health status, low education and low income are most likely to decrease consumption of prescription drugs when user charges increase.

Attitude to Health↗
PubMed1998

An experimental test of question framing in health state utility assessment.

In the standard gamble and time trade-off methods of health state utility assessment, a specified health state and an alternative are compared. This alternative can be framed in terms of a loss or a gain in reference to the first health state. In this paper, we test whether this framing affects the estimated health state utilities. The experiment was carried out on a group of pharmacy students, randomly divided between the loss or gain version (n = 182). The null hypothesis of no difference between the loss and gain versions is rejected for the standard gamble method, but not for the time trade-off method.

Cost-Benefit Analysis↗
PubMed1998

Cost-effectiveness analysis and capital costs.

Traditionally, economic evaluations in terms of cost-effectiveness analysis are based, explicitly or implicitly, on the assumption of constant returns to scale. This assumption has been criticized in the literature and the role of cost-effectiveness as a tool for decision making has been questioned. In this paper we analyze the case of increasing returns to scale due to fixed capital costs. Cost-effectiveness analysis is regarded as a tool for estimating a cost function. To this cost function two types of decision rules can be applied, the budget approach and the constant price approach. It is shown that in the presence of fixed capital costs the application of these two decision rules to a specific patient group will give different results. The budget approach may lead to suboptimizations, while using the price as a decision rule will give optimal solutions. With fixed capital costs and when an investment can be used for treating several patient groups, these groups are no longer independent. Therefore the cost-effectiveness analysis has to be performed simultaneously for all patient groups that are potential users of the investment.

Budgets↗
PubMed1998

Cystic fibrosis through a female perspective: psychosocial issues and information concerning puberty and motherhood.

The purpose of the study was to investigate psychosocial issues concerning puberty and motherhood among CF adult females, to see how they had obtained and conceived information on these matters and how they would like information to be given. Fourteen adult CF females were interviewed. The majority of the women felt socially accepted and did not remember being ashamed over their delayed puberty. Thirteen of the women had been or were living in stable sexual relationships. However, the study revealed problems with destructive behaviour during puberty due to thoughts about premature death, secret worries over delayed puberty, poorly received information about puberty and fertility, avoidance of close relationships with the opposite sex during adolescence and concerns about being a mother with a chronic illness. Information about puberty and fertility should be given individually and in small discussion groups with teenage girls combined with thorough medical and psychological guidance concerning motherhood.

Adolescent↗
PubMed1998

Relationship between quality of life instruments, health state utilities, and willingness to pay in patients with asthma.

BACKGROUND: In asthma, a substantial impact of disease is on quality of life rather than survival. To date, the quality of life effects of asthma have not been quantitated. OBJECTIVE: The purpose of this study was to quantitate the quality of life effects of asthma via measurement of the health utility of asthmatic patients, and the willingness to pay for an asthma cure. A second goal was to analyze how these measures are related to the different dimensions of quality of life as measured by general and disease specific quality of life instruments. METHODS: Health utilities were measured on a scale between 0 and 1 using the rating scale, time trade off, and standard gamble methods. Willingness to pay was elicited using both the dichotomous choice and the bidding game approach. Quality of life was assessed using both a generic instrument (the SF-36) and a disease-specific instrument (the Asthma TyPE). RESULTS: Sixty-nine patients with asthma were surveyed. The mean health utility was 0.68 with the rating scale method, 0.89 with the time trade off, and 0.91 with the standard gamble. On average, patients were willing to pay between $200 to $350 dollars more per month for an asthma cure. Nearly all correlations between dimensions of quality of life, health state utilities, and willingness to pay were in the expected direction. CONCLUSION: The two quality of life instruments performed about equally well in terms of being correlated with and being able to explain the responses to the health state utility questions and the willingness to pay questions. Correlations between the dimensions of the Asthma TyPE and the SF-36 were also fairly high. Further work should focus on validating and refining the different methods of quantitating quality of life for asthma patients.

Adult↗