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    <title>Krol, H.M.</title>
    <link>http://repub.eur.nl/res/aut/22258/</link>
    <description>List of Publications</description>
    <language>en</language>
    <image>
      <url>http://repub.eur.nl/static-eur/img/logo.png</url>
      <title>RePub, Erasmus University Rotterdam</title>
      <link>http://repub.eur.nl</link>
    </image>
    <item>
      <title>The Impact of Patients' Subjective Life Expectancy on Time Tradeoff Valuations (Article)</title>
      <link>http://repub.eur.nl/res/pub/38717/</link>
      <pubDate>2012-12-26T00:00:00Z</pubDate>
      <description>BACKGROUND: Quality-adjusted life-year (QALY) calculations in economic evaluations are typically based on general public or patient health state valuations elicited with the time tradeoff method (TTO). Such health state valuations elicited among the general public have been shown to be affected by respondents' subjective life expectancy (SLE). This suggests that TTO exercises based on time frames other than SLE may lead to biased estimates. It has not yet been investigated whether SLE also affects patient valuations.

OBJECTIVE: To empirically investigate whether patients' SLE affects TTO valuations of their current health state.

METHODS: Patients with different severities of diabetic retinopathy were asked in a telephone interview to value their own health status using TTO. The TTO time frame (t) presented was based on age- and sex-dependent actuarial life expectancy. Patients were then asked to state their SLE. Simple and multiple regression techniques were used to assess the effect of the patients' SLE on their TTO responses.

RESULTS: In total, 145 patients completed the telephone interview. Patients' TTO values were significantly influenced by their SLE. The TTO value decreased linearly with every additional year of difference between t and the patients' SLE; that is, patients were more willing to give up years the shorter their SLE compared with t.

CONCLUSION: Patients' SLE influenced their TTO valuations, suggesting that respondents' SLE may be the most appropriate time frame to use in TTO exercises in patients. The use of other time periods may bias the TTO valuations, as the respondents may experience the presented time frame as a gain or a loss. The effect seems to be larger in patient valuations than in general public valuations.

</description>
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      <title>Productivity Costs in Economic Evaluations (Doctoral Thesis)</title>
      <link>http://repub.eur.nl/res/pub/38176/</link>
      <pubDate>2012-12-21T00:00:00Z</pubDate>
      <description>The increase in health expenditures has raised important questions about
the appropriate height of health care spending as well as the justification of
these expenditures. One tool in the search of ensuring the optimal allocation
of scarce societal and health care resources is economic evaluation of health
care interventions, such as new pharmaceuticals, diagnostics or preventive
measures. In economic evaluations, the costs of an intervention are compared
to its benefits, expressed in some meaningful manner. Consistently applying
these evaluations, in theory, would ensure an optimal level of spending in the
health care sector (that is, the size of the budget, or how much to spend on
health) as well as an optimal use of the available resources within the budget
(that is, on what the budget is spent). This optimal spending can be defined in
light of the twin goals of health care policy; efficiency and equity.  As such,
economic evaluations can be seen as applied welfare economics, aimed at informing
social choices to come to a maximization of broadly defined welfare. </description>
    </item> <item>
      <title>Productivity cost calculations in health economic evaluations: Correcting for compensation mechanisms and multiplier effects (Article)</title>
      <link>http://repub.eur.nl/res/pub/37426/</link>
      <pubDate>2012-12-01T00:00:00Z</pubDate>
      <description>Productivity costs related to paid work are commonly calculated in economic evaluations of health technologies by multiplying the relevant number of work days lost with a wage rate estimate. It has been argued that actual productivity costs may either be lower or higher than current estimates due to compensation mechanisms and/or multiplier effects (related to team dependency and problems with finding good substitutes in cases of absenteeism). Empirical evidence on such mechanisms and their impact on productivity costs is scarce, however. This study aims to increase knowledge on how diminished productivity is compensated within firms. Moreover, it aims to explore how compensation and multiplier effects potentially affect productivity cost estimates. Absenteeism and compensation mechanisms were measured in a randomized trial among Dutch citizens examining the cost-effectiveness of reimbursement for smoking cessation treatment. Multiplier effects were extracted from published literature. Productivity costs were calculated applying the Friction Cost Approach. Regular estimates were subsequently adjusted for (i) compensation during regular working hours, (ii) job dependent multipliers and (iii) both compensation and multiplier effects. A total of 187 respondents included in the trial were useful for inclusion in this study, based on being in paid employment, having experienced absenteeism in the preceding six months and completing the questionnaire on absenteeism and compensation mechanisms. Over half of these respondents stated that their absenteeism was compensated during normal working hours by themselves or colleagues. Only counting productivity costs not compensated in regular working hours reduced the traditional estimate by 57%. Correcting for multiplier effects increased regular estimates by a quarter. Combining both impacts decreased traditional estimates by 29%. To conclude, large amounts of lost production are compensated in normal hours. Productivity costs estimates are strongly influenced by adjustment for compensation mechanisms and multiplier effects. The validity of such adjustments needs further examination, however. </description>
    </item> <item>
      <title>Does the EQ-5D Reflect Lost Earnings? (Article)</title>
      <link>http://repub.eur.nl/res/pub/34705/</link>
      <pubDate>2012-01-01T00:00:00Z</pubDate>
      <description>Background: An important methodological issue in economic evaluations of
healthcare is how to include productivity costs (the costs related to reduced
productivity due to illness, disability and premature death). Traditionally,
they were included in the numerator of a cost-effectiveness analysis, through
either the human-capital or the friction-cost method. It has been argued,
however, that productivity costs are already included in the denominator (i.e.
in the QALY measure) because respondents consider the effect a given health
state will have on their income when valuing health states. If that is the case,
many previous economic evaluations might have double counted productivity
costs by including them in both the numerator and the denominator.
Aim: The aim of this study was to determine whether respondents valuing
EQ-5D health states using the time trade-off (TTO) method spontaneously
consider income effects, whether this consideration influences subsequent
valuations and whether explicit ex post instructions influence valuations.
Methods: Through an online survey, we asked 321 members of the Dutch
general population to value four EQ-5D health states through three different
TTO exercises. The first exercise was a standard TTO question. Respondents
were then asked whether they had included income effects. Depending on
their answer, the second TTO exercise instructed them to either include or
exclude income effects. The third TTO exercise provided explicit information
regarding the income loss associated with the health state.
Results: Data were available from 321 members of the Dutch general public. Of
these respondents, 49% stated they had spontaneously included income effects.
Twenty-five percent of the sample did not trade any time in any of the TTO
exercises and these respondents were excluded from the analysis. Results of
t-tests showed there were only weakly significant differences in valuations for
one health state between those who spontaneously included income effects and
those who did not. Explicit instruction led to some significant differences at the
aggregate level, but the effect was inconsistent at the individual level. When
explicit information on the amount of income loss was provided, all states were
valued lower when associated with a larger income loss.</description>
    </item> <item>
      <title>In or out? Income losses in health state valuations: A review (Article)</title>
      <link>http://repub.eur.nl/res/pub/19947/</link>
      <pubDate>2010-03-01T00:00:00Z</pubDate>
      <description>Background: In 1996 the Washington Panel controversially recommended valuing productivity costs (PC) in terms of quality-adjusted life years. The Panel's assumption that respondents in health state valuation (HSV) exercises take income losses into account could not be countered since there was no evidence regarding what people consider in HSV exercises. If they do consider income losses and if this changes HSVs, then all economic evaluations that have included PC in the numerator may have double-counted these costs. Alternatively, if respondents do not consider income losses then all past economic evaluations that have not included PC in the numerator have failed to account for sizeable societal costs. Objectives: Through a review we aim to recapture the debate surrounding the appropriate method for including PC in health economic evaluations, to identify empirical evidence addressing the assumptions of the Panel, and recommend a future research agenda. Methods: Through a review we identify, outline, and critically appraise the existing empirical studies that attempt to address whether respondents include income effects in HSV exercises. Results and conclusion: Seven empirical studies were identified. Overall, it seems that not explicitly mentioning the inclusion of income will induce a minority of respondents to include these effects and this appears not to influence results. More empirical work is needed, using generic instruments, larger samples, and using the interview method of administration. © 2009, International Society for Pharmacoeconomics and Outcomes Research (ISPOR).</description>
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      <title>Breaking the silence: Exploring the potential effects of explicit instructions on incorporating income and leisure in TTO exercises (Article)</title>
      <link>http://repub.eur.nl/res/pub/25106/</link>
      <pubDate>2009-01-01T00:00:00Z</pubDate>
      <description>Objectives: An underexplored question in the debate on incorporating productivity costs as costs or effects in a cost-effectiveness (CE) analysis is whether people include effects of ill health on income in health state valuations (HSV). The same holds for the actual inclusion in HSV of the effects of ill health on leisure. This study aims to test whether respondents to HSV using time trade-off (TTO) questions include income and leisure effects without instructions. Moreover, it tests the consequences of explicit instructions to include or exclude income effects. Methods: Three questionnaires were administered among the general public. Respondents were asked to value three distinct EuroQol descriptive system health states using TTO. In version 1, respondents were asked afterwards whether they included income effects. In versions 2 and 3, respondents were instructed upfront to include or exclude income effects. They were furthermore asked whether they included leisure effects. Results: A total of 222 respondents completed the questionnaire. In version 1, 64% of the respondents spontaneously included income effects, not resulting in differences in mean valuations. In versions 2 and 3, 88% included leisure time, resulting in a significantly lower TTO value in one health state. With explicit instructions, respondents instructed to include income gave lower HSV for the worst health state presented. Conclusions: Respondents in our sample did not consistently include income effects and leisure effects. Including income effects only had (some) effect on TTO valuations after an explicit instruction. If these results are confirmed in future research, this implies that income effects may be best captured on the cost-side of the CE ratio. Spontaneous inclusion or exclusion of leisure time appeared to be more influential. </description>
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      <title>Costs, quality of life, treatment satisfaction and compliance in patients with β-thalassemia major undergoing iron chelation therapy: The ITHACA study (Article)</title>
      <link>http://repub.eur.nl/res/pub/29726/</link>
      <pubDate>2008-07-01T00:00:00Z</pubDate>
      <description>Objectives: Iron chelation treatment (ICT) in β-thalassemia major (β-TM) patients undergoing blood transfusions can cause low satisfaction, low compliance, with possible negative consequences on treatment success, patients' wellbeing, and costs. The purpose was to estimate the societal burden attributable to β-TM in terms of direct and indirect costs, health-related quality-of-life (HRQoL), satisfaction and compliance with ICT in patients undergoing transfusions and ICT. Research design and methods: The naturalistic, multicenter, longitudinal Italian-THAIassemia-Cost-&amp;-Outcomes-Assessment (ITHACA) cost-of-illness study was conducted involving patients of any age, on ICT for at least 3 years, who were enrolled at 8 Italian Thalassemia Care Centers. Costs were estimated from the societal perspective, quantified with tariffs, prices, or net earnings valid in 2006. Results: One-hundred and thirty-seven patients were enrolled (median age = 28.3, 3-48 years, 49.6% male) and retrospectively observed for a median of 11.6 months. Mean direct costs were €1242/patient/month, 55.5% attributable to ICT, 33.2% attributable to transfusions. Relevant quantity and quality of productivity was lost. Both physical and mental components of HRQoL were compromised. Little difficulties remembering to take ICT and positive satisfaction with the perceived effectiveness of therapy were declared, but not good levels of satisfaction with acceptance, perception of side effects and burden of ICT. Conclusions: The management of β-TM patients undergoing transfusions and ICT is efficacious, although costly, but overall benefits were not always perceived as optimal by patients. Efforts must be focused to improve patients' acceptance and satisfaction with their therapy; this would contribute to a better compliance and hence an increase in treatment effectiveness and patients' overall wellbeing, with expected improved allocation of human and economic resources. </description>
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      <title>A systematic review of economic analyses of pharmaceutical therapies for advanced colorectal cancer (Article)</title>
      <link>http://repub.eur.nl/res/pub/36911/</link>
      <pubDate>2007-06-01T00:00:00Z</pubDate>
      <description>Colorectal cancer is one of the most common causes of cancer in the Western world. New drugs in the treatment of advanced colorectal cancer, such as irinotecan and oxaliplatin, have substantially increased the cost of treatment. A systematic literature review on the cost (-effectiveness) of pharmaceutical therapies for advanced colorectal cancer was conducted, in which 13 articles were included. The main topics were: orally versus intravenously administered fluoropyrimidine, raltitrexed, irinotecan and oxaliplatin. Additional information was collected on the cost (-effectiveness) of the monoclonal antibodies, cetuximab and bevacizumab. Only five articles had taken the societal perspective, in most articles no data on quality of life was presented, and only two reported the cost per quality-adjusted life year. As only a limited amount of information is available on the cost-effectiveness of pharmaceutical therapies for advanced colorectal cancer, there is a need for more cost-effectiveness studies. These studies are preferably performed by taking a societal perspective and including quality of life outcomes. </description>
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