liu.seSearch for publications in DiVA
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Health economic aspects of diabetic retinopathy
Linköping University, Department of Medical and Health Sciences, Health Technology Assessment and Health Economics. Linköping University, Faculty of Health Sciences.
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

To ensure that the resources of the health care sector are used effectively, new technologies need to be evaluated before implementation to examine if they generate health outcomes at an acceptable cost. This information can be collected by performing health economic evaluations in which the costs and health outcomes of different technologies are compared. To estimate the effect on health care budgets, there is also a need for information about the prevalence of the specific disease. Health outcomes in health economic evaluations are often measured in quality-adjusted life years (QALYs), which are calculated by multiplying the remaining life years after an intervention by a weight representing the health-related quality of life (HRQoL) during those years.

This thesis aims to provide deeper knowledge of the health economic aspects of diabetic retinopathy (DR), an eye complication that affects patients with diabetes and may in the worst case lead to blindness. The focus is on three empirical and two methodological health economic research questions. The empirical research areas cover prevalence, costs, and HRQoL related to patients with DR. The methodological research questions explore the performance of different methods for estimation of QALY weights. This is of interest since it has been argued that the most common methods for estimating QALY weights may not capture all relevant vision-related aspects of quality of life. The analyses comprehend the validity of different methods for estimating QALY weights among patients with DR and if the results of one of the specific methods for estimating QALY weights, the time trade-off (TTO) exercise, are affected by patients’ subjective life expectancy (SLE).

The empirical results demonstrate that DR is seen in approximately 40% and 30% of patients with type I and type II diabetes respectively, indicating that the prevalence of DR has decreased in both of these patient groups. Healthcare costs vary considerably between different severity levels of the disease, being estimated at €26, €257, €216, and €433 per patient per year for background retinopathy, proliferative diabetic retinopathy (PDR), diabetic macular oedema (DMO), and PDR combined with DMO respectively. Blindness due to DR is associated with an increased use of transportation services, caregiving services, and assistive technologies as well as productivity losses. This suggests that preventing the progression of DR may lower healthcare costs. Patients with vision impairment due to DR have lowered HRQoL in various dimensions, but the diagnosis of DR in itself has only a limited effect on HRQoL.

The results on the methodological research questions show that different methods for estimating QALY weights seem to give different results. In comparison to EQ-5D, the Health Utilities Index Mark 3 (HUI-3) is the most sensitive method for detecting differences in QALY weights due to DR, and if decisions are to be made based on values from the general public, it can be recommended for use in cost-utility analyses of interventions directed at DR. Neither of the direct methods, TTO and the visual analogue scale, seems to be sensitive to differences in visual function, and more research is needed concerning the role of vision in people’s responses to the TTO exercises. In TTO exercises with time frames based on actuarial life expectancy, the patients’ SLE has an effect on their willingness to trade off years for full health. Thus, applying time frames deviating from patients’ SLE may result in biased QALY weights. Such bias may appear stronger within patient populations than within the general public.

In conclusion, this thesis offers estimates for prevalence, costs, and QALY weights that can be used in economic evaluations of interventions directed at DR and as benchmarks for future DR research in order to follow up consequences of changes in diabetes care. In addition, it demonstrates that the choice of method for estimating QALY weights may have an impact on whether an intervention is considered cost-effective.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2012. , 137 p.
Series
Linköping University Medical Dissertations, ISSN 0345-0082 ; 1293
Keyword [en]
diabetes, diabetic retinopathy, health economic evaluations, quality-adjusted life years, costs, quality of life, prevalence
National Category
Health Care Service and Management, Health Policy and Services and Health Economy
Identifiers
URN: urn:nbn:se:liu:diva-76283ISBN: 978-91-7519-964-1 (print)OAI: oai:DiVA.org:liu-76283DiVA: diva2:513740
Public defence
2012-05-04, Eken, Entrance 65, Campus US, Linköping University, Linköping, 09:00 (English)
Opponent
Supervisors
Available from: 2012-04-03 Created: 2012-04-02 Last updated: 2012-04-12Bibliographically approved
List of papers
1. Prevalence and healthcare costs of diabetic retinopathy: a population-based register study in Sweden
Open this publication in new window or tab >>Prevalence and healthcare costs of diabetic retinopathy: a population-based register study in Sweden
Show others...
2010 (English)In: Diabetologia, ISSN 0012-186X, E-ISSN 1432-0428, Vol. 53, no 10, 2147-2154 p.Article in journal (Refereed) Published
Abstract [en]

Aims/hypothesis

The aim of the present study was to estimate the prevalence and healthcare costs of diabetic retinopathy (DR).

Methods

This population-based study included all residents (n = 251,386) in the catchment area of the eye clinic of Linköping University Hospital, Sweden. Among patients with diabetes (n  = 12,026), those with and without DR were identified through register data from both the Care Data Warehouse in Östergötland, an administrative healthcare register, and the Swedish National Diabetes Register. Healthcare cost data were elicited by record linkage of these two registers to data for the year 2008 in the Cost Per Patient Database developed by Östergötland County Council.

Results

The prevalence of any DR was 41.8% (95% CI 38.9–44.6) for patients with type 1 diabetes and 27.9% (27.1–28.7) for patients with type 2 diabetes. Sight-threatening DR was present in 12.1% (10.2–14.0) and 5.0% (4.6–5.4) of the type 1 and type 2 diabetes populations respectively. The annual average healthcare cost of any DR was €72 (€53–91). Stratified into background retinopathy, proliferative DR, maculopathy, and the last two conditions combined, the costs were €26 (€10–42), €257 (€155–359), €216 (€113–318) and €433 (€232–635) respectively. The annual cost for DR was €106 000 per 100,000 inhabitants.

Conclusions

This study presents new information on the prevalence and costs of DR. Approximately one-third of patients with diabetes have some form of DR. Average healthcare costs increase considerably with the severity of DR, which suggests that preventing progression of DR may lower healthcare costs.

Keyword
Costs, Diabetes mellitus, Diabetic retinopathy, Epidemiology, Prevalence, Registries
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-59070 (URN)10.1007/s00125-010-1836-3 (DOI)000281612600011 ()
Available from: 2010-09-08 Created: 2010-09-08 Last updated: 2013-10-21Bibliographically approved
2. QALY weights for diabetic retinopathy: a comparison of health state valuations with HUI-3, EQ-5D, EQ-VAS, and TTO.
Open this publication in new window or tab >>QALY weights for diabetic retinopathy: a comparison of health state valuations with HUI-3, EQ-5D, EQ-VAS, and TTO.
Show others...
2012 (English)In: Value in Health, ISSN 1098-3015, E-ISSN 1524-4733, Vol. 15, no 3, 475-484 p.Article in journal (Refereed) Published
Abstract [en]

Objective: To estimate quality-adjusted life-year weights for patients with diabetic retinopathy by using various methods and to investigate the empirical validity of the different measures.

Methods: The study population comprised 152 patients with diabetes in Östergötland County, Sweden. Participants were interviewed by telephone by using the time trade-off (TTO) method and a visual analogue scale (EQ-VAS) (direct valuations) as well as the EuroQol five-dimensional questionnaire (EQ-5D) and the health utilities index mark 3 (HUI-3) (indirect valuations). The quality-adjusted life-year weights were adjusted for potential confounders by using analysis of covariance. The empirical validity of the measures was examined by testing their ability to detect hypothetical differences between severity levels of diabetic retinopathy and by investigating the correlation between the measures and the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25).

Results: All measures detected significant differences in scores between patient groups classified according to visual impairment in the better eye (analysis of covariance, P < 0.05), but only HUI-3 and EQ-VAS detected significant differences between patient groups classified according to visual impairment or pathological progression in the worse eye. HUI-3 recorded a difference of 0.43 in values between normal vision and blindness in the better eye, which was more than twice the differences captured by the other measures (0.15–0.20). In addition, HUI-3 showed the highest correlation with NEI VFQ-25 (r = 0.54; P < 0.001).

Conclusions: In cost-utility analyses, the choice of quality-adjusted life-year measure may affect whether an intervention is considered cost-effective. Furthermore, if decisions are to be based on values from the general public, HUI-3 can be recommended for cost-utility analyses of interventions directed at diabetic retinopathy.

Place, publisher, year, edition, pages
Elsevier, 2012
Keyword
diabetes mellitus, diabetic retinopathy, EQ-5D, health utility index mark 3, NEI-VFQ-25, QALY, time trade-off, TTO, VAS
National Category
Health Care Service and Management, Health Policy and Services and Health Economy
Identifiers
urn:nbn:se:liu:diva-76280 (URN)10.1016/j.jval.2011.11.031 (DOI)000303940600011 ()22583458 (PubMedID)
Note

funding agencies|AstraZeneca AB||

Available from: 2012-04-02 Created: 2012-04-02 Last updated: 2017-12-07Bibliographically approved
3. Health-related quality of life profiles of patients with diabetic retinopathy
Open this publication in new window or tab >>Health-related quality of life profiles of patients with diabetic retinopathy
Show others...
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Purpose: There are various instruments for estimating health-related quality of life (HRQoL) in patients with diabetic retinopathy (DR). However, if the results are to be compared with those for other diseases, it is essential to use measures that are applicable to all disease areas. The aim of this study was to explore the HRQoL profiles of patients with DR using two generic multi-attribute instruments, the Health State Utilities Index Mark 3 (HUI-3) and the EQ-5D questionnaire, and to investigate these questionnaires’ sensitivity to differences in HRQoL due to DR.

Methods: The study population comprised 166 Swedish diabetes patients diagnosed with DR at different severities. Patients were interviewed over the telephone using HUI-3 and EQ-5D. The vision-specific National Eye Institute Visual Functioning Questionnaire 25 (NEI VFQ-25) was also included, to give an empirical framework for the results of the generic instruments. Linear and logistic regression models were used to adjust for possible confounders.

Results: Patients with vision impairment (VI) reported lower scores in Vision, Ambulation, and Pain in HUI-3 and more problems with Usual activities and Anxiety/depression in EQ-5D. However, even though NEI VFQ-25 showed a negative association between DR severity and Mental health and Near activities, neither EQ-5D nor HUI-3 identified a negative relationship between DR severity and HRQoL.

Conclusion: The generic instruments show lowered HRQoL for patients with VI in various dimensions but were not sensitive to decrements related to the diagnosis of DR alone. The questionnaire of HUI-3 was more sensitive than EQ-5D to differences in HRQoL due to DR-related VI.

Keyword
diabetes, diabetic retinopathy, health-related quality of life, health profile, EQ-5D, Health Utilities Index, HUI-3, National Eye Institute Visual Functioning Questionnaire 25, NEI VFQ-25
National Category
Health Care Service and Management, Health Policy and Services and Health Economy
Identifiers
urn:nbn:se:liu:diva-76281 (URN)
Available from: 2012-04-02 Created: 2012-04-02 Last updated: 2012-04-10Bibliographically approved
4. The impact of patients' subjective life expectancy on time trade-off valuations
Open this publication in new window or tab >>The impact of patients' subjective life expectancy on time trade-off valuations
2013 (English)In: Medical decision making, ISSN 0272-989X, E-ISSN 1552-681X, Vol. 33, no 2, 261-270 p.Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
SAGE Publications (UK and US), 2013
Keyword
utility measurement, preferences and quality of life, health state preferences, utilities, valuations, utility inconsistencies, time tradeoff, quality adjusted life year weights, QALYs
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-76282 (URN)10.1177/0272989X12465673 (DOI)000316684200014 ()
Note

Funding Agencies|Astra Zeneca AB Sweden||Ostergotland County Council||

Available from: 2012-04-02 Created: 2012-04-02 Last updated: 2017-12-07Bibliographically approved

Open Access in DiVA

Health economic aspects of diabetic retinopathy(1766 kB)1469 downloads
File information
File name FULLTEXT01.pdfFile size 1766 kBChecksum SHA-512
8bc5b98cbe8ba40e939b9150dba4d9a4d4b4be0bae1f976228c805444ea6965c5e36db92c6003fca77e32799942550cef146acab2f65a0163495cbd20c6abb9e
Type fulltextMimetype application/pdf
omslag(187 kB)66 downloads
File information
File name COVER01.pdfFile size 187 kBChecksum SHA-512
f2f211b7cc9851a3406f35c7c95aa4547bd313b11ec80923c915eff37115557c2cd0d524d5fa087e2e8a9e4e8485efd1b067f13fdac9d5706f359764d7d68a5b
Type coverMimetype application/pdf

Authority records BETA

Heintz, Emelie

Search in DiVA

By author/editor
Heintz, Emelie
By organisation
Health Technology Assessment and Health EconomicsFaculty of Health Sciences
Health Care Service and Management, Health Policy and Services and Health Economy

Search outside of DiVA

GoogleGoogle Scholar
Total: 1469 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 1518 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf