Measuring Costs Among Cognitively
Impaired Patients in Economic Evaluations:
A Systematic Review
Bachelor thesis E.J. Lugard – i6235581
05-07-2023
Supervisor and first reviewer: Dr. I. Kremer
Second reviewer: Dr. G. van Mastrigt
Bachelor Health Sciences
Faculty of Health, Medicine and Life Sciences
Maastricht University
,Abstract
Background: Over the last decades, healthcare expenditure in the Netherlands has increased massively.
Cost-effectiveness studies are crucial in determining cost-effectiveness of healthcare interventions, in
which accuracy of data is of great importance. Economic evaluations should always be done from a
societal perspective, in which patients are included in the cost measurements. Cognitive impairment of
patients can influence the process of recalling information in these studies. Several modifiable attributes
of cost measurement methods should be adapted to the study population. This review aims to provide an
overview of the methods in which costs are currently measured among cognitively impaired patients.
Methods: A systematic review was conducted. The PubMed database was searched for trial-based
studies that conducted an economic evaluation on healthcare interventions for cognitively impaired
patients. The search was conducted on May 24th, 2023. Data was extracted using a data-extraction form
structured by the different research questions and the modifiable attributes of measurement methods.
The quality of the included articles was appraised using the CHEC-list. Data was analyzed using
quantitative methods.
Results: Of the 35 included studies, thirteen studies used a questionnaire to measure costs, nine used
databases, two used interviews, four used a combination of different methods and seven did not report
their method. The average drop-out rate of all studies was 14,89%, being the highest for a combination
of a diary and an interview (26,92%). The average percentage of missing values of all studies was
10,28%, being the highest for interviews (27,22%). Incorrect answers were not reported in any study.
The limitation that was most reported was the risk of recall bias in this specific population (n = 10). The
most reported benefit was the minimization of the risk of recall bias (n = 4).
Discussion: In about half of the included studies, patient-report data was used to measure costs, mostly
acquired with questionnaires. The most reported limitation was the risk of recall bias in this specific
population, however few studies reported measures to adapt their measurement method to this
population. The validity of this review may have been compromised for it was conducted by a single
researcher and not all relevant studies may have been included, since only one database, no grey
literature and no citation chasing were used. It is recommended that future economic evaluations adapt
their method of cost measurement (mode of data collection, recall timeframe, design and memory aids)
to their population and report their method of cost measurement in more detail. For future literature
reviews on this subject, it is recommended to make use of a multiple databases, grey literature and
citation chasing to identify more relevant studies. This could generate more valid results, for a larger
proportion of relevant studies can be identified.
2
,Table of Contents
1. Introduction .........................................................................................................................................5
2. Methods ...............................................................................................................................................8
2.1 Research design ........................................................................................................................................ 8
2.2 Search strategy ......................................................................................................................................... 8
2.3 Inclusion criteria....................................................................................................................................... 9
2.4 Data extraction ......................................................................................................................................... 9
2.5 Quality appraisal .................................................................................................................................... 10
2.6 Data analysis .......................................................................................................................................... 10
3. Results................................................................................................................................................12
3.1 Selection process..................................................................................................................................... 12
3.2 Overview of included studies .................................................................................................................. 13
3.3 Methods of cost measurement ................................................................................................................. 16
3.3.1 Questionnaire (n = 13) ....................................................................................................................................... 17
3.3.2 Database (n = 9) ................................................................................................................................................. 19
3.3.3 Diary and interview combination (n = 2) ........................................................................................................... 20
3.3.4 Interview (n = 2) ................................................................................................................................................. 21
3.3.5 Database and interview combination (n = 1) ..................................................................................................... 22
3.3.6 Diary and questionnaire combination (n = 1) .................................................................................................... 23
3.3.7 Type of cost measurement method not reported (n = 7) ..................................................................................... 23
3.4 Quality appraisal .................................................................................................................................... 24
4. Discussion..........................................................................................................................................27
4.1 Interpretation of results .......................................................................................................................... 27
4.2 Quality of included articles..................................................................................................................... 28
4.3 Strengths and limitations ........................................................................................................................ 28
4.4 Relevance for future research ................................................................................................................. 29
5. Conclusions .......................................................................................................................................30
Competing interests ...................................................................................................................................30
3
, Registration and protocol ..........................................................................................................................30
References..................................................................................................................................................31
Appendix 1: PRISMA 2020 checklist .........................................................................................................36
Appendix 2: Data-extraction form.............................................................................................................38
Appendix 3: CHEC-Extended Guidelines for Quality Assessment of Economic Evaluations ..................46
4
Impaired Patients in Economic Evaluations:
A Systematic Review
Bachelor thesis E.J. Lugard – i6235581
05-07-2023
Supervisor and first reviewer: Dr. I. Kremer
Second reviewer: Dr. G. van Mastrigt
Bachelor Health Sciences
Faculty of Health, Medicine and Life Sciences
Maastricht University
,Abstract
Background: Over the last decades, healthcare expenditure in the Netherlands has increased massively.
Cost-effectiveness studies are crucial in determining cost-effectiveness of healthcare interventions, in
which accuracy of data is of great importance. Economic evaluations should always be done from a
societal perspective, in which patients are included in the cost measurements. Cognitive impairment of
patients can influence the process of recalling information in these studies. Several modifiable attributes
of cost measurement methods should be adapted to the study population. This review aims to provide an
overview of the methods in which costs are currently measured among cognitively impaired patients.
Methods: A systematic review was conducted. The PubMed database was searched for trial-based
studies that conducted an economic evaluation on healthcare interventions for cognitively impaired
patients. The search was conducted on May 24th, 2023. Data was extracted using a data-extraction form
structured by the different research questions and the modifiable attributes of measurement methods.
The quality of the included articles was appraised using the CHEC-list. Data was analyzed using
quantitative methods.
Results: Of the 35 included studies, thirteen studies used a questionnaire to measure costs, nine used
databases, two used interviews, four used a combination of different methods and seven did not report
their method. The average drop-out rate of all studies was 14,89%, being the highest for a combination
of a diary and an interview (26,92%). The average percentage of missing values of all studies was
10,28%, being the highest for interviews (27,22%). Incorrect answers were not reported in any study.
The limitation that was most reported was the risk of recall bias in this specific population (n = 10). The
most reported benefit was the minimization of the risk of recall bias (n = 4).
Discussion: In about half of the included studies, patient-report data was used to measure costs, mostly
acquired with questionnaires. The most reported limitation was the risk of recall bias in this specific
population, however few studies reported measures to adapt their measurement method to this
population. The validity of this review may have been compromised for it was conducted by a single
researcher and not all relevant studies may have been included, since only one database, no grey
literature and no citation chasing were used. It is recommended that future economic evaluations adapt
their method of cost measurement (mode of data collection, recall timeframe, design and memory aids)
to their population and report their method of cost measurement in more detail. For future literature
reviews on this subject, it is recommended to make use of a multiple databases, grey literature and
citation chasing to identify more relevant studies. This could generate more valid results, for a larger
proportion of relevant studies can be identified.
2
,Table of Contents
1. Introduction .........................................................................................................................................5
2. Methods ...............................................................................................................................................8
2.1 Research design ........................................................................................................................................ 8
2.2 Search strategy ......................................................................................................................................... 8
2.3 Inclusion criteria....................................................................................................................................... 9
2.4 Data extraction ......................................................................................................................................... 9
2.5 Quality appraisal .................................................................................................................................... 10
2.6 Data analysis .......................................................................................................................................... 10
3. Results................................................................................................................................................12
3.1 Selection process..................................................................................................................................... 12
3.2 Overview of included studies .................................................................................................................. 13
3.3 Methods of cost measurement ................................................................................................................. 16
3.3.1 Questionnaire (n = 13) ....................................................................................................................................... 17
3.3.2 Database (n = 9) ................................................................................................................................................. 19
3.3.3 Diary and interview combination (n = 2) ........................................................................................................... 20
3.3.4 Interview (n = 2) ................................................................................................................................................. 21
3.3.5 Database and interview combination (n = 1) ..................................................................................................... 22
3.3.6 Diary and questionnaire combination (n = 1) .................................................................................................... 23
3.3.7 Type of cost measurement method not reported (n = 7) ..................................................................................... 23
3.4 Quality appraisal .................................................................................................................................... 24
4. Discussion..........................................................................................................................................27
4.1 Interpretation of results .......................................................................................................................... 27
4.2 Quality of included articles..................................................................................................................... 28
4.3 Strengths and limitations ........................................................................................................................ 28
4.4 Relevance for future research ................................................................................................................. 29
5. Conclusions .......................................................................................................................................30
Competing interests ...................................................................................................................................30
3
, Registration and protocol ..........................................................................................................................30
References..................................................................................................................................................31
Appendix 1: PRISMA 2020 checklist .........................................................................................................36
Appendix 2: Data-extraction form.............................................................................................................38
Appendix 3: CHEC-Extended Guidelines for Quality Assessment of Economic Evaluations ..................46
4
