Examining cost methodologies in survey-based observational studies in stroke: A protocol for a scoping review

Introduction

Non-communicable diseases (NCDs) are a global public health concern, with cardiovascular disease, cancer, chronic respiratory disease and diabetes being the major contributors¹. From 1990 to 2019, NCDs accounted for the highest absolute increase in Disability-Adjusted Life Years (DALYs)². In 2021, seven of the ten leading causes of death worldwide were attributed to NCDs, with ischemic heart disease at the top and stroke ranking third³. That same year, stroke accounted for the greatest loss in global DALYs among diseases affecting the nervous system and was the leading cause of DALY loss in 19 of the 21 Global Burden of Disease (GBD) regions⁴.

The burden of stroke is apparent in both the increased mortality and morbidity, with approximately 50% of survivors remaining chronically disabled⁵. Although advances in stroke management have significantly reduced age-standardised incidence, mortality and DALYs, and have increased life expectancy by shifting the burden to older populations^6,7, several studies have reported an increase in the incidence and prevalence of stroke among individuals aged 65 years or younger^8–11. The longer duration spent living with stroke translates to an increased economic burden^12–14. Therefore, conducting costing studies in stroke is important for accurately assessing the burden of disease and prioritising interventions¹⁵.

Cost of Illness (COI) studies estimate various costs, including inpatient, outpatient, and other types of care, indirect costs stemming from work absenteeism, presenteeism, temporary or lifelong disabilities, death, and intangible costs¹⁶. While this information is important for informing evidence-based decisions, understanding the methodologies used to collect these costs is equally important, as the methods directly impact the accuracy of the estimates. However, despite providing detailed information on economic losses, often, COI studies do not consider additional outcomes such as the associated disutility linked to having the disease, making it difficult to draw meaningful comparisons with other disease areas in terms of cost, benefits, or consequences^17,18. Conversely, cost analyses focused on Healthcare Expenditure (HE) primarily capture costs related to healthcare services, ignoring the broader economic impacts on patients, their households, and society as a whole¹⁷.

Previous systematic reviews on the costs associated with stroke have highlighted significant differences in the methodologies used across studies, with many not clearly defining the cost estimation approaches adopted¹⁶. These reviews primarily focused on whether a study used a top-down or bottom-up approach, rather than examining whether cost data were obtained directly from stroke patients, their caregivers, or medical professionals. Similarly, another systematic review on the cost of post-stroke care reported that cost data sources included hospital records, insurance data, local or national registries, and questionnaires, but did not specify the source of this information (primary source)¹⁹. This lack of clarity limits interpretability, hinders meaningful comparisons across studies and may introduce bias into economic evaluations, as cost estimates derived from patients may differ from those reported by caregivers, even under the same societal perspective. Therefore, challenges in comparing the cost of stroke across different studies persist due to variations in methodologies employed and data sources.

We are motivated to conduct this study after our previous experience conducting a cross-sectional survey on “the costs associated with accessing healthcare related to stroke diagnosis in Ireland”, which revealed challenges in data collection. There was a low response rate, as many of the invited individuals with strokes did not participate in the survey. Among those who participated, the response rates declined with cost-related questions. In one group (n=38), only 24 (63%) answered the first cost question, and only 18 (47%) answered the final question. In another group (n=52), only 29 (56%) completed the cost section. Additionally, some respondents reported difficulty recalling costs, which highlighted potential recall bias in self-reported healthcare expenditures. Studies have reported that cognitive and memory impairments are common following a stroke²⁰, which may affect patients’ ability to accurately recall healthcare-related expenses. This raises important considerations about the reliability of patient-reported cost data in stroke studies. However, if such data are questioned and possibly replaced by other sources, it would be challenging to capture intangible costs such as pain and emotional distress that are difficult to value without actual personal experience of the disease.

This protocol outlines the approach of a scoping review to document how previous studies of costs related to stroke have been conducted, and especially consider whether and how the authors have addressed the cognitive consequences of respondents' stroke on their survey results.

Specifically, the scoping review seeks to:

The findings from this review will help researchers, policymakers, and healthcare providers to identify the most appropriate approach to study stroke costs. It will outline how costing methodologies may be standardised for observational stroke studies to ensure accuracy of cost estimates and facilitate comparison across studies.

Protocol

Dissemination

The findings of the scoping review will be shared in relevant meetings, published in a peer-reviewed, open-access journal, presented at national and international conferences, and disseminated to other researchers and stakeholders in stroke research who may find this information relevant.

Study status

The study protocol has been registered on the Open Science Framework:

https://doi.org/10.17605/OSF.IO/S8P9A

By the time this protocol is published, the database searches will have been completed, and screening will have been initiated.

Tracked and dated amendments

Any amendments to this protocol, including the dates of the amendments and justifications, will be documented and presented in a table in the scoping review publication.

Conclusions

Given the cognitive challenges associated with stroke, it is important to develop a better understanding of the most effective approach to carry out costing in stroke.

Ethical considerations

Ethical approval and consent were not required.