Predicting functional disability and healthcare costs among community-dwelling older adults with hypertension in Thailand: Longitudinal results from the Health, Aging, and Retirement in Thailand (HART) survey

Background: Hypertension poses a severe health problem among Thai older adults, possibly increasing the prevalence and incidence of disability. Currently, there is limited information on accordance with disability among community-dwelling older adults with hypertension in Thailand. Besides, sex is an essential social determinant of health, but its effects on disability among older adults with hypertension are unclear. Furthermore, no study has estimated the prevalence of disability in the future and projected healthcare costs. The lack of a comprehensive understanding of disability and hypertension will challenge Thailand’s healthcare system in service provision and budget planning. To better understand disability among older adults with hypertension in Thailand and its impacts on healthcare systems, this proposed study aims to answer three research questions: 1) what are the significant predictors of disability among community-dwelling older adults with hypertension in Thailand? 2) are there sex differences in the relationships between risk factors at baseline and disability at follow-up in this population? and 3) what will be the prevalence of disability and healthcare costs among community-dwelling older adults with hypertension in Thailand from 2022 to 2032?
Methods: Two studies were conducted to answer the research questions. The first study investigated baseline risk factors of disability at follow-up among community-dwelling older adults with hypertension in Thailand and examined whether the relationships between risk factors and disability differed by sex. The second study estimated the prevalence of disability and future healthcare costs among community-dwelling older adults with hypertension in Thailand from 2022 to 2032. In study one, we used longitudinal data (Wave1 as baseline [2015] and Wave2 [2017]) from the Panel Survey and Study on Health, Aging, and Retirement in Thailand (HART). Descriptive analysis and logistic regression analysis were employed to perform data analysis. In study two, we used data from the HART Wave1 and Wave2, the official data from governments, and published papers. Regression analysis was used to estimate the prevalence of disability among older adults. Healthcare costs in this study were the cost of spending on outpatient services among older adults with hypertension in 2021. The micro-costing consisted of the step-down method. The cost-to-charge ratio was used to obtain the costs of hospital services provided to older adults living with hypertension. Then, the actual costs of patients with hypertension and the Consumer Price Index were used to project future healthcare costs. All costs were reported in the Thai Baht (THB) and the United States dollar (USD) using the exchange rate of $1 USD = $35 THB in 2023.
Results: The first study indicated that older age, chronic diseases, obesity, and disability at baseline significantly predicted disability at 2-year follow-up among community-dwelling older adults with hypertension in Thailand. The effects of baseline risk factors on disability at follow-up did not differ by sex. However, different disability risk factors were observed in the sex-stratified analysis. For older Thai men with hypertension, poor self-rated health was a significant risk factor. In contrast, for older Thai women with hypertension, advanced age, having more chronic conditions, and obesity were significant risk factors. The second study showed that the prevalence of disability among community-dwelling older adults with hypertension in 2022-2032 ranged from 22-33% by age groups (i.e., 60-69 years old, 70-79 years old, and 80 years old or above). The incidence of disability among community-dwelling older adults with hypertension in Thailand in 2022-2032 ranged from 11-18% by age groups. The number of older adults with any disability was estimated at 1.13 million in 2022 and is forecast to rise to 1.61 million by 2032. Future healthcare costs among community-dwelling older adults with hypertension and disability in Thailand will grow to $4.05 billion THB (about $115.69 million USD) by 2032.
Conclusion: The prevalence of disability among older adults with hypertension in Thailand will likely increase with the aging population. Our study provided useful information regarding predictors of disability, sex-specific risk factors of disability, projected prevalence, and projected healthcare costs. Customized promotion and prevention programs should be readily available to promote independence among community-dwelling older adults with hypertension in Thailand.

Keywords: disability, older adults with hypertension, older adults with hypertension and disability, future healthcare costs, costs projection.