Technological advancements, demographic shifts, and lifestyle changes have led to increased healthcare expenditures, making access to healthcare services more challenging. The close connection between healthcare services and the socio-economic development of societies is well-recognized (
1). Improving healthcare accessibility by reducing financial inequalities and increasing financial security for older adults is a crucial first step (
2). The rapid rise in healthcare expenditures, driven by advancements in medical knowledge, technological innovations, and changing lifestyle and social structures, has placed significant financial strain on healthcare systems (
3). Additionally, factors such as population growth and evolving healthcare needs, including the management of chronic diseases and aging populations, have made accessing healthcare services increasingly challenging for many communities in recent years (
4).
Financial resources for these services are a critical issue in health economics. Investment in the healthcare sector is considered one of the most essential strategies for development and poverty reduction, and universal access to healthcare is shaped by economic analyses and the priorities of different societies, along with the mutual influence of government and society through healthcare investment (
5). It has been demonstrated that the healthcare sector significantly impacts a community’s economic progress and, consequently, poverty reduction (
6). When an individual’s health is threatened by the lack of essential health determinants and the medical care system and healthcare facilities — another key health determinant — are not accessible, this risk can lead to death or disability. Disability, as one of the outcomes of the absence of health determinants, has profound individual and social consequences such as limited social participation (
7,
8).
According to the World Health Organization, over 1 billion people, or 15% of the global population, have some form of disability, with 80% of them living in low- and middle-income countries. The prevalence of disability is increasing due to factors such as aging, the rise in non-communicable diseases, lifestyle changes, and growing accidents, particularly in developing and low-income countries (
9). Studies have shown that nearly 15% of the world’s older adult population suffers from significant disabilities due to age-related conditions and musculoskeletal disorders (
10).
In addition to the healthcare needs of the general population, individuals with disabilities require a higher level of services known as rehabilitation services. These services encompass a wide range of interventions aimed at optimizing the functioning of individuals with disabilities. Rehabilitation services play a crucial role in preventing and minimizing the disabilities associated with chronic diseases and aging, such as the role of physiotherapy in preventing disability and promoting health (
11). Therefore, with the growing prevalence of disabilities, aging, and injuries resulting from accidents (
12) and disasters, rehabilitation services have become an essential component of national healthcare systems (
13). The Global Burden of Disease study in 2019 revealed that 2.41 billion people worldwide could benefit from rehabilitation services, indicating that at least one in three people will require rehabilitation during their illness or injury. This finding challenges the traditional view of rehabilitation as a service for a small minority of the population (
14).
Rehabilitation services, particularly when provided intensively and by specialists, lead to long-term or medium-term savings in healthcare and other sectors (
15,
16). These services also reduce the indirect expenditure of ongoing care and support provided by families and communities (
17). For example, a 2019 study by Mousavi et al. showed that rehabilitation services not only reduce medical expenditure and dependency on daily activities but also improve quality of life and reduce future expenditures, such as absenteeism from work. However, many patients discontinue rehabilitation services following initial medical treatment due to insufficient healthcare system support and inadequate insurance coverage. This decision can lead to greater problems for the patient and their family in the future (
18).
Socioeconomic status (SES) plays a crucial role in creating disparities in rehabilitation expenditure, particularly for individuals with disabilities. A range of factors influences access to rehabilitation services, and numerous studies have explored the determinants of the use or non-use of these services (
19). For example, a study in Ghana found that 76.3% of stroke patients did not use rehabilitation services due to economic barriers (
20). In Iran, studies have also reported low utilization of rehabilitation services among individuals with disabilities (
21). Another study in Iran revealed that socioeconomic factors play a critical role in determining access to rehabilitation services, with the Wealth Index identified as the most significant contributor to disparities. Specifically, 94.22% of the observed inequality in rehabilitation service utilization was attributed to wealth, indicating that individuals from higher SES groups had disproportionately better access compared to their lower SES counterparts (
22).
Similar patterns are observed globally; for instance, in Peru, access to rehabilitation care is inequitable, with older adults and those with lower educational attainment experiencing higher disability burdens yet facing greater barriers to accessing necessary services. The findings underscore the urgent need for policy interventions aimed at enhancing financial protection and equitable access to rehabilitation services for all individuals, regardless of their SES (
23). People with disabilities often have poorer health outcomes than those without disabilities. Despite their greater need for healthcare services, they face substantial barriers to accessing both healthcare and rehabilitation. This highlights the importance of focusing on disability as a significant issue (
24,
25).
Studies indicate that individuals or households with insurance have better access to rehabilitation services in times of injury or aging compared to those without coverage. Additionally, socioeconomic inequalities significantly impact the use of these services. Research using indicators such as the Gini coefficient and Concentration Index has measured inequalities in healthcare expenditure. Findings show that poorer households bear a larger share of health expenses through out-of-pocket payments, while wealthier individuals are more likely to access health services (
26-
28).
Despite the growing demand for rehabilitation services, no studies in Iran have specifically analyzed the inequality in healthcare and rehabilitation expenditure among individuals with disabilities or related factors.