Health inequality
Between 1998 and 2015, an average of 237,877 citizens were classified as low-income [10], and their accident injury hospitalization rate was 1.74 per 100. In comparison, an average of 22,611,119 were classified as non-low-income [11], and their accident injury hospitalization rate was 1.12 in 100. That the accident injury hospitalization rate for the low-income group was twice as high as that of the non-low-income group implies poverty and injury are correlated. In addition, low-income inpatients had more complicated injuries than non-low-income inpatients (2.3 vs 1.9) and the hospitalization mortality rate for low-income inpatients was 1.888 times higher than that of non-low-income inpatients, showing that health inequality exists between the low-income and non-low-income groups. The high hospitalization mortality rate for low-income inpatients is primarily driven by intentional injuries as it was 2.014 times higher for non-low-income inpatients.
Many researchers have attributed the more complicated and severe injuries in low-income individuals to their lower socioeconomic status, which may compel them to accept high-risk entry-level jobs that require heavy labor. Consequently, they are more susceptible to injuries, which may develop into severe and chronic conditions if left untreated. This is especially true for those who must work to support their families regardless of illness or injuries. These individuals have a higher risk of harm due to poor physical condition [12, 13].
Serious injuries require more comprehensive care at an advanced medical facility. Our results showed that a significantly lower proportion of the low-income inpatients received treatment in medical centers compared to non-low-income inpatients, providing additional evidence of health inequality. Figure 1 illustrates differences between low-income inpatients and non-low-income inpatients in hospitalization payment processes under Taiwan’s NHI program, where the cost of a doctor visit includes medical expenses plus a registration fee—a processing or administration fee set by the medical institution that typically corresponds to the level of care. Therefore, the registration fees at medical centers are higher compared to those at regional and local hospitals. Also, while Taiwan’s NHI program covers most medical expenses, inpatients are still required to pay a small portion of the medical expenses as a co-payment. To reduce health inequity, low-income inpatients are exempt from the co-payment. However, the NHI program does not cover the registration fees. Therefore, unless the local government or hospital social welfare measures (SWM) provide relief for low-income inpatients, they have to pay the registration fee. In addition, postoperative patients may also be required to pay living costs and caregiver expenses during hospitalization, and/or pay for other medical equipment or prescription drug expenses that are not covered by NHI. In general, non-low-income inpatients have private health insurance to help pay those costs; however, low-income inpatients can only rely on minimum support from the government’s SWM since they cannot afford private health insurance. Low-income inpatients’ hospitalization costs also tend to be higher than those of non-low-income inpatients because they are hospitalized longer and are more seriously injured (Table S1). Thus, low-income inpatients are more reluctant to receive surgery despite having higher CCI scores. Moreover, the out-of-pocket medical expenses are generally proportional to the level of care received; the higher the level of care, the greater the expense. In Taiwan, the highest level of medical certification accreditation is the medical center. Consequently, low-income inpatients generally lean toward regional or local hospitals because of lower expenses. However, when taking the severity of the injury into consideration, low-income inpatients are more willing to receive care in medical centers for fatal injuries as opposed to non-fatal injuries.
Figure 1. Comparison of medical costs between low-income and non-low-income inpatients under the NHI program in Taiwan.
We also observed a significant gender gap in the low-income group. The Ministry of Health and Welfare of Taiwan has reported that among low-income individuals, the number of single-person households is higher for men than for women [14]. Typically, men in Taiwan are the main source of income because of the patriarchal nature of Chinese families. Therefore, low income men are less likely to marry and more likely to accept jobs with a poor working environment, making them more vulnerable to injuries. In addition to the gender gap, the low-income and non-low-income groups differed significantly in the percentage of individuals in the 5 to 14 age group (9.3% vs 5.1%). Our findings were consistent with previous research reporting that adolescents from lower socioeconomic families were more likely to have serious injuries requiring hospitalization [15].
Cause of injury
With unintentional, non-fatal injuries, our results showed that hospitalization rates related to “medical malpractice” and “falls” were higher for the low-income group than the non-low-income group.
A multinational retrospective study on the global burden of disease (GBD) showed that, as a result of medical adverse events, disability-adjusted years (DALYs) equal 23 million globally every year, for which two-thirds come from low-income and mid-income countries [16]. Other research on these same countries also showed more medical accidents, lower patient safety, and lower medical care quality for the low-income group [17].
We further observed that falling injuries are more prevalent among low-income inpatients in the middle and older age groups (more than 45 years old), as shown in Table S2. Past research on fall risk in older adults found that low income is a contributing factor [18]. Other factors include socioeconomic status (low education, solitary living, and lack of care), living environment (inconvenient floorplan and insufficient light), and physical condition (poor vision, chronic illness, and aging) [18, 19, 20]. Accordingly, the low-income group may be more susceptible to falling and hospitalization because of poor living conditions, more living hazards, and lack of safety protection equipment [19].
Intentional injuries showed a significantly higher rate of hospitalization for “suicide” and “homicide” for low-income inpatients in both fatal and non-fatal injuries. Additionally, previous research has shown that unemployment and specific occupations were also associated with suicide and suicidal behavior [21, 22, 23, 24]. According to the low-income family study conducted by the Ministry of the Interior of Taiwan, 62% of low-income family members have suffered catastrophic illnesses in the past [12]. In addition, 47% of the breadwinners in these families are out of the workforce.
Previous research also found that poverty increases the risk of mental illness and suicide [25, 26]. Low-income individuals generally view themselves as a financial minority, and tend to feel powerless, helpless, and repressed when facing competition, factors that may be associated with contemplating suicide. Therefore, low-income individuals have a much higher risk of repeating suicide attempts that result in hospitalization [27]. Some studies also indicate that low-income and severe illness exacerbate the risk of suicide during hospitalization. Patients with both severe illness and low-income may suffer multiple complications that require long-term care. Without sufficient resources, these patients may become depressed and consider suicide as an escape and a relief for their families [28].
Furthermore, one comprehensive analysis that collected criminal data from 169 countries found a positive correlation between income inequality and homicide/injury. This is especially prevalent in low-income and mid-income countries [29]. One could use Durkheim’s Anomie theory [30] to explain this pattern. As someone tries to thrive in a society where there are no legal avenues for achieving his goals, he feels pressure to deviate from his usual behavior and engage in illegal activities. Similarly, lower social class members tend to turn their efforts to criminal activities because financial rewards in the society are lacking, and criminal activities provide a means of obtaining financial rewards [30, 31].
In contrast, non-low-income inpatients were predominantly associated with transport injuries in both non-fatal and fatal injuries. According to official statistics [32], in 2010, 48.8% and 32.3% of traffic accidents were caused by motorcycle and private passenger cars, respectively. In Taiwan, motorcycles are the most popular means of transportation (64.1 motorcycles per 100 population) [33]. Most families have at least one motorcycle. Therefore, it is no surprise that our study found motorcyclist injuries to have the highest hospital admission rates for both the low-income and non-low-income groups. As shown in Table S3, motorcyclist injuries were more frequent in the low-income group than the non-low-income group. However, injuries suffered by the driver of a motor vehicle showed a more significant difference in hospital admission rates between the two groups compared to motorcyclist injuries. In general, low-income families are less likely to own a private passenger car because of costs or access barriers; therefore, they are less vulnerable to overall transport injuries.
In summary, falling and transport injuries are the most common causes of injury in the low-income group. Typically, inpatients with injuries or older adults who are at an increased risk of falling often need to use mobility aids such as wheelchairs, canes, and walkers. However, these mobility aids are not covered by Taiwan’s NHI, as per Article 51 of the National Health Insurance Act, and low-income inpatients are effectively denied access. The health inequality between low-income inpatients and non-low-income inpatients still exists despite the implementation of Taiwan’s NHI. Government agencies should take actions and eliminate the health inequity for low-income patients.
Limitations
The data from HWDC did not provide any information on immigration status (natives, new immigrants), marital status, education level, or occupation. The low-income group reported in this research was sorted by those who qualified for insurance under the Public Assistance Act and not by actual income. The health inequality in the most vulnerable group is likely to be higher than those in a low-middle income group (income quintiles or deciles). Therefore, potential non-differential misclassification bias may exist and may have resulted in findings that favor the null hypothesis [34]. Therefore, this study may underestimate the differences between the low-income and the non-low-income groups.