3.1. Studies of the determinants of health insurance enrollment
Literature on the determinants of health insurance enrollment abounds. In Ghana, Salari et al. (2019) investigated the socio-economic determinants of health insurance enrollment and found that education, marital status, wealth and to a limited extent, age had positive correlations with enrollment in Ghana’s National Health Insurance Scheme (NHIS). They also found that the type of employment had equally important associations with the probability of enrollment, with agricultural workers and unemployed persons being less likely to enroll compared with workers in other sectors. Some of the factors identified in this study confirmed earlier findings by Duku (2018), who investigated the determinants of health insurance enrollment in the Greater Accra and Western regions of Ghana. In addition to educational level, wealth, and marital status, Duku (2018) found that travel time to the health facility, age, and sex significantly influenced health insurance enrollment. Owusu-Sekyere and Chiaraah (2014) conducted a study in the Kumasi metropolis of Ghana on the factors influencing health insurance enrollment. Contrary to the earlier studies discussed, this study did not find age, sex, and marital status to be important determinants of enrollment. However, it found that years of schooling, income, employment status, and the cost of curative care were important predictors of enrollment.
In a further study on the NHIS in Ghana, Nsiah-Boateng et al. (2019) investigated the determinants of enrollment in, and dropout from, the health insurance scheme in the Ashiedu Keteke sub-metropolis of Ghana. The study found that indigents are more likely to enroll but also more likely to drop out of the scheme. On the contrary, the study found that informal sector workers as well as formal sector workers who are contributors to the national pension scheme are less likely to enroll but more likely to retain their membership in the health insurance scheme once enrolled. Fenny et al. (2016) conducted a study that examined the factors responsible for the low enrollment and low retention of status in Ghana’s NHIS. The study found that vulnerability as measured by being the poor, aged, disabled, mentally challenged, or migrant served as a social barrier to enrollment and that the absence of family support and social support, cultural and religious norms, poor infrastructure, especially in rural communities, and the NHIS’s own weak internal administrative systems were also partly responsible for hindering health insurance enrollment.
Other studies on the determinants of health insurance enrollment in Ghana confirm the factors identified in the review above as having correlations with health insurance (Amu et al., 2018; Amu and Dickson, 2016; Agyepong et al., 2016). However, no study has yet been found that investigated the impact of household risk preferences on enrollment in health insurance. Given the voluntary nature of Ghana’s national health insurance program, an examination of this behavioral factor is crucial to understanding enrollment behavior and enhancing policy planning.
We now turn to a review of studies in jurisdictions other than Ghana where public health insurance might be compulsory, non-existent, or voluntary. Many of these studies explored the determinants of private health insurance purchase. Buchmueller et al. (2013) examined preference heterogeneity in private health insurance enrollment in Australia, a country in which there is a comprehensive universal public health insurance system. Among other things, the study found that those who have purchased other insurance products, i.e., risk averse people, are more likely to purchase private health insurance, and conversely, that those who smoke, i.e., less risk averse people, are less likely to purchase private health insurance. Thus, this study underscores the relevance of risk preferences in determining health insurance enrollment, especially in a voluntary health insurance program. These findings confirm those from an earlier study by Liu et al. (2011) on the impact of expanding public health insurance on private health insurance demand in rural China. This study found that risk averse households were more likely to purchase private health insurance for both adults and children. This was in addition to the main finding of the study—namely, that there were large positive effects of public health insurance expansion on private health insurance demand among higher income groups and communities with a history of health care financing. Similarly, Hopkins and Kidd (1996) found that less risk averse people were less likely to purchase private health insurance in Australia. Another study by Condliffe and Fiorentino (2014) confirm the findings from the above studies. They examined the impact of risk preferences, measured by engagement in risky behavior, on health insurance and health expenditures in the United States. They found that, relative to low risk preference individuals, high risk preference and moderate risk preference individuals were more likely to be uninsured. The study also found gender and educational levels to be significant predictors of health insurance enrollment.
However, the findings of these studies on the role of risk preferences contrast with the findings of Costa and Garcia (2003), who found no significant effects of attitudes towards risk on the demand for private health insurance in Catalonia, Spain. Their study found the demand for private health insurance to be driven mainly by the gaps in quality between public and private health care in addition to other socio-economic factors. This finding corroborates that of Jofre-Bonet (2000), also for Spain, who found that the quality of health care, proxied by waiting times, in the Spanish public health system, reduced the demand for private health insurance. On the contrary, Propper et al. (2001) found a negative effect of waiting lists on private health insurance purchase in the UK. Finn and Harmon (2006) examined the determinants of private health insurance enrollment in Ireland where, similar to the Australian case, there is a near robust public healthcare financing system in place, but the study did not examine the effect of risk preferences. Factors including income, education, and health status were found be significant determinants of whether or not to purchase private health insurance in Ireland.
3.2. Studies of the determinants of health expenditure and health care utilization
Our study also relates to the strand of literature that has examined the determinants of health expenditure and health care utilization. Jeon and Kwon (2013) examined the effect of private insurance on health care utilization and health expenditure in Korea, which has a universal public insurance system, and found that people with private health insurance have a higher probability of seeking outpatient care but not inpatient care. Liu and Zhao (2014) examined the impact of a voluntary health insurance program on health care utilization in urban China. Employing an instrumental variable approach, the study found that enrollment in the health insurance program significantly increased formal health care utilization for both inpatient and outpatient care in the case of children, low-income families, and residents in the poorer western region of China. However, no evidence was found that the program had reduced out-of-pocket health expenditure. Condliffe and Fiorentino (2014) found risk preferences to have a negative relationship with health expenditure in the United States--i.e., that high and moderate risk preference individuals spent significantly less on health care than low risk preference individuals--and that insured persons actually spend more on health care than uninsured individuals, contrary to expectation.
In Ghana, only a few studies exist, especially at the micro level, on the determinants of health expenditure or health care utilization. Blanchet et al. (2012) investigated the effect of Ghana’s NHIS on health care utilization using data on a sample of women in Accra. Using matching techniques, the study found that individuals who are enrolled in the NHIS were more likely to visit clinics, to seek formal health care, and to obtain prescriptions, indicating an increase in health care utilization. The results may not be easily generalizable due to the limited study area (Accra), which is more economically advantaged and better off in terms of health infrastructure and personnel. That notwithstanding, the findings confirm those of Rajkotia and Frick (2011) in the Nkoranza district of Ghana. This study attempted to test for the existence of adverse selection into the NHIS by examining how the observed payoffs to enrollment relate to household enrollment costs (where enrollment costs for a household were measured as the sum of premium payments by non-exempt members). They found that household enrollment costs are positively correlated with the odds and intensity of outpatient health care use by children. At the macro level, Angko (2013) examined the determinants of public healthcare expenditure in Ghana using annual time series data. Per capita Gross Domestic Product (GDP), health status of the population, and the age structure of the population were found to be the major determinants of health expenditure in Ghana. A similar macro level study in 26 African countries by Okunade (2005) shows that, in addition to per capita GDP and the dependency ratio, overseas development assistance, the level of income inequality, internal conflicts, and the percentage of births attended by trained personnel were identified as determinants of public health expenditure in the countries included in their sample.
This review of the literature shows that, in the case of determinants of public health insurance enrollment, the role of risk aversion has been left largely unexamined, especially in Ghana where the public health insurance system is a voluntary one. Furthermore, studies on the effect of public health insurance enrollment on health expenditure are limited in Ghana and other countries that are unique in operating voluntary public insurance programs. Our study fills these gaps in the literature and provides the basis for further research in other jurisdictions as well as a basis for effective health policy planning.