|Year : 2018 | Volume
| Issue : 2 | Page : 83-92
The effect of health insurance on maternal and child health: A systematic review
Sunday A Aderibigbe1, Ferdinand W Wit2, Michael Boele van Hensbroek3, Gordon K Osagbemi4, Tanimola M Akande4
1 Department of Epidemiology and Community Health, University of Ilorin, Kwara State; Department of Global Health, Academic Medical Center, Amsterdam Institute for Global Health and Development, University of Amsterdam, Amsterdam, The Netherlands
2 Department of Global Health, Academic Medical Center, Amsterdam Institute for Global Health and Development, University of Amsterdam, Amsterdam, The Netherlands
3 Global Child Health Group, Emma Children’s Hospital, Academic Medical Centre, Amsterdam, The Netherlands
4 Department of Epidemiology and Community Health, University of Ilorin, Kwara State, Nigeria
|Date of Web Publication||17-Jul-2019|
Sunday A Aderibigbe
Department of Epidemiology and Community Health, University of Ilorin, Kwara State
Source of Support: None, Conflict of Interest: None
Background: There has been increased interest in improving access of the rural poor to essential healthcare through community-based health insurance schemes to create an alternative from the dominant OOP expenditure being currently experienced. Aim: We performed a systematic review with the aim to determine the global effect of health insurance systems on maternal and child health. Methods: A search for primary studies reporting on the effect of health insurance on maternal and child health was done. Results: Eight articles met the inclusion criteria with four of them from low-income countries. We found that the cesarean section rates (P = 0.01) and proportion of women with low birth weight babies (P < 0.0001) were statistically significantly better in the insured women. However, the prevalence of (pre)eclampsia, the proportion of women with anemia/excessive blood loss at delivery, and mean birth weight at delivery were similar between the insured and uninsured women (P > 0.05). The risk of wasting among insured children was also reduced, although not statistically significant (P = 0.26). Conclusions: The findings suggest that health insurance probably has a beneficial effect in reducing the number of low birth weight babies born. Insurance also seems to reduce the risk for cesarean section. More research on the impact of health insurance on both maternal and child health outcomes need to be done to further establish these outcomes.
Keywords: Child health, health insurance, maternal health
|How to cite this article:|
Aderibigbe SA, Wit FW, van Hensbroek MB, Osagbemi GK, Akande TM. The effect of health insurance on maternal and child health: A systematic review. J Med Trop 2018;20:83-92
|How to cite this URL:|
Aderibigbe SA, Wit FW, van Hensbroek MB, Osagbemi GK, Akande TM. The effect of health insurance on maternal and child health: A systematic review. J Med Trop [serial online] 2018 [cited 2020 Jul 11];20:83-92. Available from: http://www.jmedtropics.org/text.asp?2018/20/2/83/262752
| Introduction|| |
In many developing countries, high cost is a hindrance to basic healthcare., Also, households pay out-of-pocket (OOP) for most healthcare services received, thereby spending a higher proportion of their income on private healthcare expenditures with the attendant catastrophic consequences on the family’s financial well being. In developed countries, however, most of these problems with regard to access and healthcare provision, as noticed in the developing nations, are almost nonexistent or at worst reduced to an insignificant level. The developed countries have better access to health services and have better health indices than the developing countries.
In nations with vast formal sectors, insurance premiums can be effortlessly collected through salary deductions from source or through tax collections. Large financial resources cannot be so generated in developing countries because a vast majority of the people work in informal settings., There has been increasing interest in the role of community-based healthcare financing schemes in improving equity and access of the poor to essential health care. These community-based health insurance (CBHI) schemes provide a mechanism for pooling of risk for sickness-related expenses at the community level and sometimes grow out of traditional risk-sharing schemes, such as burial societies in Africa.
Interventions aimed at addressing the unacceptably high maternal mortality and morbidity in developing countries include the Safe Motherhood Initiative and most recently the Millennium Development Goals (MDGs). Despite these interventions, only a slight drop has been achieved in these indicators especially in developing countries. Recent estimates indicate that approximately 350,000 maternal deaths and 3.3 million neonatal deaths occur annually, of which close to 50% and 30%, respectively, are occurring in Sub Saharan Africa (SSA). With an annual decline in maternal mortality of 1.3% and an increase in the proportion of child deaths occurring during the neonatal period in all regions of the world that is now globally at 43 deaths per 1000 live births in 2015, SSA is far from achieving the MDG of reducing the maternal mortality ratio by three quarters and reducing child deaths by two-thirds by 2015. One main barrier to achieving this MDG goals in sub-Saharan Africa is inadequate access to healthcare.
CBHI and other health insurance strategies may bring about an improvement in overall maternal and child health and survival through different direct and indirect routes. Directly, this can be done by reducing OOP expenses for healthcare services, thereby facilitating timely use of healthcare. Studies from developing countries have pointed to the fact that user fees can prevent early access to maternal health services.,,, Second, it makes women to be exposed and familiar with formal healthcare services early enough thereby providing opportunities to promote perinatal care.,
Making health insurance available in developing countries is expected to decrease healthcare spending and thereby make more money available to households for other needs especially more nutritious foods. Furthermore, health insurance is expected to improve access to care for childhood illnesses and other common diseases, thereby decreasing morbidity and mortality. For example, if there were no costs related to seeking healthcare, the mother might be able to rush a severely ill child to the clinic without having to wait for her husband for approval to spend on the child’s healthcare. Making optimal use of the so-called “golden hours” may therefore improve outcomes.
Although there are several theoretical reasons why CBHI may improve maternal and child health especially in developing countries, studies conducted in this field have not systematically been reviewed especially in the developing countries. In most reviews undertaken so far in high-income countries, health status improvements in maternal and child health as a direct result of insurance has also rarely been measured directly and quantitatively.,, We therefore performed such a systematic review to include both the high and low-income countries, with the aim to determine the effect of health insurance systems on maternal and child health.
| Methods|| |
Studies primarily reporting on health insurance and maternal or child health outcomes were searched for in the following databases in June 2016: PubMed (1950–2016), Embase (1980–2016), Africa Index Medicus (1960–2016), Africa Journals On-line (2004–2016), and Web of Science (1975–2016).
A standardized search protocol was developed based on the Cochrane Collaboration guidelines using the following keywords: “Health Insurance,” “Health Outcomes,” “Children,” “Under-Fives,” “Low Birth Weight,” and “Pregnant Women.” The search strategy aimed to identify all relevant articles and conference abstracts. Relevant articles were translated wherever necessary. Finally, reference lists of all selected articles were reviewed for relevant articles. Selection of articles and data extraction was done independently by two of the reviewers (ASA and MBVH); discrepancies were resolved by discussion.
Studies that presented data on the following were included: health outcomes in an insured population compared with an uninsured population of children less than 5 years of age and/or pregnant women. The child health outcomes considered included growth, development, malnutrition, mortality (infant mortality, under-five mortality), major morbidities (episodes of malaria, etc.), and anemia. The health outcomes considered for the pregnant women included anemia in pregnancy, pregnancy complications, perinatal mortality, low birth weight babies, complications at delivery, maternal mortality, and maternal morbidities.
Studies assessing restricted populations such as children with diseases that require specialized care and services and individual case reports and case reviews were excluded. All other relevant nonprimary articles on health insurance and health outcomes in pregnant women and children were used for the discussion section.
The following data were collected for the children: prevalence of anemia, prevalence of wasting/failure to thrive, and mean birth weight. For the maternal aspect, prevalence of anemia/excessive blood loss, prevalence of preeclampsia/eclampsia, prevalence of cesarean section, mean gestational age at delivery, and percentage of women with low birth weight babies. All data were entered into excel database.
Health insurance is a type of insurance that covers the cost of an insured individual’s medical and surgical expenses. Depending on the type of health insurance coverage, either the insured pays costs OOP and is then reimbursed, or the insurer makes payments directly to the provider. For the purpose of this review, health insurance systems were defined as mechanisms that are generally recognized as having the aim of achieving universal coverage with adequate financial protection for all against healthcare costs regardless of whether its social health insurance or community-based health insurance. Studies were classified as from low-income settings if carried out in Asia, Africa, and South and Central America. Those from Europe and North America were classified as from high-income settings.
Comprehensive meta-analysis software version 3 (Biostat Inc., Englewood, NJ, USA) and STATA version 12 (StataCorp, College Station, TX, USA) were used for data analysis. Descriptive data of all identified studies are presented in [Table 1] and [Table 2]. Pooled mean birth weight estimates (95% confidence intervals, CIs) and pooled analysis of the prevalence of preeclampsia (as a complication of pregnancy) estimates (95% CIs) as well as Forest plots were generated for studies done in insured and uninsured women. A random effect model was employed for the pooled analysis. Other parameters (anemia, child mortality, perinatal survival, malaria as a major morbidity, and infant mortality and growth) were only reported by one of the studies each and hence were not subjected to any form of pooled analysis. Two-sided P values of <0.05 were considered as statistically significant.
| Results|| |
Systematic reviews and meta-analyses (PRISMA) guidelines were followed in presenting the findings.
Selection of articles
A search of the following databases was performed: PubMed, Web of Science, Embase, Africa Index Medicus, and Africa Journals On-line retrieved 1479 hits, of which 31 qualified using the selection criteria described earlier [Figure 1]. From the 31 articles left, 23 were excluded either because they did not present relevant findings exclusively on the study target population (children under five or pregnant women) or they did not present data on health insurance and health outcomes.
Description of selected studies
Eight articles met the inclusion criteria and were included in the review. Four studies were from low-income settings: Ghana,, Nigeria, and Philippines; and four were from high-income settings: Canada and USA.,, The four studies from the high-income setting were retrospective case comparison studies whereas two from the low-income settings were prospective randomized controlled studies. One was also a prospective cohort study but not randomized whereas the last was a retrospective study.
One of the Ghanaian studies was a household randomized, controlled, unblinded trial in which 2194 households containing 2592 Ghanaian children under 5 years were randomized into a prepayment scheme allowing free primary care, including drugs, or to a control group whose families paid user fees for healthcare. The other Ghanaian study was a retrospective static-group comparison of birth records of women who delivered before and after the introduction of the country’s health insurance program. A total of 1433 birth records were abstracted for review out of which 1046 were delivered after introduction of health insurance (and mothers were insured) and 387 under the OOP payment era.
The Nigerian study was a prospective cohort study of 150 women who were health insurance enrolees. They were matched with 150 insurance nonenrolees within the same time period. The study compared the pregnancy outcome of the two groups. The women were followed-up from antenatal care enrolment until 6 weeks after delivery.
The Philippines study was a prospective randomized controlled study. It presented evidence on the health effects of health insurance intervention targeted at poor children using data from a randomized policy experiment known as the Quality Improvement Demonstration Study.
The Canadian study was a retrospective case comparison study of uninsured women (n = 71) presenting for prenatal care at two primary care centers. The controls were chosen from insured women (n = 72) presenting for prenatal care during the same period. Perinatal outcomes assessed included gestational age and birth weight.
One of the US studies was a retrospective cross-sectional comparative study in which the authors looked at the capitated prepaid insurance program versus the traditional fee-for-service system and their effect on prenatal care and birth outcomes for women and children. Patients were sampled from computerized Medicaid claim files. The study was conducted in two sites with each site being divided into the prepaid and the fee-for-service groups. In total, 949 women were recruited into the prepaid group from both sites whereas 1387 were recruited into the fee-for-service group.
One of the remaining two US studies was a retrospective case comparison study that looked at the impact of managed care on hospital obstetric outcomes in Medicaid-sponsored women and this was compared to women on fee-for-service. A total of 525,517 records of women were abstracted for the study. The second study by Oleske et al. was also a retrospective case comparison studies to determine if payment method influenced the likelihood of selected obstetrical process measures and pregnancy outcome indicators among Medicaid women when compared with women on fee-for-service.
Health insurance and pregnancies (including effect on newborns)
The prevalence of anemia/excessive blood loss, eclampsia/preeclampsia rate, and mean gestational age at delivery were similar in both the insured and the uninsured groups of women whereas the cesarean section rates were found to be significantly different in both the groups with the insured women having a better outcome.
Pooled analysis for cesarean section rates between the two groups were found to be statistically different (odds ratio, OR = 0.90, 95% CI = 0.83–0.98, P = 0.01) with insured women having less need for cesarean section than uninsured women. The pooled analysis of prevalence of (pre)eclampsia revealed that insured women had a similar risk of developing (pre)eclampsia compared to uninsured women (OR = 0.96, 95% CI = 0.85–1.08, P = 0.49). The proportion of insured women with anemia/excessive blood loss at delivery was not different from the proportion in uninsured women (OR = 0.76, 95% CI = 0.24–2.42, P = 0.64) [Figure 2].
Two studies reported the mean gestational age at delivery: one of the studies reported this to be 39.2 weeks for the insured and 39.0 weeks for the uninsured group (P = 0.289). The second study was carried out in two sites. The two sites reported no difference between the insured and uninsured women.
Low birth weight is a pregnancy outcome used as a marker of the efficacy of primary healthcare services. The mean birth weight of infants revealed that there was no difference in the mean birth weight of both groups (insured vs. uninsured: 3234 vs. 3236 g) (standard difference in mean = 0.0129 kg, 95% CI = −0.17–0.20, P = 0.89). However, further analysis showed that insured women had a reduced risk of having a low birth weight baby than the uninsured group (OR = 0.74, 95% CI = 0.62–0.87, P < 0.0001) [Figure 2].
Health insurance and children
The Ghanaian study presented data on anemia, child mortality, major morbidities in children under 5 years of age, especially malaria, and growth indicators whereas the study from the Philippines only reported wasting in insured compared to uninsured children. The prevalence of moderate anemia in the Ghanaian study in the insured and uninsured was 3.2% and 3.1%, respectively (P = 0.88) whereas that for severe anemia was 0.2% and 0.3%, respectively (P = 0.71). A pooled analysis of the prevalence of wasting from the two studies (three sites) revealed that the risk of wasting among the insured children was reduced when compared with the risk in uninsured children although the difference was not statistically significant (OR = 0.88, 95% CI = 0.71–1.10, P = 0.26) [Figure 3].
| Discussion|| |
Health insurance in general
Removing financial barriers to healthcare services is one of the essential first steps toward improved and timely access to quality healthcare for the poor. Studies have shown that health insurance will increase access to and utilization of healthcare services,, which is expected to bring about an improvement in the health status of the enrolees. However, there is limited evidence from utilization studies that increased access actually results in better health outcomes, through a direct causal link between enrolling in a health insurance scheme and better health status. The outcomes shown to be correlated with health insurance range from death to objective physiological measures of health (such as hypertension) and subjective measures (such as self-reported health status). Also, with particular reference to CBHI schemes, membership of these schemes are meant to be voluntary, hence making them prone to adverse selection that will eventually make such schemes financially unsustainable. This concept of adverse selection has been studied both in high-income and low/middle-income countries,,,, and have been found to be real and a threat to the success of any health insurance scheme. With adverse selection, the relationship between enrolment in health insurance and health outcomes may then be difficult to correctly measure as there is likelihood that only the high-risk or unhealthy individuals get enrolled in the insurance scheme in the first place.
Health insurance and pregnancy outcomes
It should be noted that the result of the pooled analysis of the studies that reported on prevalence of low birth weight between insured and uninsured women showed that the insured women had a significantly reduced risk of having a low birth weight baby than the uninsured group. This finding was also reported by Baldwin et al. in which expansion of the Medicaid program brought about a reduction in prevalence of low birth weight babies. These findings were reported by both high and low-income countries alike. Low birth weight has a profound effect on the survival of the newborn and is an indicator of long-term survival and development of infants, hence such health insurance schemes that have been shown to reduce the risk of low birth weight may then be among the worthwhile investments of all stakeholders. However, only one out of the eight studies reported was a randomized controlled trial that has been argued to provide more scientific evidence of causality. Hence, there continues to be a need for more research in this regard.
The prevalence of (pre)eclampsia and anemia/excessive blood loss in the two groups was found to be similar. Although these findings seem to give credence to the conclusions from other studies that health insurance may not necessarily bring about a better health status, it is however a sign that with increased access to quality healthcare and the financial protection that is expected to come from health insurance, more women may reduce their risks of unfavorable pregnancy outcomes. This assertion is further strengthened by the finding that the risk for cesarean section was found to be statistically significantly reduced among the insured women. A study found that extending health insurance to the uninsured population would result in an improvement in population health outcomes. A review study found weak evidence suggestive that expanding Medicaid for pregnant women led to improved birth outcomes.
Health insurance and child outcomes
Only one study was identified that measured anemia in insured and uninsured children in a low-income country; this study reported that there was no difference in the prevalence of anemia in the two groups, yet other studies done in developed countries found a significantly higher prevalence of subclinical anemia among uninsured compared to insured children. This study was however not included in this review because it did not set out to compare insured vs. uninsured children ab initio. The finding was obtained during further post hoc subgroup analysis of their results. More research needs to be done to arrive at a conclusion on the effect of insurance on anemia in children. However, it is generally known that a common cause of anemia in children is, among other causes, iron deficiency that is commonly caused by iron-deficient diets. If provision of health insurance decreases healthcare spending and makes more money available to households especially for more nutritious foods, this in turn may bring about a reduction in the prevalence of iron-deficiency anemia in these children. In addition, health insurance is expected to bring about earlier and better access to treatment of childhood illnesses and diseases and thereby decreasing morbidity and mortality in children.Risk of wasting in insured children was found to be reduced relative to uninsured children, although the findings were not statistically significant. The authors reported that “there are larger health status improvements among patients in the intervention compared to control hospitals.” This finding is especially important for low-income countries that are increasingly imbibing the culture of health insurance. One of the main causes of neonatal and infant mortality in the low-income countries is malnutrition and infections. Therefore, if health insurance has the potential to reduce OOP spending on healthcare and protecting against financial shocks because of large healthcare expenditures, introducing health insurance maybe the way to go in order to guarantee universal health coverage in these countries. This may help in reducing the prevalence of malnutrition among under-five children, by making more money available to poor rural households for food.
| Conclusion|| |
This review has shown that health insurance may have a beneficial effect on health outcomes by significantly reducing the risk for low birth weight and has given some indications of improving the birth weight of babies and reducing the risk of wasting. It did also give an indication of a significant reduction in the risk for cesarean section. Overall, evidence regarding the effect of health insurance in bringing about improved health outcomes is inconclusive, partly due to the small number of studies focusing on these outcomes coupled with the fact that almost all the studies were not randomized controlled trials, in addition to the problem of adverse selection in health insurance enrolment, which has remained largely unresolved. More research into the impact of health insurance on maternal and pediatric health outcomes needs to be done, which will provide much needed information that can contribute to policy formulation.
Financial support and sponsorship
The work was supported by the The Health Insurance Fund, through a grant from the Dutch Ministry of Foreign Affairs; PharmAccess Foundation; and Hygiea Nigeria Limited. The funding bodies had no role in study design, data collection and analysis, interpretation of outcomes, decision to publish, or preparation of the manuscript.
Conflicts of interest
There are no conflicts of interest.
| References|| |
WHO. The World Health Report 2000: health systems: improving performance. Public Health Rep 2001;116:268-9.
Gottret P, Schieber G. Health Financing Revisited: A Practitioner’s Guide. World Bank Publications; 2006.
Robyn PJ, Sauerborn R, Bärnighausen T. Provider payment in community-based health insurance schemes in developing countries: a systematic review. Health Policy Plan 2013;28:111-22.
Woolhandler S, Himmelstein DU. Paying for national health insurance: and not getting it. Health Aff Proj Hope 2002;21:88-98.
Bennett S. The role of community-based health insurance within the health care financing system: a framework for analysis. Health Policy Plan 2004;19:147-58.
Ekman B. Community-based health insurance in low-income countries: a systematic review of the evidence. Health Policy Plan 2004;19:249-70.
AbouZahr C, Wardlaw T. Maternal mortality at the end of a decade: signs of progress? Bull World Health Organ 2001;79:561-8.
Hogan MC, Foreman KJ, Naghavi M, Ahn SY, Wang M, Makela SM et al.
Maternal mortality for 181 countries, 1980-2008: a systematic analysis of progress towards Millennium Development Goal 5. Lancet 2010;375:1609-23.
Oestergaard MZ, Inoue M, Yoshida S, Mahanani WR, Gore FM, Cousens S et al.
Neonatal mortality levels for 193 countries in 2009 with trends since 1990: a systematic analysis of progress, projections, and priorities. PLoS Med 2011;8:e1001080.
Gelband H, Liljestrand J, Nemer L, Islam M, Zupan J. The evidence base for interventions to reduce maternal and neonatal mortality in low and middle-income countries. Available at: http://www.eldis.org/assets/Docs/29845.html
. [Accessed October 22, 2012].
Borghi J, Ensor T, Somanathan A, Lissner C, Mills A. Mobilising financial resources for maternal health. Lancet 2006;368:1457-65.
Ensor T, Ronoh J. Effective financing of maternal health services: a review of the literature. Health Policy Amst Neth 2005;75:49-58.
Mbugua JK, Bloom GH, Segall MM. Impact of user charges on vulnerable groups: the case of Kibwezi in rural Kenya. Soc Sci Med 1982 1995;41:829-35.
Stekelenburg J, Kyanamina S, Mukelabai M, Wolffers I, van Roosmalen J. Waiting too long: low use of maternal health services in Kalabo, Zambia. Trop Med Int Health TM IH 2004;9:390-8.
Bhatia J, Cleland J. Determinants of maternal care in a region of South India. Health Transit Rev 1995;5:127-42.
Nuwaha F, Amooti-kaguna B. Predictors of home deliveries in Rakai District, Uganda. Afr J Reprod Health 1999;3:79-86.
Freeman JD, Kadiyala S, Bell JF, Martin DP. The causal effect of health insurance on utilization and outcomes in adults: a systematic review of US studies. Med Care 2008;46:1023-32.
Cochrane Handbook for Systematic Reviews of Interventions. New York: Wiley 2008.
Liberati A, Altman DG, Tetzlaff J, Mulrow C, Gøtzsche PC, Ioannidis JPA et al.
The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration. Ann Intern Med 2009;151:W-65.
Ansah EK, Narh-Bana S, Asiamah S, Dzordzordzi V, Biantey K, Dickson K et al.
Effect of removing direct payment for health care on utilisation and health outcomes in Ghanaian children: a randomised controlled trial. PLoS Med 2009;6:e1000007.
Ibrahim A, O’Keefe AM, Hawkins A, Hossain MB. Levels and determinants of low birth weight in infants delivered under the National Health Insurance Scheme in Northern Ghana. Matern Child Health J 2015;19:1230-6.
Lawani LO, Iyoke CA, Onoh RC, Nkwo PO, Ibrahim IA, Ekwedigwe KC et al.
Obstetric benefits of health insurance: a comparative analysis of obstetric indices and outcome of enrollees and non-enrollees in southeast Nigeria. J Obstet Gynaecol 2016;36:946-9.
Quimbo SA, Peabody JW, Shimkhada R, Florentino J, Solon O. Evidence of a causal link between health outcomes, insurance coverage, and a policy to expand access: experimental data from children in the Philippines. Health Econ 2011;20:620-30.
Jarvis C, Munoz M, Graves L, Stephenson R, D’Souza V, Jimenez V. Retrospective review of prenatal care and perinatal outcomes in a group of uninsured pregnant women. J Obstet Gynaecol Can 2011;33:235-43.
Oleske DM, Branca ML, Schmidt JB, Ferguson R, Linn ES. A comparison of capitated and fee-for-service Medicaid reimbursement methods on pregnancy outcomes. Health Serv Res 1998;33:55-73.
Oleske DM, Linn ES, Nachman KL, Marder RJ, Sangl JA, Smith T. Effect of Medicaid managed care on pregnancy complications. Obstet Gynecol 2000;95:6-13.
Carey TS, Weis K, Homer C. Prepaid versus traditional Medicaid plans: lack of effect on pregnancy outcomes and prenatal care. Health Serv Res 1991;26:165-81.
Ibrahim A, O’Keefe AM. Do infant birth outcomes vary among mothers with and without health insurance coverage in Sub-Saharan Africa? Findings from the National Health Insurance and Cash and Carry Eras in Ghana, West Africa. Int J MCH AIDS 2014;2:200-8.
Peabody JW, Rahman MO, Gertler PJ, Mann J, Farley DO, Luck J. Policy and Health: Implications for Development in Asia. Cambridge: Cambridge University Press 2000.
Levy H, Meltzer D. The impact of health insurance on health. Annu Rev Public Health 2008;29:399-409.
Brown ME, Bindman AB, Lurie N. Monitoring the consequences of uninsurance: a review of methodologies. Med Care Res Rev 1998;55:177-210.
Sapelli C, Vial B. Self-selection and moral hazard in Chilean health insurance. J Health Econ 2003;22:459-76.
Savage E, Wright DJ. Moral hazard and adverse selection in Australian private hospitals: 1989–1990. J Health Econ 2003;22:331-59.
Ilayperuma SK. Adverse selection in health insurance markets? Evidence from state small-group health insurance reforms. J Public Econ 2005;89:1865-77.
Wang H, Zhang L, Yip W, Hsiao W. Adverse selection in a voluntary Rural Mutual Health Care health insurance scheme in China. Soc Sci Med 2006;63:1236-45.
Noterman J-P., Criel B, Kegels G, Isu K. A prepayment scheme for hospital care in the Masisi district in Zaire: a critical evaluation. Soc Sci Med 1995;40;919-30.
Baldwin LM, Larson EH, Connell FA, Nordlund D, Cain KC, Cawthon ML et al.
The effect of expanding Medicaid prenatal services on birth outcomes. Am J Public Health 1998;88:1623-9.
Thornton JA, Rice JL. Does extending health insurance coverage to the uninsured improve population health outcomes? Appl Health Econ Health Policy 2008;6:217-30.
Howell EM. The impact of the Medicaid expansions for pregnant women: a synthesis of the evidence. Med Care Res Rev 2001;58:3-30.
Kristinsson G, Shtivelman S, Hom J, Tunik MG. Prevalence of occult anemia in an urban pediatric emergency department: what is our response? Pediatr Emerg Care 2012;28:313-5.
Spaan E, Mathijssen J, Tromp N, Mc Bain F, ten Have A, Baltussen R. The impact of health insurance in Africa and Asia: a systematic review. Bull World Health Organ 2012;90:685-92.
[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2]