Background
Over the last two decades, Nigeria has documented both progress and challenges in improving the health of its population [
1]. Although under-5 mortality decreased by 38% between 1990 and 2013, 14% of child deaths in the world still occurred in Nigeria in 2013 [
2]. Minimal gains have occurred for maternal mortality over the past 25 years, with Nigeria’s maternal mortality ratio consistently hovering around 500 deaths per 100,000 live births since 1990 [
3]. In 2013, 30% of the world’s malaria cases and deaths occurred within Nigeria’s borders [
4].
Nigeria and its development partners have made several efforts to address the country’s health needs. To date, investments to scale up polio immunization campaigns and malaria control have been particularly large [
5,
6]; for instance, the Global Polio Eradication Initiative (GPEI) plans to spend nearly $1.5 billion on efforts in Nigeria between 2013 and 2018 [
7]. Beyond disease-specific programs, Nigeria has also enacted policies to improve access to and quality of health care [
8‐
16]. In 2014, the National Health Bill was passed, aiming to strengthen Nigeria’s primary health care systems, bolster monitoring and evaluation capacities, and move toward universal health coverage through improved financial protections [
17].
Health policies and programs are typically implemented in a phased manner in Nigeria, largely due to the country’s large size and decentralized health system [
10,
13,
18]. State governments oversee health funding and logistic support, whereas local government areas (LGAs) are the geographic units from which primary health services are provided [
10,
19]. Historically, LGAs have been under-funded and operate with less capacity to implement health initiatives than originally planned [
20]. In combination with the country’s large and diverse population, it often takes years before interventions have reached all states. For instance, over a third of states rolled-out the pentavalent vaccine two years after it was originally introduced in the country [
21], while mass distribution campaigns for long-lasting insecticide-treated nets (LLINs) occurred state by state between 2008 and 2014 [
6,
22,
23]. This highlights the need to track and assess trends in intervention coverage and health outcomes at the subnational level in Nigeria.
A number of other populous countries, such as Mexico and Brazil, have been successful in using subnational benchmarking exercises to inform policy decisions and program priorities [
24‐
26]. Although efforts have been made to synthesize subnational health information in Nigeria, these data have not often been comparable over time, nor have they presented the country’s full geography [
13,
27‐
32]. Recently, there have been efforts to develop a LGA-level tool for evaluating progress on health, education, and environmental indicators by Nigeria’s Millennium Development Goal (MDG) office [
33], a critical step to improving subnational monitoring systems. However, this tool shows information for each indicator for only 1 year and thus cannot provide an understanding of trends over time – a vital component to capturing the effects of specific health policies and programs.
By synthesizing data from multiple sources, we provide the first-ever analysis of state-level trends for a range of Nigeria’s key maternal and child health (MCH) outcomes and interventions from 2000 to 2013.
Discussion
This study represents the first-ever assessment of state-level trends for a range of MCH interventions and outcomes in Nigeria, highlighting the country’s mixture of progress and ongoing challenges in improving local health service provision. Every state recorded declines in under-5 mortality – a major success – yet, absolute rates of child deaths still ranked among the highest in sub-Saharan Africa [
2]. For a subset of malaria interventions, coverage increased substantially between 2009 and 2013; however, coverage remained quite low, particularly for IPTp2 and ACTs, a cause for concern given Nigeria’s large malaria burden [
4]. Coverage of certain immunizations increased, especially for OPV3, an important result given Nigeria’s aims to end wild polio transmission [
56]. At the same time, similar gains were not actualized for DPT3 coverage across states, suggesting that more routine delivery platforms for multi-dose vaccines may be faltering amid disease-focused immunization campaigns [
40,
58]. Coverage of other key MCH interventions, such as ANC4 and SBA, generally stagnated or declined, and stark differences in coverage have persisted across states since 2000. Benchmarking state-level performance for MCH indicators demonstrated the continued entrenchment of North-South differences, particularly for more routine services, and showed that overall intervention coverage generally remained low despite recent gains for a subset of MCH interventions.
Nigeria’s state-level trends in under-5 mortality likely reflect the complex nature of improving health outcomes amid local changes in health system access, delivery of services, broader socio-economic gains, and overall development. While all states experienced reductions in under-5 mortality between 2000 and 2013, it is unlikely that these gains were driven by the same factors in each state. In states where malaria transmission is particularly high and coverage of ITNs increased, such as Bauchi, improved childhood survival may be attributable to expanded malaria control programming. In contrast, in urban areas where malaria transmission is somewhat lower and women’s educational attainment rose since 2000, such as Edo, socio-economic advances may play a stronger role in reducing under-5 deaths. Assessing how different intervention packages and socio-economic forces are contributing the largest gains in childhood survival – and doing so at local levels – is critical to accelerating improved health throughout Nigeria. For disease-specific programs that feature well-funded, focused campaigns (namely malaria and polio) [
5‐
7], the scale-up of intervention coverage was less varied across states. For instance, by 2013, many states in more rural, poor areas reached levels of OPV3 coverage found in the wealthier states of Nigeria. Although absolute levels of immunization coverage remained lower than optimal, the gap between states with the highest and lowest levels of coverage narrowed over time. Conversely, inequalities in the coverage of several MCH interventions and services provided through more routine platforms continued across states, often following geographic patterns for urbanicity, wealth, and educational attainment [
32,
59]. These findings suggest that barriers to accessing and using health services likely remain in many states, particularly those in more remote, impoverished areas. These factors involve ongoing violence in northern Nigeria [
60‐
62]; demand-side influences (proximity to facilities and care [
63‐
65], affordability of transportation to health facilities [
66], cost of health care [
67], knowledge of available services and trust in providers [
28], religious views or cultural mores [
68,
69]); and supply-side dynamics (availability of skilled medical staff and their interactions with patients [
70‐
72], inconsistent stocks of pharmaceuticals and medical supplies across levels of care [
73‐
75], inadequate facility infrastructure [
76]). In combination, these factors may have a compounding effect on hindering health-care-seeking behaviors. Additional work on identifying which of these factors are most easily affected by policy levers and programs promoting heighted utilization of routine services in Nigeria should be prioritized.
Nigeria’s gains in improving polio immunization coverage, particularly when compared to trends in DPT3 vaccination rates, highlight the differences in the country’s health system functions across specific interventions. As one of the last polio-endemic countries in the world, Nigeria has received tremendous resources and policy attention for eliminating polio, especially through the GPEI [
56,
77]. Due to targeted immunization campaigns and developing disease surveillance structures [
56,
78,
79], Nigeria increased OPV3 immunization coverage by 25 percentage points since 2000 and created a strong detection-response system for finding its remaining polio cases. Such progress is particularly impressive given that Nigeria has experienced tensions and violence around polio vaccination, notably culminating in boycotts of immunization campaigns in Kano, Zamfara, and Kaduna in 2003 and 2004 [
80,
81], and multiple shootings in 2013 [
82]. On the contrary, Nigeria saw minimal progress for DPT3 immunization rates, another three-dose vaccine that is delivered through more routine EPI services rather than mass campaigns. This contrast with Nigeria’s gains in OPV3 coverage reflects how program-focused investments and commitment can likely improve vaccination rates, as well as possible missed opportunities for integrating service delivery [
55,
58].
Diverging state-level trends for MCH interventions revealed geographic disparities along a continuum of care for maternal health services. In a health system where both demand and supply for health services are strong, we might expect to see similar coverage levels for ANC1, ANC4, SBA, and IFD, or that women have least four ANC visits prior to delivery and give birth in a health facility and/or in the presence of skilled attendant [
83]. We found that a subset of states, largely located in the southern regions of Nigeria, appeared to have strong linkages between these services, experiencing minimal differences in coverage for ANC1 and ANC4, for example. However, the majority of states saw some kind of breakdown in this MCH service continuum. These findings point to two related but separate challenges to bolstering Nigeria’s continuum of care for MCH services: (1) improving the frequency of ANC visits and (2) cultivating stronger demand and capacity for giving birth with skilled birth attendants or in health facilities. Previous research has identified cost, transportation, and capacity of the health facility as barriers for women seeking ANC services [
84,
85] and SBA [
14,
86,
87]. Local health authorities may consider expanding and scaling up existing programs which include outreach campaigns, improving facility-based resources for ANC and routine deliveries, and innovative incentive structures, such as conditional cash transfers, that explicitly link ANC to post-natal services [
1,
14,
16,
88‐
91].
This study further demonstrates the importance of setting ambitious yet realistic health system goals, as well as approaching such target-setting with an equity lens. Nigeria established several high-reaching health program goals to improve MCH outcomes, which included achieving 80% ITN coverage by 2013 [
92], 78% DPT3 coverage by 2013 [
54], and rates of 38% for EBF by 2013 [
10]. We found that national coverage of these interventions – 47% for ITN ownership, 46% for DPT3, and 15% for EBF – registered well below the country’s targets in 2013. While a few states met or exceeded these targets for EBF and DPT3 (e.g., Osun and Ekiti had EBF rates exceeding 40% in 2013), most states fell quite short of the country’s health program goals. Many of these targets may have been overly ambitious given baseline levels of intervention coverage (e.g., at 14% ITN ownership in 2009, Nigeria remained 66 percentage points away from its goal of 80% in 2013); at the same time, Nigeria’s goals align with global recommendations and targets for improving priority MCH outcomes (e.g. the MDGs). To accelerate Nigeria’s progress toward its health system goals for 2015 and beyond, a heightened focus on the country’s most disadvantaged populations will be required. EBF, for example, is considered highly cost-effective for improving childhood survival, requires minimal investments in health system infrastructure to scale up, and has been expanded rapidly in other African countries [
42]; thus, strengthening educational outreach about EBF [
93] and expanding facility-based breastfeeding programs, such as the Baby Friendly Hospital Initiative [
94], across levels of care may promote better child health outcomes in states with low levels of EBF. Without a greater focus on local health needs and addressing Nigeria’s persistent health inequalities, the gaps between states with the highest and lowest levels of intervention coverage will likely widen over time. This finding also emphasizes the need for incorporating explicit equity goals within the next generation of international target-setting with the Sustainable Development Goals [
95].
Our findings correspond with recent policy developments in Nigeria, namely the National Health Bill’s enactment in December 2014 [
17]. This bill aims to address many of the MCH indicators analyzed in our study, with leadership claiming that its effective implementation will save over 3 million “lives of mothers, newborns, and under-5’s by 2022” [
96]. The National Health Bill’s success hinges upon successful execution throughout Nigeria, a feat that has challenged the country’s past health reforms [
11,
12,
97]. The use of subnational benchmarking to monitor indicators related to the National Health Bill will be critical for tracking local progress, promptly identifying obstacles in implementation, and building local accountability mechanisms. These efforts may be further improved by strengthening local health information systems, namely Nigeria’s District Health Information System (DHIS2) [
98], and expanding the types of indicators captured by these systems (e.g. data pertaining to non-communicable diseases).
Limitations
Our findings need to be interpreted within the context of some study limitations. First, we were unable to estimate trends for a number of priority MCH indicators due to data scarcity. For instance, we were unable to generate intervention estimates for HIV/AIDS treatment or case management of pneumonia as they were not captured by data sources that met inclusion criteria. Estimates of state-level maternal deaths also could not be appropriately generated due to small numbers. Second, our results do not reflect the quality of interventions received, which is a critical input for understanding whether interventions are effectively provided and thus result in their intended health gains. Third, most indicators were based on self-reports from survey respondents, and thus may be prone to various self-report biases. Fourth, our results provide minimal information about supply-side factors that affect health service provision, such as facility stocks of pharmaceuticals and medical supplies, human resources for health, and facility infrastructure. With the expansion of DHIS2 and recent release of Nigeria’s MDG Information System [
33], it is possible that future analyses may account for such supply-side influences. Fifth, our findings were limited to state-level analyses due to geographic data restrictions. In the future, it would be ideal to track health trends at the LGA- or ward-level and stratified by wealth quintiles to provide more localized, actionable results. Finally, our study was descriptive in nature, and thus could not provide insights into the causes of gains, declines, and differences in state-level performance over time. Evaluating the underlying drivers of these changes over time and across states would provide invaluable insights into which types of programs work – and which do not – to improve health outcomes.
Competing interests
All authors declare that they have no competing interests.
Authors’ contributions
AW and RB contributed to all parts of the analysis, produced the tables and figures, and wrote the first draft of the manuscript. NF contributed to interpretation of findings, manuscript writing, and producing tables and figures. LDL contributed to analyses and methods development. EG conceptualized the project and provided guidance on data analysis and manuscript writing. All authors read and approved the final manuscript.