Based on the keywords selected to constitute the basis of our bibliographic research, we identified a total of 2492 articles: 624 identified in PubMed and 1868 identified in Scopus. Among these articles, 2460 articles dealing with information systems specific only to certain health issues were excluded from the study. Thirty-two (32) articles were relevant according to the selection criteria (full articles, written in English or French, peer reviewed and published between 2005 and 2019). Then, we carefully reviewed the titles and abstracts of the 32 articles to check whether the technical and organizational aspects of the HIS on which our articles should be examined were taken into consideration. This step, selected 14 articles corresponding to the objectives of our study.
Faced with public health challenges, such as SDGs, the essential role of information in a health system is increasingly highlighted in all countries . Indeed, reliable and solid health information facilitates, on one hand better monitoring of SDGs indicators and on the other hand, the development of health policies based on established facts. Nowadays, unfortunately, due to a lack of reliable data, HIS in many countries are struggling to meet information needs in order to monitor their health indicators. .
A systematic review of the 14 resulted scientific articles enabled us to understand the state of health information management in some countries in Africa in which such information had been subjected to peer reviewed scientific publications as shown in the figure 4( Places concerned by the information systems studied in our study). These selected articles dealt with issues related to the evaluation, organization, data quality, improvement or development of integrated information systems or data warehouse (DW) as depicted in figure 5 (Themes covered in the 14 articles examined).
Four articles dealing with general HIS issues in Africa [8, 12, 16, 20] and 10 others dealing with HIS-specific issues from 12 countries were identified: South Africa [13, 14], Benin , Botswana [14, 15], Ghana , Malawi [1, 5, 10], Mozambique , Rwanda , Sierra Leone [14, 18], Tanzania , Zambia , Zanzibar [14, 17], Zimbabwe . Although the literature on health information systems in these countries has been limited, the analysis of the literature available enabled us to identify the organizational and technical structure of each HIS.
From the 14 selected articles, 13 (92.9%) were qualitative in nature. All 10 articles dealing with HIS issues from 12 African countries addresses the topic of health data warehouses, 10/10 (100%).
2.1 Insufficient integration of stakeholders and coordination in the HIS implementation
A health system, insofar as it involves several actors to achieve its objectives, should also proceed by involving all these actors in the implementation of a reliable HIS strategy.
The review of the literature shows that taking into account the needs of all stakeholders in the health system is the common point between the countries identified in the study to set up HIS in Africa, although these systems have been implemented in different ways.
It is by drawing on their national health plans and involving all stakeholders that some countries have identified the needs and defined all the aspects to be taken into account in the conceptual phase of their HIS . Although the development of national HIS strategies has not been sufficiently highlighted, it has nevertheless been noted in the literature that some countries that have taken into account the needs of all stakeholders have put in place coherent strategies for the integrated management of their HIS . However, it should be noted that these strategies are generally short termed in nature, often after the project is implemented . Insufficiently asserted coordination supported with well-defined roles and responsibilities also makes it more difficult to ensure the sustainability of these integrated HIS, making them less and less effective with doubtful information quality. This situation tends to promote the fragmentation of HIS within actors using specific information systems to collect the specific data they need. This fragmentation of the HIS is sometimes encouraged by some funding organizations that prioritize certain subsystem needs to the detriment of others and the global needs of the integrated HIS . Health programs collecting more specific data to meet the objectives of their donor agencies have little involvement in more comprehensive strategies for developing and managing more integrated HIS . This explains the fact that many HIS projects have experienced governance problems as a whole . This is why some countries such as Malawi have optimized the quality of their data by asserting their leadership, including by implementing a national strategy. It has also been observed that 11 of the 12 countries under study (92%) did not have a national strategy, but rather strategies implemented under a specific project. Malawi is the only one that has a national strategy to which all actors, including donors, must align. This strategy was accompanied by a procedural guide to facilitate the design of a HIS integrating all sub-systems .
Despite the implementation of coherent strategies such as national health plans that integrate the development and management of HIS, it is clear that insufficient integration of all stakeholders and coordination of HIS is not conducive to the production of comprehensive data. Indeed, collecting data from multiple non-harmonized tools makes it difficult for managers to fill out various paper or electronic forms at the same time for several programs . As a consequence of the inadequacy and reliability of data in regular HIS, some countries are forced to conduct ad hoc survey based on already validated data collection methodologies in order to have a health information for decision support such as Service Availability Readiness Assessment survey, demographic and health survey, etc. to estimate certain necessary indicators .
In 2007, the WHO, like many other partners working to improve HIS established some mechanisms to align their support with national strategies, policies and procedures developed by partner countries . In this perspective, some countries have undertaken to assess and develop their national HIS management policies. The fact that all the initiatives should be aligned to these agendas and policies for the identification and harmonization of indicators is one of the first requirements of this approach [15, 16].
2.2 Organization of technical and infrastructural support for the implementation of HIS
To enable the considered countries to achieve better health outcomes, several funding agencies had advocated the integration of data into Data Warehouses. To materialize this recommendation requires the commitment of all actors to the plans and strategies implemented by the countries. In this regard, some mechanisms to align international efforts with national systems have been set up, including the International Health Partnership (IHP+) and the Partnership for Statistics for Development in the 21st Century (PARIS21). Some initiatives, in line with this logic, have been undertaken with the District Health Information System (DHIS) software, among others, in South Africa, Sierra Leone, Zanzibar and Botswana .
In South Africa, the approach had been to validate a standard model on which to build a DW based on the DHIS software. This DW operates in parallel with other existing subsystems. It is notified at all levels of the health pyramid and subsystems, regardless of their specific needs. At the level of three other countries, the approach was to integrate all subsystems into a single DW. In Botswana for instance, it was intended to integrate all the paper forms of the subsystems into the DHIS software without any prior standardization, resulting in data overlap and duplication. Zanzibar and Sierra Leone, for their part, opted for a consensual (with all stakeholders) sorting of data from the different sources before their integration into a unique DW. Although using the same approach in standardizing data to be pre-integrated, their recording into the data warehouses was different in the two countries. In Zanzibar, paper-based forms were used to collect data from health facilities and made available to health districts, which were then filled in the DW. To overcome the errors which may occur with a manual process associated with the use of paper forms, the Zanzibar Ministry of Health had undertaken a project to use the OpenMRS clinical management software at the health facility level for processing and recording data in the DHIS warehouse. However, this OpenMRS-based project is experiencing difficulties in its implementation due to limited local technical capacity .
Sierra Leone has had an approach that takes into account the context of unequal distribution of technical infrastructures throughout the country. The adapted and validated digital DHIS solution served as a repository for the national HIS at all levels of the health system. The adaptation of DHIS was done in such a way that in areas with a digital infrastructure, this repository exchanged data with a hospital management software (HMS), such as OpenMRS where the SDX-HD standard facilitates this data exchange. The DHIS solution also provides the ability to enter data from paper or mobile phones. It is therefore a model that allows data to be recorded at all levels and aggregated in one place . This evolutionary approach, based on a collaborative architecture, has enabled Sierra Leone health system to have increasingly accurate health data that is accepted by several organizations that use it.
Six other countries (Ghana, Mozambique, Rwanda, Tanzania, Zambia and Mozambique) which received support from the International Health Partnership have used the DHIS software to implement their HIS. In Zambia, Rwanda and Tanzania for instance, the software has been adapted by standardizing and computerizing the various registers to collect data on care delivery from the health facilities. While Ghana and Mozambique have adapted the software from the standardized tools collected. This, in order to record aggregated data at the facilities, district and regional levels . For the majority of cases, initiatives to implement integrated HIS in the different targeted developing countries have been technically supported by the use of the DHIS solution. This digital solution, with open source code, has enabled several projects, even with various approaches, to digitize data management and analysis from the health district to the central level . At the structural level, DHIS was either filled in from the paper-based supports which allowed the collection of care services, or by using an Extract, Transform & Load (ETL) process that extracts data from the given HIS to transform them and load them into a central DW.
2.2.1. Presentation of the common platform used in the HIS projects in Africa: DHIS
DHIS is an open source software platform for the integration, analysis and dissemination of routine health data developed by the Health Information Systems Program (HISP) with the support of the Department of Computer Science at the University of Oslo in Norway . Initially designed and developed for data collection at the level of basic health committees and community information systems in health districts, the platform evolved into a web-based version in 2006 with an adaptation at the national level, hence DHIS2 for version 2. It is oriented towards the capture of aggregate data from health programs. The application has a specific module, the "tracker" that can be configured to allow data to be recorded in the most granular way possible and facilitate automated compilation. This module, which is far from playing the role of an electronic patient record, is more oriented towards data specific to certain health programs and almost not towards care services with more complex data.
From the organizational and technical aspects reviewed from the articles in our study, we have identified the strengths and weaknesses of HIS in developing countries in Table 2.