Coverage, universal access and equity in health: a characterization of scientific production in nursing

Objectives: to characterize the scientific contribution nursing has made regarding coverage, universal access and equity in health, and to understand this production in terms of subjects and objects of study. Material and methods: this was cross-sectional, documentary research; the units of analysis were 97 journals and 410 documents, retrieved from the Web of Science in the category, "nursing". Descriptors associated to coverage, access and equity in health, and the Mesh thesaurus, were applied. We used bibliometric laws and indicators, and analyzed the most important articles according to amount of citations and collaboration. Results: the document retrieval allowed for 25 years of observation of production, an institutional and an international collaboration of 31% and 7%, respectively. The mean number of coauthors per article was 3.5, with a transience rate of 93%. The visibility index was 67.7%, and 24.6% of production was concentrated in four core journals. A review from the nursing category with 286 citations, and a Brazilian author who was the most productive, are issues worth highlighting. Conclusions: the nursing collective should strengthen future research on the subject, defining lines and sub-lines of research, increasing internationalization and building it with the joint participation of the academy and nursing community.

it involves solving how the health system is financed, how it protects people from the financial consequences that facing an illness brings to them for the needed care, as well as how the resources available in that system are optimally used (2)(3) . Thus two other essential concepts arise: access and equity. Universal access in health means an absence of geographic, economic, sociocultural, and organizational or gender barriers, and this is achieved through the progressive removal of barriers that prevent people from using all comprehensive health services, determined equitably and at a national level (4) . In turn, universal health equity is a broad, inclusive, and multidimensional concept, consisting of aspects related to achieving good health through processes that not only have to do with the distribution of health care, but also with social justice and non-discrimination in the delivery of such care (5) . Health is not only a function of the health sector; in order to achieve it, other factors such as living conditions and working conditions, psychosocial factors and socioeconomic status are involved (6) . In other words, universal equity in health means achieving health without any social circumstance to prevent it (5).
Once the conceptual contribution of the study was determined, a bibliometric analysis was used for characterization because, while it allows us to look back at how scientifi c advances have been achieved and released, it also reveals the generation of useful results and measures the development of scientifi c disciplines on certain research lines (7) . Bibliometric indicators of production quantify both the number of documents published, by country, institution and authors, as well as the citations of those documents as a measure of their impact or importance (8) . These are measurements obtained from the statistical analysis of the basic elements of journals or articles with which indicators are built to measure the quality, impact, relationships or collaboration and scientifi c activity, i.e., the quantifi cation and temporal evolution of the production (9) . Thus, the information stored in databases represents raw material which, once analyzed, allows for the extraction of knowledge that can contribute to understanding scientifi c efforts and making strategic decisions in a particular fi eld of knowledge (10) .
Based on the information above, this study had two objectives: fi rst, to characterize the scientifi c contribution of nursing in coverage, universal access and equity in health through bibliometric indicators; and, second, to understand the trends of this production in terms of studied subjects and phenomena .

Materials and methods
The type of study and unit of analyze was: bibliometric, descriptive and exploratory research, whose unit of analysis was serial publications and documents recovered from the category, "Nursing", in "coverage", "access" and "equity", and each separately associated with the terms "health", "health care", "health services" and "universal".

Descriptor
Search strategy

Annual Accumulated
Collaboration: only 31% of this production (127) had institutional collaboration; the most common partnership (27) was university/hospital. The rate of collaboration or co-authorship, i.e., the average number of authors per paper, throughout the period was 3.5. The highest value was obtained by a co-authored article from 2007, (11) with 12 Canadian authors, which described how the realtime access that hospital or community nurses had to electronic resources could not only obtain information simultaneously about patient results or about the best evidence to support the practice, but also revealed the close relationship between nursing interventions and patient outcomes. This is a key issue in planning the best interventions in a timely manner, and thereby facilitates access to better health care in the short term (11) . Mendoza-Parra S.  seeking care health. They emphasized that, with more evidence, not only could it improve the access of men to health care, but it would also improve the quality of life of the women who informally have to take over that care, and therefore also reduce national health costs associated with delayed health care (18) .

Discussion and conclusions
It is worth highlighting that the entry of Scielo and The visibility achieved by the citable documents (67%) is also important, and almost 30% are categorized in other scientifi c fi elds, indicating that those papers produced by Nursing on the issue not only impact its own group, but also contribute to the knowledge of other scientifi c areas (9) .
Regarding the journals, it is expected that countries with a lot of data in the WOS occupy the greatest amount of indexed journals, which makes it more relevant that It is a fact that the worldwide nursing community already has core journals in the area, but there remains a need to strengthen future research by better organizing it in terms of research lines and sub lines, internationalization, and creating a close link between academia, now linked to nursing, which is developed at a community level.