METHODS: Semantic analysis of data was performed to describe and understand different meanings of different fields existing in the studied bases. In addition, there were two main procedures, executed with database operations tools and PLSQL programming language: cleaning and standardization of databases; registration information extraction and deterministic deduplication thereof. Both procedures were first performed on each database separately and after the unification of the records,  was held again a deterministic deduplication.

RESULTS: Performed procedures allowed a decision-making to chose fields used in data model for the unified database creation. Five database's representative fields related to patients were selected: first name and last name; birth date; state and country code of residence. Initially, the unified cadastral database resulted in 570,649,706 records, after deduplication there was a reduction culminating in 106,433,845 records. This reduction is explained because these databases are not fully integrated. Moreover, there is not always agreement between semantic systems and in some cases changes occur in the data format over the period within the same system. CONCLUSIONS: The results show that data deduplication is necessary and should be carried out thoroughly. Where the databases had limited patients’ registration information, the technique enabled to capture, in more complete basis, additional information. Futhermore, it allowed to identify and assist in the understanding of positive and negative aspects within systems and trace clinical condition of patients, enabling pharmacoeconomic and epidemiological studies that define effectiveness and efficiency of public policies and embedded technologies. As future work, is important ensure the univocity of records.