Although there are now several bibliographic databases of research publications, such as Google Scholar, Pubmed, Scopus, and the Web of Science (WoS), and some also include counts of citations, there is at present no similarly comprehensive database of the rapidly growing number of clinical practice guidelines (CPGs), with their references, which sometimes number in the hundreds. CPGs have been shown to be useful for the evaluation of clinical (as opposed to basic) biomedical research, which often suffers from relatively low counts of citations in the serial literature. The objectives were to introduce a new citation database, clinical impact (R), and demonstrate how it can be used to evaluate research impact of clinical research publications by exploring the characteristics of CPG citations of two sets of papers, as well as show temporal variation of clinical impactand the WoS. The paper includes the methodology used to retain the data and also the rationale adopted to achieve data quality. The analysis showed that although CPGs tend preferentially to cite papers from their own country, this is not always the case. It also showed that cited papers tend to have a more clinical research level than uncited papers. An analysis of diachronous citations in both clinical impactand the WoS showed that although the WoS citations showed a decreasing trend after a peak at 2-3 years after publication, this was less clear for CPG citations and a longer timescale would be needed to evaluate their impact on these documents.