*2.1. Search Strategy and Timeframe*

Specific search terms and their combinations for finding the literature were thoroughly researched and tested. The search terms were chosen based on the aim of this study and were adjusted to retrieve the most relevant studies that fall under the scope of the

selected topic. MeSH term "telemedicine" was used in the test searches and retrieved a large number of results, out of which many were irrelevant as there were publications on phone consultations, remote monitoring, wearable tracking/monitoring devices, etc. Therefore, to narrow down the search and retrieve more relevant results, this term was not used and was replaced with more specific keywords. In addition, the queries were adapted to match each chosen database's syntax. Three databases were chosen for the search: PubMed, Web of Science, and IEEE Xplore. The search queries used for the selected databases are presented in Table 1. Special tags and MeSH terms were used for targeting the most relevant studies—tag TIAB was used in PubMed for searching in the title, abstract, and keywords, MH for MeSH terms, TS for searching in the title, abstract, and keywords in Web of Science, and "All metadata" for searching in IEEE Xplory. IEEE Xplory digital library does not use MeSH terms. Thus, additional synonyms to some keywords were added to expand the search. The filters applied for the searches were 10 years' time span, English language, and full text available.

**Table 1.** Search strategy and the number of papers retrieved from the databases. The asterisk (\*) in the search quies in PubMed and Web of Science represents any group of characters. It also represents no character.


Apart from the database search, grey literature ("includes a range of documents not controlled by commercial publishing organizations") [33] was searched using similar search terms through Google Scholar and reviewing the reference lists of included studies to identify literature that has not been formally published in scientific journals. Manuscripts that were not yet published, conference papers, dissertations, government documents, and other types of grey literature [34] were searched and screened for eligibility. The search was carried out from 1 March 2021–15 April 2021.
