Table 1.

Comparison of the SLR studies

Study	Search string	Number of primary studies	RQs	Followed guidelines	Conceptual model
[21]	-	8	-		-
[22]	-	-	-	-	-
[23]	-	24	-		-
[24]	(“blockchain” OR “distributed ledger technology”) AND (“clinical trials” OR “clinical trial data management” OR “electronic health records” OR “smart contracts”)	16		PRISMA	-