Table 4.

Key challenges (KC) of a blockchain-based electronic health record architecture.

No	Key challenges	References	Experts
KC1	High energy consumption	[39]	—a
KC2	High and unpredictable transactions costs	[10,12,20,24,37]	E2, E7
KC3	Requires high storage, bandwidth and computational power, low scalability	[7,10,12,20,39,40]	E7
KC4	Access and authorization issues	[10]	E5, E6, E7
KC5	Accountability for development and administration	[23]	E5, E7
KC6	Public availability of transactions	[7,10,12,20,24,37,39,41]	E2, E3, E7, E9
KC7	51% attack	[7,37]	—
KC8	Slow processing speed	[7,12,39]	E2, E4, E7
KC9	Data imports need verification	[10,20]	E2, E4, E7, E9
KC10	Technical skills of patient and health care professional	[10]	E2, E5, E7, E8, E9
KC11	Incentives for provision of computational resources	[23]	E2, E4, E7
KC12	Standardization	[20]	E1, E3, E5, E6

^aNot applicable.