Table 2.

Study design features (n=37).

Features				Studies, n (%)		Study ID
Study aim
	Blood glucose estimation (predictions)		10 (27)		S3, S18, S19, S21, S23, S25, S27, S28, S32, S33, S37
	Glucose level monitoring		10 (27)		S7-S11, S15, S20, S24, S26, S30
	Diagnostic solution		5 (14)		S4, S29, S33, S34, S35
	Diabetes classification		4 (11)		S12-S14, S17
	Self-administration and monitoring		4 (11)		S1, S5, S6, S31
	Prevention		2 (5)		S2, S16
	Other disease predictions, detection, and monitoring (hypoglycemia and foot temperature)		2 (5)		S22, S36
Privacy and security
	Not mentioned		31 (84)		S1-S22, S24-S26, S29, S30, S34-S37
	Mentioned		6 (16)		S23, S27, S28, S31, S32, S33
Data source
	Private		25 (68)		S2, S3, S5, S7, S8-S19, S21, S22, S24, S26, S29, S34-S37
	Public		4 (11)		S1, S4, S6, S25
	Not mentioned		2 (5)		S20, S30
Participant demographics
	Age group (years)a
		Children and young adults (≤18)	1 (3)		S8
		Adult (19-65)	18 (49)		S2-S5, S8, S10, S13, S15, S16, S17, S19, S21, S22, S27, S29, S31, S33, S34
		Older adult (>65)	6 (16)		S2, S4, S15, S21, S22, S33
		Not mentioned	19 (51)		S1, S6, S7, S9, S11, S12, S14, S18, S20, S23-S26, S28, S30, S32, S35-S37
	Gender
		Male	10 (27)		S2, S3, S5, S13, S15, S17, S18, S27, S29, S34
		Female	10 (27)		S2, S3, S5, S13, S15, S17, S18, S27, S29, S34
		Not mentioned	27 (73)		S1, S4, S6-S12, S14, S16, S19-S26, S28, S30-S33, S35-S37
	Diabetesb
		Yes	14 (38)		S1, S4, S5-S7, S10, S12, S14, S15, S18, S19, S21, S27, S34, S36
		No	15 (41)		S1, S5, S6, S8-S10, S12, S14, S18, S19, S27, S29, S31, S33, S36
		Not mentioned	17 (46)		S2, S3, S11, S13, S16, S17, S20, S22-S26, S29, S30, S32, S35, S37

^aNumbers do not add up as participants in some studies belong to more than one age group.

^bNumbers do not add up as participants in some studies were diabetic and nondiabetic.