Performance of Dexcom G5 and FreeStyle Libre sensors tested simultaneously in people with type 1 or 2 diabetes and advanced chronic kidney disease

Table 1 Baseline characteristics

Variable	All, n = 40	FAS population, n = 33
Age in yr	64.1 (9.2)	63.2 (9.2)
	66 (41; 77)	65.5 (41; 77)
	n = 39	n = 32
HbA1c in mmol/mol	53.1 (11.0)	53.9 (11.5)
	53 (31; 75)	54 (31; 75)
	n = 40	n = 33
HbA1c %	7 (3.2)	7.1 (3.2)
	53 (5; 9)	7.1 (5; 9)
	n = 40	n = 33
Dialysis
Not in dialysis	20 (50.0%)	17 (51.5%)
Hemodialysis	11 (27.5%)	7 (21.2%)
Peritoneal dialysis	9 (22.5%)	9 (27.3%)
Diabetes duration	28.5 (14.7)	29.2 (15.4)
	27.5 (5.3; 64.5)	28.5 (5.3; 64.5)
	n = 32	n = 26
Sex
Man	29 (74.4%)	22 (68.8%)
Woman	10 (25.6%)	10 (31.3%)
Smoking
No	25 (71.4%)	19 (67.9%)
Yes	3 (8.6%)	3 (10.7%)
Do not know	7 (20.0%)	6 (21.4%)
Systolic blood pressure in mmHg	145.6 (24.2)	146.5 (24.7)
	145 (95; 213)	142.5 (95; 213)
	n = 37	n = 30
Diastolic blood pressure in mmHg	77.4 (13.7)	78.6 (13.8)
	80 (52; 103)	80 (52; 103)
	n = 37	n = 30
Insulin delivery
Basal insulin only	12 (32.4%)	10 (33.3%)
Mix insulin	2 (5.4%)	2 (6.7%)
MDI	24 (64.9%)	20 (66.7%)
Other glucose lowering treatment	5 (13.5%)	3 (10.0%)
Total insulin dose per day	73.0 (60.3)	65.7 (63.8)
	45 (8; 277)	41 (8; 277)
	n = 25	n = 20
Type of diabetes
Type 1	11 (30.6%)	10 (33.3%)
Type 2	25 (69.4%)	20 (66.7%)

For categorical variables n (%) is presented. For continuous variables mean (SD)/median (min; max)/n = is presented. FAS: Full analysis set; MDI: Multiple daily injection.

Table 2 Mean absolute relative difference, mean absolute difference and mean difference for Dexcom G5 and FreeStyle Libre

Variable	FreeStyle Libre (isCGM)	Dexcom G5 CGM	Difference (isCGM-CGM)	P value1
Mean MARD	20.9 (8.6)	15.2 (12.2)	5.72 (10.17)	0.0036
	19.8 (8.5; 43.1)	11.9 (2.2; 60.5)	6.5 (-26.75; 24.68)
	n = 33	n = 33	(2.11; 9.32)
			n = 33
Mean MAD	1.76 (0.78)	1.21 (0.78)	0.548 (0.795)	0.0004
	1.65 (0.48; 4.48)	0.95 (0.23; 3.12)	0.679 (-1.662; 2.11)
	n = 33	n = 33	(0.267; 0.830)
			n = 33
Mean MD	-1.10 (1.24)	-0.107 (0.937)	-0.998 (1.278)	0.0002
	-1.46 (-4.48; 1.63)	-0.229 (-2.47; 3.007)	-1.1 (-3.586; 2.431)
	n = 33	n = 33	(-1.451; -0.545)
			n = 33
Persons in dialysis
Mean MARD	19.3 (7.4)	15.5 (14.8)	3.80 (11.09)	0.19
	17.7 (8.5; 33.7)	8.6 (4.1; 60.5)	6.51 (-26.75; 15.75)
	n = 16	n = 16	(-2.11; 9.71)
			n = 16
Mean MAD	1.74 (0.91)	1.26 (0.85)	0.489 (0.828)	0.035
	1.65 (0.77; 4.48)	0.99 (0.43; 3.12)	0.611 (-1.236; 1.65)
	n = 16	n = 16	(0.048; 0.931)
			n = 16
Mean MD	-1.29 (1.29)	0.056 (1.232)	-1.34 (1.30)	0.0019
	-1.32 (-4.48; 0.96)	-0.252 (-2.47; 3.007)	-1.46 (-3.59; 1.07)
	n = 16	n = 16	(-2.03; -0.65)
			n = 16
People not in dialysis
Mean MARD	22.5 (9.5)	15.0 (9.6)	7.53 (9.19)	0.0033
	19.8 (8.8; 43.1)	12.5 (2.2; 38.5)	6 (-15.59; 24.68)
	n = 17	n = 17	(2.80; 12.25)
			n = 17
Mean MAD	1.77 (0.65)	1.16 (0.72)	0.604 (0.784)	0.0057
	1.67 (0.48; 3.22)	0.95 (0.23; 2.77)	0.679 (-1.662; 2.11)
	n = 17	n = 17	(0.201; 1.007)
			n = 17
Mean MD	-0.934 (1.211)	-0.260 (0.529)	-0.673 (1.209)	0.037
	-1.482 (-2.586; 1.632)	-0.223 (-1.323; 0.932)	-0.855 (-2.348; 2.431)
	n = 17	n = 17	(-1.295; -0.052)
			n = 17
Glucose values < 3.9 mmol/L
Mean MARD	53.0 (37.1)	89.8 (66.8)	-36.9 (42.0)	0.027
	35.3 (12.8; 115.2)	66.7 (7.7; 197.4)	-44.7 (-127.2; 7.1)
	n = 9	n = 9	(-69.2; -4.5)
			n = 9
Mean MAD	1.81 (1.33)	3.10 (2.47)	-1.29 (1.52)	0.027
	1.2 (0.47; 3.9)	1.8 (0.27; 7.2)	-1.3 (-4.65; 0.2)
	n = 9	n = 9	(-2.46; -0.12)
			n = 9
Mean MD	1.18 (1.96)	3.03 (2.54)	-1.85 (1.42)	0.0078
	1.2 (-1.2; 3.9)	1.8 (0.27; 7.2)	-1.8 (-4.65; 0.2)
			(-2.94; -0.76)
	n = 9	n = 9	n = 99
Glucose values 3.9-10.0 mmol/L
Mean MARD	22.6 (8.9)	14.8 (10.6)	7.83 (9.88)	< 0.0001
	21 (8.7; 44.1)	11.9 (1.5; 40.5)	8.05 (-13.18; 28.95)
	n = 33	n = 33	(4.32; 11.33)
			n = 33
Mean MAD	1.60 (0.62)	1.03 (0.71)	0.568 (0.689)	< 0.0001
	1.45 (0.5; 2.98)	0.82 (0.13; 2.59)	0.633 (-0.918; 2.045)
	n = 33	n = 33	(0.323; 0.812)
			n = 33
Mean MD	-0.868 (1.183)	0.136 (0.859)	-1.00 (1.19)	< 0.0001
	-1.067 (-2.9; 2.508)	-0.017 (-2.1; 2.445)	-1.07 (-3.57; 1.38)
	n = 33	n = 33	(-1.43; -0.58)
			n = 33
Glucose values > 10.0 mmol/L
Mean MARD	16.6 (11.1)	12.3 (11.6)	4.22 (8.63)	0.010
	15.3 (1.9; 59)	7.9 (1.9; 50.4)	4.69 (-25.08; 16.94)
	n = 31	n = 31	(1.06; 7.39)
			n = 31
Mean MAD	2.06 (1.29)	1.54 (1.31)	0.520 (1.139)	0.016
	1.9 (0.2; 6.45)	1.04 (0.2; 5.5)	0.533 (-3.4; 2.18)
	n = 31	n = 31	(0.102; 0.938)
			n = 31
Mean MD	-1.82 (1.56)	-0.944 (1.633)	-0.875 (1.777)	0.0087
	-1.89 (-6.45; 1.16)	-0.563 (-5.5; 2.7)	-0.95 (-4.1; 5.72)
	n = 31	n = 31	(-1.527; -0.223)
			n = 31
Hemodialysis
Mean MARD	21.4 (9.1)	20.3 (18.9)	1.13 (14.27)	0.86
	20.7 (8.5; 33.7)	17 (5.6; 60.5)	2.88 (-26.75; 15.75)
	n = 7	n = 7	(-12.07; 14.33)
			n = 7
Mean MAD	1.79 (0.69)	1.44 (0.87)	0.354 (1.012)	0.38
	1.89 (0.77; 2.73)	1.28 (0.56; 3.12)	0.211 (-1.236; 1.614)
	n = 7	n = 7	(-0.582; 1.290)
			n = 7
Mean MD	-0.905 (1.451)	0.378 (1.185)	-1.28 (1.47)	0.063
	-1.606 (-2.733; 0.96)	0.056 (-0.433; 3.007)	-1.99 (-2.54; 1.07)
	n = 7	n = 7	(-2.65; 0.08)
			n = 7
Peritoneal dialysis
Mean MARD	17.6 (5.9)	11.7 (10.4)	5.88 (8.16)	0.078
	14.9 (12.1; 28.8)	6.9 (4.1; 36.7)	7.18 (-14.64; 13.35)
	n = 9	n = 9	(-0.39; 12.15)
			n = 9
Mean MAD	1.71 (1.09)	1.11 (0.86)	0.595 (0.700)	0.043
	1.4 (0.96; 4.48)	0.77 (0.43; 2.83)	0.736 (-0.89; 1.65)
	n = 9	n = 9	(0.057; 1.132)
			n = 9
Mean MD	-1.58 (1.15)	-0.193 (1.278)	-1.39 (1.23)	0.0039
	-1.25 (-4.48; -0.8)	-0.442 (-2.47; 2.195)	-1 (-3.59; -0.33)
	n = 9	n = 9	(-2.34; -0.44)
			n = 9

¹For comparison between FreeStyle Libre and Dexcom G5 the Fisher´s Non-Parametric Permutation test for matched pairs was used. For continuous variables, distribution of differences is given by mean (SD)/median (min; max)/(95% confidence interval for mean)/n = is presented and the distribution of values within the two sensors is given by mean (SD)/median (min; max)/n = is presented. CGM: Continuous glucose monitoring; MAD: Mean absolute difference; MARD: Mean absolute relative difference; MD: Mean difference; isCGM: Intermittent glucose monitoring.

Table 3 Patient experience of FreeStyle Libre and Dexcom G5 measured on a visual analogue scale

Variable	FreeStyle Libre isCGM, n = 31	Dexcom G5 CGM, n = 31	Change from FreeStyle Libre isCGM to Dexcom G5 CGM
				P value
My experience of the system was very positive	8.35 (2.03)	6.84 (2.70)	-1.52 (3.41)	0.023
	9.00 (3.00; 10.00)	8.00 (2.00; 10.00)	-2.00 (-7.00; 7.00)
	(7.61; 9.10)	(5.85; 7.83)	(-2.77; -0.26)
	n = 31	n = 31	n = 31
The insertion of the sensor was easy	9.03 (1.71)	8.27 (2.29)	-0.767 (1.455)	0.0084
	10.00 (2.00; 10.00)	9.00 (1.00; 10.00)	0.000 (-5.000; 2.000)
	(8.39; 9.67)	(7.41; 9.12)	(-1.310; -0.223)
	n = 30	n = 30	n = 30
I felt safe during my time using the system	7.94 (2.67)	7.19 (2.46)	-0.742 (3.916)	0.32
	9.00 (0.00; 10.00)	8.00 (3.00; 10.00)	-1.000 (-7.000; 9.000)
	(6.96; 8.91)	(6.29; 8.09)	(-2.178; 0.694)
	n = 31	n = 31	n = 31
It was easy to use the system	9.52 (0.96)	7.60 (2.62)	-1.93 (2.21)	< 0.0001
	10.00 (6.00; 10.00)	9.00 (2.00; 10.00)	-1.00 (-7.00; 0.00)
	(9.16; 9.87)	(6.62; 8.58)	(-2.76; -1.11)
	n = 31	n = 30	n = 30
It was easy to interpret the information on the receiver screen	9.42 (0.99)	7.97 (2.46)	-1.45 (1.98)	< 0.0001
	10.00 (7.00; 10.00)	9.00 (1.00; 10.00)	-1.00 (-7.00; 1.00)
	(9.06; 9.78)	(7.07; 8.87)	(-2.18; -0.73)
	n = 31	n = 31	n = 31
I was not in pain or had discomfort in connection to my use of the system	9.74 (0.73)	8.48 (2.78)	-1.26 (2.68)	0.0078
	10.00 (7.00; 10.00)	10.00 (0.00; 10.00)	0.00 (-10.00; 0.00)
	(9.47; 10.01)	(7.46; 9.50)	(-2.24; -0.27)
	n = 31	n = 31	n = 31
I experienced no problem scanning/contact with the system	9.55 (0.93)	7.19 (3.29)	-2.35 (3.23)	< 0.0001
	10.00 (7.00; 10.00)	9.00 (0.00; 10.00)	-1.00 (-10.00; 2.00)
	(9.21; 9.89)	(5.99; 8.40)	(-3.54; -1.17)
	n = 31	n = 31	n = 31
The sensor was comfortable to have on my body in my daily life	9.20 (1.40)	7.23 (2.69)	-1.90 (2.34)	< 0.0001
	10.00 (4.00; 10.00)	8.00 (1.00; 10.00)	-1.00 (-8.00; 1.00)
	(8.68; 9.72)	(6.24; 8.21)	(-2.77; -1.03)
	n = 30	n = 31	n = 30
The system did not disturb my daily life	9.33 (1.09)	7.74 (2.62)	-1.50 (2.43)	0.0024
	10.00 (6.00; 10.00)	9.00 (3.00; 10.00)	0.00 (-7.00; 4.00)
	(8.93; 9.74)	(6.78; 8.70)	(-2.41; -0.59)
	n = 30	n = 31	n = 30
I would like to use the system in my daily life	8.45 (2.86)	5.42 (3.49)	-2.66 (4.98)	0.0096
	10.00 (0.00; 10.00)	6.00 (0.00; 10.00)	-3.00 (-10.00; 9.00)
	(7.36; 9.54)	(4.14; 6.70)	(-4.55; -0.76)
	n = 29	n = 31	n = 29
It was easy to calibrate the Dexcom G5		8.40 (2.21)
		10.00 (3.00; 10.00)
		(7.58; 9.22)
		n = 30
The alarms did not disturb my daily life		7.97 (2.74)
		9.00 (0.00; 10.00)
		(6.95; 8.99)
		n = 30

For categorical variables n (%) is presented. For continuous variables mean (SD)/median (min; max)/(95% confidence interval for mean)/n = is presented. For comparison over time, Fisher’s non-parametric permutation test for paired observations was used for continuous variables. The evaluation of questions of the flash glucose monitoring/continuous glucose monitoring were expressed on a visual analogue scale with lowest value (0) meaning Not true at all and highest value (10) meaning completely true.