Peripheral arterial disease is associated with retinal fluid and microvascular alterations in type 2 diabetes

Table 2 Clinical characteristics of participants by capillary plexus parafoveal vascular density-superficial capillary plexus parafoveal vessel density quartiles, n (%)/mean ± SD

	SCP, quartile 1 (n = 53)	SCP, quartile 2 (n = 53)	SCP, quartile 3 (n = 53)	SCP, quartile 4 (n = 53)	P value
Parafoveal VD, %	41.0 ± 2.9	45.0 ± 0.6	47.7 ± 0.6	50.7 ± 1.6
Age, years	57.3 ± 11.7	60.1 ± 8.4	58.4 ± 8.8	54.0 ± 8.7	0.051
Sex, male	38 (71.7)	33 (62.3)	36 (67.9)	32 (60.4)	0.593
Smoking status					0.216
Never	25 (47.2)	30 (56.6)	28 (52.8)	30 (56.6)
Current	20 (37.7)	11 (20.8)	10 (18.9)	10 (18.9)
Ex-smoker	8 (15.1)	12 (22.6)	15 (28.3)	13 (24.5)
Smoking, pack-years	10.7 ± 14.2	12.6 ± 17.2	8.4 ± 14.3	8.1 ± 13.6	0.231
Duration of diabetes, years	17.0 ± 9.4	19.3 ± 7.9	18.1 ± 7.0	16.0 ± 7.7	0.385
Medication					0.527
Insulin only	0 (0.0)	1 (1.9)	0 (0.0)	0 (0.0)
OHA	31 (58.5)	37 (69.8)	36 (67.9)	36 (67.9)
Insulin + OHA	22 (41.5)	15 (28.3)	17 (32.1)	17 (32.1)
HTN	25 (47.2)	26 (49.1)	29 (54.7)	14 (26.4)	0.020
DR stage					0.003
No DR	3 (5.7)	5 (9.4)	7 (13.2)	10 (18.9)
Mild NPDR	15 (28.3)	22 (41.5)	27 (50.9)	30 (56.6)
Moderate NPDR	15 (28.3)	15 (28.3)	11 (20.8)	6 (11.3)
Severe NPDR	13 (24.5)	10 (18.9)	8 (15.1)	5 (9.4)
PDR	7 (13.2)	1 (1.9)	0 (0.0)	2 (3.8)
Biological parameters
HbA1c	7.9 ± 1.3	7.7 ± 1.1	7.8 ± 1.3	7.6 ± 1.2	0.181
Fasting glucose	144.8 ± 44.8	145.7 ± 46.6	147.7 ± 54.6	148.3 ± 45.4	0.669
Total cholesterol	145.5 ± 37.7	142.5 ± 32.2	150.7 ± 38.2	138.8 ± 29.8	0.583
Triglyceride	129.5 ± 76.4	127.7 ± 68.6	155.6 ± 92.8	114.9 ± 45.0	0.723
HDLc	44.1 ± 11.5	46.9 ± 12.6	42.5 ± 9.3	45.4 ± 10.3	0.942
LDLc	91.1 ± 32.4	87.4 ± 26.2	96.7 ± 30.8	86.3 ± 23.3	0.765
Creatinine	1.0 ± 0.7	1.1 ± 0.9	1.1 ± 1.0	0.9 ± 0.2	0.269
eGFR	81.4 ± 22.5	76.2 ± 24.2	78.6 ± 19.8	88.7 ± 18.0	0.067
Clinical parameters
BMI, kg/m2	25.3 ± 3.7	24.8 ± 3.7	26.4 ± 3.5	26.1 ± 3.9	0.081
SBP, mmHg	132.0 ± 19.8	132.9 ± 19.1	134.7 ± 15.7	133.9 ± 18.5	0.508
DBP, mmHg	74.4 ± 11.8	75.9 ± 11.9	75.5 ± 9.5	75.8 ± 10.6	0.562
Visual acuity, logMAR	0.09 ± 0.10	0.06 ± 0.09	0.08 ± 0.09	0.05 ± 0.07	0.067
OCTA parameters
FAZ size, mm2	0.34 ± 0.10	0.33 ± 0.01	0.30 ± 0.11	0.34 ± 0.10	0.516
FAZ perimeter, mm	2.4 ± 0.4	2.3 ± 0.3	2.2 ± 0.4	2.4 ± 0.4	0.433
SCP fovea VD, %	13.3 ± 3.9	14.6 ± 4.9	16.6 ± 4.8	16.0 ± 4.9	< 0.001
DCP fovea VD, %	25.8 ± 6.6	28.3 ± 5.9	30.3 ± 5.9	28.8 ± 5.7	0.004
DCP parafoveal VD, %	46.8 ± 4.4	49.2 ± 3.4	50.5 ± 2.8	51.0 ± 3.6	< 0.001
Signal strength	66.7 ± 6.9	66.1 ± 6.1	69.5 ± 6.9	70.3 ± 6.9	0.001
OCT parameters
CFT, μm	251.5 ± 25.1	250.0 ± 23.2	256.0 ± 24.5	246.3 ± 19.7	0.508
PFT, μm	314.7 ± 20.3	313.0 ± 19.0	316.3 ± 13.8	317.9 ± 15.3	0.218
Inner retinal CFT, μm	69.9 ± 13.0	69.8 ± 12.1	73.1 ± 14.6	67.7 ± 11.2	0.679
Inner retinal PFT, μm	125.5 ± 11.3	124.9 ± 10.6	128.9 ± 8.4	132.0 ± 8.1	< 0.001
Presence of PAD	11 (20.8)	8 (15.1)	5 (9.4)	1 (1.9)	0.019
Development of IRF	25 (47.2)	12 (22.6)	9 (17.0)	7 (13.2)	< 0.001
Development of DME	6 (11.3)	4 (7.5)	2 (3.8)	3 (5.7)	0.473

SCP: Superficial capillary plexus; VD: Vascular density; OHA: Oral hypoglycemic agents; HTN: Hypertension; DR: Diabetic retinopathy; NPDR: Non-proliferative diabetic retinopathy; PDR: Proliferative diabetic retinopathy; HbA1c: Glycated hemoglobin; HDLc: High-density lipoprotein cholesterol; LDLc: Low-density lipoprotein cholesterol; eGFR: Estimated glomerular filtration rate; BMI: Body mass index; SBP: Systolic blood pressure; DBP: Diastolic blood pressure; logMAR: Logarithm of the minimum angle of resolution; OCTA: Optical coherence tomography angiography; FAZ: Foveal avascular zone; DCP: Deep capillary plexus; OCT: Optical coherence tomography; CFT: Central foveal thickness; PFT: Parafoveal thickness; PAD: Peripheral arterial disease; IRF: Intra-retinal fluid; DME: Diabetic macular edema.