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

Table 3 Clinical characteristics of participants by capillary plexus parafoveal vascular density-deep capillary plexus parafoveal vessel density quartiles, n (%)/mean ± SD

	DCP, quartile 1 (n = 53)	DCP, quartile 2 (n = 53)	DCP, quartile 3 (n = 53)	DCP, quartile 4 (n = 53)	P value
Parafoveal VD, %	44.0 ± 2.3	48.5 ± 1.0	51.2 ± 0.7	53.9 ± 1.1	< 0.001
Age, years	58.0 ± 10.5	58.1 ± 9.5	57.7 ± 8.9	55.9 ± 9.9	0.273
Sex, male	38 (70.4)	28 (52.8)	41 (77.4)	32 (60.4)	0.042
Smoking status					0.010
Never	22 (43.1)	35 (68.6)	17 (37.8)	25 (49.0)
Current	16 (31.4)	3 (5.9)	17 (37.8)	15 (29.4)
Ex-smoker	13 (25.5)	13 (25.5)	11 (24.4)	11 (21.6)
Smoking, pack-years	27.4 ± 8.1	33.8 ± 9.3	24.5 ± 11.6	28.4 ± 12.3	0.695
Duration of diabetes, years	17.1 ± 7.9	18.4 ± 8.5	18.9 ± 8.0	15.8 ± 8.1	0.521
Medication					0.563
Insulin only	0 (0.0)	0 (0.0)	1 (1.9)	0 (0.0)
OHA	36 (66.7)	33 (62.3)	38 (71.7)	33 (62.3)
Insulin + OHA	18 (33.3)	20 (37.7)	14 (26.4)	20 (37.7)
HTN	25 (46.3)	19 (35.8)	27 (50.9)	23 (43.4)	0.460
DR stage					< 0.001
No DR	4 (7.4)	3 (5.7)	6 (11.3)	13 (24.5)
Mild NPDR	15 (27.8)	23 (43.4)	28 (52.8)	28 (52.8)
Moderate NPDR	11 (20.4)	16 (30.2)	13 (24.5)	7 (13.2)
Severe NPDR	16 (29.6)	11 (20.8)	6 (11.3)	3 (5.7)
PDR	8 (14.8)	0 (0.0)	0 (0.0)	2 (3.8)
Biological parameters
HbA1c	7.9 ± 1.3	7.9 ± 1.2	7.6 ± 1.1	7.6 ± 1.3	0.037
Fasting glucose	150.5 ± 47.2	151.2 ± 51.6	143.9 ± 37.6	140.2 ± 53.0	0.191
Total cholesterol	146.4 ± 40.0	142.3 ± 29.2	143.9 ± 38.5	145.8 ± 31.2	0.982
Triglyceride	136.4 ± 70.3	129.4 ± 62.5	119.5 ± 69.7	144.8 ± 90.8	0.739
HDLc	43.9 ± 10.8	45.7 ± 11.2	45.5 ± 12.7	44.0 ± 9.3	0.998
LDLc	93.2 ± 33.7	87.9 ± 25.9	89.2 ± 29.9	91.9 ± 24.3	0.887
Creatinine	1.0 ± 0.7	1.0 ± 0.3	1.2 ± 1.3	0.9 ± 0.3	0.852
eGFR	80.6 ± 23.2	79.3 ± 20.2	81.9 ± 24.1	82.8 ± 19.0	0.485
Clinical parameters
BMI, kg/m2	25.5 ± 3.9	25.7 ± 3.8	25.9 ± 4.1	25.7 ± 3.1	0.694
SBP, mmHg	138.8 ± 19.6	131.5 ± 19.4	133.7 ± 18.6	129.2 ± 13.7	0.016
DBP, mmHg	78.4 ± 11.4	74.2 ± 11.2	74.4 ± 10.8	74.7 ± 10.0	0.107
Visual acuity, logMAR	0.08 ± 0.12	0.07 ± 0.09	0.06 ± 0.07	0.06 ± 0.07	0.083
OCTA parameters
FAZ size, mm2	0.34 ± 0.11	0.33 ± 0.10	0.32 ± 0.09	0.32 ± 0.10	0.119
FAZ perimeter, mm	2.4 ± 0.4	2.4 ± 0.4	2.3 ± 0.4	2.3 ± 0.4	0.158
SCP fovea VD, %	14.5 ± 5.0	15.6 ± 5.2	14.8 ± 4.1	15.8 ± 4.9	0.314
DCP fovea VD, %	43.6 ± 4.6	46.2 ± 3.3	46.6 ± 2.9	48.1 ± 3.5	< 0.001
DCP parafoveal VD, %	26.2 ± 7.2	29.1 ± 5.6	28.3 ± 5.1	29.8 ± 6.4	0.009
Signal strength	63.6 ± 5.5	66.8 ± 7.4	70.6 ± 5.2	71.9 ± 6.2	< 0.001
OCT parameters
CFT, μm	250.1 ± 25.2	252.4 ± 22.3	251.3 ± 23.3	250.0 ± 22.9	0.925
PFT, μm	319.3 ± 20.2	318.0 ± 15.5	313.9 ± 16.9	310.6 ± 15.0	0.004
Inner retinal CFT, μm	69.8 ± 14.4	70.1 ± 10.9	70.4 ± 13.8	70.1 ± 12.4	0.893
Inner retinal PFT, μm	128.5 ± 11.2	128.0 ± 9.7	128.0 ± 10.3	126.7 ± 9.1	0.368
Presence of PAD	14 (25.9)	9 (17.0)	0 (0.0)	3 (5.7)	< 0.001
Development of IRF	24 (45.3)	12 (24.0)	4 (8.2)	4 (8.2)	< 0.001
Development of DME	10 (18.9)	3 (5.7)	1 (1.9)	1 (1.9)	0.003

DCP: Deep 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; SCP: Superficial 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.