Levels of anti-insulin antibodies in diabetic retinopathy patients: an observational cross-sectional study

Figures & data

Table 1. Socio-demographic characteristics of the study participants.

Feature	DR group		DM only group		Control group
	No. (40)	%	No. (25)	%	No. (25)	%
Gender
Female	26	65	19	76	10	40
Male	14	35	6	24	15	60
Education level
None	8	20	3	12	2	8
Basic	13	32.5	7	28	7	28
Secondary	12	30	11	44	11	44
Tertiary	7	17.5	4	16	5	20
Occupation
Retired	14	35	12	48	3	12
Self-employed	22	55	13	52	17	68
Civil servant	1	2.5	0	0	0	0
Teacher	2	5	0	0	0	0
Nurse	1	2.5	0	0	2	8
Student	0	0	0	0	3	12

Data presented in frequency (No.) and percentages (%): DM: Diabetes mellitus; DR: Diabetic retinopathy.

Table 2. Medications used by the study participants.

Medication	DR group		DM only group
	No. (40)	%	No. (25)	%
Metformin	38	95	23	92
Nifedipine	13	32.5	10	40
Amaryl	2	5	22	88
Lisinopril	6	15	9	36
Dionil	6	15	0	0
Insulin	5	12.5	1	4
Losartan	2	5	7	28
Atorvastatin	2	5	9	36
Amlodipine	5	12.5	8	32
Aspirin	2	5	1	4

Data was presented in frequency (No.) and percentage (%).

DM: Diabetes mellitus; DR: Diabetic retinopathy.

Table 3. Clinical and biochemical characteristics of study participants.

	Control (n = 25) median (min-max)	DM Only (n = 25) median (min-max)	DR (n = 40) median (min-max)	p-value
FBG (/mmol/l)	4.9 (3.8–6.10)^A	7.5 (4.40–14.40)^B	9.5 (4.40–21.40)^B	0.001
BMI (/kg/m^2)	23.0 (18–39)^A	29.0 (22–42)^B	28.0 (20–38)^B	0.005
Age (years)	38 (23–83)^A	65 (43–83)^B	59 (40–76)^B	0.001
SYS (mmHg)	134 (91–214)^A	145 (103–203)^B	146 (110–238)^B	0.001
DIA (mmHg)	88 (57–114)^B	80 (55–102)^A	84 (60–127)^B	0.001
IgE (IU/ml)	197.6 (6.8–477.6)	55.5 (7.9–519.2)	101.5 (7.8–763.7)	0.115
IgG (mg/ml)	200 (7–565)^A	50 (5–500)^B	86 (5–560)^B	0.017

A p-value < 0.05 was considered statistically significant. A and B denote significant differences between groups (one-way ANOVA with Tukey HSD posthoc analyses).

DIA: Diastolic blood pressure; FBG: Fasting blood glucose; IgE: Immunoglobulin E; IgG: Immunoglobulin G; Max: Maximum; Min: Minimum; SYS: Systolic blood pressure.

Table 4. Association between participants' features and anti-insulin IgE antibodies.

Participants' features	Retinopathy group		Diabetes only group		Control group
	r	p-value	r	p-value	r	p-value
Age	-0.04	0.83	0.01	0.97	0.30	0.15
Gender	0.22	0.18	0.21	0.31	0.07	0.74
BMI	-0.13	0.43	-0.12	0.58	0.13	0.55
Educational level	-0.11	0.51	0.13	0.53	-0.37	0.07
Systolic BP	-0.01	0.97	-0.09	0.67	0.24	0.24
Diastolic BP	0.06	0.74	-0.16	0.45	0.05	0.83
Occupation	0.05	0.78	0.01	0.98	-0.37	0.07
Fasting blood glucose	0.10	0.52	-0.30	0.15	-0.27	0.19
Metformin	-0.16	0.33	-0.20	0.92	N/A	N/A
Lisinopril	0.13	0.44	0.06	0.77	N/A	N/A
Amaryl	-0.21	0.18	0.23	0.28	N/A	N/A
Nifedipine	-0.32^†	0.04	0.15	0.47	N/A	N/A
Losartan	-0.22	0.17	0.13	0.52	N/A	N/A
Atorvastatin	0.03	0.84	0.01	0.96	N/A	N/A
Amlodipine	-0.14	0.37	-0.07	0.73	N/A	N/A
Aspirin	0.11	0.49	-0.21	0.30	N/A	N/A

† Significant at 0.05 alpha level.

N/A: Not applicable.

Table 5. Association between participants' features and anti-insulin IgG antibodies.

Participants' features	Retinopathy group		Diabetes group		Control group
	r	p-value	r	p-value	r	p-value
Age	-0.18	0.26	-0.02	0.91	0.07	0.73
Gender	0.22	0.18	0.22	0.28	0.13	0.53
BMI	-0.21	0.19	-0.14	0.51	0.03	0.88
Educational level	0.003	0.98	0.16	0.45	-0.05	0.81
Systolic BP	-0.01	0.96	-0.08	0.72	0.06	0.76
Diastolic BP	0.06	0.73	-0.14	0.49	0.01	0.98
Occupation	0.17	0.30	0.01	0.98	-0.26	0.21
Fasting blood glucose	0.04	0.79	-0.30	0.15	-0.22	0.29
Metformin	0.32^†	0.04	-0.02	0.94	N/A	N/A
Lisinopril	0.07	0.69	0.04	0.86	N/A	N/A
Amaryl	-0.04	0.83	0.20	0.34	N/A	N/A
Nifedipine	-0.04	0.79	0.15	0.47	N/A	N/A
Losartan	-0.77	0.64	0.16	0.46	N/A	N/A
Atorvastatin	-0.10	0.55	0.02	0.93	N/A	N/A
Aspirin	-0.20	0.22	-0.21	0.31	N/A	N/A

† Significant at 0.05 alpha level.

N/A: Not applicable.

Table 6. Multivariate analysis to determine predictors among study participants.

Features	OR (95% CI)	p-value
Diabetes only
Age (year)	1.12 (0.95–1.32)	0.17
BMI (kg/m^2)	1.00 (0.71–1.39 )	0.97
Systolic BP (mmHg)	1.21 (1.02–1.43)	0.03
Diastolic BP(mmHg)	0.60 (0.042–0.87)	0.007
FBG (mmol/l)	5.13 (3.09–7.71)	0.013
Serum IgE (IU/ml)	0.99 (0.97–1.00)	0.139
Serum IgG (ng/ml)	1.01 (1.00–1.01)	0.081
Diabetic retinopathy
Age (year)	1.04 (0.89–1.21)	0.629
BMI (kg/m^2)	0.88 (0.63–1.23)	0.461
Systolic BP (mmHg)	1.21 (1.02–1.43)	0.028
Diastolic BP(mmHg)	0.65 (0.45–0.94)	0.021
FBG (mmol/l)	1.97 (1.12–3.44)	0.012
Serum IgE (IU/ml)	0.99 (0.98–1.01)	0.274
Serum IgG (ng/ml	1.01 (1.00–1.02)	0.090

p-value <0.05 is considered significant.

FBG: Fasting blood glucose; OR: Odd ratios.