A socioeconomic and behavioral survey of patients with difficult-to-control type 2 diabetes mellitus reveals an association between diabetic retinopathy and educational attainment

Figures & data

Figure 1 Association between retinopathy level and educational level attainment in participants with T2DM.

Notes: (A) <65 years of age; (B) ≥65 years of age, educational attainment (total educational years): junior high school (9 years); high school (12 years); vocational college (13–15 years); junior college including technical college (14–15 years); university including graduate school (≥16 years). Retinopathy levels; NDR, SDR, PPDR, PDR, and PRP. Pearson’s χ² test: <65 years of age: n=126, χ² 21.58, P=0.0058; ≥65 years of age: n=104, χ² 3.58, P=0.89.
Abbreviations: NDR, no diabetic retinopathy; PPDR, preproliferative diabetic retinopathy; PDR, proliferative diabetic retinopathy; PRP, panretinal photocoagulation; SDR, simple diabetic retinopathy; T2DM, type 2 diabetes mellitus.

Figure 2 Comparison of (A) personal and (B) household income by retinopathy level for participants with T2DM <65 years of age.

Notes: Retinopathy levels: NDR, SDR, PPDR, PDR, and PRP. Kruskal–Wallis rank sum test: personal income: χ² 1.33, P=0.51; household income: χ² 6.87, P=0.032.
Abbreviations: JPY, Japanese Yen (JPY 1 million = USD 10,000); NDR, no diabetic retinopathy; PDR, proliferative diabetic retinopathy; PPDR, preproliferative diabetic retinopathy; PRP, panretinal photocoagulation; SDR, simple diabetic retinopathy; T2DM, type 2 diabetes mellitus.

Figure 3 Comparison of (A) personal and (B) household income by educational attainment for participants with T2DM <65 years of age.

Notes: Educational attainment (total educational years): junior high school (9 years); high school (12 years); vocational college (13–15 years); Junior college including technical college (14–15 years); university including graduate school (≥16 years), Kruskal–Wallis rank sum test: personal income: χ² 14.01, P=0.0073; household income: χ² 10.87, P=0.028.
Abbreviations: JPY, Japanese Yen (JPY 1 million = USD 10,000); T2DM, type 2 diabetes mellitus.

Table 1 Patient characteristics

Characteristic	Total	Age <65 years	Age ≥65 years	P-value1
Number of patients	238	128	110
Age (years)	61.4±12.4	52.9±10.0	71.3±5.7
Male/female	129/109	71/57	58/52	0.672
BMI (kg/m^2)	25.6±4.6	26.5±4.8	24.3±4.0	<0.001
Diabetes duration (years)	13.2±9.7	10.3±7.6	16.6±10.9	<0.001
HbA1c (%)	7.70±4.5	7.52±1.0	7.89±6.5	0.525
Retinopathy ±2 (retinopathy rate)	111/121 (47.8%)	61/663 (48.0%)	50/554 (47.6%)	0.950
Nephropathy ±5 (nephropathy rate)	95/143 (39.9%)	45/83 (35.2%)	50/60 (45.5%)	0.106

Notes: Values are presented as mean ± standard deviation.

1 Age <65 versus ≥65 years, frequency analysis was performed with Fisher’s exact test.

2 Retinopathy includes simple, preproliferative, proliferative retinopathy, and panretinal photocoagulation.

3 One patient did not have eye examination by ophthalmologists.

4 Five patients did not have eye examination by ophthalmologists.

5 Nephropathy includes stages 2–5 nephropathy.

Abbreviations: BMI, body mass index; HbA1c, hemoglobin A1c.

Table 2 Ordinal logistic regression analysis1 of factors associated with retinopathy level2 in patients with T2DM all ages

Parameter	Estimate	Standard error	Chi-square test	P-value4
Age	−0.02764	0.01583	3.05	0.0807
Sex (female)	−0.38540	0.16622	5.38	0.0204
Diabetes duration	0.06717	0.01753	14.68	0.00015
Q13 General risk preference, weather	−0.00717	0.00740	0.94	0.3326
Q2 General risk averse, travel	0.01384	0.01285	1.16	0.2815
Q3 Dissatisfaction to life	0.09261	0.15301	0.37	0.5450
Q8 Procrastination, if now (2&3 vs 1)	0.39389	0.15333	6.60	0.01025
Q10 Medical spending	0.00002	0.00001	2.76	0.0967
Q13 Risk loving, lottery	0.00005	0.00005	1.29	0.2558
Q15 Educational level (high)	−0.32113	0.11304	8.07	0.00455
Q16 Job (worked)	−0.40064	0.17874	5.02	0.0250
Q18 Household income	0.00079	0.00069	1.31	0.2532
Q18 Household income/person	−0.00170	0.00161	1.12	0.2892
Q19 Savings (1&3&4 vs 2)	0.79641	0.30449	6.84	0.00895
Q19 Savings (1&3 vs 4)	0.10406	0.15369	0.46	0.4984
Q20 Economic status (affluent)	0.21864	0.22167	0.97	0.3240

Notes:

1 Whole model test: degrees of freedom 16, likelihood ratio chi-square test 52.54, P-value <0.0001.

2 Levels of diabetic retinopathy; 0, NDR; 1, SDR; 2, PPDR + PDR + PRP.

3 Survey questionnaires are shown in Figure S2.

4 Wald test for effects.

5 P<0.01, significant by effect likelihood ratio test.

Abbreviations: NDR, no diabetic retinopathy; PDR, proliferative diabetic retinopathy; PPDR, preproliferative diabetic retinopathy; PRP, panretinal photocoagulation; SDR, simple diabetic retinopathy; T2DM, type 2 diabetes mellitus.

Table 3 Ordinal logistic regression analysis1 of factors associated with nephropathy levels2 in patients with T2DM all ages

Parameter	Estimate	Standard error	Chi-square test	P-value4
Age	0.03890	0.01613	5.82	0.0158
Sex (female)	−0.57584	0.17368	10.99	0.00095
BMI	0.12557	0.03464	13.14	0.00035
Q13 General risk preference, weather	0.01035	0.00776	1.78	0.1819
Q3 Dissatisfaction to life	0.08581	0.15771	0.30	0.5864
Q6 Sleep enough	−0.44858	0.14285	9.86	0.00175
Q8 Procrastination, if now (2 vs 3&1)	0.32860	0.17183	3.66	0.0558
Q9 Medical uncertainty (unacceptable)	−0.39584	0.18867	4.40	0.0359
Q12 Pay for reducing CVD risk	−0.00002	0.00002	1.92	0.1656
Q13 Risk loving, lottery	0.00008	0.00004	3.54	0.0598
Q13 Risk averse, insurance	−0.00004	0.00002	3.15	0.0758
Q15 Educational level (high)	−0.19004	0.11540	2.71	0.0996
Q16 Job (worked)	−0.38579	0.18095	4.55	0.0330
Q18 Household income/person	−0.00261	0.00140	3.45	0.0631
Q19 Savings (3&4&1 vs 2)	0.42929	0.31374	1.87	0.1712
Q20 Economic status (affluent)	0.37107	0.23395	2.52	0.1127

Notes:

1 Whole model test: degrees of freedom 16, likelihood ratio chi-square test 57.05, P-value <0.0001.

2 Levels of nephropathy; stages 1–5.

3 Survey questionnaires are shown in Figure S2.

4 Wald test for effects.

5 P<0.01, significant by effect likelihood ratio test.

Abbreviations: BMI, body mass index; T2DM, type 2 diabetes mellitus; CVD, cardiovascular disease.

Table 4 Ordinal logistic regression analysis1 of factors associated with retinopathy level2 in patients with T2DM <65 years of age

Parameter	Estimate	Standard error	Chi-square test	P-value4
Sex (female)	−0.59851	0.24340	6.05	0.0139
Diabetes duration	0.05826	0.02885	4.08	0.0434
Q33 Dissatisfaction to life	0.39370	0.21583	3.33	0.0681
Q7 Procrastination, childhood (2 vs 3&1)	0.71680	0.31475	5.19	0.0228
Q8 Procrastination, if now (2 vs 3&1)	0.32618	0.25436	1.64	0.1997
Q10 Medical spending	0.00005	0.00002	6.45	0.0111
Q13 Risk loving, lottery	0.00010	0.00005	3.86	0.0495
Q14 Risk averse, insurance	−0.00006	0.00003	4.16	0.0415
Q15 Educational level (high)	−0.58845	0.16983	12.01	0.00055
Q16 Job (worked)	−0.59446	0.25188	5.57	0.0183
Q19 Savings (3&1–4&2)	0.34967	0.21029	2.76	0.0963
Q20 Economic status (affluent)	0.48419	0.29603	2.68	0.1019

Notes:

1 Whole model test: degrees of freedom 12, likelihood ratio chi-square 48.55, P-value <0.0001.

2 Levels of diabetic retinopathy; 0, NDR; 1, SDR; 2, PPDR + PDR + PRP.

3 Survey questionnaires are shown in Figure S2.

4 Wald test for effects.

5 P<0.01, significant by effect likelihood ratio test.

Abbreviations: NDR, no diabetic retinopathy; PDR, proliferative diabetic retinopathy; PPDR, preproliferative diabetic retinopathy; PRP, panretinal photocoagulation; SDR, simple diabetic retinopathy; T2DM, type 2 diabetes mellitus.

Table 5 Ordinal logistic regression analysis1 of factors associated with nephropathy levels2 in patients with T2DM <65 years of age

Parameter	Estimate	Standard error	Chi-square test	P-value4
Age	0.08739	0.03009	8.44	0.00375
Sex (female)	−0.76274	0.30759	6.15	0.0131
BMI	0.13791	0.05130	7.23	0.00725
Q13 General risk preference, weather	0.01964	0.01290	2.32	0.1278
Q5 Sleeping hours	−0.13897	0.24355	0.33	0.5683
Q6 Sleep enough	−0.56260	0.27186	4.28	0.0385
Q7 Procrastination, childhood (2 vs 3&1)	0.38849	0.27289	2.03	0.1546
Q9 Medical uncertainty (unacceptable)	−0.68812	0.28418	5.86	0.0155
Q13 Risk loving, lottery	0.00011	0.00007	2.40	0.1214
Q14 Risk averse, insurance	−0.00009	0.00007	1.97	0.1608
Q15 Educational level (high)	−0.42920	0.19364	4.91	0.0267
Q17 Income	−0.00113	0.00127	0.80	0.3701
Q18 Household income/person	−0.00556	0.00231	5.81	0.0159

Notes:

1 Whole model test: degrees of freedom 13, likelihood ratio chi-square test 44.33, P-value <0.0001.

2 Levels of nephropathy; stages 1–5.

3 Survey questionnaires are shown in Figure S2.

4 Wald test for effects.

5 P<0.01, significant by effect likelihood ratio test.

Abbreviations: BMI, body mass index; T2DM, type 2 diabetes mellitus.

Table 6 Ordinal logistic regression analysis1 of factors associated with retinopathy levels2 in patients with T2DM ≥65 years

Parameter	Estimate	Standard error	Chi-square test	P-value4
Age	−0.10114	0.04474	5.11	0.0238
Diabetes duration	0.10235	0.02830	13.08	0.00035
Q13 General risk preference, weather	−0.01902	0.01142	2.77	0.0959
Q7 Proclatination, childhood (2&1 vs 3)	0.49517	0.25583	3.75	0.0529
Q8 Procrastination, if now (3&2 vs 1)	0.52443	0.25508	4.23	0.0398
Q9 Medical uncertainty (unacceptable)	0.86806	0.30157	8.29	0.00405
Q12 Pay for reducing CVD risk	0.00001	0.00002	0.20	0.6561
Q13 Risk loving, lottery	0.00027	0.00014	3.51	0.0609
Q16 Job (worked)	−0.78320	0.28168	7.73	0.00545

Notes:

1 Whole model test: degrees of freedom 9, likelihood ratio chi-square 33.4, P-value <0.0001.

2 Levels of diabetic retinopathy; 0, NDR; 1, SDR; 2, PPDR + PDR + PRP.

3 Survey questionnaires are shown in Figure S2.

4 Wald test for effects.

5 P<0.01, significant by effect likelihood ratio test.

Abbreviations: CVD, cardiovascular disease; NDR, no diabetic retinopathy; PDR, proliferative diabetic retinopathy; PPDR, preproliferative diabetic retinopathy; PRP, panretinal photocoagulation; SDR, simple diabetic retinopathy; T2DM, type 2 diabetes mellitus.

Table 7 Ordinal logistic regression analysis1 of factors associated with nephropathy levels2 in patients with T2DM

Parameter	Estimate	Standard error	Chi-square test	P-value4
Diabetes duration	0.05668	0.01885	9.04	0.00265
Q63 Sleep enough	−0.15117	0.16279	0.86	0.3531
Q8 Procrastination, if now (2 vs 1&3)	0.36467	0.22726	2.57	0.1086
Q13 Risk loving, lottery	0.00030	0.00011	6.60	0.0102
Q20 Economic status (affluent)	0.16770	0.22285	0.57	0.4517

Notes:

1 Whole model test: degrees of freedom 5, likelihood ratio chi-square 16.77, P-value <0.0050.

2 Levels of nephropathy; stages 1–5.

3 Survey questionnaires are shown in Figure S2.

4 Wald test for effects.

5 P<0.01, significant by effect likelihood ratio test.

Abbreviation: T2DM, type 2 diabetes mellitus.

Figure S1 Study flow diagram.

Abbreviations: T1DM, type 1 diabetes mellitus; T2DM, type 2 diabetes mellitus.

Figure S2 Survey questionnaires.