Fig. 1Receiver operating characteristic curves. (A) Single diagnostic criterion and (B) combination of two diagnostic criteria for screening of diabetes mellitus in the older group. (A) When the single criterion was used, area under the curve (AUC) of glycosylated hemoglobin (HbA1c) was 0.859 (95% confidence interval [CI], 0.809 to 0.901), the AUC of fasting plasma glucose (FPG) was 0.817 (95% CI, 0.762 to 0.863), and the AUC of 2-hour plasma glucose (2-h PG) after the 75 g oral glucose tolerance test, which was the largest, was 0.946 (95% CI, 0.910 to 0.971). (B) When the combination of two criteria was used, the AUC of HbA1c and FPG was 0.884 (95% CI, 0.836 to 0.921), the AUC of HbA1c and 2-h PG, which was the largest, was 0.966 (95% CI, 0.935 to 0.985), and the AUC of FPG and 2-h PG was 0.959 (95% CI, 0.925 to 0.980).
Table 1Comparison of clinical and laboratory characteristics of study patients stratified by age
Characteristic |
<65 Years (n=153) |
≥65 Years (n=156) |
P value |
Age, yr |
47.2±11.9 |
71.0±49.4 |
<0.001 |
Male sex |
83 (54.2) |
77 (49.4) |
NS |
Familial history of diabetes |
73 (47.7) |
18 (11.5) |
<0.001 |
Cardiovascular event |
2 (1.3) |
22 (14.1) |
<0.001 |
Cerebrovascular event |
4 (2.6) |
16 (10.3) |
0.009 |
Smoking |
51 (33.3) |
47 (30.1) |
NS |
Dyslipidemia medication |
16 (10.5) |
49 (31.4) |
<0.001 |
Hypertension medication |
38 (24.8) |
92 (59.0) |
<0.001 |
SBP, mm Hg |
132±16 |
130±14 |
NS |
DBP, mm Hg |
80±12 |
75±8 |
<0.001 |
BMI, kg/m2
|
26.3±4.4 |
25.3±3.4 |
0.042 |
HbA1c, % |
8.2±2.1 |
6.8±1.2 |
<0.001 |
FPG, mg/dL |
170±56 |
130±43 |
<0.001 |
2-h PG, mg/dL |
311±102 |
257±81 |
<0.001 |
Fasting insulin, µIU/mL |
10.9±5.1 |
13.8±15.8 |
0.047 |
2-h insulin, µIU/mL |
44.5±42.3 |
64.9±48.8 |
0.003 |
Fasting C-peptide, pmol/mL |
0.9±0.4 |
1.2±0.7 |
0.006 |
2-h C-peptide, pmol/mL |
2.5±1.4 |
3.7±1.9 |
<0.001 |
HOMA-IR |
1.7±0.9 |
2.0±1.7 |
NS |
HOMA-β |
45.7±30.6 |
76.0±54.4 |
<0.001 |
Total cholesterol, mg/dL |
202±45 |
178±40 |
<0.001 |
HDL-C, mg/dL |
48±12 |
49±12 |
NS |
LDL-C, mg/dL |
129±41 |
112±38 |
0.001 |
Triglycerides, mg/dL |
202±155 |
159±90 |
0.004 |
eGFR, mL/min/1.73 m2
|
113.7±28.8 |
95.6±28.3 |
<0.001 |
Table 2The prevalence of diabetes using HbA1c, FPG, and 2-h PG criteria according to age group
Diagnostic criterion |
<65 Years (n=153) |
≥65 Years (n=156) |
P value |
HbA1c |
124 (81) |
96 (61.5) |
<0.001 |
FPG |
124 (81) |
71 (45.5) |
<0.001 |
2-h PG |
140 (91.5) |
132 (84.6 ) |
NS |
Table 3Percentage of patients stratified by number of diagnostic criteria satisfied according to age group
No. of satisfied DM diagnostic criteria |
<65 Years (n=153) |
≥65 Years (n=156) |
P value |
3 |
108 (70.6) |
51 (32.7) |
<0.001 |
2 |
19 (12.4) |
41 (26.3) |
0.002 |
HbA1c+FPG |
1 (0.7) |
5 (3.2) |
NS |
HbA1c+2-h PG |
10 (6.5) |
27 (17.3) |
0.005 |
FPG+2-h PG |
8 (5.2) |
9 (5.8) |
NS |
1 |
26 (17.0) |
64 (41.0) |
<0.001 |
HbA1c |
5 (3.3) |
13 (8.3) |
NS |
FPG |
7 (4.6) |
6 (3.8) |
NS |
2-h PG |
14 (9.2) |
45 (28.8) |
<0.001 |
Table 4Percentage of patients who met 2-h PG criteria among patients with undiagnosed diabetes using FPG levels
FPG, mg/dL |
2-h PG, mg/dL |
<65 Years (n=106) |
≥65 Years (n=114) |
<140 |
≥200 |
<140 |
≥200 |
<100 |
58 (54.72) |
2 (1.89) |
19 (16.67) |
11 (9.65) |
100–125 |
24 (22.64) |
22 (20.75) |
23 (20.17) |
61 (53.51) |
Subtotal |
82 (77.36) |
24 (22.64) |
42 (36.84) |
72 (63.16) |
Table 5Sensitivity and specificity of diagnostic criteria for diabetes mellitus in the older group
Variable |
Sensitivity, % |
Specificity, % |
HbA1c >6.4 % |
61.54 |
100 |
FPG, mg/dL |
|
|
>117 |
61.54 |
90.59 |
>125 |
45.51 |
100 |
2-h PG >198 mg/dL |
84.62 |
100 |
HbA1c & FPG |
71.15 |
92.94 |
HbA1c & 2-h PG |
85.90 |
97.65 |
FPG & 2-h PG |
85.26 |
94.12 |