Table 3. Numbers (n) and percentages (%)* of DR severity level among IHS-JVN patients, by their characteristics.
| Characteristic | No Apparent DR | Mild NPDR | Moderate NPDR | Severe NPDR | Evidence of PDR | Hypothesis tests of independence | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| n | % | n | % | n | % | n | % | n | % | Chi-Sq | (df) | P-value | |
| Age | |||||||||||||
| Less than 50 years | 14826 | 80.5 | 1440 | 7.8 | 1692 | 9.2 | 38 | 0.2 | 413 | 2.2 | 292.2 | (12) | < 0.0001 |
| 50 to 59 years | 10868 | 79.6 | 1260 | 9.2 | 1195 | 8.7 | 20 | 0.1 | 315 | 2.3 | |||
| 60 to 69 years | 7576 | 79.9 | 1031 | 10.9 | 630 | 6.6 | 6 | 0.1 | 233 | 2.5 | |||
| 70 years and older | 3111 | 79.0 | 553 | 14.0 | 181 | 4.6 | 3 | 0.1 | 91 | 2.3 | |||
| Gender** | |||||||||||||
| Male | 15525 | 77.9 | 1921 | 9.6 | 1953 | 9.8 | 27 | 0.1 | 495 | 2.5 | 147.4 | (4) | < 0.0001 |
| Female | 20853 | 81.6 | 2363 | 9.2 | 1745 | 6.8 | 40 | 0.2 | 557 | 2.2 | |||
| Area | |||||||||||||
| Southwest | 20508 | 78.0 | 2516 | 9.6 | 2559 | 9.7 | 35 | 0.1 | 674 | 2.6 | 317.4 | (20) | < 0.0001 |
| Alaska | 452 | 92.2 | 25 | 5.1 | 10 | 2.0 | 0 | 0.0 | 3 | 0.6 | |||
| East of Mississippi River | 1357 | 82.3 | 154 | 9.3 | 100 | 6.1 | 1 | 0.1 | 37 | 2.3 | |||
| Northern Plains | 3455 | 80.6 | 399 | 9.3 | 324 | 7.6 | 9 | 0.2 | 99 | 2.3 | |||
| Northwest | 4279 | 82.9 | 458 | 8.9 | 337 | 6.5 | 8 | 0.2 | 78 | 1.5 | |||
| Oklahoma | 6330 | 83.2 | 732 | 9.6 | 368 | 4.8 | 14 | 0.2 | 161 | 2.1 | |||
| Duration of diabetes | |||||||||||||
| Less than 1 year | 5362 | 94.5 | 148 | 2.6 | 133 | 2.3 | 3 | 0.1 | 31 | 0.5 | 5901.4 | (16) | < 0.0001 |
| 1 to 5 years | 11713 | 92.9 | 475 | 3.8 | 367 | 2.9 | 4 | 0.0 | 52 | 0.4 | |||
| 6 to 10 years | 7508 | 83.2 | 786 | 8.7 | 610 | 6.8 | 13 | 0.1 | 103 | 1.1 | |||
| More than 10 years | 8569 | 59.8 | 2593 | 18.1 | 2351 | 16.4 | 43 | 0.3 | 777 | 5.4 | |||
| Unknown/missing | 3229 | 84.1 | 282 | 7.3 | 237 | 6.2 | 4 | 0.1 | 89 | 2.3 | |||
| Diabetes therapy | |||||||||||||
| Diet only | 3971 | 94.5 | 124 | 3.0 | 72 | 1.7 | 0 | 0.0 | 34 | 0.8 | 4588.9 | (16) | < 0.0001 |
| Oral medications | 20393 | 87.0 | 1543 | 6.6 | 1263 | 5.4 | 17 | 0.1 | 232 | 1.0 | |||
| Insulin only | 2994 | 56.3 | 1017 | 19.1 | 906 | 17.0 | 20 | 0.4 | 382 | 7.2 | |||
| Insulin & oral medications | 5466 | 65.0 | 1358 | 16.2 | 1230 | 14.6 | 25 | 0.3 | 328 | 3.9 | |||
| Unknown/missing | 3557 | 86.6 | 242 | 5.9 | 227 | 5.5 | 5 | 0.1 | 76 | 1.9 | |||
| Glycemic control | |||||||||||||
| A1c of less than 6% (< 42 mmol/mol) | 3974 | 92.7 | 155 | 3.6 | 101 | 2.4 | 0 | 0.0 | 55 | 1.3 | 2416.0 | (20) | < 0.0001 |
| A1c of 6 to 7.9% (42 to 63 mmol/mol) | 14077 | 87.2 | 1180 | 7.3 | 619 | 3.8 | 9 | 0.1 | 265 | 1.6 | |||
| A1c of 8 to 10% (64 to 86 mmol/mol) | 6195 | 72.4 | 1191 | 13.9 | 883 | 10.3 | 18 | 0.2 | 269 | 3.1 | |||
| A1c of greater than 10% (> 86 mmol/mol) | 5934 | 67.5 | 1108 | 12.6 | 1428 | 16.2 | 29 | 0.3 | 293 | 3.3 | |||
| Missing but poor glycemic control noted | 597 | 77.4 | 87 | 11.3 | 72 | 9.3 | 3 | 0.4 | 12 | 1.6 | |||
| Unknown/missing | 5604 | 80.9 | 563 | 8.1 | 595 | 8.6 | 8 | 0.1 | 158 | 2.3 | |||
| Technology | |||||||||||||
| NMFP | 24557 | 84.6 | 2345 | 8.1 | 1590 | 5.5 | 50 | 0.2 | 480 | 1.7 | 1214.8 | (4) | < 0.0001 |
| UWFI | 11824 | 71.8 | 1939 | 11.8 | 2108 | 12.8 | 17 | 0.1 | 572 | 3.5 | |||
Excludes patients with ungradable images; All chi-square tests examine the likelihood of having a certain severity level of DR.
* Row percentage;
**3 people were 'other' for gender and were excluded.
IHS-JVN = Indian Health Service-Joslin Vision Network Teleophthalmology Program; DR = diabetic retinopathy; NPDR = nonproliferative diabetic retinopathy;
NMFP = nonmydriatic flash photography; UWFI = ultrawide-field imaging; df = degrees of freedom.