Table 1. Characteristics of the IHS-JVN patients, by gradable or ungradable images.
| Characteristic | Patients with gradable images for DR or DME | Patients with ungradable images for both DR and DME | Hypothesis tests of independence, gradable vs. ungradable | |||||
|---|---|---|---|---|---|---|---|---|
| (n = 46584) | (n = 7414) | (n = 53998) | ||||||
| n | Column % | Row % | n | Row % | Chi-Sq | (df) | P-value | |
| Social-demographics | ||||||||
| Age | ||||||||
| Less than 50 years | 18793 | 40.3 | 93.2 | 1381 | 6.8 | 2844.7 | (3) | < 0.0001 |
| 50 to 59 years | 13977 | 30.0 | 88.6 | 1805 | 11.4 | |||
| 60 to 69 years | 9737 | 20.9 | 80.7 | 2324 | 19.3 | |||
| 70 years and older | 4077 | 8.8 | 68.2 | 1904 | 31.8 | |||
| Gender* | ||||||||
| Male | 20476 | 44.0 | 85.0 | 3627 | 15.0 | 64.3 | (2) | < 0.0001 |
| Female | 26105 | 56.0 | 87.3 | 3786 | 12.7 | |||
| Area | ||||||||
| Southwest | 26829 | 57.6 | 87.0 | 4008 | 13.0 | 191.2 | (5) | < 0.0001 |
| Alaska | 499 | 1.1 | 88.3 | 66 | 11.7 | |||
| East of Mississippi River | 1743 | 3.7 | 79.0 | 462 | 21.0 | |||
| Northern Plains | 4401 | 9.4 | 82.4 | 941 | 17.6 | |||
| Northwest | 5326 | 11.4 | 86.8 | 807 | 13.2 | |||
| Oklahoma | 7786 | 16.7 | 87.3 | 1130 | 12.7 | |||
| Health summary data | ||||||||
| Duration of diabetes | ||||||||
| Less than 1 year | 5780 | 12.4 | 91.9 | 511 | 8.1 | 1015.2 | (4) | < 0.0001 |
| 1 to 5 years | 12862 | 27.6 | 90.5 | 1347 | 9.5 | |||
| 6 to 10 years | 9237 | 19.8 | 88.3 | 1220 | 11.7 | |||
| More than 10 years | 14769 | 31.7 | 80.1 | 3668 | 19.9 | |||
| Unknown/missing | 3936 | 8.4 | 85.5 | 668 | 14.5 | |||
| Diabetes therapy | ||||||||
| Diet only | 4287 | 9.2 | 87.8 | 593 | 12.2 | 373.3 | (4) | < 0.0001 |
| Oral medications | 23990 | 51.5 | 88.4 | 3152 | 11.6 | |||
| Insulin only | 5467 | 11.7 | 80.5 | 1324 | 19.5 | |||
| Insulin & oral medications | 8638 | 18.5 | 83.5 | 1710 | 16.5 | |||
| Unknown/missing | 4202 | 9.0 | 86.9 | 635 | 13.1 | |||
| Glycemic control | ||||||||
| A1c of less than 6% (< 42 mmol/mol) | 4393 | 9.4 | 87.3 | 638 | 12.7 | 77.9 | (5) | < 0.0001 |
| A1c of 6 to 7.9% (42 to 63 mmol/mol) | 16499 | 35.4 | 86.9 | 2488 | 13.1 | |||
| A1c of 8 to 10% (64 to 86 mmol/mol) | 8788 | 18.9 | 86.2 | 1409 | 13.8 | |||
| A1c of greater than 10% (> 86 mmol/mol) | 8980 | 19.3 | 87.2 | 1320 | 12.8 | |||
| Missing but poor glycemic control noted | 797 | 1.7 | 82.6 | 168 | 17.4 | |||
| Unknown/missing | 7127 | 15.3 | 83.7 | 1391 | 16.3 | |||
| Technology | ||||||||
| NMFP | 30049 | 64.5 | 81.2 | 6948 | 18.8 | 2529.8 | (1) | < 0.0001 |
| UWFI** | 16535 | 35.5 | 97.3 | 466 | 2.7 | |||
Column percentages are shown to characterize the analytic sample, patients with gradable images only.
Row percentages are shown to examine differences in the likelihood of having gradable images, based on patient characteristics.
All chi-square tests examining likelihood of having gradable versus ungradable images (by characteristic) indicate the 2 groups differ along these characteristics.
*3 people were 'other' for gender and were excluded.
**UWFI became available in this program Sept 2014.
IHS-JVN = Indian Health Service-Joslin Vision Network Teleophthalmology Program; DR = diabetic retinopathy; DME = diabetic Macular Edema; NMFP = nonmydriatic flash photography; UWFI = ultrawide-field imaging; df = degrees of freedom.