Table 5. Numbers (n) and percentages (%)* of STR among IHS-JVN patients, by their characteristics.
| Characteristic | No STR Apparent | STR Apparent | Hypothesis tests of independence | ||||
|---|---|---|---|---|---|---|---|
| n | % | n | % | Chi-Sq | (df) | P-value | |
| Age | |||||||
| Less than 50 years | 17585 | 95.9 | 759 | 4.1 | 8.7 | (3) | 0.0337 |
| 50 to 59 years | 12914 | 95.4 | 627 | 4.6 | |||
| 60 to 69 years | 8928 | 95.9 | 377 | 4.1 | |||
| 70 years and older | 3628 | 96.3 | 141 | 3.7 | |||
| Gender** | |||||||
| Male | 18754 | 95.4 | 913 | 4.6 | 14.3 | (1) | 0.0002 |
| Female | 24298 | 96.1 | 991 | 3.9 | |||
| Area | |||||||
| Southwest | 24816 | 95.5 | 1174 | 4.5 | 23.6 | (5) | 0.0003 |
| Alaska | 481 | 98.8 | 6 | 1.2 | |||
| East of Mississippi River | 1561 | 96.0 | 65 | 4.0 | |||
| Northern Plains | 4041 | 95.6 | 184 | 4.4 | |||
| Northwest | 4912 | 96.4 | 186 | 3.6 | |||
| Oklahoma | 7244 | 96.2 | 289 | 3.8 | |||
| Duration of diabetes | |||||||
| Less than 1 year | 5580 | 98.7 | 72 | 1.3 | 556.5 | (8) | < 0.0001 |
| 1 to 5 years | 12388 | 98.9 | 137 | 1.1 | |||
| 6 to 10 years | 8688 | 97.3 | 243 | 2.7 | |||
| More than 10 years | 12775 | 90.7 | 1305 | 9.3 | |||
| Unknown/missing | 3624 | 96.1 | 147 | 3.9 | |||
| Diabetes therapy | |||||||
| Diet only | 4114 | 98.7 | 53 | 1.3 | 1358.1 | (4) | < 0.0001 |
| Oral medications | 22712 | 97.8 | 515 | 2.2 | |||
| Insulin only | 4610 | 88.5 | 599 | 11.5 | |||
| Insulin & oral medications | 7677 | 92.5 | 621 | 7.5 | |||
| Unknown/missing | 3942 | 97.1 | 116 | 2.9 | |||
| Glycemic control | |||||||
| A1c of less than 6% (< 42 mmol/mol) | 4149 | 98.2 | 78 | 1.8 | 439.4 | (5) | < 0.0001 |
| A1c of 6 to 7.9% (42 to 63 mmol/mol) | 15569 | 97.6 | 389 | 2.4 | |||
| A1c of 8 to 10% (64 to 86 mmol/mol) | 7972 | 94.5 | 467 | 5.5 | |||
| A1c of greater than 10% (> 86 mmol/mol) | 8060 | 92.6 | 643 | 7.4 | |||
| Missing but poor glycemic control noted | 727 | 94.3 | 44 | 5.7 | |||
| Unknown/missing | 6578 | 95.9 | 283 | 4.1 | |||
| Technology | |||||||
| NMFP | 27782 | 96.4 | 1040 | 3.6 | 77.7 | (1) | < 0.0001 |
| UWFI | 15273 | 94.6 | 864 | 5.4 | |||
Excludes patients with ungradable images; All chi-square tests examine the likelihood of having STR.
* Row percentage;
**3 people were 'other' for gender and were excluded.
IHS-JVN = Indian Health Service-Joslin Vision Network Teleophthalmology Program; STR = sight threatening retinopathy; NMFP = nonmydriatic flash photography; UWFI = ultrawide-field imaging; df = degrees of freedom.