Table.
Univariable Linear Mixed-Effects Model of Geographic Atrophy Growth Rate
| GA Area Growth Rate (mm2/y) | Eye-Specific GA Border Expansion Rate (mm/y)* | |||
|---|---|---|---|---|
| Estimate (95% CI) | P | Estimate (95% CI) | P | |
| Baseline GA area (mm2) | 0.17 (0.14–0.19) | <0.001 | 0.002 (−0.000 to 0.004) | 0.051 |
| Baseline GA perimeter (mm) | 0.12 (0.11–0.14) | <0.001 | 0.001 (−0.000 to 0.002) | 0.15 |
| Baseline lesion number | 0.25 (0.10–0.39) | <0.001 | −0.002 (−0.010 to 0.006) | 0.66 |
| Baseline multifocal GA | 1.06 (0.56–1.55) | <0.001 | 0.014 (−0.014 to 0.042) | 0.34 |
| Baseline GA in the fellow eye | 0.78 (0.28–1.29) | 0.002 | −0.005 (−0.032 to 0.023) | 0.73 |
| Baseline circularity index† | −2.81 (−3.57 to −2.04) | <0.001 | −0.031 (−0.077 to 0.015) | 0.18 |
| Distance between GA border and the foveal center (mm)‡ | 1.87 (1.57–2.17) | <0.001 | 0.037 (0.016–0.058) | <0.001 |
*
Eye-specific GA border expansion rates were calculated as the mean local border expansion rates of all points on the GA border in each eye over 1 year.
†
The circularity index was calculated as (4 × π × total area)/Total perimeter2, ranging from 0 to 1. A circularity close to 1 indicates a circular GA, and a circularity index close to 0 indicates a noncircular or multifocal GA.
‡
The distance between the GA border and the foveal center was defined as the mean distance from all pixels on the GA border to the foveal center averaged between the two visits spaced over 1 year.