Table 1.
ICD-9 codes used in patients using hydroxychloroquine (n=678)
| No. of patients with this code | % with code with confirmed toxicity (n) | No. of patients with only this code | % with only this code with confirmed toxicity (n) | % without code without confirmed toxicity | Additional codes used in patients with confirmed toxicity | |
|---|---|---|---|---|---|---|
| Toxic maculopathy | 44 | 81.82 (36) | 35 | 80 (28) | 97.48 | Drusen (3), AMD (3), and background retinopathy (3) |
| Background retinopathy | 116 | 8.62 (10) | 101 | 4.95 (5) | 92.35 | Drusen (1), AMD (1), and toxic Maculopathy (3) |
| Drusen (degenerative) | 149 | 4.70 (7) | 101 | 0.99 (1) | 91.30 | AMD (3), Toxic maculopathy (3), and background retinopathy (1) |
| Non-exudative AMD | 430 | 3.02 (13) | 382 | 1.83 (7) | 83.87 | Toxic maculopathy (3), background retinopathy (1), and drusen (3) |
Abbreviation: AMD, age-related macular degeneration.