Evaluation of risk factors for retinal damage due to chloroquine and hydroxychloroquine

To evaluate risk factors for retinal damage due to the intake of chloroquine and hydroxychloroquine.

In a retrospective chart review, patients receiving or having received one of the drugs were classified as affected by maculopathy or retinopathy, or as not affected on the basis of the documented findings. Uncertain cases were excluded. The risk factors as postulated by the American Academy of Ophthalmology (AAO) and additional factors like diagnosis of underlying disease, total dose, nicotine abuse and the sum of the AAO risk factors were compared between both groups.

51 patients with a history of or ongoing treatment with chloroquine (23 individuals) or hydroxychloroquine (28 individuals) were included. Most of the postulated risk factors were expectedly elevated in the affected group. Significant differences applied to age, duration of intake and the sum of AAO risk factors. Surprisingly, positive smoking history was more frequent in the not affected. The toxic threshold of the daily chloroquine dose was exceeded by most of the patients.

Age and the duration of intake are major risk factors. Smoking seems to be negligible. The sum of AAO risk factors can give an estimation of the individual risk profile. Individual and weight-adapted dosing is especially essential for chloroquine.