Choroidal thickening induced by pioglitazone in diabetic patients.

Purpose: This study aimed to determine the changes in choroidal thickness induced by pioglitazone in diabetic patients.

Methods: A total of 261 patients diagnosed with type 2 diabetes who had taken oral pioglitazone for more than 6 months were included in the study. After excluding patients who did not undergo regular eye examinations or who had ophthalmic surgery/interventions during the treatment period, a total of 40 eyes were included. The study examined the duration and dosage of pioglitazone, patient age, ocular axial length, refraction, glycated hemoglobin, systolic blood pressure, corrected visual acuity, macular thickness, choroidal thickness, and choroid vascular index. Patients were categorized into a high dose group if their pioglitazone dose was 30mg or more per day, and a low dose group if it was 15mg or less. Choroidal thickness was measured below the subfovea and a 500 µm radius nasal and temporal to that location.

Results: Choroidal thickness significantly increased after 6 and 12 months of pioglitazone in all subjects (6.70µm, 13.65µm, each). When stratified by pioglitazone dosage, choroidal thickness increased at 6 and 12 months in both the high (4.48µm, 0.84µm, each) and low dose groups (6.85µm, 21.45µm, each), with a greater change observed in low dose group (p<0.05, respectively). Based on the location of choroidal thickness measurements, a significant increase in choroidal thickness was observed at 6 and 12 months of pioglitazone treatment in the subfoveal (7.00µm, 13.15µm, each) and nasal regions (6.43µm, 19.24µm, each), while a significant increase was only observed after 6 months of treatment in the temporal region (8.53µm) (p<0.05, respectively). The largest increase in choroidal thickness was observed in the nasal side.

Conclusion: This study found that choroidal thickness increased in diabetic patients after taking pioglitazone. Regular eye examinations are recommended for diabetic patients who are on pioglitazone.