Comparison of risk factors and different therapeutic options for ocular toxoplasmosis recurrence: a retrospective...

Ocular toxoplasmosis is a leading cause of vision impairment and is burdened by the risk of recurrence. This study, conducted at the University Hospital of Verona, aimed to identify potential risk factors associated with disease recurrence.

A total of 86 patients were treated for ocular toxoplasmosis between 1996 and 2023, with 43 completing treatment and follow-up of at least 18 months after treatment. Patients were treated with one of two therapeutic options: either trimethoprim-sulfamethoxazole or pyrimethamine-sulfametopyrazine. Over the study period, 21 patients experienced at least one recurrence, with a median time for the first recurrence of approximately six years. The average follow-up duration was eight years, and the probability of recurrence after seven years was 58%. Sleep duration emerged as a significant risk factor, as patients who slept between six and eight hours per night had a lower likelihood of recurrence. No significant associations were found with other factors, including gender, ethnicity, country of birth, education level, smoking, alcohol consumption, age at diagnosis, autoimmune diseases, vitamin deficiencies, vaccinations, cat ownership, consumption of raw or undercooked meat, place of residence, occupational soil exposure, primary infection (IgM positive), or the affected eye's laterality. Moderate evidence suggested a potential link between recurrences and psychological factors, such as stressful life events, lesion location, and pregnancy following the first diagnosis. Notably, women who experienced pregnancy after diagnosis had a threefold increased risk of recurrence. Regarding visual outcomes, there was modest evidence indicating that patients treated with trimethoprim-sulfamethoxazole achieved better final visual acuity compared to those treated with pyrimethamine. However, this difference was not statistically significant, and the underlying mechanism remains unclear.

The findings highlight the potential role of sleep duration in reducing recurrence risk and suggest a possible association between psychological stress, post-diagnosis pregnancy, and recurrence. Additionally, trimethoprim-sulfamethoxazole treatment may contribute to better long-term visual acuity, although further research is needed to confirm these observations.