Clinical Ophthalmology (Jul 2020)
Initial Treatment Response in Ocular Myasthenia Gravis: A Comparison Between Low and Moderate Doses of Prednisolone
Abstract
Thanatporn Threetong,1,2 Anuchit Poonyathalang,1 Pisit Preechawat,1 Panitha Jindahra,3 Tanyatuth Padungkiatsagul,1 Kavin Vanikieti1 1Department of Ophthalmology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand; 2Department of Ophthalmology, Faculty of Medicine, Burapha University, Chonburi, Thailand; 3Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, ThailandCorrespondence: Tanyatuth PadungkiatsagulDepartment of Ophthalmology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 270 Rama VI Road, Bangkok 10400, ThailandTel +662 201 1526Fax +662 201 2729Email [email protected]: To evaluate the initial treatment response to low doses of prednisolone, compared with moderate doses, in ocular myasthenia gravis (OMG).Patients and Methods: A retrospective chart review of patients with adult-onset (age ≥ 15 years old) OMG, who were treated with prednisolone, was conducted. Subjects were divided into two groups according to their prednisolone dosing regimen. The low-dose group was defined as those with an average 12-week cumulative dose of prednisolone < 0.435 mg/kg/day and the moderate-dose group averaged 0.435– 1.000 mg/kg/day. The primary outcome of interest was the comparison of clinical response to prednisolone at 12 weeks between the low-dose and moderate-dose groups. The secondary outcome was the difference in adverse events between treatment groups.Results: Of 34 subjects, 16 subjects (47.1%) were male. The mean age at onset was 44.0± 18.1 years. The most common presenting ocular feature was ptosis with ophthalmoplegia (22 subjects, 64.7%), followed by isolated ptosis (nine subjects, 26.5%) and isolated ophthalmoplegia (three subjects, 8.8%). Half of the subjects were treated with low-dose prednisolone and the other half were treated with moderate-dose prednisolone. There were no substantial differences in baseline characteristics between treatment groups. After 12 weeks of treatment, nine of 17 subjects (52.9%) and 13 of 17 subjects (76.5%) in the low- and moderate-dose groups, respectively, were regarded as responsive to the prednisolone treatment (P=0.28). Adverse events were exclusively observed in the moderate-dose group.Conclusion: Treatment of OMG with an average 12-week cumulative dose of prednisolone < 0.435 mg/kg/day (low dose) shows a comparable responsive outcome to 0.435– 1.000 mg/kg/day of prednisolone (moderate dose). Treating OMG with low-dose prednisolone can minimize prednisolone-related adverse events. However, a prospective randomized controlled trial with a larger study population is warranted in order to gain more insight into the proper dosage of prednisolone for OMG.Keywords: ocular myasthenia gravis, low dose, moderate dose, prednisolone, treatment outcome
