The Natural History of the Progression of Atrophy Secondary to Stargardt Disease (ProgStar) Studies: Design and Baseline Characteristics: ProgStar Report No. 1.

PURPOSE: To describe the design and baseline characteristics of patients enrolled into 2 natural history studies of Stargardt disease (STGD1). DESIGN: Multicenter retrospective and prospective cohort studies. PARTICIPANTS: Three hundred sixty-five unique patients aged 6 years and older at baseline harboring disease-causing variants in the ABCA4 gene and with specified ocular lesions were enrolled from 9 centers in the United States and Europe. METHODS: In the retrospective study, patients contributed medical record data from at least 2 and up to 4 visits for at least 1 examination modality: fundus autofluorescence (FAF), spectral-domain (SD) optical coherence tomography (SD OCT), and/or microperimetry (MP). The total observational period was at least 2 years and up to 5 years between single visits. Demographic and visual acuity (VA) data also were obtained. In the prospective study, eligible patients were examined at baseline using a standard protocol, with 6-month follow-up visits planned for a 2-year period for serial Early Treatment Diabetic Retinopathy Study (ETDRS) best-corrected VA, SD OCT, FAF, and MP. MAIN OUTCOME MEASURES: Design and rationale of a multicenter study to determine the progression of STGD1 in 2 large retrospective and prospective international cohorts. Detailed baseline characteristics of both cohorts are presented, including demographics, and structural and functional retinal metrics. RESULTS: Into the retrospective study, 251 patients (458 eyes) were enrolled; mean follow-up ± standard deviation was 3.9±1.6 years. At baseline, 36% had no or mild VA loss, and 47% of the study eyes had areas of definitely decreased autofluorescence (DDAF) with an average lesion area of 2.5±2.9 mm(2) (range, 0.02-16.03 mm(2)). Two hundred fifty-nine patients (489 eyes) were enrolled in the prospective study. At baseline, 20% had no or mild VA loss, and 64% had areas of DDAF with an average lesion area of 4.0±4.4 mm(2) (range, 0.03-24.24 mm(2)). The mean retinal sensitivity with MP was 10.8±5.0 dB. CONCLUSIONS: The ProgStar cohorts have baseline characteristics that encompass a wide range of disease severity and are expected to provide valuable data on progression based on serial quantitative measurements derived from multiple methods, which will be critical to the design of planned clinical trials.