A 79-year-old woman presents with new-onset pain in her neck and both shoulders. She takes 7.5 mg of prednisone per day for giant-cell arteritis. Occipital tenderness and diplopia developed 11 months before presentation. At that time, her erythrocyte sedimentation rate was elevated, at 78 mm per hour, and a temporal-artery biopsy revealed granulomatous arteritis. The diplopia resolved after 6 days of treatment with 60 mg of prednisone daily. Neither headache nor visual symptoms developed when the glucocorticoids were tapered. How should this patient's care be managed?