Gastroesophageal reflux disease Quiz: Ace Your Exams

A 58-year-old man presents to the primary care clinic for a two-month history of hoarseness and a dry cough that worsens at night. The patient also reports a one-year history of heartburn that worsens after eating and a sour taste in the mouth relieved with over-the-counter antacids. There is no associated chest pain, nausea, vomiting, blood in the stool, or unintentional weight loss. Past medical history is significant for type 2 diabetes mellitus. The patient drinks one glass of wine daily with dinner. Vital signs are within normal limits. On physical examination, the patient is pale. On cardiopulmonary auscultation, there are diffuse wheezes and normal heart sounds. There is mild tenderness to palpation in the epigastrium. Which of the following findings that is present in this patient, indicates the need for further studies prior to initiating treatment?