Ozempic (Semaglutide) side effect: The patient has been on Ozempic for many months, and chronic diarrhea is a known side effect of this medication. The temporal relationship between the medication use and the onset of diarrhea supports this diagnosis.

Irritable Bowel Syndrome (IBS): Although less likely given the patient's age and new onset of symptoms, IBS can occur at any age and should be considered, especially if other causes are ruled out.
Bile Acid Diarrhea: This condition is more common in older adults and can be caused by various factors, including gastrointestinal surgery, bile acid malabsorption, or other medical conditions.
Small Intestinal Bacterial Overgrowth (SIBO): This condition can cause chronic diarrhea and is more common in older adults, especially those with multiple medical comorbidities.

Colorectal Cancer: Although less likely without blood in the stool, colorectal cancer can still present with chronic diarrhea and should be ruled out, especially in an older adult.
Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis can present with chronic diarrhea and should be considered, even though they are less common in older adults without a prior history.
Infectious Diarrhea: Certain infections, such as Clostridioides difficile (C. diff), can cause chronic diarrhea and are important to rule out, especially in patients with multiple medical comorbidities.

VIPoma or other rare endocrine tumors: These tumors can cause chronic, watery diarrhea due to the secretion of vasoactive intestinal peptide (VIP) or other hormones.
Lymphocytic or Collagenous Colitis: These are rare conditions that can cause chronic diarrhea, often with a more insidious onset.
Short Bowel Syndrome: This condition can result from significant small bowel resection or disease, leading to chronic diarrhea due to malabsorption.