A 55-year-old woman with a 10-year history of diabetes mellitus (DM) presents with 2 months of numbness in the toes, needle-like pain in the thigh skin, urinary incontinence, and anhidrosis. Examination shows weight loss, poor nutrition, atrophy of interosseous muscles in both hands, and muscle strength grade IV. No crackles or wheezes are heard in the lungs, and pathological reflexes are negative. Fasting blood glucose (FBG) is 14.1 mmol/L, and blood ketones are negative. What is the most likely diagnosis?