Osteoporosis

A 58-year-old man with chronic kidney disease stage 3b (eGFR 35 mL/min/1.73 m²) and osteoporosis (T-score −2.7 on DEXA) presents for management. He has had no prior fractures. His serum calcium is 8.2 mg/dL (normal 8.5–10.5), phosphate is 4.8 mg/dL (normal 2.5–4.5), and PTH is 120 pg/mL (normal 15–65). What is the most appropriate next step?

A 62-year-old postmenopausal woman presents with a T-score of −2.8 on DEXA scan. Her serum calcium is 9.2 mg/dL, phosphate 3.5 mg/dL, and alkaline phosphatase is normal. A 58-year-old man with similar bone density loss has a serum calcium of 7.8 mg/dL, phosphate 2.1 mg/dL, and alkaline phosphatase elevated at 95 U/L. Which feature best distinguishes osteoporosis from osteomalacia in this comparison?

Which of the following T-score ranges defines osteoporosis according to WHO diagnostic criteria?

A 65-year-old man with chronic kidney disease stage 3b (eGFR 35 mL/min/1.73m²) is found to have a T-score of −2.8 on DXA scan. Before starting bisphosphonate therapy, which investigation is most appropriate to exclude secondary causes of osteoporosis?

A 62-year-old postmenopausal woman presents with a T-score of −2.8 on DEXA scan. Which is the most common cause of osteoporosis in this patient?