The most appropriate treatment recommendation for this patient is parathyroidectomy. She has primary hyperparathyroidism as shown by her elevated serum calcium and parathyroid hormone levels. She also has evidence of kidney compromise with an elevated creatinine level and decreased estimated glomerular filtration rate (eGFR). Impaired kidney function (defined as eGFR <60 mL/min/1.73 m², 24-h urine calcium >400 mg/24 h [10 mmol/24 h], or the presence of nephrolithiasis or nephrocalcinosis by radiograph, ultrasound, or CT) is an indication for surgical treatment of hyperparathyroidism in otherwise asymptomatic patients. Other indications for surgery in asymptomatic patients include age younger than 50 years; a serum calcium level greater than or equal to 1 mg/dL (0.25 mmol/L) above upper limit of normal; a T-score of −2.5 or worse at the lumbar spine, total hip, femoral neck, or distal radius; or in those in whom medical surveillance is neither desired nor possible. Patients with these indications are considered to have the highest potential benefit from surgery.

A bisphosphonate, such as alendronate, would not be the treatment of choice for this patient as she does not have osteoporosis nor does she meet Fracture Risk Assessment Tool (FRAX) criteria for therapy. The FRAX calculator defines the 10-year fracture risk for patients with T-scores in the −1.0 to –2.5 range. The FRAX calculator (www.shef.ac.uk/FRAX) incorporates multiple risk factors including gender, fracture history, femoral neck bone mineral density, glucocorticoid usage, smoking, BMI, age, and alcohol intake to determine projected fracture risk. If the risk of major osteoporotic fracture is greater than or equal to 20% or the risk of hip fracture is greater than or equal to 3%, the patient's benefit from therapy exceeds the risk, and she should be offered treatment. Additionally, bisphosphonates should be used with caution in patients with compromised kidney function.

If the patient declines surgical intervention, a calcimimetic agent such as cinacalcet would be an appropriate therapy. Cinacalcet has recently been FDA approved as an alternative for patients unable or unwilling to undergo parathyroidectomy. Cinacalcet lowers calcium levels by stimulating the calcium-sensing receptors of the parathyroid glands and inhibiting parathyroid hormone secretion. However, it is expensive and has multiple drug interactions, which make it less desirable in this patient.

Because this patient is considered to be at increased risk of complications due to untreated hypercalcemia, clinical observation alone would not be appropriate.