PTH and primary hyperparathyroidism: ARDs = autoimmune rheumatologic diseases; BMI = body mass index; Cr = creatinine; GFR = glomerular filtration rate; Ca = calcium; P = phosphorus; PTH = parathyroid hormone; U Ca = 24-hour urinary calcium; 25(OH)D = 25-hydroxyvitamin D; DEXA = dual-energy X-ray absorptiometry; FT = femur total; L1-4 = lumbar vertebrae 1–4; PHPT = primary hyperparathyroidism