Table 1.
Comparison of new and old guidelines for parathyroid surgery in asymptomatic PHPT
| Measurement | 1990 | 2002 | 2008 |
|---|---|---|---|
| Serum calcium (>upper limit of normal) | 1–1.6 mg/dl (0.25–0.4 mmol/liter) | 1.0 mg/dl (0.25 mmol/liter) | 1.0 mg/dl (0.25 mmol/liter) |
| 24-h urine for calcium | >400 mg/d (>10 mmol/d) | >400 mg/d (>10 mmol/d) | Not indicated |
| Creatinine clearance (calculated) | Reduced by 30% | Reduced by 30% | Reduced to <60 ml/min |
| BMD | Z-score <−2.0 in forearm | T-score <−2.5 at any site | T-score <−2.5 at any site and/or previous fracture fragility |
| Age (yr) | <50 | <50 | <50 |
Surgery is also indicated in patients for whom medical surveillance is neither desired nor possible.
Some physicians still regard 24-h urinary calcium excretion >400 mg as an indication for surgery.
Lumbar spine, total hip, femoral neck, or 33% radius (1/3 site). This recommendation is made recognizing that other skeletal features may contribute to fracture risk in PHPT and that the validity of this cut-point for any site vis-à-vis fracture risk prediction has not been established in PHPT.
Consistent with the position established by the International Society for Clinical Densitometry, the use of Z-scores instead of T-scores is recommended in evaluating BMD in premenopausal women and men younger than 50 yr.