Utility of biochemical screening in the context of evaluating patients with a presumptive diagnosis of osteoporosis
C Rajeswaran, J Spencer & SM Orme
Osteoporosis is a reduction in bone mass, with micro-architectural deterioration, leading to an increased risk of fragility fractures. A secondary cause for osteoporosis (caused by a specific well-defined clinical disorder) is found in a proportion of patients, which varies in different patient populations.
We evaluated the utility of a 'standard panel' (FBC, PV, plasma protein electrophoresis & BJP, thyroid function tests, U&Es, calcium and bone profile, fasting lipids and LFTs) of biochemical investigations in 327 consecutive patients (287 Female: 40 Male) referred to the osteoporosis service from April 1999 to March 2000. Patients were characterised following measurement of spinal/femoral neck Bone Mineral Density (BMD) following a DEXA bone scan (LUNAR, Madison, Wisconsin, USA).
There were 88 patients with osteoporosis (T < -2.5 SD), 91 with osteopenia (T >-2.5 & < -1.0 SD), 130 with normal BMDs (T > 1.0 SD) and 20 who did not have bone scans. No cases of multiple myeloma were found. 2.2% of patients with osteoporosis had hypercalcaemia due to hyperparathyroidism, 9% had hypocalcaemia (due to coeliac disease, vitamin D deficiency, & phenytoin therapy), 8% hypothyroidism an 1% thyrotoxicosis.
In summary we found no utility in performing a myeloma screen. A small proportion of patients had abnormalities of calcium homeostasis or thyroid disease and we recommend that a 'screening' biochemical evaluation should be restricted to calcium/bone profile and thyroid function tests in patients with a presumptive diagnosis of osteoporosis.