Frequência das alterações laboratoriais e custo-efetividade de exames na investigação de osteoporose

Abstract

Osteoporosis (OP) is the most common osteometabolic disease. It is characterized by reduced bone mass and bone quality deterioration with consequent increase in bone fragility and fracture risk. Several factors may contribute to bone loss and they should be identified and corrected so that OP treatment can be effective. This study aims to assess the frequency of laboratory abnormalities and cost-effectiveness of tests used in OP investigation. Cross-sectional quantitative study analyzed 185 charts of, postmenopausal women attending the general outpatient clinic of Endocrinology at Felicio Rocho, Hospital - Belo Horizonte, Brazil; OP diagnois was made by lumbar spine and / or proximal femur bone mineral densitometries. Patients with renal or hepatic or other diseases or in use of medication that could result in loss of bone mass were excluded. Calcium was the most requested test (100% of patients) in the laboratory investigation of the OP, but was altered in only 8.65% of patients. The thyroid-stimulating hormone (TSH) was the second most requested test and was amended in 12.57% of cases. The parathyroid hormone (PTH) was requested for 82.16% of patients and was abnormal in 35.53% of them, while calciuria was requested for 67.03% and was abnormal in 18.55%. The 25-hydroxy vitamin D (25OHD) was the more frequently amended (42.11%) test in this population, being asked to 82.16% of patients. The examination of insulin growth factor-like 1 (IGF1) was requested in only 2.7% of patients, but was changed in 40.0%, having been asked only in patients with high clinical suspicion. Protein electrophoresis was performed in 23.78% of patients and was abnormal in 13.64% of patients. No patient had cortisol or screen antibodies for celiac disease changed. To assess the cost-effectiveness of laboratory investigation of OP we used the group of patients without treatment for OP who performed all examinations of the “minimal complete workup” (n = 62), which are: calcium, urine calcium, PTH, and 25OHD TSH. Strategies on these tests were assembled to evaluate the cost and effectiveness in diagnosing disorders that affect bone mass. The strategy using PTH, urine calcium and 25OHD for all women and TSH for those users of levothyroxine performs 100% of diagnoses at a cost of R$ 123.34 per patient and R$ 149.94 per diagnosis. The strategy using PTH and urinary calcium for all patients, 25OH for those with abnormalities in one of the previous tests and TSH for users of levothyroxine identified 84.31% of the disorders at a lower cost of R$ 98.42 per patient and R$ 141.91 per diagnosis. There is no consensus on the minimum workup to evaluate patients with OP. A number of disorders that affect bone mass are common and easily diagnosed and treated. In this study population, calciuria, PTH, 25OHD and TSH were cost-effectiveness in the investigation of major disorders that contribute to low bone mass.