Background: Primary osteoporosis is the main cause of reduced quality of bone. In some cases however, osteoporosis is caused by an underlying disease. For this reason routine laboratory examination is advised in most guidelines. The prevalence of laboratory abnormalities in clinical setting has been established in previous studies. There is a lack of similar data in primary care populations, nor are there studies that have evaluated the medical benefit of routine laboratory examination. The goal was assessment of the prevalence and practical consequences of abnormalities in routine laboratory examination in osteoporosis in primary care.
Method: In a population study of women≧65 years with clinical risk factors for osteoporosis (n=2320), and in a population (n=2699) of persons referred for bone densitometry by GPs, we collected blood samples (including: ESR, TSH/T4, Calcium, Albumin, Creatinine and 25-hydroxyvitamin D) regardless if there was osteoporosis or not. Of all participants with one or more abnormalities, we collected data from the GPs about already existing diagnoses and previous laboratory abnormalities and the consequences for treatment in one year follow up.
Results: The prevalence of laboratory abnormalities in participants with osteoporosis (n=1334) except for 25-hydroxyvitamin D was 4.9%, which was a new finding in 1.8%. In 0.7% this influenced treatment or led to new diagnoses connected with osteoporosis. The prevalence of 25-hydroxyvitamin D≤50 nmol/L was 50%. There was no association between the presence of osteoporosis or (recent) fractures and laboratory abnormalities (OR 1.00, 95%CI: 0.92-1.08, respectively OR 1.28, 95%CI: 0.88-1.87).
Conclusion: In these primary care populations the prevalence of relevant laboratory abnormalities was limited and there was no association with osteoporosis. Since all patients with osteoporosis are treated with vitamin D supplementation, the need for measurement of 25-hydroxyvitamin D is debatable. The results of this study should be a reason to reconsider the advice for routine laboratory examination in osteoporosis guidelines.
Disclosure: The authors declared no competing interests.