Clinical utility of laboratory testing in women with osteoporosis

The yield of routine laboratory examination in osteoporosis evaluation in primary care

This study evaluated the yield of routine laboratory examination in a large population of older women in primary care. The prevalence of laboratory abnormalities was low and the clinical consequences in follow-up were limited. There was a weak association of laboratory abnormalities with osteoporosis but no association with vertebral fractures and recent fractures.

PURPOSE

Most osteoporosis guidelines advice routine laboratory examination. We have investigated the yield of laboratory examinations in facture risk evaluation of elderly women in primary care.

METHODS

We assessed the prevalence of laboratory abnormalities and their association with risk factors for fractures, recent fractures, low bone mineral density (BMD), and prevalent vertebral fracture in 8996 women ≥ 65 years of age participating in a primary care fracture risk screening study. In a sample of 2208 of these participants, we also evaluated the medical consequences in the medical records during a follow-up period of ≥ 1 year.

RESULTS

Vitamin D deficiency (< 30 nmol/L) was present in 13% and insufficiency (< 50 nmol/L) in 43% of the study sample. The prevalence of other laboratory abnormalities (ESR, calcium, creatinine, FT4) was 4.6% in women with risk factors for fractures, 6.1% in women with low BMD (T-score ≤  - 2.5), 6.0% after a prevalent vertebral fracture, 5.2% after a recent fracture and 2.6% in the absence of important risk factors for fractures. Laboratory abnormalities other than vitamin D were associated with low BMD (OR 1.4, 95%CI 1.1-1.8) but not with prevalent vertebral fractures nor recent fractures. Low BMD was associated with renal failure (OR 2.0, 95%CI 1.3-3.4), vitamin D insufficiency (OR 1.2, 95%CI 1.0-1.3) and deficiency (OR 1.3, 95%CI 1.1-.5). In the follow-up period, 82% of the laboratory abnormalities did not result in a new diagnosis or treatment reported in the medical records.

CONCLUSIONS

We identified a low prevalence of laboratory abnormalities in a primary care population of older women and the majority of these findings had no medical consequences.

Osteoporosis

Osteoporosis is a common systemic skeletal disorder resulting in bone fragility and increased fracture risk. Evidence-based screening strategies improve identification of patients who are most likely to benefit from drug treatment to prevent fracture. In addition, careful consideration of when pharmacotherapy should be started, choice of medication, and duration of treatment maximizes the benefits of fracture prevention while minimizing potential harms of long-term drug exposure.

Predicting the risk of osteoporosis in older Vietnamese women using machine learning approaches

Osteoporosis contributes significantly to health and economic burdens worldwide. However, the development of osteoporosis-related prediction tools has been limited for lower-middle-income countries, especially Vietnam. This study aims to develop prediction models for the Vietnamese population as well as evaluate the existing tools to forecast the risk of osteoporosis and evaluate the contribution of covariates that previous studies have determined to be risk factors for osteoporosis. The prediction models were developed to predict the risk of osteoporosis using machine learning algorithms. The performance of the included prediction models was evaluated based on two scenarios; in the first one, the original test parameters were directly modeled, and in the second the original test parameters were transformed into binary covariates. The area under the receiver operating characteristic curve, the Brier score, precision, recall and F1-score were calculated to evaluate the models' performance in both scenarios. The contribution of the covariates was estimated using the Permutation Feature Importance estimation. Four models, namely, Logistic Regression, Support Vector Machine, Random Forest and Neural Network, were developed through two scenarios. During the validation phase, these four models performed competitively against the reference models, with the areas under the curve above 0.81. Age, height and weight contributed the most to the risk of osteoporosis, while the correlation of the other covariates with the outcome was minor. Machine learning algorithms have a proven advantage in predicting the risk of osteoporosis among Vietnamese women over 50 years old. Additional research is required to more deeply evaluate the performance of the models on other high-risk populations.

Investigation and management of osteoporosis in aged trauma patients: a treatment algorithm adapted to the German guidelines for osteoporosis

BACKGROUND

Osteoporosis-associated fractures are of increasing importance in trauma surgery. Systematic diagnostics and treatment of osteoporosis during a hospital stay, however, remain inadequate. Therefore, a specific algorithm for diagnosing and treating osteoporosis in trauma surgery patients was developed based on the DVO (German Osteology Society) guideline for osteoporosis from 2014.

METHODS

In a first step, the individuals' age and risk profile for osteoporosis is identified considering specific fractures indicating osteoporosis and risk factors assessed by a specific questionnaire. In addition, physical activity, risk of falls, dietary habits and the individuals' medication are considered. Basic osteoporosis laboratory tests, a bone densitometry by dual-energy X-ray absorptiometry (DXA) and, if needed, X-rays of the spine are carried out to identify prevalent vertebral body fractures.

RESULTS

Based on the treatment algorithm adapted to the new guidelines for osteoporosis in the majority of proximal femoral fractures, treatment of osteoporosis could already be indicated without prior DXA. In case of preexisting glucocorticoid therapy, a history of previous fractures or other risk factors according to the risk questionnaire, the threshold of treatment has to be adjusted given the table of T-scores.

CONCLUSIONS

The treatment algorithm for diagnosing and treating osteoporosis in in-patient trauma surgery patients can help identify high-risk patients systematically and efficiently. As a result, osteoporosis-associated fractures or failure of osteosynthesis could be reduced, yet a prospective validation of the algorithm has to be completed.

Evaluation of thyroid function status among postmenopausal women with and without osteoporosis

OBJECTIVE

To investigate the relationship between thyroid function status and bone mineral density (BMD) among women with postmenopausal osteoporosis.

METHODS

A retrospective study was performed among 1217 women aged 45-80years who attended the Department of Obstetrics and Gynecology at Dokuz Eylul University, Izmir, Turkey, between August 1, 2009, and June 1, 2013. Eligible participants were grouped according to the presence or absence of osteoporosis as defined by BMD measurements at the lumbar vertebrae (L1-L4), femoral neck, or trochanter of the femur. Serum levels of free tri-iodothyronine, free tetraiodothyronine, and thyroid-stimulating hormone (TSH) were assessed.

RESULTS

The 303 women with osteoporosis had a lower mean TSH level (1.8mIU/L) than did the 914 women without osteoporosis (1.9mIU/L; P=0.01). A positive correlation between TSH level and measures of BMD was observed (P=0.01). The TSH level was associated with a protective effect in a regression model for development of osteoporosis; the odds ratio was 0.68 (95% confidence interval 0.53-0.86).

CONCLUSION

Osteoporosis appeared to be independently associated with serum TSH level. Maintaining TSH levels within the upper limit of the reference range during treatment of hypothyroidism could be important to prevent osteoporosis among postmenopausal women.

Role of Thyroid Hormones in Skeletal Development and Bone Maintenance

The skeleton is an exquisitely sensitive and archetypal T3-target tissue that demonstrates the critical role for thyroid hormones during development, linear growth, and adult bone turnover and maintenance. Thyrotoxicosis is an established cause of secondary osteoporosis, and abnormal thyroid hormone signaling has recently been identified as a novel risk factor for osteoarthritis. Skeletal phenotypes in genetically modified mice have faithfully reproduced genetic disorders in humans, revealing the complex physiological relationship between centrally regulated thyroid status and the peripheral actions of thyroid hormones. Studies in mutant mice also established the paradigm that T3 exerts anabolic actions during growth and catabolic effects on adult bone. Thus, the skeleton represents an ideal physiological system in which to characterize thyroid hormone transport, metabolism, and action during development and adulthood and in response to injury. Future analysis of T3 action in individual skeletal cell lineages will provide new insights into cell-specific molecular mechanisms and may ultimately identify novel therapeutic targets for chronic degenerative diseases such as osteoporosis and osteoarthritis. This review provides a comprehensive analysis of the current state of the art.

Clinical utility of routine laboratory testing to identify possible secondary causes in older men with osteoporosis: the Osteoporotic Fractures in Men (MrOS) Study

We investigated the value of routine laboratory testing for identifying underlying causes in older men diagnosed with osteoporosis. Most osteoporotic and nonosteoporotic men had ≥1 laboratory abnormality. Few individual laboratory abnormalities were more common in osteoporotic men. The benefit of routine laboratory testing in older osteoporotic men may be low.

INTRODUCTION

To evaluate the utility of recommended laboratory testing to identify secondary causes in older men with osteoporosis, we examined prevalence of laboratory abnormalities in older men with and without osteoporosis.

METHODS

One thousand five hundred seventy-two men aged ≥65 years in the Osteoporotic Fractures in Men study completed bone mineral density (BMD) testing and a battery of laboratory measures, including serum calcium, phosphorus, alkaline phosphatase, parathyroid hormone (PTH), thyroid-stimulating hormone (TSH), 25-OH vitamin D, total testosterone, spot urine calcium/creatinine ratio, spot urine albumin/creatinine ratio, creatinine-derived estimated glomerular filtration rate, 24-h urine calcium, and 24-h urine free cortisol. Using cross-sectional analyses, we calculated prevalence ratios (PRs) and 95 % confidence intervals (CI) for the association of any and specific laboratory abnormalities with osteoporosis and the number of men with osteoporosis needed to test to identify one additional laboratory abnormality compared to testing men without osteoporosis.

RESULTS

Approximately 60 % of men had ≥1 laboratory abnormality in both men with and without osteoporosis. Among individual tests, only vitamin D insufficiency (PR, 1.13; 95 % CI, 1.05-1.22) and high alkaline phosphatase (PR, 3.05; 95 % CI, 1.52-6.11) were more likely in men with osteoporosis. Hypercortisolism and hyperthyroidism were uncommon and not significantly more frequent in men with osteoporosis. No osteoporotic men had hypercalciuria.

CONCLUSIONS

Though most of these older men had ≥1 laboratory abnormality, few routinely recommended individual tests were more common in men with osteoporosis than in those without osteoporosis. Possibly excepting vitamin D and alkaline phosphatase, benefit of routine laboratory testing to identify possible secondary causes in older osteoporotic men appears low. Results may not be generalizable to younger men or to older men in whom history and exam findings raise clinical suspicion for a secondary cause of osteoporosis.

Relationship between subclinical thyroid dysfunction and the risk of fracture: a meta-analysis of prospective cohort studies

To identify the relationship between subclinical thyroid dysfunction and the risk of fracture, we conducted a meta-analysis of prospective cohort studies. Results showed that subclinical hyperthyroidism is associated with an increased risk of fracture, especially in elder.

INTRODUCTION

There are conflicting data on the association between subclinical thyroid dysfunction and the risk of fracture. This study is aimed at providing a summary of prospective evidence of the relationship between subclinical thyroid dysfunction and the risk of fracture.

METHODS

We systematically searched the MEDLINE, EMBASE, and the Chinese Biomedical literature database (CBM) from 1974 to August 2014 to identify prospective cohort studies which have studied the risk of fracture in patients with subclinical thyroid dysfunction. Various fractures were reported as the sole outcome.

RESULTS

Five population-based cohort studies including 314,146 participants with relationship of endogenous or exogenous subclinical thyroid dysfunction or euthyroidism and fractures were identified as eligible for the meta-analysis. In an unadjusted model, the relative risk (RR) of subclinical hypothyroidism for fracture was 1.30 (CI 1.08-1.56). Risk estimates were lower in a multivariable-adjusted model (RR = 1.20, CI 0.70-2.04) and when higher quality studies (RR = 0.95, CI 0.58-1.57) were analyzed. For subclinical hyperthyroidism, the RR was 1.52 (CI 1.33-1.73) in unadjusted model and 1.25 (CI 1.11-1.41) in a multivariable-adjusted model. An analysis of higher quality studies revealed a RR 1.18 (CI 1.07-1.29). Subgroup analysis indicated that the RR for risk of fracture was higher in the endogenous group than the exogenous group, taking thyroid-altering medicine in subclinical hyperthyroidism. Similar finding was also demonstrated in subclinical hypothyroidism.

CONCLUSIONS

Despite heterogeneity across the studies, data suggest that subclinical hyperthyroidism is associated with an increased risk of fracture in the population older than 60 years. No evidence could prove a definite association between subclinical hypothyroidism and the risk of fracture yet.

Are cataracts associated with osteoporosis?

BACKGROUND

Calcium is considered an important factor in the development of both osteoporosis and cataract. This study evaluated the association between osteoporosis and cataracts.

OBJECTIVE

To evaluate the prevalence of osteoporosis among patients undergoing cataract surgery, and the association between the two.

PATIENTS AND METHODS

This was a retrospective observational case-control study, conducted in the Central District of Clalit Health Services (a district of the largest health maintenance organization in Israel). All Clalit members in the district older than 50 years who underwent cataract surgery from 2000 to 2007 (n=12,984) and 25,968 age- and sex-matched controls comprised the sample. Electronic medical records of all patients in the study were reviewed. The main outcome measure was the prevalence of osteoporosis and the odds ratio of having osteoporosis among cataract patients compared with controls.

RESULTS

Demographically, 41.8% were men with a mean age of 68.7 ± 8.2 years. A logistic regression model for osteoporosis showed that age, female sex, higher socioeconomic class, smoking, chronic renal failure, hyperthyroidism, rheumatoid arthritis, inflammatory bowel diseases, and cataract are all associated with increased prevalence of osteoporosis. Obesity is a protective factor for osteoporosis. In all age-groups, osteoporosis was more prevalent in cataract patients than in the control group.

CONCLUSION

Among other well-known risk factors, osteoporosis is associated with the presence of cataracts. Common pathophysiological associations with both conditions, such as calcium imbalance, hormonal abnormalities, and shared genetic predisposition, are discussed.

The value of laboratory tests in diagnosing secondary osteoporosis at a fracture and osteoporosis outpatient clinic

BACKGROUND

As more and more patients meeting the criteria for osteoporosis are referred to a fracture and osteoporosis outpatient clinic (FO clinic), the laboratory costs to screen for secondary osteoporosis also increases. This study was conducted to determine the value of screening on underlying diseases at an FO clinic by obtaining a standard set of laboratory tests.

METHODS

We included all 541 patients ≥50 years with a fracture referred to our FO clinic, during the period January 2005 to January 2007. The bone mineral density (BMD) was measured by dual energy x-ray absorptiometry and expressed as a T score. A standard set of laboratory tests was obtained to screen on underlying diseases.

RESULTS

Laboratory results were as often abnormal in patients with a normal BMD compared to patients with a low BMD. Underlying diseases were infrequently diagnosed. However, the prevalence of secondary osteoporosis in men was quite high, up to 18.2%. The costs to diagnose 1 patient with an underlying disease did vary between €92 and €972 depending on the group of patients described.

CONCLUSION

Screening all patients, referred to an FO clinic, for underlying diseases by obtaining a standard set of laboratory tests is probably not useful since laboratory tests are as often abnormal in patients with a normal BMD compared to patients with a low BMD. Moreover, the prevalence of secondary osteoporosis is low, while laboratory costs are substantial.

Prevalence of subclinical contributors to low bone mineral density and/or fragility fracture

OBJECTIVE

The prevalence of subclinical contributors to low bone mineral density (BMD) and/or fragility fracture is debated. We evaluated the prevalence of subclinical contributors to low BMD and/or fragility fracture in the presence of normal 25-hydroxyvitamin D (25OHVitD) levels.

DESIGN

Prospective observational study.

METHODS

Among 1095 consecutive outpatients evaluated for low BMD and/or fragility fractures, 602 (563 females, age 65.4±10.0 years) with apparent primary osteoporosis were enrolled. A general chemistry profile, phosphate, 25OHVitD, cortisol after 1-mg overnight dexamethasone suppression test, antitissue transglutaminase and endomysial antibodies and testosterone (in males) were performed. Serum and urinary calcium and parathyroid hormone levels were also evaluated after 25OHVitD levels normalization. Vertebral deformities were assessed by radiograph.

RESULTS

In total, 70.8% of patients had low 25OHVitD levels. Additional subclinical contributors to low BMD and/or fragility fracture were diagnosed in 45% of patients, with idiopathic hypercalciuria (IH, 34.1%) and primary hyperparathyroidism (PHPT, 4.5%) being the most frequent contributors, apart from hypovitaminosis D. Furthermore, 33.2% of IH and 18.5% of PHPT patients were diagnosed only after 25OHVitD levels normalization. The subclinical contributors to low BMD and/or fragility fracture besides hypovitaminosis D were associated inversely with age (odds ratio (OR) 1.02, 95% CI 1-1.04, P=0.04) and BMI (OR 1.1, 95% CI 1.05-1.17, P=0.0001) and directly with fragility fractures (OR 1.89, 95% CI 1.31-2.73, P=0.001), regardless of BMD.

CONCLUSIONS

Subclinical contributors to low BMD and/or fragility fracture besides hypovitaminosis D are present in more than 40% of the subjects with apparent primary osteoporosis. Hypovitaminosis D masks a substantial proportion of IH and PHPT patients.

Secondary causes of osteoporosis in fracture patients

OBJECTIVE

Identification and treatment of osteoporosis in the fragility fracture population and interventions to reduce the risk of future fracture are improving in orthopaedic practice. This study investigated the prevalence of vitamin D insufficiency and deficiency and other secondary causes of low bone density in patients who have sustained a fragility fracture and were referred from fracture clinic to a metabolic bone disease clinic (MBDC) for further assessment.

DESIGN

Retrospective chart audit.

SETTING

University hospital fracture clinic.

PATIENTS

Three hundred ninety-nine patients referred from the orthopaedic division to the MBDC over a 3-year period.

INTERVENTION

A standardized chart audit form was developed, and electronic charts were retrospectively audited.

MAIN OUTCOME MEASUREMENTS

Secondary causes of osteoporosis and routine blood test results.

RESULTS

Three hundred eight of 399 patients had blood investigations completed. A total of 98 patients (32%) had 125 secondary causes of osteoporosis other than vitamin D deficiency or insufficiency recorded in their electronic chart, including medication use, premature ovarian failure, hypogonadism, smoking, excessive alcohol use, renal impairment, gastrointestinal conditions, and endocrine conditions. Mean serum vitamin D level was 69.0 nmol/L in 83 men and 75.4 nmol/L in 186 women. Serum vitamin D levels were deficient at ≤25 nmol/L in 7 patients, insufficient at 26-74 nmol/L in 137 patients, and sufficient at ≥75 nmol/L in 125 patients. Investigation of causes of secondary osteoporosis can inform and influence specific treatment regimens.

CONCLUSIONS

More than one-half of patients sustaining a fragility fracture and referred to the MBDC were vitamin D insufficient or deficient, and nearly one-third had a secondary cause of osteoporosis other than vitamin D insufficiency/deficiency. A standardized list of blood and urine analyses and radiographs has been implemented for fragility fracture patients and selected other fracture patients who are undergoing investigation for osteoporosis.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

The skeletal consequences of thyrotoxicosis

Euthyroid status is essential for normal skeletal development and the maintenance of adult bone structure and strength. Established thyrotoxicosis has long been recognised as a cause of high bone turnover osteoporosis and fracture but more recent studies have suggested that subclinical hyperthyroidism and long-term suppressive doses of thyroxine (T4) may also result in decreased bone mineral density (BMD) and an increased risk of fragility fracture, particularly in postmenopausal women. Furthermore, large population studies of euthyroid individuals have demonstrated that a hypothalamic-pituitary-thyroid axis set point at the upper end of the normal reference range is associated with reduced BMD and increased fracture susceptibility. Despite these findings, the cellular and molecular mechanisms of thyroid hormone action in bone remain controversial and incompletely understood. In this review, we discuss the role of thyroid hormones in bone and the skeletal consequences of hyperthyroidism.

The prevalence of recognized contributors to secondary osteoporosis in South East Asian men and post-menopausal women. Are Z score diagnostic thresholds useful predictors of their presence?

The prevalence of secondary contributors to osteoporosis in our population of SE Asian patients is high. Though various low thresholds Z score values have been proposed as suggestive of a high likelihood of secondary osteoporosis, they appear to have only limited discriminatory value in identifying a secondary cause.

INTRODUCTION

Many patients with osteoporosis have significant secondary contributors towards their bone loss. The sensitivity and diagnostic utility of using Z score thresholds to screen for secondary osteoporosis have not yet been convincingly demonstrated nor has there been any previous attempt to estimate the prevalence of secondary osteoporosis in South East Asia. We aimed to study the prevalence of commonly recognized contributors and to determine the discriminatory ability of Z score thresholds in screening for them in Singaporean men and post-menopausal women with osteoporosis.

METHOD

Three hundred thirty-two consecutive patients seen at the osteoporosis clinic of the largest hospital in Singapore were evaluated. The frequencies of the different contributors were determined and sensitivities, specificities, and positive and negative predictive values (PPV and NPV) of pre-specified Z score cut-off values calculated.

RESULTS

Vitamin D deficiency was present in 18.5% of the patients, hyperthyroidism in 10.11%, primary hyperparathyroidism in 1%, secondary hyperparathyroidism in 6%, hypercalciuria in 21.63%, glucocorticoid use in 8.43%, and hypogonadism in 9.4% of males. A Z score value of <-1 had a sensitivity of 71.7 % and NPV of 66.2 % in identifying the presence of a secondary contributor in post-menopausal women. The sensitivity and NPV of a similar threshold in men was 59.1 and 40 %, respectively. ROC curves used to investigate various Z score diagnostic thresholds for sensitivity and specificity showed that they provided poor predictive value for the presence of secondary osteoporosis.

CONCLUSION

Secondary contributors are common in our patients with osteoporosis. Z score diagnostic thresholds have only limited value in discriminating between primary and secondary osteoporosis.

Secondary osteoporosis in men and women: clinical challenge of an unresolved issue

OBJECTIVE

To evaluate the clinical and etiological factors of osteoporosis. We also tested the FRAX algorithm to compare the assessment of fracture risk in patients with primary or secondary osteoporosis.

METHODS

A prospective study carried out in a large sample of 123 men and 246 women. All subjects had a biochemical, densitometric, and radiological examination of thoracic and lumbar spine.

RESULTS

The prevalence of primary (men 52.9% vs women 50%; p = nonsignificant) and secondary (men 21.1% vs women 17.5%; p = nonsignificant) osteoporosis did not differ between the sexes. In contrast, the prevalence of primary osteoporosis was significantly higher than secondary causes (p < 0.0001) in both men and women. While women came to our attention for prevention of osteoporosis, men sought help because of clinical symptoms or disease-related complications, such as fractures. As evaluated by the FRAX tool, patients with osteopenia do not need treatment, in agreement with Italian guidelines. The estimated risk of major osteoporotic and hip fractures was significantly higher in women with secondary osteoporosis compared to men and also compared to women with primary osteoporosis.

CONCLUSION

The prevalence of secondary osteoporosis in men is similar to that in women and it is less frequent than commonly reported. In patients with secondary osteoporosis, FRAX calculation may provide an estimate of a particularly high fracture risk in patients whose bone fragility is usually attributed to another disease.

[Increase of PTH in post-menopausal osteoporosis]

AIMS

Increased parathyroid values (PTH) serum values can be observed in postmenopausal women. However, the clinical repercussion and causes of this finding are poorly understood. This study has aimed to analyze the prevalence and conditions associated to the increased serum PTH levels in postmenopausal women with osteoporosis as well as their clinical characteristics.

METHODS

Post-menopausal women with osteoporosis were included in the study. PTH, 25-hydroxyvitamin D (25OHD), 24-h urinary calcium, glomerular filtration rate (GFR) and calcium intake were evaluated. The prevalence of increased PTH serum values and its relationship with vitamin D deficiency and insufficiency, kidney failure, hypercalciuria and calcium intake deficiency were evaluated, these being conditions that may increase PTH secretion.

RESULTS

A total of 204 postmenopausal women with osteoporosis with a mean age of 64 years were included. Increase PTH levels (>65 pg/ml) were observed in 35% and 5 women had primary hyperparathyroidism. Women with increased serum PTH levels were older (67 ± 9 years) were old than those with normal PTH levels (63 ± 11 years) (P=0.03). PTH elevation was associated to calcium intake deficiency (<800 mg/d) in 81% of the women, to a vitamin D deficiency and insufficiency in 55% and 86%, respectively, renal insufficiency in 35% and hypercalciuria in 17% of the patients. These values, however, did not differ when compared with patients with normal PTH serum levels. Serum PTH levels were related to age (r=0.19, P=0.01) but not to 25OHD or GFR values.

CONCLUSIONS

One third of the post-menopausal women with osteoporosis had elevated PTH levels. This was due to primary hyperparathyroidism in 10%. The prevalence of conditions associated to the increase in PTH (reduced calcium intake, 25-hydroxyvitamin D, renal failure and hypercalciuria) is similar to that observed in women with normal PTH values.

The utility of BMD Z-score diagnostic thresholds for secondary causes of osteoporosis

This very large dual X-ray absorptiometry (DXA) cohort confirmed a significant, inverse relationship between bone mineral density (BMD) Z-scores and the presence of secondary causes of osteoporosis but receiver operating characteristic (ROC) curves indicate that Z-score diagnostic thresholds (such as -2.0) discriminate poorly between the presence and absence of secondary causes of osteoporosis.

INTRODUCTION

BMD Z-score diagnostic thresholds have been proposed to detect secondary causes of osteoporosis. To determine the sensitivity and diagnostic utility of such thresholds, we analyzed comprehensive BMD and personal health information data from a large, multispecialty group practice.

METHODS

Adult subjects were assigned their lowest axial BMD Z-score and ICD-9 diagnosis codes for secondary causes of osteoporosis when cited at least twice in their electronic medical record. Multiple logistic regression was used to model the prevalence of matching ICD-9 codes as a function of Z-score. ROC curves were used to investigate various Z-score cut points for sensitivity and specificity.

RESULTS

Eighteen thousand six hundred seventy-four subjects were analyzed. Secondary causes of osteoporosis were identified in 31% of men and 16% of women. The frequency of secondary causes varied with age and between genders and varied inversely with Z-score. No inflection point was observed in this relationship to suggest a useful clinical decision threshold. The difference in mean Z-score of those with and without a secondary cause of osteoporosis was biologically slight (±0.3). Low Z-score diagnostic thresholds were insensitive to the presence of secondary causes of osteoporosis and provided relatively poor predictive value.

CONCLUSIONS

This DXA cohort confirmed a significant inverse relationship between Z-score and the presence of secondary causes of osteoporosis but diagnostic Z-score thresholds discriminate poorly between the presence and absence of secondary causes of osteoporosis. If only patients with very low Z-scores are evaluated for secondary causes of osteoporosis the diagnostic specificity may be high but most cases will be missed.

Markers of autoimmune liver diseases in postmenopausal women with osteoporosis

INTRODUCTION

Osteoporosis is a common complication of chronic liver diseases. However, there is limited information about autoimmune liver diseases as a factor of secondary osteoporosis. Therefore, we aimed to investigate the autoantibodies of autoimmune liver diseases in patients with osteoporosis.

METHODS

One hundred fifty female patients with postmenopausal osteoporosis were included. Bone mineral density was measured by dual energy X-ray absorptiometry. We analysized autoantibodies including antinuclear antibodies, liver membrane antibodies, anti-liver/kidney microsomal autoantibodies1, liver-specific protein, antismooth muscle antibodies, and anti-mitochondrial antibodies by indirect immunofluorescence. Serum was assayed for the levels of aminotransferases.

RESULTS

The mean age of the patients was 63,13 ± 8,6 years. The mean values of L1-L4 T-scores and femur total T-scores were -3,08 ± 0,58 and -1,53 ± 0,81, respectively. Among the 150 patients with osteoporosis, 14 (9.3%) were antinuclear antibodies, four (2.7%) were liver membrane antibodies, three (2.0%) were anti-liver/kidney microsomal autoantibodies1, and two (1.3%) were liver-specific protein positive. None of the patients had anti-mitochondrial antibodies or smooth muscle antibodies positivity. The mean values of levels of aminotransferases were within normal range.

CONCLUSIONS

The presence of liver membrane antibodies, liver-specific protein, and anti-liver/kidney microsomal autoantibodies1 has permitted us to see that there may be some suspicious clues of autoimmune liver diseases in patients with osteoporosis as a secondary risk factor. On the other hand, there is a need for comprehensive studies with a larger sample size and studies designed to compare the results with a normal population to understand the clinical importance of our findings.

The relationship between serum TSH and bone mineral density in men and postmenopausal women: the Tromsø study

BACKGROUND

Hyperthyroidism is associated with osteoporosis, and it has recently been suggested that thyroid-stimulating hormone (TSH) has bone protective properties. We wanted to explore the relationship between serum TSH and bone mineral density (BMD) in a healthy population.

METHODS

This study included 993 postmenopausal females and 968 males with valid measurements of BMD at the hip and forearm in the fifth Tromsø study conducted in 2001. Participants with major diseases or medication affecting BMD or thyroid function were excluded. The subjects were divided into six different groups based on the 2.5 and 97.5 percentiles of serum TSH and the quartiles in between. Multiple linear regression adjusting for age; weight; height; smoking status; physical activity level; and for women, use of hormonal replacement therapy was used in the analyses.

RESULTS

After multivariate adjustment, the 28 men and 18 women with serum TSH below the 2.5 percentile had significantly lower BMD at the ultradistal (women) and distal (both sexes) forearm than the 921 men and 950 women with serum TSH in the normal range. Also, the 25 postmenopausal women with serum TSH above the 97.5 percentile had significantly higher BMD at the femoral neck than women with serum TSH in the normal range. Across the normal range of serum TSH, there was no association between TSH and BMD, and serum TSH as a continuous variable had no effect on BMD in the multiple linear regression model.

CONCLUSIONS

Within the normal range of serum TSH, serum TSH was not associated with BMD. The small groups of men and women with serum TSH consistent with hyperthyroidism had lower BMD at the forearm than those with serum TSH in the normal range.

Patient assessment in the diagnosis, prevention, and treatment of osteoporosis

Assessment of the patient with osteoporosis includes history and physical examination, laboratory testing, and imaging studies. Information gathered during this assessment assists clinicians in targeting strategies to prevent fractures. The medical history should contain items such as personal and family history of fractures, lifestyle, intake of substances such as vitamin D, calcium, corticosteroids, and other medications. The physical examination can reveal relevant information such as height loss and risk of falls. Bone mineral density (BMD), most commonly determined by dual-energy x-ray absorptiometry, best predicts fracture risk in patients without previous fracture. BMD testing is most efficient in women over 65 years old but is also helpful for men and women with risk factors. Serial BMD tests can identify individuals losing bone mass, but clinicians should be aware of what constitutes a significant change. Laboratory testing can detect other risk factors and can provide clues to etiology. Selection of laboratory tests should be individualized, as there is no consensus regarding which tests are optimal. Biochemical markers of bone turnover have a potential role in fracture risk assessment and in gauging response to therapy, but are not widely used at present. Clinicians should be aware of problems with vitamin D measurement, including seasonal variation, variability among laboratories, and the desirable therapeutic range. Careful assessment of the osteoporotic patient is essential in developing a comprehensive plan that reduces fracture risk and improves quality of life.

Thyroid-stimulating hormone restores bone volume, microarchitecture, and strength in aged ovariectomized rats

We show the systemic administration of low levels of TSH increases bone volume and improves bone microarchitecture and strength in aged OVX rats. TSH's actions are mediated by its inhibitory effects on RANKL-induced osteoclast formation and bone resorption coupled with stimulatory effects on osteoblast differentiation and bone formation, suggesting TSH directly affects bone remodeling in vivo.

INTRODUCTION

Thyroid-stimulating hormone (TSH) receptor haploinsufficient mice with normal circulating thyroid hormone levels have reduced bone mass, suggesting that TSH directly affects bone remodeling. We examined whether systemic TSH administration restored bone volume in aged ovariectomized (OVX) rats and influenced osteoclast formation and osteoblast differentiation in vitro.

MATERIALS AND METHODS

Sprague-Dawley rats were OVX at 6 months, and TSH therapy was started immediately after surgery (prevention mode; n = 80) or 7 mo later (restoration mode; n = 152). Hind limbs and lumbar spine BMD was measured at 2- or 4-wk intervals in vivo and ex vivo on termination at 8-16 wk. Long bones were subjected to microCT, histomorphometric, and biomechanical analyses. The direct effect of TSH was examined in osteoclast and osteoblast progenitor cultures and established rat osteosarcoma-derived osteoblastic cells. Data were analyzed by ANOVA Dunnett test.

RESULTS

In the prevention mode, low doses (0.1 and 0.3 microg) of native rat TSH prevented the progressive bone loss, and importantly, did not increase serum triiodothyroxine (T3) and thyroxine (T4) levels in aged OVX rats. In restoration mode, animals receiving 0.1 and 0.3 microg TSH had increased BMD (10-11%), trabecular bone volume (100-130%), trabecular number (25-40%), trabecular thickness (45-60%), cortical thickness (5-16%), mineral apposition and bone formation rate (200-300%), and enhanced mechanical strength of the femur (51-60%) compared with control OVX rats. In vitro studies suggest that TSH's action is mediated by its inhibitory effects on RANKL-induced osteoclast formation, as shown in hematopoietic stem cells cultivated from TSH-treated OVX rats. TSH also stimulates osteoblast differentiation, as shown by effects on alkaline phosphatase activity, osteocalcin expression, and mineralization rate.

CONCLUSIONS

These results show for the first time that systemically administered TSH prevents bone loss and restores bone mass in aged OVX rats through both antiresorptive and anabolic effects on bone remodeling.

Alendronate treatment in women with normal to severely impaired renal function: an analysis of the fracture intervention trial

To determine if alendronate had differential effects on BMD and fracture by renal function, we performed a secondary data analysis of women participating in the FIT. Alendronate increased BMD and decreased fractures to a similar degree among women with and without reduced renal function. There was no increase in adverse events among women with impaired renal function treated with alendronate. Alendronate is safe and effective among this group of women with reduced renal function.

INTRODUCTION

Alendronate is cleared by the kidney and may have sustained effects on bone in subjects with impaired renal function. We hypothesized that, with decreasing renal function, alendronate treatment would result in greater increases in BMD and greater decreases in fractures and that the frequency of adverse events would be increased.

MATERIALS AND METHODS

We studied women participating in the Fracture Intervention Trial (FIT), a randomized controlled trial of alendronate or placebo (n = 6458). We estimated baseline creatinine clearance (eGFR) using the Cockcroft Gault Formula.

RESULTS

Five hundred eighty-one (9.9%) participants had a severely reduced eGFR (<45 ml/minute). Alendronate increased BMD regardless of eGFR, but women with reduced eGFR had a 5.6% (95% CI: 4.8-6.5) increase in total hip BMD compared with 4.8% (95% CI: 4.6-5.0) among women with normal to moderate renal dysfunction (interaction: p = 0.04). Compared with placebo, alendronate increased spine BMD by 6.6 +/- 5.8%, but there was no significant interaction for the increase in spine BMD (interaction: p = 0.75). Treatment with alendronate reduced the risk of clinical fractures to a similar degree in those with (OR: 0.78; 95% CI: 0.51-1.21) and without reduced renal function (OR: 0.80; 95% CI; 0.70-0.93; p for interaction = 0.89). Treatment with alendronate reduced the risk of spine fractures to a similar degree in those with (OR: 0.72; 95% CI: 0.31-1.7) and without reduced renal function (OR: 0.50; 95% CI: 0.32-0.76; p for interaction = 0.44). There were no differences in adverse events by renal function.

CONCLUSIONS

Alendronate is safe and effective at increasing BMD and decreasing fractures among this group of women with reduced renal function.

Diagnostic de l’ostéoporose: quels examens biologiques faut-il faire ?

Malignant or metabolic causes of low bone mineral density must be sought after either a fragility fracture or the discovery of low bone density measurements. Laboratory tests for calcium and phosphate metabolism are normal in osteoporosis. Vitamin D deficiency is frequent and requires supplementation. Markers of bone remodeling can be useful in cases where the treatment decision is difficult.

[Secondary screening for osteoporosis in patients admitted for hip fracture to a rehabilitation center. Results of a survey]

GOALS

To determine prevalence, risk factors and treatment of osteoporosis in patients with hip fracture observed in a rehabilitation ward.

BACKGROUND

Hip fractures are associated with up to 20% excess mortality in the first year after fracture and cause functional disability in most survivors. Despite available risk indices and physician information, osteoporosis is still underdiagnosed and undertreated.

METHOD

We obtained history, clinical and biological data, and bone density (BD) data in 41 patients admitted with hip fracture to a rehabilitation care centre.

RESULTS

Only 3 patients had known osteoporosis. Although 50% had at least 1 clinical risk factor, all patients showed osteopenic BD scores and 68% had osteoporotic scores; only one was correctly treated.

DISCUSSION

As with international studies, our study shows that osteoporosis is underdiagnosed. Risk assessment tools allow for routine screening and preventive measures incorporated into standard care practice. The prevention of osteoporotic fracture can be promoted in rehabilitation centres.

Diagnosis, screening, prevention, and treatment of osteoporosis

Osteoporosis is the most common bone disease in humans and affects both men and women. The clinical and public health implications of the disease are substantial because of the mortality, morbidity, and cost of medical care associated with osteoporotic fractures. Osteoporosis is diagnosed on the basis of a low-impact or fragility fracture or low bone mineral density, which was best assessed by central dual-energy x-ray absorptiometry. Both nonpharmacological therapy (calcium and vitamin D supplementation, weight-bearing exercise, and fall prevention) and pharmacological treatments (antiresorptive and anabolic agents) may be helpful in the prevention and treatment of osteoporosis. Therefore, clinicians need to be vigilant in instituting primary prevention measures for those at high risk for osteoporosis and in instituting treatment for patients diagnosed as having the disease either by screening or a history of fracture. This article provides an overview of the diagnosis, screening, prevention, and treatment of osteoporosis.