Failure of successful renal transplant to produce appropriate levels of 1,25-dihydroxyvitamin D

INTRODUCTION

Bone metabolism disturbances following renal transplantation (RT) are complex and multifactorial in origin. Abnormalities in 1,25-dihydroxyvitamin D levels in RT patients under treatment at our Bone Center prompted this retrospective study.

METHODS

Parameters of vitamin D metabolism were compared in RT patients and a cohort of patients with primary hyperparathyroidism (PHTP) who mimicked the hyperparathyroid state of the RT patients. Thirty-one RT recipients (from 300 reviewed) matched our inclusion criteria with a stable graft function for more than 1 year and a glomerular filtration rate (GFR) >50 mL/min per 1.73 m(2) (Group A); these were compared with 42 consecutive patients with PHTP who had been referred to the same Bone Center for treatment for over 1 month (Group B). Statistical analysis included the chi-square or Fisher's exact tests for categorical data and the Wilcoxon rank sum test for quantitative measures.

RESULTS

The mean (+/-SD) 1,25-dihydroxyvitamin D level was significantly lower (p < 0.001) in Group A patients (29.8 +/- 16.2) than in Group B patients (70.2 +/- 25.9) despite non-significant differences in the levels of parathyroid hormone (PTH) (mean: 184.0 vs.101.1;p < 0.29), phosphorus (mean: 3.2 vs. 3.1; p < 0.3) and 1,25-vitamin D (mean: 19.5 vs. 25.2; p < 0.06). Group A patients had lower levels (p < 0.05) of mean serum calcium and calculated GFR (9.3 mg/dL, 65.7 mL/min) than Group B patients (10.6 mg/dL, 97.6 mL/min). 1,25-Dihydroxyvitamin D significantly correlated with calcium (p < 0.001), 25-vitamin D (p < 0.005) and GFR (p < 0.001) in both groups, but there was a notable lack of association between 1,25-dihydroxyvitamin D and PTH (p < 0.64) or phosphorus (p < 0.26) in Group A patients. In this group, 1,25-dihydroxyvitamin D was not influenced by the type of immunosuppresion regimen (p < 0.06), use of biphosphonates (p < 0.73), presence of diabetes (p < 0.59), menopause in women (p < 0.08), season (p < 0.43) or race (p < 0.31). Our data indicate that 1,25-dihydroxyvitamin D metabolism remains disturbed for a considerable time after successful RT, with the result that the level of 1,25-dihydroxyvitamin D in RT patients is lower despite physiological signals that should stimulate its production. Our analysis of many clinical variables was unable to elucidate the underlying mechanism(s) for this disturbance.

CONCLUSION

Successful RT may not produce appropriate levels of 1,25-dihydroxyvitamin D commensurate to the elevated levels of PTH. This abnormality along with sustained hyperparathyroidism may contribute to bone loss following transplantation.

Fracture risk reduction during treatment with teriparatide is independent of pretreatment bone turnover

INTRODUCTION

Teriparatide is a bone formation agent that increases bone turnover and mass, resulting in an increase in bone strength and a decrease in fracture risk.

METHODS

The primary purpose of this analysis was to evaluate the association between pretreatment bone turnover marker (BTM) concentrations and the absolute and relative fracture risks after adjusting for baseline femoral neck BMD, number of prevalent vertebral fractures, and age. Because femoral neck BMD is commonly attained in the assessment of patients at risk for osteoporosis, we examined the ability of a multivariate assessment including pretreatment BTM concentration and femoral neck BMD to predict future fracture risk after adjusting for the number of prevalent vertebral fractures. We examined data from the Fracture Prevention Trial, a study designed to determine the effect of teriparatide 20 mcg/day and teriparatide 40 mcg/day on vertebral and nonvertebral fracture risk in postmenopausal women with osteoporosis. BTM were analyzed in two subsets of women within the Fracture Prevention Trial, and included serum bone-specific alkaline phosphatase (BSAP), serum carboxy-terminal extension peptide of procollagen type I (PICP), serum amino-terminal extension peptide of procollagen type I (PINP), urinary free deoxypyridinoline (DPD), and urinary N-terminal telopeptide (NTX).

RESULTS

Teriparatide significantly reduced the risk of fracture [four BTM subset (n = 520), placebo = 14.3%, teriparatide = 5.8%, P < 0.05; PINP subset (n = 771), placebo = 17.7%, teriparatide = 5.5%, P < 0.05]. Subjects with the highest pretreatment BTM concentrations had the greatest fracture risk. Teriparatide-mediated absolute risk reduction was greatest for women with high pretreatment bone turnover; however, the relative fracture risk reduction was independent of pretreatment bone turnover. After adjusting for pretreatment BTM and number of prevalent vertebral fractures, baseline femoral neck BMD was not a significant predictor of fracture risk.

CONCLUSION

Teriparatide-mediated relative fracture risk reduction was independent of pretreatment bone turnover, demonstrating that this therapy offers clinical benefit to patients across a range of disease severity.

Risedronate, a novel pyridinyl bisphosphonate for the treatment of osteoporosis and Paget’s disease of bone

Osteoporosis and Paget's disease of bone are the most common metabolic bone diseases. They cause considerable disability and pain, and reduce quality of life. The elderly are at greatest risk of osteoporotic fractures, and in an ageing world population, the burden of the disease is likely to increase. Bisphosphonates are known to be effective antiresorptive agents for the treatment of Paget's disease of bone, postmenopausal osteoporosis (PMO) and corticosteroid-induced osteoporosis (CIO). However, some bisphosphonates have been associated with troublesome gastrointestinal side-effects. Risedronate is a novel pyridinyl bisphosphonate recently approved in the USA for the treatment of Paget's disease, and is under development for the treatment of PMO and CIO. Risedronate is effective and well-tolerated in the treatment of Paget's disease. It has the shortest treatment regimen of any oral bisphosphonate; a two month course of therapy results in sustained remission, as determined by biochemical indices. The results of recent clinical trials suggest that risedronate is also an effective, well-tolerated therapy for PMO and CIO. Risedronate represents an advance in the therapeutic options available for the treatment of Paget's disease, and is expected to be of further value for treatment of PMO and CIO when it receives approval for use in these conditions.

Ultrasound of the skeleton: review of its clinical applications and pitfalls

Quantitative ultrasound (QUS) is receiving considerable attention in the assessment of osteoporosis because of its ease of use, lack of radiation exposure, region of interest, and relatively low costs. These features have made the technique appealing for screening adult and pediatric patients. This article discusses some of the clinical applications, limitations, and strengths of QUS.

Role of alendronate and risedronate in preventing and treating osteoporosis

Alendronate and risedronate, the two oral bisphosphonates approved in the United States for preventing and treating osteoporosis, have never been compared in direct head-to-head trials, but they appear to have similar pharmacokinetics, drug interactions, adverse effect profiles, and efficacy. Alendronate, however, can be given as a once-weekly dose, whereas risedronate is not yet available in this dosage form. On the other hand, alendronate is not approved for preventing glucocorticoid-induced osteoporosis, whereas risedronate carries this indication.

Tolerability of risedronate in postmenopausal women intolerant of alendronate

Bisphosphonates are effective treatments for osteoporosis, but some have been associated with upper gastrointestinal intolerance. This randomized, double-blind study assessed the upper gastrointestinal tolerability of risedronate in postmenopausal women who had discontinued alendronate treatment because of upper gastrointestinal adverse events. Sixty-six women who had previously discontinued treatment with alendronate 10 mg/day because of upper gastrointestinal symptoms received placebo (N=31) or risedronate 5 mg (N=35) daily for 3 months. The primary outcome was the rate of discontinuation due to upper gastrointestinal adverse events: 5/31 (16.1%) in the placebo group, and 4/35 (11.4%) in the risedronate group. Discontinuation rates were also similar in the two treatment groups among subgroups of patients with a history of gastrointestinal disorder, prior use of acid suppression drugs, and concomitant use of NSAIDs. The overall incidence of upper gastrointestinal events was comparable between the placebo (19.4%) and risedronate (20.0%) groups. Overall, risedronate 5 mg/day for 3 months was as well tolerated as placebo in patients who could not tolerate alendronate 10 mg. These results are consistent with, and complement those from previous studies showing that risedronate 5 mg has a gastrointestinal tolerability similar to that of placebo.

Rechallenge of patients who had discontinued alendronate therapy because of upper gastrointestinal symptoms

BACKGROUND

There have been reports from physicians in clinical practice that up to 30% of patients taking bisphosphonate therapy develop upper gastrointestinal (UGI) symptoms, many or most of which they assume to be related to the drug. However, in several large placebo-controlled clinical trials of bisphosphonates, the incidence of UGI symptoms has been > or =30%, even among patients receiving placebo, perhaps reflecting a high background incidence of UGI events in osteoporotic patients.

OBJECTIVE

To assess the relationship between alendronate treatment and UGI complaints in patients who had discontinued treatment with alendronate in clinical practice because of UGI symptoms, we compared the incidence of such events on rechallenge with alendronate or placebo.

METHODS

This was a multicenter, double-blind trial in which postmenopausal women with osteoporosis who had previously discontinued alendronate therapy because of a UGI adverse experience were randomized to daily treatment with either alendronate 10 mg or matching placebo (1:1 ratio) for 8 weeks. The primary end point was the cumulative incidence of discontinuations due to any UGI adverse experience. Secondary end points were the incidence of any clinical adverse experiences and the percentage change from baseline in urinary N-telopeptide adjusted for urinary creatinine at week 8.

RESULTS

A total of 172 women were included in the study. They were a mean of 20.9 years past menopause, ranging in age from 41 to 90 years (mean, 67.0 years); 90.7% were white. On rechallenge, 14.8% (13/88) of patients in the alendronate group and 16.7% (14/84) in the placebo group discontinued treatment because of UGI adverse experiences.

CONCLUSION

The results of this study suggest that many UGI adverse experiences reported during therapy with alendronate may reflect a high background incidence of UGI complaints and an increased sensitivity to detection of such complaints, rather than a causal relationship to therapy.

Raloxifene: a new choice for treating and preventing osteoporosis

Selective estrogen receptor modulators (SERMs) are a new class of drugs that provide a new option for addressing the health challenges of postmenopausal women. This review discusses the proposed mechanism of action of SERMs and describes clinical findings on raloxifene, a SERM now available for treating and preventing osteoporosis.

Cyclical etidronate in the treatment of postmenopausal osteoporosis: efficacy and safety after seven years of treatment

PURPOSE

To determine the efficacy and safety of cyclical etidronate for up to 7 years in the treatment of postmenopausal osteoporosis and to examine the effects of discontinuing treatment after 2 or 5 years of therapy.

PATIENTS AND METHODS

Patients were randomized at entry into the original study in 1986 to blinded treatment for 2 years with either a calcium (placebo) or an intermittent cyclical etidronate regimen, which most patients continued for a third year. Following this phase of the study, patients were enrolled into an open-label, follow-up study (years 4 and 5), during which all patients received cyclical etidronate treatment. In the present double-blind study (years 6 and 7), patients were rerandomized to receive intermittent cyclical therapy with either etidronate or placebo; all patients received calcium. The treatment regimen consisted of 400 mg/day etidronate or placebo for 14 days, followed by 76 days of elemental calcium (500 mg/day); this cycle was repeated approximately 4 times in each year. Of the 193 patients who continued in years 6 and 7 of the study, 93 were randomized to receive cyclical etidronate and 100 were randomized to receive calcium only. For purposes of efficacy analyses, patients were categorized by their total years of cumulative etidronate treatment (7, 5, 4, or 2 years). There were 51, 46, 42, and 54 patients in the 7-, 5-, 4-, and 2-year groups, respectively. Annual assessments included lumbar spine bone mineral density (BMD), as measured by densitometry, and vertebral radiographs.

RESULTS

The groups receiving cyclical etidronate during this 2-year study period (7- and 4-year groups) had statistically significant mean percent increases in spinal BMD of 1.8% and 2.2%, respectively (P < 0.05) at the week 104 observation time. The 5- and 2-year groups, which did not receive etidronate during this period, had mean values of 1.4% and 0.2%, respectively (not significant) at week 104. In the 7-, 5-, 4-, and 2-year groups, the increases in spinal BMD at the end of 7 years were 7.6%, 8.6%, 8.1%, and 3.9%, respectively; these values were statistically significant for all groups compared with original baseline (year 0) (P < 0.05). BMD of the femur and wrist was maintained throughout the 7-year period. The incidence and rate of vertebral fractures were lowest in patients with the longest exposure to etidronate. Etidronate was well tolerated during the study, with low incidences of gastrointestinal side effects and nonvertebral fractures.

CONCLUSIONS

Long-term cyclical etidronate is a safe, effective, and well-tolerated treatment for postmenopausal osteoporosis. Bone mass is maintained for at least 2 years after treatment with etidronate is stopped; however, further gains in spinal bone mass are seen in patients who continue therapy.

Regional body FDG-PET in postoperative recurrent hyperparathyroidism

PURPOSE

The use of preoperative imaging studies in patients with persistent or recurrent hyperparathyroidism after initial operation is generally accepted to improve the success rate and minimize the morbidity from reoperative surgery. The purpose of this study was to define the performance of FDG-PET for the localization of hyperfunctioning parathyroid tissue prior to reoperation.

METHOD

Twenty patients with biochemical evidence of recurrent or persistent hyperparathyroidism following previous neck surgery were investigated. Regional body PET imaging of the neck and upper chest (axial field of view 27.5 cm) was acquired 45 min after 5-10 mCi FDG was given intravenously.

RESULTS

Subsequent surgery revealed solitary parathyroid adenomas in 14 patients, seven hyperplastic glands in 2 patients, and parathyroid carcinoma in 1 patients. FDG-PET correctly identified 79% (11/14) of the parathyroid adenomas, 29% (2/7) of the hyperplastic glands, and the parathyroid carcinoma. FDG-PET was negative in 79% (30/38) of the surgically identified normal parathyroid glands. Eight false-positive findings led to a positive predictive value of 64%.

CONCLUSION

These preliminary data suggest that regional body FDG-PET is a promising procedure in the evaluation of patients with persistent or recurrent postoperative hyperparathyroidism.

Dose-response relationships for alendronate treatment in osteoporotic elderly women. Alendronate Elderly Osteoporosis Study Centers

Alendronate (ALN) is an aminobisphosphonate employed as an antiresorptive agent in the treatment of osteoporosis. The present study was carried out to determine dose-response relationships, particularly the effects of relatively low doses of ALN, on bone mineral density (BMD), biochemical indexes of bone and mineral metabolism, and bone histology, with particular attention to effects in elderly women. This prospective, randomized, double blind, 2-yr multicenter study compared the effects of placebo with those of 1.0, 2.5, or 5.0 mg ALN daily. All subjects received supplemental calcium (500 mg daily) as the carbonate. We studied 359 women with lumbar spine BMD at least 2.0 SD below the peak young adult mean. Subjects were stratified by age, with 135 aged 60-69 yr and 224 aged 70-85 yr. Histomorphometry was performed on transiliac bone biopsies obtained from 104 subjects after 1 yr and from 83 subjects after 2 yr. This study elucidated the previously uninvestigated lower region of the dose-response curve for ALN in osteoporosis. Over 2 yr, treatment with 1.0, 2.5, or 5.0 mg/day increased lumbar spine BMD, on the average, by 0.65%, 3.54%, and 5.67%, respectively, compared with that in the placebo group (P < 0.001 vs. placebo for the 2.5 and 5 mg groups). Significant dose-related increases were also seen in BMD at appendicular sites and in total body BMD. Dose-dependent reductions in bone turnover to new steady states were indicated by serum and urine biochemical markers as well as by histomorphometry. There was also a dose-related reduction in the proportion of subjects suffering nonvertebral fractures (P < 0.05). Safety profiles were similar for the ALN and placebo groups and for both age strata. Efficacy was similar for both age strata. There was no evidence of impaired mineralization or other histological abnormalities due to ALN treatment. We conclude that treatment with ALN over a period of 2 yr was well tolerated and produced dose-dependent increases in BMD without evidence of a plateau over the dose range of 1.0-5.0 mg daily. One milligram daily did not result in a significant effect on BMD, and 5.0 mg daily produced favorable effects at all sites measured. Other studies have demonstrated somewhat greater effects on 10 mg daily. ALN, was equally effective and well tolerated in osteoporotic women over 70 yr old as in younger women with the same condition.

Bisphosphonate therapy

The bisphosphonates are long-lived synthetic analogs of pyrophosphate, a natural, short-lived inhibitor of bone. Oral doses share similar qualities (ie, they inhibit bone resorption, poor absorption, and potential gastrointestinal irritants), but each one has a unique spectrum of potency and a probable mechanism of action. The parent compound, etidronate, was first used in multicentered trials for the treatment of primary osteoporosis and showed some success in increasing bone density and perhaps controlling fracture rates. The recently approved drug alendronate is a more potent agent than etidronate, produces a greater increase in bone density, and decreases fractures. Oral and intravenous pamidronate have similar positive effects on bone density. Studies with tiludronate, risedronate, and clodronate show similar promise as therapeutic agents.

Effects of amiodarone on thyroid function

PURPOSE

To review the literature on the effects of amiodarone on thyroid physiology and management of amiodarone-induced thyroid disease.

DATA SOURCES

English-language articles identified through a MEDLINE search (for 1975 to 1995, using the terms amiodarone and thyroid) and selected cross-referenced articles.

STUDY SELECTION

Articles on the effects of amiodarone on thyroid physiology and function tests and occurrence, recognition, and management of amiodarone-induced thyroid disease.

DATA EXTRACTION

Data were manually extracted from selected studies and reports; emphasis was placed on information relevant to the practicing clinician.

DATA SYNTHESIS

Amiodarone can have many effects on thyroid function test results, even in the absence of hyperthyroidism or hypothyroidism. It may cause an increase in serum levels of thyroxine, reverse triiodothyronine, and thyroid-stimulating hormone and a decrease in serum triiodothyronine levels. Thyrotoxicosis occurs in some patients and is related to several pathogenetic mechanisms. It often present dramatically with obvious clinical manifestations and further changes in thyroid function test results. Medical options include therapy with thionamides, perchlorate, and prednisone. Radioactive iodine is of little use. Thyroidectomy is effective and is the only measure that consistently allows continued use of amiodarone. Unlike thyrotoxicosis, hypothyroidism is related to a persistent Wolff-Chaikoff effect and often has a vague presentation. The goal of treatment of amiodarone-induced hypothyroidism is to bring serum thyroxine levels to the upper end of the normal range, as often seen in euthyroid patients who are receiving amiodarone.

CONCLUSIONS

Thyroid dysfunction commonly occurs with amiodarone therapy. It may be difficult to recognize the dysfunction because of the many changes in thyroid function test results that occur in euthyroid patients who are receiving amiodarone. Effective strategies exist for the management of hyperthyroidism and hypothyroidism; these should be tailored to the needs of the individual patient.

Comparison of FDG-PET and sestamibi-SPECT in primary hyperparathyroidism

Preoperative localization of hyperfunctioning parathyroid tissue in patients with primary hyperparathyroidism has been a longstanding diagnostic challenge. This study directly compared FDG-PET and sestamibi-SPECT for preoperative detection of abnormal parathyroid tissue.

METHODS

Twenty-one consecutive patients with primary hyperparathyroidism were studied prospectively before surgical neck exploration. SPECT of the neck and chest was performed at 15 min and 2 hr after intravenous 99mTc-sestamibi. Regional body PET was performed 45 min after intravenous FDG.

RESULTS

Surgery revealed 19 solitary parathyroid adenomas, 2 parathyroid adenomas in one patient; and 3 hyperplastic parathyroid glands in one patient, and 51 normal parathyroid glands. The diagnostic sensitivities for detection of parathyroid adenomas of 43% (9 of 21) for dual-phase sestamibi-SPECT and 86% (18 of 21) for FDG-PET were significantly different (p < 0.001). The difference in diagnostic specificities of 78% (40 of 51) for FDG-PET and 90% (46 of 51) for dual-phase sestamibi-SPECT approached statistical significance (p = 0.063).

CONCLUSION

This study demonstrates that FDG-PET is more sensitive than sestamibi-SPECT in the preoperative localization of parathyroid adenomas in patients with primary hyperparathyroidism.

Amiodarone induced hyperthyroidism: a case series and brief review of literature

To delineate the incidence, clinical features, diagnosis, and treatment options for amiodarone induced hyperthyroidism (AIH), we reviewed the medical records of ten patients with AIH. Eight of these 10 patients were detected on initial review of the records of 200 patients in treatment with amiodarone, and the other 2 following notification by their endocrinologists. AIH occurred in 4.2% of patients being treated with amiodarone. At the time of diagnosis of AIH, the mean (SD) values for age, duration of treatment with amiodarone, and dose of amiodarone were 62.9 (8.96) years, 38.3 (20) months, and 366.7 (122) mg/day, respectively. The most common clinical features were weight loss and goiter (each seen in 90% of patients). Serum thyroxine (T4), triiodothyronine, and free thyroxine index (FTI) showed an increase of 84%, 47%, and 110%, while thyroid stimulating hormone (TSH) and resin T4 uptake decreased 96% and 14%, respectively, from previous values. The most consistent laboratory findings, seen in all patients, were subnormal TSH and abnormally high FTI. One patient required no treatment; another underwent prompt total thyroidectomy. The other eight were treated medically; two of them underwent total thyroidectomy later, for medical failure or adverse effects. Amiodarone was continued in four patients. The most commonly used antithyroid medication was propylthiouracil. AIH presents in the early or late phases of treatment with amiodarone with typical clinical features of a hyperthyroid state, fall in TSH, and increase in FTI. Antithyroid medications are reasonably effective in the management of AIH.

Prevention and osteoporosis management

BACKGROUND

Primary osteoporosis affects one in four women over the age of 65 and reflects lifelong processes and trends.

SUMMARY

Skeletal bone constantly repairs the microscopic damage it sustains as a result of the normal activities of living. Women achieve their maximum bone density by the close of adolescence. Hereditary, nutritional, hormonal, and life-style factors affect the process of osteoporosis. Bone densitometry can detect very small deficits long before losses become clinically apparent. Intervention can halt osteoporosis at any point and perhaps increase bone density, but no known therapy can restore the normal bone architecture once it is lost.

KEY POINTS

Women should maintain an adequate intake of calcium throughout their lifetime, especially during adolescence. Bone densitometry at the time of menopause detects preclinical osteoporosis and enables physicians to start therapy to preserve the bone structure.

Primary hyperparathyroidism: preoperative parathyroid imaging with regional body FDG PET

PURPOSE

To explore the feasibility of use of positron emission tomography (PET) with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) to localize abnormal parathyroid tissue.

MATERIALS AND METHODS

Regional body FDG PET with attenuation correction was performed in 17 adult patients with primary hyperparathyroidism (HPT) prior to surgical neck exploration. The regional body FDG PET results were correlated with surgical and histopathologic findings.

RESULTS

Surgical neck exploration revealed 18 parathyroid adenomas in 16 patients and four hyperplastic parathyroid glands in one patient. Regional body FDG PET allowed correct localization of 17 of the 18 parathyroid adenomas (94% sensitivity) and two of the four hyperplastic parathyroid glands (50% sensitivity). Three false-positive FDG PET findings were encountered, including two follicular thyroid adenomas.

CONCLUSION

Regional body FDG PET is a promising procedure for preoperative localization of pathologic parathyroid tissue in patients with primary HPT.

Four-year study of intermittent cyclic etidronate treatment of postmenopausal osteoporosis: three years of blinded therapy followed by one year of open therapy

PURPOSE

To determine the effect of long-term intermittent cyclic etidronate treatment on spinal bone density and vertebral fracture rates.

PATIENTS AND METHODS

Postmenopausal osteoporotic women (n = 423) were randomized initially into a 2-year, double-blind, multicenter study; it was extended to a third year of blinded treatment followed by open-label treatment: 357 patients continued treatment in Year 3 (305 receiving blinded therapy and 52 receiving calcium supplementation) and 277 in Year 4. During Years 1 through 3, patients received double-blind treatment with phosphate (1.0 g) or placebo twice daily for 3 days, etidronate (400 mg) or placebo daily for 14 days, and calcium (500 mg) daily for the remainder of each 91-day treatment cycle. During Year 4, open-label intermittent cyclic etidronate therapy (without preceding phosphate) was administered to all patients. Spinal bone density and vertebral fracture rates were the main outcome measures.

RESULTS

During Year 3, etidronate therapy maintained the significant increases in spinal bone mineral density of the first 2 years. Over the 3-year period, proximal femur bone density increased in etidronate-treated patients. Etidronate therapy for 3 years significantly decreased the vertebral fracture rate in patients at higher risk for fracture (low spinal bone density and three or more vertebral fractures at study entry), as compared with nonetidronate treatment (228 versus 412 fractures per 1,000 patient-years, respectively; p < 0.05). After 1 year of open-label treatment, patients previously treated with etidronate maintained bone mass, and vertebral fracture rates in all groups were lower than in any other study period. There were no apparent serious adverse effects.

CONCLUSIONS

Three years of intermittent cyclic etidronate therapy produced significant increases in spinal and hip bone density, with a significant reduction in vertebral fracture rates in patients at higher fracture risk. Maintenance of bone mass and low fracture rate were observed when etidronate was continued for an additional year.

From bathtub ring to osteoporosis: a clinical review of the bisphosphonates

BACKGROUND

Etidronate and pamidronate are bisphosphonates, a class of chemical compounds originally used to soften hard water and prevent soap scum. Etidronate was serendipitously found to abate calcification in a child with myositis ossificans progressiva.

OBJECTIVE

Review the basic pharmacology of these compounds, as well as clinical uses of the approved and nonapproved forms.

DISCUSSION

Etidronate is approved for the treatment of hypercalcemia, Paget's disease of bone, and ectopic calcification, and has been used to treat hyperparathyroidism and nephrolithiasis with limited success. Recently it has been used to treat osteoporosis. Pamidronate is approved to treat hypercalcemia. These two drugs are the only bisphosphonates available in the United States.

CONCLUSIONS

Clinical trials with etidronate have aroused widespread interest in the application of bisphosphonates to treat osteoporosis. Many trials are underway to evaluate these new drugs. More information will be available within the next 5 years.

Chemical and histological features of men with osteoporosis

Six men (average age, 42) underwent evaluation for idiopathic osteoporosis. Standard measurements of serum and urine were studied. Lumbar skeletal mineral density was measured by dual-photon absorptiometry. Skeletal biopsies of the iliac crest were obtained after double-labeling with tetracycline. Average renal cyclic adenosine monophosphate and urinary calcium values were elevated. Lumbar spinal density was 72% of age-matched norms, and histomorphometric analyses of bone revealed decreased trabecular bone volume and formation rate and increased trabecular osteoid area, osteoclast number, and calcification rate. The results suggest that idiopathic osteoporosis in these men is associated with increased parathyroid hormone secretion as assessed by increased renal cyclic adenosine monophosphate and high skeletal remodeling activity.

Transient osteoporosis of the hip: clinical and imaging features

Transient osteoporosis of the hip is a form of reflex sympathetic dystrophy characterized by pain, limping, limitation of hip joint motion, and delayed radiographic patchy osteoporosis of the proximal femur. Spontaneous resolution is usually paralleled by radiographic recovery, usually within a few months. We present clinical and imaging features in seven cases of unilateral transient osteoporosis of the hip. In the appropriate clinical setting, conventional radiography will support the diagnosis. The role of more sensitive imaging techniques such as bone scintigraphy and magnetic resonance imaging in the early diagnosis of this disease has yet to be defined.

Stress fractures in young athletic women: case reports of unsuspected cortisol-induced osteoporosis

Stress fractures in the female athlete are common events, usually occurring in the lower limb and less often in the pelvic girdle. Two cases are presented of young women athletes who presented with initial lower limb stress fractures, but subsequently fractures of the pelvis and hip thought to be associated with their athletic activity. After careful medical evaluation, they were diagnosed with Cushing's syndrome. One patient had a microadenoma of the pituitary gland secreting excessive amounts of ACTH, and the other had a benign adenoma of the left adrenal gland. Both women had significant decreases in their spinal mineral density. After treatment, partial reversal of these spinal losses occurred. Although stress fractures in the female athlete might be common and thought to be associated with problems of amenorrhea, presentation of unusual anatomical sites for these fractures necessitates a more thorough evaluation for correctable secondary causes.

Effect of supplemental calcium on serum and urinary calcium in osteoporotic patients

A retrospective analysis of osteoporotic patient records was conducted to evaluate the effect of supplemental calcium (Ca) on urinary and serum Ca. Forty-seven patients composed the Ca-supplemented group and 17 patients the nonsupplemented group. Serum Ca values (mean +/- SD) were 9.3 +/- 0.3 and 9.4 +/- 0.4 mg/dl in the nonsupplemented and supplemented groups, respectively. Daily urinary Ca was 137 +/- 88 and 162 +/- 89 mg, respectively. Each group had similar concentrations of serum phosphorus, albumin and creatinine. Data from the Ca-supplemented group were divided into low and high Ca intake. In the low intake group (less than 1000 mg Ca/day), serum and urinary Ca were 9.4 +/- 0.4 and 166 +/- 88. In the high intake group (greater than 1000 mg/day), the values were 9.5 +/- 0.5 and 160 +/- 90, respectively. Seventeen and 36% of nonsupplemented and supplemented patients used estrogen, respectively. No significant effects of estrogen therapy were observed on serum or urinary Ca in either group. More detailed analysis of five patients was undertaken to evaluate the combined effect of supplemental vitamin D (ergocalciferol or calcitriol) and Ca on urinary Ca output. Baseline urinary Ca was 33 +/- 19 mg with an average daily Ca supplement of 1160 mg. After 4-8 weeks of supplemention with Ca and vitamin D, urinary Ca increased to only 68 +/- 33 mg. We conclude that supplemental Ca does not appear to cause a significant increase in urinary Ca and that added vitamin D has little effect on elevating urinary Ca in some older women.(ABSTRACT TRUNCATED AT 250 WORDS)

Therapies for symptomatic primary osteoporosis

There is no universally accepted pharmacologic treatment for primary symptomatic osteoporosis. However, three agents discussed in this review show varying degrees of promise. Calcitonin increases bone density and has the added benefit of analgesic properties. Etidronate disodium, a diphosphonate approved for symptomatic Paget's disease, has been shown to increase bone density and decrease fractures in osteoporosis. Sodium fluoride, although an effective stimulator of bone growth in low turnover osteoporosis, has been associated with toxicity and increased fractures.

Angiotropic large-cell lymphoma in a patient with adrenal insufficiency

Angiotropic large-cell lymphoma is a rare disorder characterized by a proliferation of malignant lymphoid cells within the lumina of small vessels. The skin and central nervous system are typically affected; however, involvement of other organs has been described. We document an unusual case of this disorder in a patient who suffered clinically significant adrenal insufficiency and subsequently died. Autopsy disclosed angiotropic large-cell lymphoma involving both adrenal glands.

Intermittent cyclical etidronate treatment of postmenopausal osteoporosis

BACKGROUND

To determine the effects of etidronate (a bisphosphonate that inhibits osteoclast-mediated bone resorption) in the treatment of postmenopausal osteoporosis, we conducted a prospective, two-year, double-blind, placebo-controlled, multicenter study in 429 women who had one to four vertebral compression fractures plus radiographic evidence of osteopenia.

METHODS

The patients were randomly assigned to treatment with phosphate (1.0 g) or placebo twice daily on days 1 through 3, etidronate (400 mg) or placebo daily on days 4 through 17, and supplemental calcium (500 mg) daily on days 18 through 91 (group 1, placebo and placebo; group 2, phosphate and placebo; group 3, placebo and etidronate; and group 4, phosphate and etidronate). The treatment cycles were repeated eight times. The bone density of the spine was measured by dual-photon absorptiometry, and the rates of new vertebral fractures were determined from sequential radiographs.

RESULTS

After two years, the patients receiving etidronate (groups 3 and 4) had significant increases in their mean (+/- SE) spinal bone density (4.2 +/- 0.8 percent and 5.2 +/- 0.7 percent, respectively; P less than 0.017). The rate of new vertebral fractures was reduced by half in the etidronate-treated patients (groups 3 and 4 combined) as compared with the patients who did not receive etidronate (groups 1 and 2 combined) (29.5 vs. 62.9 fractures per 1000 patient-years; P = 0.043); the effect of treatment was most striking in the subgroup of patients with the lowest spinal bone mineral density at base line, in whom fracture rates were reduced by two thirds (42.3 vs. 132.7 fractures per 1000 patient-years; P = 0.004). The addition of phosphate provided no apparent benefit. There were no significant adverse effects of treatment.

CONCLUSIONS

Intermittent cyclical therapy with etidronate for two years significantly increases spinal bone mass and reduces the incidence of new vertebral fractures in women with postmenopausal osteoporosis.

Effect of a pulsing electromagnetic field on metabolically derived osteoporosis in rats: a pilot study

The literature suggests that a pulsating electromagnetic field (PEMF) is effective against bone loss in disuse osteoporosis. This study was conducted to evaluate the effects of PEMF on metabolically derived osteoporosis in rats. Sixteen 5 month old female Sprague-Dawley rats were divided into three groups (G-1,2,3). G-1 was given a normal diet and no exposure to PEMF; G-2,3 were oophrectomized and fed a low calcium diet for 8 months; and G-3 was also exposed for 24 hr/day to PEMF generated by applying a 15 Hz, 5.6 A peak to peak square wave to Helmholtz coils (64 cm I.D., 200 turns/coil). The rats were sacrificed at 4, 6, and 8 months. Skeletal changes were analyzed by measurements of acid extracted bone calcium and bone mineral content (BMC) using single photon absorptiometry (SPA). Although all animals started at approximately the same weight (mean of 290.0 g), G-2 showed a more progressive increase. While the mean weight after 8 months in G-1 was 350.0 g, and 352.5 g for G-3, that in G-2 was 400.0 g. The calcium content of the femur in G-2 and G-3 at 8 months was lower than that of G-1, but there were no significant differences among the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Gorham's syndrome: a case report and review of the literature

Gorham's syndrome is a rare disorder involving a proliferation of vascular channels associated with extensive loss of bony matrix. A case report is presented with a review of the 97 previously reported cases. The age of patients at presentation has ranged from less than one to 75 years (mean: 27 years). Sixty-four percent have been men. Fifty-seven percent have had a history of prior trauma. Laboratory values for systemic measures have usually been normal. The disease usually arrests spontaneously, but this is unpredictable. Sixteen patients (16 percent) have died of the disorder, with 10 deaths due to chest wall involvement, three to spinal cord transection, two to sepsis, and one to asphyxia and aspiration. Although the mechanism of bone loss is unknown, osteoclasts were focally increased in the case described herein. Further information and investigation are needed to better understand this unusual disorder.

Hyperparathyroidism, hyperthyroidism, and Cushing's disease

In this article, normal and hyperactive states of parathyroid, thyroid, and cortisol production are examined. Their role in bone loss and the rationale for therapeutic intervention are also discussed.

Symmetrical bone scan in a patient with acute hypercalcemia

A previously healthy 49-year-old woman had symptoms of acute hypercalcemia that was not parathyroid-hormone mediated. Despite no clinical signs or symptoms of arthritis, a bone scan showed increased uptake in the juxtaarticular areas of the joints in the upper and lower extremities. The biopsy specimen of skeletal lesions noted on roentgenograms supported a diagnosis of multiple myeloma. Symmetrical lesions on bone scan in a patient with asymptomatic joints and acute hypercalcemia may be the first sign of an underlying hematologic malignant neoplasm.

Measurement of sialyl transferase activity and serum glycoproteins in malignant and beningn (hyperparathyroid) hypercalcemia

Serum sialyl tranferase activity (STA) and protein bound carbohydrate were measured in hypercalcemic patients with surgically documented hyperparathyroidism (n = 15) or with cancer without skeletal metastases (n = 10). Precipitable protein-bound sialic acid and hexosamine, but not neutral hexoses or fucose were significantly (P less than 0.025) increased 40% and 21% respectively, in the perchlorate treated sera of cancer patients. Measurements of some specific serum glycoproteins by radial immunodiffusion assay were also different (P less than 0.05). Mean seromucoid protein was almost twice as great in the group with cancer (P less than 0.005), but four of these values overlapped those from the patients with hyperparathyroidism. The mean STA was 21.1 (range, 9.0-46.8) activity units in the patients with the cancer and 9.2 (range 1.0-17.8) in the patients with hyperparathyroidism (P less than 0.005). Six of the patients with cancer had values above the upper limit of the group with hyperparathyroidism. A discriminant function generated from these data correctly classified all the patients with hyperparathyroidism and 70% of those with cancer. Measurements of seromucoid and STA deserve further consideration as a way to discriminate some cases of hypercalcemia.

Adverse effects of liquid protein fast on the handling of magnesium, calcium and phosphorus

We have studied the effect of a vitamin- and potassium-supplemented liquid protein fast on mineral metabolism of six obese subjects (five women, 1 man) for 40 days. Each patient was admitted to a metabolic ward and was given daily 300 Kcal, 75 mg of calcium, 406 mg of phosphorus, 7 mg of magnesium, 33 meq of potassium, and 11.5 g of nitrogen. Urinary calcium, phosphorus and magnesium levels were greatest during the first week, but decreased as the fast continued to 21, 31 and 300 percent, respectively, above intake. Cumulative urinary losses of calcium, phosphorus and magnesium were 58, 75 and 500 percent greater, respectively, than the cumulative intake. Fecal losses for calcium, phosphorus and magnesium were less than urinary losses throughout the study. Cumulative fecal losses of magnesium were more than 30 percent greater than dietary intake. Mean daily balances were -104 mg (calcium), -48 mg (magnesium) and -363 mg (phosphorus). Serum phosphorus and magnesium levels did not change. However, serum calcium levels decreased (-0.5 mg/dl, p less than 0.05). Serum bicarbonate levels decreased 20 percent during the first 8 days of the fast, at which time urinary ammonium was maximal, but later returned to control values despite sustained increases in serum and urinary acids throughout the fast. Ammonium excretion was 260 to 300 percent above control values. Urinary titratable acid excretion was greatest early in the fast but subsequently decreased as the excretion of phosphorus declined. Titratable acid accounted for less of the excreted acid (7 to 21 percent) than did ammonia (70 to 90 percent). It is concluded that a liquid protein fast results in negative mineral balance that is not reflected by serum values and is due primarily to renal losses. The losses of magnesium were proportionally greater than those of calcium and phosphorus. These studies indicate that a liquid protein fast results in depletion of the intracellular and/or skeletal stores of these minerals.

Acute effects of increased meat protein on urinary electrolytes and cyclic adenosine monophosphate and serum parathyroid hormone

The effect of a high meat protein diet on urinary electrolytes, cyclic AMP, and serum immunoassayable parathyroid hormone was studied in six subjects fed a high meat protein diet (1.5 to 2.9 g/kg) for 7 days. The diet produced minor decreases in serum calcium and phosphorus but increased endogenous creatinine clearance by about 20% (p less than 0.02) and urinary calcium by about 80% (p less than 0.01) without changing urinary sodium. Urinary calcium correlated (p less than 0.01) with urinary sulfate (r = 0.60), ammonia (r = 0.72), and nitrogen (r = 0.60). Urinary cyclic AMP increased (p less than 0.01) 14% while serum parathyroid hormone (measured by C-terminal assays) decreased (p less than 0.05) by more than 30%. It was concluded 1) that this diet acutely altered renal handling of calcium at a site different from that of sodium, 2) that the excretion of acidic products of protein metabolism contributed to these changes, and 3) that parathyroid hormone secretion was not changed acutely.

Acute effects of dietary protein on calcium metabolism in patients with osteoporosis

Five untreated osteoporotic patients were studied in a metabolic unit for 30 days while receiving control (0.8 gm/kg) and high (2.0 gm/kg) protein diets of purified proteins. The high protein diet increased urinary calcium and produced a negative calcium balance without causing significant change in calcium absorption, serum chemical values, or urinary sodium and potassium. Variable effects of calcium and/or estrogens were found on the negative balance. Hence, increased dietary protein acutely causes a negative calcium balance in osteoporotic patients and may contribute to bone loss in this disease.