Relationship between local and total body bone mineral in epileptic patients and normal subjects

The Effect of Pregabalin on Bone Metabolism

The aim of the study was to determine the effect of pregabalin as monotherapy on biochemical markers and bone mineral density. 40 patients diagnosed with neuropathic pain or fibromyalgia syndrome who were using pregabalin for at least 6 months and age and sex matched 40 healthy individuals were recruited for this cross-sectional study. Bone mineral density of both groups were measured by dual energy x ray absorbsiometry(DXA), bone biochemical markers, serum calcium, and vitamin D levels were investigated. Association between pregabalin use and bone biochemical markers, serum calcium, vitamin D levels were evaluated. The mean age of 40 patients (27 females, 13 males) was 40.6 ± 7.1 years and the mean age of 40 healthy individuals (27 females, 13 males) was 40.4 ± 7.3 years. The other demographic data were similar. There were no significant differences in lumbar and femur neck BMD scores between 2 groups. Also, there were no associations neither between pregabalin use and biochemical markers including serum calcium levels nor between pregabalin use and vitamin D levels. However, the patients who had been used pregabalin less than 24 months had low lumbar t and z scores than patients who had been used pregabalin more than 24 months. This effect was more prominent in male patients. Although no negative effect of pregabalin was found on bone metabolism in these group of patients, we have suggested that further prospective controlled studies with large sample size in different age groups could provide new data about the effects of pregabalin on bone metabolism. We suggest to investigate the bone metabolism especially in male patients on pregabalin treatment who had been used pregabalin treatment less than 24 months.

The problem of osteoporosis in epileptic patients taking antiepileptic drugs

INTRODUCTION

Epilepsy is a common neurological disorder associated with recurrent seizures. Therapy with antiepileptic drugs (AEDs) helps achieve seizure remission in approximately 70% of epileptic patients. Treatment with AEDs is frequently lifelong and there are reports suggesting its negative influence on bone health. This is especially important in terms of general occurrence of osteoporosis, affecting over 50 million people worldwide.

AREAS COVERED

This study refers to two main groups of AEDs: hepatic enzyme inducers (carbamazepine, oxcarbazepine, phenobarbital, phenytoin, primidone and topiramate) and non-inducers (clobazam, clonazepam, ethosuximide, gabapentin, lacosamide, lamotrigine, levetiracetam, pregabalin, tiagabine, valproate, vigabatrin and zonisamide). Some reports indicate that enzyme inducers may exert a more negative influence on bone mineral density (BMD) compared to non-inducers. Bone problems may appear in both sexes during AED therapy, although women are additionally burdened with postmenopausal osteoporosis. Supplementation of vitamin D and calcium in patients on AEDs is recommended.

EXPERT OPINION

Apart from enzyme inducers, valproate (an even enzyme inhibitor) may also negatively affect BMD. However, the untoward effects of AEDs may depend upon their doses and duration of treatment. Although the problem of supplementation of vitamin D and calcium in epileptic patients on AEDs is controversial, there are recommendations to do so.

Treating epilepsy in the elderly: safety considerations

The incidence of epilepsy increases with advancing age. Epilepsy in the elderly has different aetiologies from that in younger populations, cerebrovascular disease being the most common condition associated with seizures. Partial seizures are the predominant seizure type in older patients. A diagnosis of epilepsy in the elderly is based mainly on the history and is frequently delayed. In addition, seizure imitators are especially frequent. In many cases ancillary tests for diagnosis may show normal age-related variants, sometimes making results difficult to interpret. Treating epilepsy in the elderly is problematic due to a number of issues that relate to age and comorbidity. The physical changes associated with increasing age frequently lead to changes in the pharmacokinetics of many anticonvulsants. The treatment of epilepsy in the elderly is also complicated by the existence of other diseases that might affect the metabolism or excretion of anticonvulsants and the presence of concomitant medications that might interact with them. Moreover, specific trials of anticonvulsants in the aged population are scarce. General guidelines for treatment include starting at lower doses, slowing the titration schedule, individualising the choice of anticonvulsant to the characteristics of the patient, avoiding anticonvulsants with important cognitive or sedative adverse effects, and where possible, treating with monotherapy.

Bone mineral density of epileptic patients on long-term antiepileptic drug therapy: a quantitative digital radiography study

In order to assess the bone atrophy lesions of epileptic patients, the bone mineral densities (BMDs) of their lumbar spines and femoral necks were measured using quantitative digital radiography (QDR). The study groups were 44 patients on long-term medication for epilepsy and 62 healthy control subjects. We selected patients who had been taking phenytoin, barbiturates, and/or acetazolamide for at least 5 years. BMDs at both sites were significantly lower in the patient group than in the control group. No sex differences were found in BMDs. There were no significant correlations with the onset or the duration of illness and BMD. We compared BMD according to the type of epileptic drug being taken and theorized that phenytoin, barbiturates, and acetazolamide reduced BMD. BMDs of the 15 patients were measured again 7 years later, and were found to be significantly lower at both sites than in the previous examination. These results confirm the presence of bone atrophy lesions in epileptic patients on long-term antiepileptic drugs. Patients on antiepileptic therapy for long periods should have their BMDs checked, because they are prone to developing bone atrophy.

New methods for identifying "at risk" patients for osteoporosis

Bone loss was determined in 178 women in the early postmenopausal period by photon absorptiometry measurement of forearm bone mineral content (BMC) every three months for two years. With a sequential cut-off technique, the results of a single determination of body fat mass, urinary calcium and hydroxyproline, and serum alkaline phosphatase, carried out at the first examination, correctly identified 79% of "fast bone losers" (bone loss greater than 3% annually) and 78% of "slow bone losers". The simple biochemical screening procedure was hereafter tested in a new group of 70 early postmenopausal women, who were followed for two years with measurement of local and total BMC. With this simple approach the majority of women at highest risk of osteoporotic fractures in later life can be identified in the early postmenopausal period and can be started on prophylactic hormone replacement therapy.

Bisphosphonate whole body retention test: relations to bone mineralization rate, renal function and bone mineral content in osteoporosis and metabolic bone disorders

The bisphosphonate whole body retention test (WBR) has been used to estimate bone mineralization rate (bone turnover). Bisphosphonates given i.v. are taken up by bone or excreted in urine. The aim of the present investigation was to test the efficacy of WBR in estimating bone mineralization rate (m) and to evaluate the influence of renal function (Clcr) and bone mass (forearm bone mineral content; BMC) on WBR. The 24-h retention of 3.7 MBq 99mTc-HMBP (1-hydroxymethylene-1,1-bisphosphonate) (Osteoscan) given i.v. was measured by a medium sensitive whole body counter in thirty-one patients with hyperparathyroidism (n = 14), hyperthyroidism (n = 8) or hypothyroidism (n = 9) (group 1) and in seventy-six females with postmenopausal spinal crush fracture osteoporosis (group 2). In the same individuals m was calculated from a 7-day 47Ca-kinetic study using the expanding calcium pool model. Multiple regression analysis of WBR vs. m and Clcr in group 1 disclosed that WBR correlated positively to m [rp = 0.49, P less than 0.01 (rp = partial correlation coefficient)] and inversely to Clcr (rp = -0.44, P less than 0.02). Inclusion of BMC in the analysis did not reveal any significant partial correlation between WBR and BMC (rp = -0.33, 0.05 less than P less than 0.10). In group 2 WBR correlated inversely to Clcr (rp = -0.48, P less than 0.001) but showed no significant relation to m (rp = 0.10, NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Bone turnover and balance evaluated by a combined calcium balance and 47calcium kinetic study and dynamic histomorphometry

Bone resorption and formation rates were evaluated at the organ level using calcium kinetic methods and at the trabecular bone tissue level using dynamic histomorphometry in 20 patients with various metabolic bone diseases (primary hyperparathyroidism (N = 9), hyperthyroidism (N = 6), and hypothyroidism (N = 5). Highly significant correlations were demonstrated between resorption and formation rates at organ level (r = .90, P less than .001) and at tissue level (volume referent) (r = .93, P less than .001), indicating a high degree of coupling between resorption and formation within the three disease states. Tissue level resorption rates (surface referent, as well as volume referent) both correlated significantly (P less than .01) to organ level resorption rate (r = .60 and r = .63, respectively). Fractional active resorption surface and cellular level resorption rate did not reveal significant correlations to calcium kinetic estimates. No correlation could be demonstrated between organ level mineralization rate and formative or labeled trabecular surfaces. However, all tetracycline based tissue level formation rates revealed highly significant correlations (P less than .01) to organ level mineralization rate (calcification rate, r = .71; surface referent bone formation rate, r = .59; volume referent bone formation rate, r = .68). Based on histomorphometric parameters for resorption and formation, actual and predicted tissue level trabecular bone balances were calculated. Both the actual and predicted bone balance correlated significantly to the organ level calcium balance (P less than .05). Correction for skeletal size based on BMC measurements did not improve any of the correlations significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Prediction of rapid bone loss in postmenopausal women

Bone loss was determined in 178 women in the early postmenopausal period by photon absorptiometry measurement of forearm bone mineral content (BMC) every 3 months for 2 years. With a sequential cut-off technique, the results of a single determination of body fat mass, urinary calcium and hydroxyproline, and serum alkaline phosphatase, carried out at the first examination, correctly identified 79% of "fast bone losers" (bone loss greater than 3% annually) and 78% of "slow bone losers". With this simple approach the majority of women at highest risk of osteoporotic fractures in later life can be identified in the early postmenopausal period and started on prophylactic hormone replacement therapy.

Representativity of regional to total bone mineral in healthy subjects and 'anticonvulsive treated' epileptic patients. Measurements by single and dual photon absorptiometry

Dual photon (153Gd) and single photon (125I) absorptiometry were used to measure the regional bone mineral content (BMC) and density (BMD), as well as the total body mineral content (TBBM) and density (TBBD), in sixty-nine healthy subjects and in twenty-three epileptics on phenobarbitone. The BMCs (and BMDs) of all regions were significantly correlated to each other and to the TBBM (and TBBD). No difference in the ability to discriminate between the different study groups was found for the various regions, excepting the BMD of the head. The relationship between the forearm BMC and TBBM was highly significant, and identical in the five groups. The relationships between spinal BMC and forearm BMC, and TBBM differed in the five groups. It is concluded that some local measurement may be used as estimates of the total body bone mineral in some groups of patients with minor metabolic bone disease and healthy subjects.

Bone changes occurring spontaneously and caused by estrogen in early postmenopausal women: a local or generalised phenomenon?

Regional values of bone mineral content and bone mineral density were calculated from total body dual photon absorptiometry scans of 52 early postmenopausal women treated with oestrogen for one year and of 52 similar women treated with placebo. The six regions were head, arms, chest, spine, pelvis, and legs. In addition, bone mineral density of the lumbar spine was measured by dual photon absorptiometry and bone mineral content of the forearm by single photon absorptiometry, using separate special purpose scanners. All regions were unchanged after one year of treatment with oestrogen, excluding the lumbar spine, for which values rose. Values for all regions except the lumbar spine fell significantly in the placebo group. The rates of loss ranged from 2% to 8%, with no significant differences among the regions. It is concluded that loss of bone in the early menopause is a generalised phenomenon, affecting all parts of the skeleton. Furthermore, oestrogen prophylaxis for loss of bone is effective in all parts of the skeleton. Finally, it is suggested that the measurement of bone mineral content in the forearm should be used for clinical follow up of bone changes, as this method is superior to others in the ratio of change to precision.

The effect of glucocorticoids on bone mass in rheumatoid arthritis patients. Influence of menopausal state

We studied 97 patients with definite or classic rheumatoid arthritis (RA). Fifty-four patients (19 premenopausal women, 25 postmenopausal women, and 10 men) had been treated with low-dose glucocorticoids for at least 12 months (mean dose less than 10 mg/day). The remaining 43 patients (15 premenopausal women, 17 postmenopausal women, and 11 men) had been treated with penicillamine, and served as a patient control group. The distal forearm bone mineral content (BMC) was measured in all patients by single photon absorptiometry using 125I, and the total body bone mineral (TBBM) was measured in 61 patients by dual photon absorptiometry using 153Gd. Compared with normal controls, both treatment groups had significantly decreased BMC and TBBM (0.01 less than P less than 0.001). When the patients were stratified according to pre- and postmenopausal state, we found significantly lower BMC and TBBM values in the premenopausal glucocorticoid-treated women than in penicillamine-treated women. However, no differences in BMC and TBBM values were found in the corresponding postmenopausal groups. In the premenopausal women treated with glucocorticoids, the duration of treatment and cumulative dose correlated with BMC. No such correlations were found in the postmenopausal women. We conclude that 1) RA is associated with loss of bone mass, 2) systemic glucocorticoid treatment further aggravates the bone loss, 3) in postmenopausal RA patients, the bone loss resulting from menopause and from the disease itself is not accelerated by low-dose glucocorticoids, and 4) in premenopausal RA patients, however, the bone mass is significantly affected by glucocorticoid treatment. We therefore suggest that these factors be considered when prescribing glucocorticoids, in order to minimize the bone loss.

Relationship between local and total bone mineral in normal pubertal boys

The bone mineral content of the distal forearm (BMC) using single-photon absorptiometry and total body bone mineral (TBBM) using dual-photon absorptiometry were determined in 19 normal boys at different pubertal stages. A highly significant correlation between BMC and TBBM was seen (r = 0.78, P less than 0.001) with a standard error of estimate (SEE) of 13%. Subgroups of early and late pubertal stages did not show any significant differences in the regression lines indicating an identical relationship between BMC and TBBM at various stages of pubertal development although great changes in bone mineral content take place. Due to high accuracy and reproducibility of both methods, which are non-invasive and harmless, measurement of BMC is suitable to estimate changes in total mineral content of the body. This may be of importance in various diseases with disturbance in growth and bone metabolism.