Effects of raloxifene on lipid and bone metabolism in postmenopausal women with type 2 diabetes

A narrative review of diabetic bone disease: Characteristics, pathogenesis, and treatment

Recently, the increasing prevalence of diabetes mellitus has made it a major chronic illness which poses a substantial threat to human health. The prevalence of osteoporosis among patients with diabetes mellitus has grown considerably. Diabetic bone disease is a secondary osteoporosis induced by diabetes mellitus. Patients with diabetic bone disease exhibit variable degrees of bone loss, low bone mineral density, bone microarchitecture degradation, and increased bone fragility with continued diabetes mellitus, increasing their risk of fracture and impairing their ability to heal after fractures. At present, there is extensive research interest in diabetic bone disease and many significant outcomes have been reported. However, there are no comprehensive review is reported. This review elaborates on diabetic bone disease in the aspects of characteristics, pathogenesis, and treatment.

Challenges to Improve Bone Healing Under Diabetic Conditions

Diabetes mellitus (DM) can affect bone metabolism and the bone microenvironment, resulting in impaired bone healing. The mechanisms include oxidative stress, inflammation, the production of advanced glycation end products (AGEs), etc. Improving bone healing in diabetic patients has important clinical significance in promoting fracture healing and improving bone integration. In this paper, we reviewed the methods of improving bone healing under diabetic conditions, including drug therapy, biochemical cues, hyperbaric oxygen, ultrasound, laser and pulsed electromagnetic fields, although most studies are in preclinical stages. Meanwhile, we also pointed out some shortcomings and challenges, hoping to provide a potential therapeutic strategy for accelerating bone healing in patients with diabetes.

The Effect of Raloxifene Treatment on Lipid Profile in Elderly Individuals: A Systematic Review and Meta-analysis of Randomized Clinical Trials

PURPOSE

To perform a systematic review and meta-analysis of randomized clinical trials (RCTs) to elucidate the effects of raloxifene on the lipid profile in elderly individuals.

METHODS

A systematic review and meta-analysis of RCTs was performed following the PRISMA statement. Data on triglycerides (TGs), total cholesterol (TC), HDL-C, and LDL-C were extracted. Relevant publications up to October 2020 were detected through searches in the PubMed/MEDLINE, Web of Science, Scopus, and Embase databases. Changes were reported as weighted mean differences (WMDs) and 95% CIs using random-effects models.

FINDINGS

Nine studies were selected, with a duration of intervention ranging from 2 and 12 months and a raloxifene dose of 60 to 120 mg/d. Studies were performed in healthy individuals and in those with disorders, such as osteoporosis, type 2 diabetes, and kidney disease required long-term hemodialysis. Overall, TG (WMD, -6.50 mg/dL; 95% CI, -34.18 to 21.20 mg/eL; P = 0.646), LDL-C (WMD, -17.86 mg/dL; 95% CI, -42.44 to 6.72 mg/dL; P = 0.154), and HDL-C (WMD, 2.35 mg/dL; 95% CI, -1.14 to 5.84 mg/dL; P = 0.187) levels did not change significantly after the administration of raloxifene. In contrast, TC levels decreased after raloxifene therapy (WMD, -6.59 mg/dL; 95% CI, -13.13 to -0.05 mg/dL; P = 0.048).

IMPLICATIONS

Raloxifene therapy decreased TC levels but did not alter TG, HDL-C, and LDL-C concentrations in elderly individuals. Regarding the LDL-C levels, although the finding lacked statistical significance, we believe that there was a mean reduction that deserves further clinical attention as much as TC.

Association of dyslipidaemia with osteoporosis in postmenopausal women

Objective

To assess the association of dyslipidaemia with osteoporosis in postmenopausal women.

Methods

Data from 160 postmenopausal women with newly diagnosed osteoporosis (osteoporosis group) and 156 healthy controls (control group) were retrospectively reviewed from 2016 to 2020. The primary outcomes were laboratory values assessed by a multivariate binary logistic regression model.

Results

Factors that greatly increased the risk of being in the osteoporosis group included high low-density lipoprotein (LDL) and low high-density lipoprotein (HDL) levels. The osteoporosis group had lower HDL and higher LDL levels than the control group. A multivariate binary logistic regression model showed that lower HDL and higher LDL levels were the only variables that were significantly associated with osteoporosis (odds ratio 1.86, 95% confidence interval: 3.66–4.25 and odds ratio 1.47, 95% confidence interval: 1.25–2.74, respectively).

Conclusion

Low HDL and high LDL levels may be associated with the occurrence of osteoporosis in postmenopausal women.

An update on therapies for the treatment of diabetes-induced osteoporosis

Introduction: Currently, 424 million people aged between 20 and 79 years worldwide are diabetic. More than 25% of adults aged over 65 years in North America have Type 2 diabetes mellitus (DM). Diabetes-induced osteoporosis (DM-OS) is caused by chronic hyperglycemia, advanced glycated end products and oxidative stress. The increase in the prevalence of DM-OS has prompted researchers to develop new biological therapies for the management of DM-OS. Areas covered: This review covered the current and novel biological agents used in the management of DM-OS. Data were retrieved from PubMed, Scopus, American Diabetes Association and International Osteoporosis Foundation websites, and ClinicalTrials.gov. The keywords for the search included: DM, osteoporosis, and management. Expert opinion: Several biological molecules have been examined in order to find efficient drugs for the treatment of DM-OS. These biological agents include anti-osteoporosis drugs: net anabolics (parathyroid hormone/analogs, androgens, calcilytics, anti-sclerostin antibody), net anti-resorptive osteoporosis drugs (calcitonin, estrogen, selective estrogen receptor modulators, bisphosphonates, RANKL antibody) and anti-diabetic drugs (alpha glucosidase inhibitors, sulfonylureas, biguanides, meglitinides, thiazolidinediones, GLP-1 receptor agonists, dipeptidylpeptidase-4 inhibitors, sodium glucose co-transporter-2 inhibitors, insulin). Biological medications that effectively decrease hyperglycemia and, at the same time, maintain bone health would be an ideal drug/drug combination for the treatment of DM-OS.

Type 2 Diabetes and Osteoporosis: A Guide to Optimal Management

CONTEXT

Both type 2 diabetes (T2D) and osteoporosis are affected by aging and quite often coexist. Furthermore, the fracture risk in patients with T2D is increased. The aim of this article is to review updated information on osteoporosis and fracture risk in patients with T2D, to discuss the effects of diabetes treatment on bone metabolism, as well as the effect of antiosteoporotic medications on the incidence and control of T2D, and to provide a personalized guide to the optimal management.

EVIDENCE ACQUISITION

A systematic literature search for human studies was conducted in three electronic databases (PubMed, Cochrane, and EMBASE) until March 2017. Regarding recommendations, we adopted the grading system introduced by the American College of Physicians.

EVIDENCE SYNTHESIS

The results are presented in systematic tables. Healthy diet and physical exercise are very important for the prevention and treatment of both entities. Metformin, sulfonylureas, dipeptidyl peptidase-4 inhibitors, and glucagon-like peptide-1 receptor agonists should be preferred for the treatment of T2D in these patients, whereas strict targets should be avoided for the fear of hypoglycemia, falls, and fractures. Insulin should be used with caution and with careful measures to avoid hypoglycemia. Thiazolidinediones and canagliflozin should be avoided, whereas other sodium-dependent glucose transporter 2 inhibitors are less well-validated options. Insulin therapy is the preferred method for achieving glycemic control in hospitalized patients with T2D and fractures. The treatment and monitoring of osteoporosis should be continued without important amendments because of the presence of T2D.

CONCLUSIONS

Patients with coexisting T2D and osteoporosis should be managed in an optimal way according to scientific evidence.

Effects of raloxifene and alendronate on non-enzymatic collagen cross-links and bone strength in ovariectomized rabbits in sequential treatments after daily human parathyroid hormone (1-34) administration

This study investigated the effects of raloxifene and alendronate to follow parathyroid hormone (PTH) on bone collagen and biomechanical properties in ovariectomized rabbits. Sequential treatments of raloxifene and alendronate after hPTH(1-34) treatment improved biomechanical properties with and without bone collagen improvement, respectively.

INTRODUCTION

The standard sequential treatment to follow human parathyroid hormone (hPTH) (1-34) therapy for osteoporosis has yet to be determined. The objective of this study was to compare the effects of raloxifene and alendronate treatments to follow daily hPTH(1-34) treatment on non-enzymatic collagen cross-links, bone mass, and bone strength in ovariectomized (OVX) rabbits.

METHODS

From 3 months after ovariectomy, seven month-old female New Zealand white rabbits were given either vehicle or hPTH(1-34) (8 μg/kg/day), once daily for 5 months. After hPTH(1-34) treatment, the hPTH(1-34)-treated animals were divided into two groups, and given raloxifene (10 mg/kg, daily) orally or alendronate (100 μg/kg, twice weekly) subcutaneously for 5 months. We evaluated bone mineral density (BMD), bone structural parameters, advanced glycation end product (AGE) content in collagen, and bone mechanical parameters including intrinsic parameters in the femur.

RESULTS

Raloxifene (hPTH/RLX) and alendronate (hPTH/ALN) to follow hPTH(1-34) increased cortical thickness, maximum load, and maximum stress and decreased endocortical surface in the diaphysis, in addition to increasing total BMD in the distal metaphysis. Decreased trabecular AGE, pentosidine, and homocysteine contents and increased toughness and breaking energy were noted with hPTH/RLX treatment only. With hPTH/ALN treatment, no effects on non-enzymatic collagen cross-link AGEs were noted although increases in stiffness and elastic modulus were observed.

CONCLUSION

These results suggest that sequential treatments with hPTH(1-34) and antiresorptive drugs (raloxifene and alendronate) have a beneficial effect on bone mass and biomechanical properties in OVX rabbits.

Efficacy of Osteoporosis Therapies in Diabetic Patients

Diabetes is characterized by increased fracture risk and by reduced bone strength for a given density. Contributing factors may include lower bone turnover and accumulation of advanced glycation endproducts. There are concerns that the pharmacological therapies for osteoporosis, particularly anti-resorptive therapies that suppress bone turnover, may not be as effective in the setting of diabetes. This review considers clinical trials and observational studies that have assessed the efficacy of anti-resorptive and anabolic therapies in diabetic patients. Post hoc analyses of randomized trials indicate that raloxifene has similar efficacy for prevention of vertebral fractures in diabetic compared with non-diabetic patients. Evidence from randomized clinical trials is lacking for anti-fracture efficacy of other osteoporosis therapies in diabetes. However, observational studies suggest that bisphosphonates are effective in preventing fractures in diabetic patients. The great majority of diabetic patients in studies to date have been type 2, and efficacy of osteoporosis therapies in type 1 diabetic patients remains to be addressed. Further evaluation of the efficacy of osteoporosis therapies in the setting of diabetes is needed to provide optimal fracture prevention for this population.

Fracture risk and healthcare resource utilization and costs among osteoporosis patients with type 2 diabetes mellitus and without diabetes mellitus in Japan: retrospective analysis of a hospital claims database

Background

Osteoporosis, osteoporosis-related fractures, and diabetes are considerable health burdens in Japan. Diabetes in patients with osteoporosis has been reported to be associated with increased fracture risk. This retrospective analysis of a Japanese hospital claims database investigated the real-world effect of type 2 diabetes mellitus (T2DM) on the incidence of clinical fractures, costs, and healthcare resource utilization in patients with osteoporosis and a subgroup of patients prescribed raloxifene.

Methods

Women aged ≥50 years diagnosed with osteoporosis who had a first prescription claim for osteoporosis treatment with a pre-index period ≥12 months and a post-index period of 30 months were selected from a database extract (April 2008-July 2013). Patients prescribed raloxifene were classed as a subgroup. Patients diagnosed with T2DM constituted the T2DM group; all other patients (excluding patients with type 1 diabetes mellitus) constituted the non-diabetes mellitus (non-DM) group. Groups were matched by exact matching, using selected baseline characteristics. Patient demographic and clinical characteristics were compared using chi-squared tests, t-tests, or Wilcoxon rank sum tests. Time to first fracture was examined using Kaplan-Meier survival analysis.

Results

Overall, the T2DM and non-DM groups had 7580 and 7979 patients, respectively; following matching, there were 3273 patients per group. In the raloxifene subgroup, the T2DM and non-DM groups had 668 and 699 patients, respectively; following matching, there were 239 patients per group. At baseline, the T2DM group (overall and raloxifene subgroup) had significantly higher healthcare resource utilization and comorbidities. During the post-index period, a similar pattern was observed in the overall group, even after matching; the T2DM group also had a higher incidence of fracture. In the raloxifene subgroup, after matching, there were no significant differences in fracture incidence or costs and fewer differences in healthcare resource utilization between the T2DM and non-DM groups.

Conclusions

These findings suggest that comorbid T2DM increases fracture incidence in patients with osteoporosis, compared with patients without DM. Increases in fracture incidence were accompanied by greater costs and healthcare resource utilization, which are important considerations for clinical practice in Japan. Further research investigating the use of raloxifene for treatment of osteoporosis with comorbid T2DM may also be warranted.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-016-1344-9) contains supplementary material, which is available to authorized users.

Biochemical bone turnover markers in diabetes mellitus - A systematic review

BACKGROUND

Diabetes mellitus is associated with an increased risk of fractures, which is not explained by bone mineral density. Other markers as bone turnover markers (BTMs) may be useful.

AIM

To assess the relationship between BTMs, diabetes, and fractures.

METHODS

A systematic literature search was conducted in August 2014. The databases searched were Medline at Pubmed and Embase. Medline at Pubmed was searched by "Diabetes Mellitus" (MESH) and "bone turnover markers" and Embase was searched using the Emtree by "Diabetes Mellitus" and "bone turnover", resulting in 611 studies. The eligibility criteria for the studies were to assess BTM in either type 1 diabetes (T1D) or type 2 diabetes (T2D) patients.

RESULTS

Of the 611 eligible studies, removal of duplicates and screening by title and abstract lead to 114 potential studies for full-text review. All these studies were full-text screened for eligibility and 45 studies were included. Two additional studies were added from other sources. Among the 47 studies included there were 1 meta-analysis, 29 cross-sectional studies, 13 randomized controlled trials, and 4 longitudinal studies. Both T1D and T2D were studied. Most studies reported fasting BTM and excluded renal disease.

CONCLUSION

Markers of bone resorption and formation seem to be lower in diabetes patients. Bone specific alkaline phosphatase is normal or increased, which suggests that the matrix becomes hypermineralized in diabetes patients. The BTMs: C-terminal cross-link of collagen, insulin-like growth factor-1, and sclerostin may potentially predict fractures, but longitudinal trials are needed. This article is part of a Special Issue entitled Bone and diabetes.

The Effects of Bazedoxifene on Bone, Glucose, and Lipid Metabolism in Postmenopausal Women With Type 2 Diabetes: An Exploratory Pilot Study

Background

Selective estrogen receptor modulators (SERMs) decrease homocysteine and cross-linking of pentosidine and reduce low-density lipoprotein cholesterol (LDL-C), and they are expected to improve bone quality and atherosclerosis. Therefore, the potential effects of bazedoxifene on bone (bone resorption, bone formation, and bone quality), as well as on glucose and lipid metabolism markers, were examined in Japanese postmenopausal women with type 2 diabetes mellitus (T2DM).

Methods

Eligible patients received 20 mg of bazedoxifene tablets once daily and were followed up for 12 weeks. Bone resorption markers including tartrate-resistant acid phosphatase 5b (TRACP-5b), bone formation markers and bone quality markers such as homocysteine and serum pentosidine, total cholesterol (TC), LDL-C, high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), and HbA1c were all measured.

Results

Twenty patients completed this study. All bone resorption markers decreased significantly 4 weeks after bazedoxifene treatment. In particular, TRACP-5b decreased significantly at 12 weeks (median percent change: -20.6%), and the minimum significant change (MSC) achievement rate of TRACP-5b was 65%. Bazedoxifene also decreased bone formation markers. However, bazedoxifene did not improve bone quality markers. LDL-C, HDL-C, and non-HDL-C were decreased, but TG was unchanged. Glucose metabolism was not changed after bazedoxifene treatment. In a subgroup analysis, the group of patients in whom the percent change in TRACP-5b exceeded the MSC had no change in pentosidine levels at 12 weeks. However, in the group of patients in whom the percent change in TRACP-5b did not exceed the MSC, pentosidine levels tended to increase.

Conclusions

Bazedoxifene may improve bone resorption markers and LDL-C without affecting glucose metabolism in Japanese postmenopausal women with T2DM.

Raloxifene prevents skeletal fragility in adult female Zucker Diabetic Sprague-Dawley rats

Fracture risk in type 2 diabetes is increased despite normal or high bone mineral density, implicating poor bone quality as a risk factor. Raloxifene improves bone material and mechanical properties independent of bone mineral density. This study aimed to determine if raloxifene prevents the negative effects of diabetes on skeletal fragility in diabetes-prone rats. Adult Zucker Diabetic Sprague-Dawley (ZDSD) female rats (20-week-old, n = 24) were fed a diabetogenic high-fat diet and were randomized to receive daily subcutaneous injections of raloxifene or vehicle for 12 weeks. Blood glucose was measured weekly and glycated hemoglobin was measured at baseline and 12 weeks. At sacrifice, femora and lumbar vertebrae were harvested for imaging and mechanical testing. Raloxifene-treated rats had a lower incidence of type 2 diabetes compared with vehicle-treated rats. In addition, raloxifene-treated rats had blood glucose levels significantly lower than both diabetic vehicle-treated rats as well as vehicle-treated rats that did not become diabetic. Femoral toughness was greater in raloxifene-treated rats compared with both diabetic and non-diabetic vehicle-treated ZDSD rats, due to greater energy absorption in the post-yield region of the stress-strain curve. Similar differences between groups were observed for the structural (extrinsic) mechanical properties of energy-to-failure, post-yield energy-to-failure, and post-yield displacement. These results show that raloxifene is beneficial in preventing the onset of diabetes and improving bone material properties in the diabetes-prone ZDSD rat. This presents unique therapeutic potential for raloxifene in preserving bone quality in diabetes as well as in diabetes prevention, if these results can be supported by future experimental and clinical studies.

Raloxifene modifies the insulin sensitivity and lipid profile of postmenopausal insulin resistant women

OBJECTIVE

To investigate the effects of raloxifene on the insulin sensitivity and lipid profile in insulin-sensitive and insulin-resistant postmenopausal women.

STUDY DESIGN

This placebo-controlled, double-blind, randomized study involved 64 postmenopausal women aged between 45 and 55 years. All subjects were screened with the insulin resistance homeostasis model assessment (IR-HOMA) and those patients in the lowest quartile (n = 16) were assigned as insulin sensitive and those in the highest quartile as insulin resistant (n = 16). Patients in both groups received either raloxifene hydrochloride (60 mg/day) or a placebo for a period of 12 weeks. Insulin sensitivity, the serum lipid profile and anthropometric measurements were established before and after therapy.

RESULTS

Women with the highest IR-HOMA scores were associated with a significantly higher weight, body mass index, waist and waist-to-hip ratio (p < 0.05). Raloxifene significantly reduced the IR-HOMA scores from 5.76 ± 2.91 to 1.93 ± 0.96 (p = 0.02) and modified the lipid profile in insulin-resistant patients when compared with the placebo group and those patients receiving raloxifene in the insulin-sensitive group.

CONCLUSION

Raloxifene reduced insulin resistance and modified the lipid profile in insulin-resistant postmenopausal women.