Use of thiazolidinediones and risk of osteoporotic fracture: disease or drugs?

Glucose-Lowering Drugs and Fracture Risk-a Systematic Review

PURPOSE OF REVIEW

Diabetes mellitus (DM) is associated with increased fracture risk. The aim of this systematic review was to examine the effects of different classes of glucose-lowering drugs on fracture risk in patients with type 2 DM. The heterogeneity of the included studies did not allow formal statistical analyses.

RECENT FINDINGS

Sixty studies were included in the review. Metformin, dipeptidylpeptidase-IV inhibitors, glucagon-like peptide-1 receptor agonists, and sodium-glucose cotransporter 2-inhibitors do not appear to increase fracture risk. Results for insulin and sulphonylureas were more disparate, although there may be an increased fracture risk related to hypoglycemia and falls with these treatments. Glitazones were consistently associated with increased fracture risk in women, although the evidence was sparser in men. New glucose-lowering drugs are continuously being developed and better understanding of these is leading to changes in prescription patterns. Our findings warrant continued research on the effects of glucose-lowering drugs on fracture risk, elucidating the class-specific effects of these drugs.

Drugs Causing Bone Loss

Drugs may cause bone loss by lowering sex steroid levels (e.g., aromatase inhibitors in breast cancer, GnRH agonists in prostate cancer, or depot medroxyprogestone acetate - DMPA), interfere with vitamin D levels (liver inducing anti-epileptic drugs), or directly by toxic effects on bone cells (chemotherapy, phenytoin, or thiazolidinedions, which diverts mesenchymal stem cells from forming osteoblasts to forming adipocytes). However, besides effects on the mineralized matrix, interactions with collagen and other parts of the unmineralized matrix may decrease bone biomechanical competence in a manner that may not correlate with bone mineral density (BMD) measured by dual energy absorptiometry (DXA).Some drugs and drug classes may decrease BMD like the thiazolidinediones and consequently increase fracture risk. Other drugs such as glucocorticoids may decrease BMD, and thus increase fracture risk. However, glucocorticoids may also interfere with the unmineralized matrix leading to an increase in fracture risk, not mirrored in BMD changes. Some drugs such as selective serotonin reuptake inhibitors (SSRI), paracetamol, and non-steroidal anti-inflammatory drugs (NSAIDs) may not per se be associated with bone loss, but fracture risk may be increased, possibly stemming from an increased risk of falls stemming from effects on postural balance mediated by effects on the central nervous system or cardiovascular system.This paper performs a systematic review of drugs inducing bone loss or associated with fracture risk. The chapter is organized by the Anatomical Therapeutic Chemical (ATC) classification.

Sodium-glucose co-transporter 2 inhibitors and the risk of fractures: A propensity score-matched cohort study

PURPOSE

To determine the risk of fractures associated with sodium-glucose co-transporter 2 inhibitors (SGLT2i) compared with dipeptidyl peptidase-4 inhibitors (DPP4i).

METHODS

We conducted a retrospective cohort study using data from the Truven Health MarketScan (2009-2015) databases. Our cohort included patients newly initiating treatment with SGLT2i or DPP-4i between 1 April 2013 and 31 March 2015 that were matched 1:1 using high dimensional propensity scores. Patients were followed up in an as-treated approach starting from initiation of treatment until the earliest of any fracture, treatment discontinuation, disenrollment, or end of data (31 December 2015). Risk of fractures was determined at any time during the follow-up, early in therapy (1-14 days of the follow-up), and later in therapy (15 days and beyond). Cox proportional hazards models were used to determine hazard ratios and robust 95% confidence intervals (95% CI).

RESULTS

After matching, our cohort included 30 549 patients in each treatment group. Over a median follow-up of 219 days, there were 745 fractures overall. The most common site for fractures was the foot (32.7%). The effect estimates for fracture risk occurring at any time during follow-up, early in therapy, and later in therapy were HR 1.11 [95% CI 0.96-1.28], HR 1.82 [95% CI 0.99-3.32], and HR 1.07 [95% CI 0.92-1.24], respectively.

CONCLUSION

There is a possible increase in risk for fractures early in therapy with SGLT2i. Beyond this initial period, SGLT2is had no apparent effect on the incidence of fractures.

Fucoidan from Undaria pinnatifida has anti-diabetic effects by stimulation of glucose uptake and reduction of basal lipolysis in 3T3-L1 adipocytes

Fucoidan, a sulfated polysaccharide derived from brown seaweeds, has been shown to reduce blood glucose levels and improve insulin sensitivity in mice. We investigated the effects of fucoidan on lipid accumulation, lipolysis, and glucose uptake in 3T3-L1 cells to test the hypothesis that fucoidan exerts an anti-diabetic function by acting directly on adipocytes. The 3T3-L1 cells were treated with 10, 50, 100, and 200 μg/mL of fucoidan from Undaria pinnatifida. Oil Red O staining and AdipoRed assay were used to determine lipid accumulation during adipocyte differentiation. Fucoidan was shown to reduce lipid accumulation and glycerol-3-phosphate dehydrogenase (GPDH) activity in a dose-dependent manner (P < .01). The expression of peroxisome proliferator-activated receptor γ (PPARγ), a major transcription factor associated with adipocyte differentiation, was also suppressed upon treatment with fucoidan. Treatment with fucoidan stimulated glucose uptake in normal adipocytes and restored insulin-stimulated glucose uptake in obesity-induced insulin resistant adipocytes, which were made by incubating hypertrophied 3T3-L1 cells with the conditioned media of RAW 264.7 macrophages (RAW-CM) (P < .01). In the presence of RAW-CM, fucoidan enhanced epinephrine-stimulated lipolysis but reduced basal lipolysis, as determined by non-esterified fatty acid into the culture medium (P < .001). These results suggest that fucoidan may have anti-diabetic effects by improving insulin-stimulated glucose uptake and inhibiting basal lipolysis in adipocytes without inducing adipogenesis.

DPP-4 inhibitor impedes lipopolysaccharide-induced osteoclast formation and bone resorption in vivo

OBJECTIVES

Dipeptidyl peptidase 4 (DPP-4) inhibition is a new therapeutic strategy for type 2 diabetic patients. DPP-4 has been reported to enhance inflammation. However, the effect of DPP-4 inhibition on inflammation remains unknown. Lipopolysaccharide (LPS) is a strong inducer of inflammation and osteoclast formation. In this study, we investigated in vivo effects of DPP-4 inhibition on LPS-induced osteoclast formation and bone resorption, as well as in vitro effects of DPP-4 inhibition on RANKL-induced osteoclastogenesis and TNF-α-induced osteoclastogenesis.

METHODS

LPS with or without a DPP-4 inhibitor was subcutaneously injected into mouse calvaria for 5 days. Histological sections of calvaria were stained for tartrate-resistant acid phosphatase, and osteoclast numbers were determined. The ratio of calvaria bone resorption was evaluated via microfocal computed tomography reconstruction images.

RESULTS

Osteoclast number and bone resorption were significantly lower in mice that underwent LPS and DPP-4 inhibitor co-administration than in those that underwent LPS administration alone. Moreover, RANKL, TNF-α, and M-CSF expression was reduced in the LPS and DPP-4 inhibitor co-administration group. In vitro, there were no direct effects of DPP-4 inhibitor or DPP-4 on RANKL- and TNF-α-induced osteoclastogenesis, or on LPS-induced RANKL expression in stromal cells. Nevertheless, macrophages from LPS and DPP-4 inhibitor co-administered mice exhibited lower TNF-α expression than macrophages from LPS-only mice. Notably, TNF-α expression was not reduced in LPS and DPP-4 inhibitor co-treated macrophages in vitro, compared with macrophages treated with LPS alone.

The Glucagon-Like Peptide-1 Receptor Agonist Exendin-4 Inhibits Lipopolysaccharide-Induced Osteoclast Formation and Bone Resorption via Inhibition of TNF-α Expression in Macrophages

Glucagon-like peptide-1 (GLP-1) receptor agonists are an effective treatment approach for type 2 diabetes. Recently, anti-inflammatory effects of GLP-1 receptor agonists have also been reported. Lipopolysaccharide (LPS) induces inflammation and osteoclast formation. In this study, we investigated the effect of exendin-4, a widely used GLP-1 receptor agonist, in LPS-induced osteoclast formation and bone resorption. LPS with or without exendin-4 was administered on mouse calvariae by daily subcutaneous injection. The number of osteoclasts, the ratio of bone resorption pits, and the level of C-terminal cross-linked telopeptide of type I collagen (CTX) were significantly lower in LPS- and exendin-4-coadministered mice than in mice administered with LPS alone. RANKL and TNF-α mRNA expression levels were lower in the exendin-4- and LPS-coadministered group than in the LPS-administered group. Our in vitro results showed no direct effects of exendin-4 on RANKL-induced osteoclast formation, TNF-α-induced osteoclast formation, or LPS-induced RANKL expression in stromal cells. Conversely, TNF-α mRNA expression was inhibited in the exendin-4- and LPS-cotreated macrophages compared with cells treated with LPS alone. These results indicate that the GLP-1 receptor agonist exendin-4 may inhibit LPS-induced osteoclast formation and bone resorption by inhibiting LPS-induced TNF-α production in macrophages.

Fracture risk in patients with type 2 diabetes mellitus and possible risk factors: a systematic review and meta-analysis

Aim

Patients with type 2 diabetes mellitus (T2DM) have an increased risk of bone fractures. A variable increase in fracture risk has been reported depending on skeletal site, diabetes duration, study design, insulin use, and so on. The present meta-analysis aimed to investigate the association between T2DM with fracture risk and possible risk factors.

Methods

Different databases including PubMed, Institute for Scientific Information, and Scopus were searched up to May 2016. All epidemiologic studies on the association between T2DM and fracture risk were included. The relevant data obtained from these papers were analyzed by a random effects model and publication bias was assessed by funnel plot. All analyses were done by R software (version 3.2.1) and STATA (version 11.1).

Results

Thirty eligible studies were selected for the meta-analysis. We found a statistically significant positive association between T2DM and hip, vertebral, or foot fractures and no association between T2DM and wrist, proximal humerus, or ankle fractures. Overall, T2DM was associated with an increased risk of any fracture (summary relative risk =1.05, 95% confidence interval: 1.04, 1.06) and increased with age, duration of diabetes, and insulin therapy.

Conclusion

Our findings strongly support an association between T2DM and increased risk of overall fracture. These findings emphasize the need for fracture prevention strategies in patients with diabetes.

Pear pomace ethanol extract improves insulin resistance through enhancement of insulin signaling pathway without lipid accumulation

BACKGROUND/OBJECTIVES

The anti-diabetic activity of pear through inhibition of α-glucosidase has been demonstrated. However, little has been reported about the effect of pear on insulin signaling pathway in obesity. The aims of this study are to establish pear pomace 50% ethanol extract (PPE)-induced improvement of insulin sensitivity and characterize its action mechanism in 3T3-L1 cells and high-fat diet (HFD)-fed C57BL/6 mice.

MATERIALS/METHODS

Lipid accumulation, monocyte chemoattractant protein-1 (MCP-1) secretion and glucose uptake were measure in 3T3-L1 cells. Mice were fed HFD (60% kcal from fat) and orally ingested PPE once daily for 8 weeks and body weight, homeostasis model assessment of insulin resistance (HOMA-IR), and serum lipids were measured. The expression of proteins involved in insulin signaling pathway was evaluated by western blot assay in 3T3-L1 cells and adipose tissue of mice.

RESULTS

In 3T3-L1 cells, without affecting cell viability and lipid accumulation, PPE inhibited MCP-1 secretion, improved glucose uptake, and increased protein expression of phosphorylated insulin receptor substrate 1 [p-IRS-1, (Tyr⁶³²)], p-Akt, and glucose transporter type 4 (GLUT4). Additionally, in HFD-fed mice, PPE reduced body weight, HOMA-IR, and serum lipids including triglyceride and LDL-cholesterol. Furthermore, in adipose tissue, PPE up-regulated GLUT4 expression and expression ratio of p-IRS-1 (Tyr⁶³²)/IRS, whereas, down-regulated p-IRS-1 (Ser³⁰⁷)/IRS.

CONCLUSIONS

Our results collectively show that PPE improves glucose uptake in 3T3-L1 cells and insulin sensitivity in mice fed a HFD through stimulation of the insulin signaling pathway. Furthermore, PPE-induced improvement of insulin sensitivity was not accompanied with lipid accumulation.

Long-term use of dipeptidyl peptidase-4 inhibitors and risk of fracture: A retrospective population-based cohort study

AIMS

To investigate the association between long-term dipeptidyl peptidase-4 (DPP-4) inhibitor use and risk of fracture among people with type 2 diabetes mellitus (T2DM).

METHODS

A retrospective population-based cohort study, using data from the Clinical Practice Research Datalink database (2007-2015), was conducted. All those (N = 328 254) with at least one prescription for a non-insulin antidiabetic drug (NIAD), aged ≥18 years at the time of data collection, were included. Cox proportional hazards models were used to estimate the hazard ratios of any fracture, osteoporotic fracture and hip fracture in DPP-4 inhibitor users compared with those using other NIADs. Analyses were stratified by continuous duration of DPP-4 inhibitor use. Time-dependent adjustments were made for age, sex, lifestyle, comorbidity and concomitant drug use.

RESULTS

Current use of DPP-4 inhibitors was not associated with risk of any fracture (adjusted hazard ratio [HR] 0.99 [95% confidence interval {CI} 0.93-1.06]) as compared with current other NIAD use. Current use of DPP-4 inhibitors was also not associated with risk of osteoporotic or hip fracture. After stratification by continuous duration of DPP-4 inhibitor use the highest category was not associated with any (>4.0-8.5 years of use, adjusted HR 0.99 [95% CI 0.70-1.41]), osteoporotic (>3.0-8.5 years of use, adjusted HR 0.75 [95% CI 0.52-1.09]) or hip (>2.0-8.5 years of use; adjusted HR 1.24 [95% CI 0.85-1.79]) fracture.

CONCLUSION

Continuous long-term DPP-4 inhibitor use (defined as >4.0-8.5 years of DPP-4 inhibitor use for any fracture, >3.0-8.5 years for osteoporotic fracture and >2.0-8.5 years for hip fracture was not associated with risk of any, osteoporotic or hip fracture. These findings may be of value for clinical decisions regarding treatment of patients with T2DM, especially those at high risk of fracture.

Severity of Diabetes Mellitus and Total Hip or Knee Replacement: A Population-Based Case-Control Study

It is generally thought that people with diabetes mellitus (DM) are more likely to suffer from osteoarthritis (OA) due to an increased body mass index (BMI), resulting in mechanical destruction of cartilage. However, previous studies have suggested a coexisting metabolic causality.To evaluate the risk of hip or knee replacement, as a proxy for severe OA, in patients with DM. We additionally evaluated the risk of total joint replacement (TJR) with various proxies for increased DM severity.A population-based case-control study was performed, using the Clinical Practice Research Datalink (CPRD). Cases (n = 94,609) were defined as patients >18 years who had undergone TJR between 2000 and 2012. Controls were matched by age, gender, and general practice. Conditional logistic regression was used to estimate the risk of total knee (TKR) and total hip replacement (THR) surgery associated with use of antidiabetic drugs (ADs). We additionally stratified current AD users by proxies for DM severity.Current AD use was significantly associated with a lower risk of TKR (OR = 0.86 (95% CI = 0.78-0.94)) and THR (OR = 0.90 (95% CI = 0.82-0.99)) compared to patients not using ADs. Moreover, risk of TKR and THR was decreased with increasing HbA1c.This study does not support the theory that DM patients are more likely to suffer from severe OA as compared to patients without diabetes. Moreover, risk of severe OA necessitating TJR decreases with increasing DM severity. This is possibly due to dissimilarities in methodology, a decrease in eligibility for surgery, or variability of OA phenotypes.

Use of thiazolidinediones and the risk of elective hip or knee replacement: a population based case-control study

AIMS

Osteoarthritis (OA) is the most common musculoskeletal condition in the elderly population. However, no disease modifying drug exists for this disease. In vivo animal studies have suggested that thiazolidinediones (TZD) may be used as disease modifying osteoarthritis drugs (DMOADs). To our knowledge, this has not yet been examined in humans before. The aim was to determine the risk of total joint replacement (TJR) in patients using TZDs compared with diabetic patients using other antidiabetic drugs.

METHODS

A population based case-control study was performed using the Clinical Practice Research Datalink (CPRD). Cases (n = 94 609) were defined as patients >18 years of age who had undergone total knee (TKR) or hip replacement (THR) between 2000 and 2012. Controls were matched by age, gender and practice/surgery. Conditional logistic regression analyses were used to estimate the risk of TKR and THR with the use of TZDs in patients currently using one or more antidiabetic drugs. In order to determine effect with prolonged use, we also stratified TZD users by total number of prescriptions prior to surgery. We statistically adjusted our analyses for lifestyle factory, comorbidities and concomitant drug use.

RESULTS

There was no difference in risk of TKR (OR 1.09, 95% CI 0.93, 1.27) and THR (OR 0.92, 95% CI 0.76, 1.10) when TZD users were compared with other AD users. Furthermore, we did not find an association with prolonged use of TZDs and TJR.

CONCLUSION

Despite promising results from animal in vivo studies, this study did not find any evidence for a disease modifying osteoarthritic effect of TZDs.

Use of Glucagon-Like-Peptide 1 Receptor Agonists and Risk of Fracture as Compared to Use of Other Anti-hyperglycemic Drugs

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are a new class of drugs that might have a potential beneficial effect on bone metabolism. Data on the effect of GLP-1 RAs and fracture risk are lacking. The aim of the present study was to investigate the association between the use of GLP-1 and the risk of fracture. A case-control study was performed using Danish National Health Service data. Cases were those who sustained a fracture and controls were those without a fracture during the study period (2007-2011), all aged 18 years and above. Conditional logistic regression estimated the odds ratios (OR) of fracture with current use of DPP4-I use. Analyses were adjusted for comorbidities and recent drug use. Among cases (n = 229,114), there were 6993 current non-insulin anti-diabetic drug (NIAD) users (excluding incretin users) and 255 GLP-1 RA users. Similarly, among controls (n = 229,114), 7209 were NIAD users (excluding incretin users) and 220 were GLP-1 RA users. Current GLP-1 RA use was not associated with a decreased risk of fracture [adjusted (adj.) OR 1.16; 95% CI 0.83-1.63]. Osteoporotic fracture risk was also not associated with current GLP-1 RA use (adj. OR 0.78; 95% CI 0.44-1.39). In our nation-wide case-control study, we identified that the use of GLP-1 RA was not associated with fracture risk as compared to the use of other anti-hyperglycemic drugs. Additionally, current GLP-1 RA use, stratified by cumulative or average daily dose, is not associated with fracture risk. Further research should focus on long-term use of GLP-1 RA and fracture risk.

Bone fracture risk is not associated with the use of glucagon-like peptide-1 receptor agonists: a population-based cohort analysis

Glucagon-like Peptide-1 receptor agonists (GLP1-ra) are a relatively new class of anti-hyperglycemic drugs which may positively affect bone metabolism and thereby decrease (osteoporotic) bone fracture risk. Data on the effect of GLP1-ra on fracture risk are scarce and limited to clinical trial data only. The aim of this study was to investigate, in a population-based cohort, the association between the use of GLP1-ra and bone fracture risk. We conducted a population-based cohort study, with the use of data from the Clinical Practice Research Datalink (CPRD) database (2007-2012). The study population (N = 216,816) consisted of all individuals with type 2 diabetes patients with at least one prescription for a non-insulin anti-diabetic drug and were over 18 years of age. Cox proportional hazards models were used to estimate the hazard ratio of fracture in GLP1-ra users versus never-GLP1-ra users. Time-dependent adjustments were made for age, sex, lifestyle, comorbidity and the use of other drugs. There was no decreased risk of fracture with current use of GLP1-ra compared to never-GLP1-ra use (adjusted HR 0.99, 95 % CI 0.82-1.19). Osteoporotic fracture risk was also not decreased by current GLP1-ra use (adjusted HR 0.97; 95 % CI 0.72-1.32). In addition, stratification according to cumulative dose did not show a decreased bone fracture risk with increasing cumulative GLP1-ra dose. We showed in a population-based cohort study that GLP1-ra use is not associated with a decreased bone fracture risk compared to users of other anti-hyperglycemic drugs. Future research is needed to elucidate the potential working mechanisms of GLP1-ra on bone.

Use of dipeptidyl peptidase 4 inhibitors and fracture risk compared to use of other anti-hyperglycemic drugs

INTRODUCTION

Dipeptidyl peptidase-4 inhibitors (DPP4-Is) are a new class of anti-hyperglycemic drugs which might have a potential beneficial effect on bone metabolism. Data on the effect of DPP4-I use and fracture risk is limited and conflicting. The aim of the present study was to investigate the association between use of DPP4-Is and fracture risk.

METHODS

A case-control study was conducted using data from the Danish National Health Service. Cases were those who sustained a fracture, and controls were those without a fracture during the study period (2007-2011), all aged 18 years and older. Conditional logistic regression estimated the odds ratios of fracture with current use of DPP4-I use. Analyses were adjusted for comorbidities and recent drug use.

RESULTS

Among the cases there were 6993 current non-insulin anti-diabetic drug (NIAD) users (excluding incretin users) and 643 DPP4-I users. There were 7209 NIAD users (excluding incretin users) among the controls and 707 DPP4-I users. Current DPP4-I use was not associated with risk of any fracture (adjusted [adj.] OR: 0.97, 95% CI: 0.79-1.18) or major osteoporotic fracture (adj. OR: 0.96, 95% CI: 0.72-1.28). Stratification of current DPP4-I use to cumulative and average daily dose did not show an association.

CONCLUSIONS

In a population-based case-control study we identified that short-term use of DPP4-I was not associated with fracture risk as compared to users of other anti-hyperglycemic drugs. Additionally, results suggest that increasing daily dose and cumulative DPP4-I exposure were not associated with fracture risk. However, more research is needed to assess the effect of long-term DPP4-I use on the risk of fracture.

(2S)-7,4'-dihydroxy-8-prenylflavan stimulates adipogenesis and glucose uptake through p38MAPK pathway in 3T3-L1 cells

Adipose tissue plays a key role in the development of obesity and diabetes. Natural products are one of the main sources for discovering new lead compounds. In the present study, (2S)-7,4'-dihydroxy-8-prenylflavan (DHPF), a natural prenylated flavan isolated from Morus yunnanensis, was found to significantly promote adipogenesis and increase glucose uptake in 3T3-L1 cells. Real-time PCR results showed that DHPF increased the expression of glucose and lipid metabolism-related genes (C/EBPα, PPARγ, aP2, GLUT4 and adiponectin) and decreased the expression of inflammatory cytokine TNF-α. Western blotting further revealed that DHPF activated p38 MAPK at the initial stage of 3T3-L1 preadipocyte differentiation. DHPF-induced activation of p38, adipogenesis and glucose uptake were effectively blocked by SB203580, a specific p38 inhibitor. These results indicate that DHPF could stimulate adipogenesis and increase glucose uptake through the p38 MAPK pathway, and DHPF may be useful for the prevention and treatment of obesity-associated disorders such as type 2 diabetes (T2D).

The risk of colorectal cancer in patients with type 2 diabetes: associations with treatment stage and obesity

OBJECTIVE

To assess the risk of colorectal cancer associated with type 2 diabetes, as compared with a nondiabetic reference population, and to study additional associations between treatment stage and duration of obesity and colorectal cancer risk.

RESEARCH DESIGN AND METHODS

We conducted an observational population-based cohort study within the Clinical Practice Research Datalink (1987-2012). All patients (≥18 years) with at least one prescription for an antidiabetic drug (n = 300,039) were matched (1:1) by birth year, sex, and practice to a comparison cohort without diabetes. Cox proportional hazards models were used to derive adjusted hazard ratios (HRs) for colorectal cancer associated with type 2 diabetes. Within the diabetic cohort, associations of colorectal cancer with treatment stages and duration of obesity (BMI ≥30 kg/m(2)) were studied.

RESULTS

After a median follow-up of 4.5 years, 2,759 cases of colorectal cancer were observed among the diabetic study population. Type 2 diabetes was associated with a 1.3-fold increased risk of colorectal cancer (HR 1.26 [95% CI 1.18-1.33]). Among diabetic patients, no association was found with treatment stages. A trend of increased colorectal cancer risk was observed with longer duration of obesity. Risk of colorectal cancer was significantly increased for patients with recorded duration of obesity of 4-8 years (HR 1.19 [1.06-1.34]) and >8 years (1.28 [1.11-1.49]).

CONCLUSIONS

Type 2 diabetes is associated with a moderately increased risk of colorectal cancer. Among diabetic patients, an increased risk was observed for patients who suffered from obesity for a total duration of 4 years or more.

Use of dipeptidyl peptidase-4 inhibitors for type 2 diabetes mellitus and risk of fracture

INTRODUCTION

Although patients with type 2 diabetes mellitus have an increased bone mineral density as compared to healthy patients, their risk of fracture is elevated. Incretins, new anti-diabetic drugs, may have a protective effect on bone mineral density. However, data on the effect of incretins on fracture risk are limited. Therefore the aim of this study was to investigate the association between the use of DPP4-I and the risk of fracture.

METHODS

A retrospective population based cohort study, using data from the Clinical Practice Research Datalink (CPRD) database (2007-2012), was conducted. Patients (N=216,816) with at least one prescription for a non-insulin anti-diabetic drug (NIAD), aged 18+ during data collection, were matched to one control patient. Cox proportional hazards models were used to estimate the hazard ratio of any fracture in DPP4 inhibitor (DPP4-I) users versus controls and versus other NIAD patients. Time-dependent adjustments were made for age, sex, life style, comorbidity and drug use.

RESULTS

The actual duration of DPP4-I use was 1.3years. There was no different risk of fracture comparing current DPP4-I users to controls (adjusted hazard ratio (adj. HR) 0.89, 95% confidence interval (CI) 0.71-1.13). There was also no increased risk comparing current DPP4-I users to other NIAD users, adj. HR 1.03 (95% CI 0.92-1.15).

CONCLUSIONS

DPP4-I use was not associated with fracture risk compared to controls and to other NIAD users. However, the duration of DPP4-I use in our database might have been too short to show an association with fracture risk.

Fracture risk in diabetic elderly men: the MrOS study

AIMS/HYPOTHESIS

Diabetes mellitus is associated with increased fracture risk in women but few studies are available in men. To evaluate the relationship between diabetes and prospective non-vertebral fractures in elderly men, we used data from the Osteoporotic Fractures in Men (MrOS) study.

METHODS

The MrOS enrolled 5,994 men (aged ≥65 years). Diabetes (ascertained by self-report, the use of medication for diabetes or an elevated fasting glucose level) was reported in 881 individuals, 80 of whom were using insulin. Hip and spine bone mineral density (BMD) was measured using dual x-ray absorptiometry (DXA). After recruitment, the men were followed for incident non-vertebral fractures using a triannual (3 yearly) questionnaire for an average of 9.1 (SD 2.7) years. The Cox proportional hazards model was used to assess the incident risk of fractures.

RESULTS

In models adjusted for age, race, clinic site and total hip BMD, the risk of non-vertebral fracture was higher in men with diabetes compared with normoglycaemic men (HR 1.30, 95% CI 1.09, 1.54) and was elevated in men using insulin (HR 2.46, 95% CI 1.69, 3.59). Men with impaired fasting glucose did not have a higher risk of fracture compared with normoglycaemic men (HR 1.04, 95% CI 0.89, 1.21). After multivariable adjustment, the risk of non-vertebral fracture remained higher only among men with diabetes who were using insulin (HR 1.74, 95% CI 1.13, 2.69).

CONCLUSIONS/INTERPRETATION

Men with diabetes who are using insulin have an increased risk of non-vertebral fracture for a given age and BMD.

Increased fracture risk in patients with type 2 diabetes mellitus: an overview of the underlying mechanisms and the usefulness of imaging modalities and fracture risk assessment tools

Type 2 diabetes mellitus has recently been linked to an increased fracture risk. Since bone mass seems to be normal to elevated in patient with type 2 diabetes, the increased fracture risk is thought to be due to both an increased falling frequency and decreased bone quality. The increased falling frequency is mainly a result of complications of the disease such as a retinopathy and polyneuropathy. Bone quality is affected through changes in bone shape, bone micro-architecture, and in material properties such as bone mineralization and the quality of collagen. Commonly used methods for predicting fracture risk such as dual energy X-ray absorptiometry and fracture risk assessment tools are helpful in patients with type 2 diabetes mellitus, but underestimate the absolute fracture risk for a given score. New imaging modalities such as high resolution peripheral quantitative computed tomography are promising for giving insight in the complex etiology underlying the fragility of the diabetic bone, as they can give more insight into the microarchitecture and geometry of the bone. We present an overview of the contributing mechanisms to the increased fracture risk and the usefulness of imaging modalities and risk assessment tools in predicting fracture risk in patients with type 2 diabetes.

Expression of glucagon-like peptide-1 receptor and glucose‑dependent insulinotropic polypeptide receptor is regulated by the glucose concentration in mouse osteoblastic MC3T3-E1 cells

Glucose-dependent insulinotropic polypeptide receptor (GIPR) and glucagon-like peptide-1 receptor (GLP‑1R) are incretin receptors that play important roles in regulating insulin secretion from pancreatic β cells. Incretin receptors are also thought to play a potential role in bone metabolism. Osteoblasts in animals and humans express GIPR; however, the presence of GLP-1R in these cells has not been reported to date. Thus, the aim of this study was to determine whether GLP-1R and GIPR are expressed in osteoblastic cells, and whether their expression levels are regulated by the extracellular glucose concentration. Mouse osteoblastic MC3T3-E1 cells were cultured in medium containing normal (5.6 mM) or high (10, 20 or 30 mM) glucose concentrations, with or without bone morphogenetic protein-2 (BMP-2). RT-PCR, western blot analysis and immunofluorescence were carried out to determine GIPR and GLP-1R mRNA and protein expression levels. Cell proliferation was also assessed. The GLP-1R and GIPR mRNA expression levels were higher in the MC3T3-E1 cells cultured in medium containing high glucose concentrations with BMP-2 compared with the cells cultured in medium containing normal glucose concentrations with or without BMP-2. GLP-1R protein expression increased following culture in high-glucose medium with BMP-2 compared with culture under normal glucose conditions. However, the cellular localization of GLP-1R was not affected by either glucose or BMP-2. In conclusion, our data demonstrate that the expression of GLP-1R and GIPR is regulated by glucose concentrations in MC3T3-E1 cells undergoing differentiation induced by BMP-2. Our results reveal the potential role of incretins in bone metabolism.

Risk of fracture in patients with Parkinson's disease

The aim of the study was to determine fracture risk in incident Parkinson's disease (PD) patients. This study showed that fracture risk assessment may be indicated among patients with PD, in particular when they have recently used selective serotonin re-uptake inhibitors or high-dose antipsychotics, or have a history of fracture, falling, low body mass index (BMI) or renal disease.

INTRODUCTION

PD is a movement disorder associated with falling and detrimental effects on bone. Both are recognized risk factors for fracture. Therefore, the aim was to determine fracture risk in incident PD patients stratified by treatment, severity, duration of disease and related comorbidities.

METHODS

We conducted a retrospective cohort study using the UK General Practice Research Database (1987-2011). Each PD patient was matched by age, sex, calendar time and practice to a control patient without history of PD.

RESULTS

We identified 4,687 incident PD patients. Compared to controls, a statistically significant increased risk was observed for any fracture (adjusted hazard ratio [AHR], 1.89; 95 % confidence interval [CI], 1.67-2.14), osteoporotic fracture (AHR, 1.99; 95 % CI, 1.72-2.30) and hip fracture (AHR 3.08; 95 % CI, 2.43-3.89). Fracture risk further increased with history of fracture, falling, low BMI, renal disease, antidepressant use and use of high-dose antipsychotics.

CONCLUSION

This study showed that incident PD patients have a statistically significant increased risk of fracture. Therefore, fracture risk assessment may be indicated among PD patients, who, besides the general risk factors for fracture, like increasing age and female gender, have recently used selective serotonin re-uptake inhibitors or high-dose antipsychotics or have a history of fracture, falling, low BMI or renal disease.

The future of thiazolidinedione therapy in the management of type 2 diabetes mellitus

Since their approval, thiazolidinediones (TZDs) have been used extensively as insulin-sensitizers for the management of type 2 diabetes mellitus (T2DM). Activation of peroxisomal proliferator-activated receptor gamma (PPARγ) nuclear receptors by TZDs leads to a vast spectrum of metabolic and antiinflammatory effects. In the past decade, clinicians and scientists across the fields of metabolism, diabetes, liver disease (NAFLD), atherosclerosis, inflammation, infertility, and even cancer have had high hopes about the potential for TZDs to treat many of these diseases. However, an increasing awareness about undesirable "off-target" effects of TZDs have made us rethink their role and be more cautious about the long-term benefits and risks related to their use. This review examines the most relevant work on the benefits and risks associated with TZD treatment, with a focus on the only PPARγ agonist currently available (pioglitazone), aiming to offer the reader a balanced overview about the current and future role of TZDs in the management of insulin-resistant states and T2DM.

Risk of fracture with thiazolidinediones: an individual patient data meta-analysis

BACKGROUND

The use of thiazolidinediones (TZDs) has been associated with increased fracture risks. Our aim was to estimate the risk of fracture with TZDs in three different healthcare registries, using exactly the same study design, and to perform an individual patient data meta-analysis of these three studies.

METHODS

Population-based cohort studies were performed utilizing the British General Practice Research Database (GPRD), the Dutch PHARMO Record Linkage System (RLS), and the Danish National Health Registers. In all three databases, the exposed cohort consisted of all patients (aged 18+) with at least one prescription of antidiabetic (AD) medication. Cox proportional hazards models were used to estimate hazard ratios (HRs) of fracture. The total period of follow-up for each patient was divided into periods of current exposure and past exposure, with patients moving between current and past use.

RESULTS

In all three registries, the risk of fracture was increased for women who were exposed to TZDs: HR 1.48 (1.37-1.60) in GPRD, HR 1.35 (1.15-1.58) in PHARMO, and HR 1.22 (1.03-1.44) in Denmark. Combining the data in an individual patient data meta-analysis resulted, for women, in a 1.4-fold increased risk of any fracture for current TZD users versus other AD drug users [adj. HR 1.44 (1.35-1.53)]. For men, there was no increased fracture risk [adj. HR 1.05 (0.96-1.14)]. Risks were increased for fractures of the radius/ulna, humerus, tibia/fibula, ankle, and foot, but not for hip/femur or vertebral fractures. Current TZD users with more than 25 TZD prescriptions ever before had a 1.6-fold increased risk of fracture compared with other AD drug users [HR 1.59 (1.46-1.74)].

CONCLUSION

In this study, we consistently found a 1.2- to 1.5-fold increased risk of fractures for women using TZDs, but not for men, across three different healthcare registries. TZD users had an increased risk for fractures of the extremities, and risks further increased for prolonged users of TZDs.