Associations with fracture in patients with diabetes: a nested case-control study

Diabetes and osteoporosis - Treating two entities: A challenge or cause for concern?

People with T1D and T2D have an increased risk of fractures than the general population, posing several significant pathophysiologic, diagnostic, and therapeutic challenges. The pathophysiology is still not fully elucidated, but it is considered a combination of increased skeletal fragility and falls. Diagnostics issues exist, as regular and even newer scan methods underestimate the true incidence of osteoporosis and thus the fracture risk. Therefore, co-managing diabetes and osteoporosis by using top-line strategies is essential to preserve bone health and minimize the risk of falls. The therapeutic focus should start with lifestyle implementation and physical exercise interventions to reduce diabetic complications, strengthen bones, and improve postural control strategies. In addition, osteoporosis should be treated according to current guidelines by including bisphosphonates and antidiabetic drugs that support bone health. Finally, potentially modifiable risk factors for falls should be managed.

The risk of major osteoporotic fractures with GLP-1 receptor agonists when compared to DPP-4 inhibitors: A Danish nationwide cohort study

BACKGROUND

Type 2 diabetes mellitus (T2D) is associated with an increased fracture risk. There is little evidence for the effects of glucagon-like peptide 1 receptor agonists (GLP-1RA) on fracture risk in T2D. We aimed to investigate the risk of major osteoporotic fractures (MOF) for treatment with GLP-1RA compared to dipeptidyl peptidase 4 inhibitors (DPP-4i) as add-on therapies to metformin.

METHODS

We conducted a population-based cohort study using Danish national health registries. Diagnoses were obtained from discharge diagnosis codes (ICD-10 and ICD-8-system) from the Danish National Patient Registry, and all redeemed drug prescriptions were obtained from the Danish National Prescription Registry (ATC classification system). Subjects treated with metformin in combination with either GLP-1RA or DPP-4i were enrolled from 2007 to 2018. Subjects were propensity-score matched 1:1 based on age, sex, and index date. MOF were defined as hip, vertebral, humerus, or forearm fractures. A Cox proportional hazards model was utilized to estimate hazard rate ratios (HR) for MOF, and survival curves were plotted using the Kaplan-Meier estimator. In addition, Aalen's Additive Hazards model was applied to examine additive rather than relative hazard effects while allowing time-varying effects.

RESULTS

In total, 42,816 individuals treated with either combination were identified and included. After matching, 32,266 individuals were included in the main analysis (16,133 in each group). Median follow-up times were 642 days and 529 days in the GLP-1RA and DPP-4i group, respectively. We found a crude HR of 0.89 [0.76-1.05] for MOF with GLP-1RA compared to DPP-4i. In the fully adjusted model, we obtained an unaltered HR of 0.86 [0.73-1.03]. For the case of hip fracture, we found a crude HR of 0.68 [0.49-0.96] and a similar adjusted HR. Fracture risk was lower in the GLP-1RA group when examining higher daily doses of the medications, when allowing follow-up to continue after medication change, and when examining hip fractures, specifically. Additional subgroup- and sensitivity analyses yielded results similar to the main analysis.

CONCLUSION

In our primary analysis, we did not observe a significantly different risk of MOF between treatment with GLP-1RA and DPP-4i. We conclude that GLP-1RA are safe in terms of fracture.

SGLT2 inhibitor treatment is not associated with an increased risk of osteoporotic fractures when compared to GLP-1 receptor agonists: A nationwide cohort study

BACKGROUND

Type 2 diabetes mellitus (T2D) is associated with an increased fracture risk. It is debated whether sodium-glucose cotransporter 2 (SGLT2) inhibitors influence fracture risk in T2D. We aimed to investigate the risk of major osteoporotic fractures (MOF) with SGLT2 inhibitors compared to glucagon-like peptide 1 (GLP-1) receptor agonists when used as add-on therapies to metformin.

METHODS

We conducted a population-based cohort study using Danish national health registries. Diagnoses were obtained from discharge diagnosis codes (ICD-10 and ICD-8-system) from the Danish National Patient Registry, and all redeemed drug prescriptions were obtained from the Danish National Prescription Registry (ATC classification system). Subjects treated with metformin in combination with either SGLT2 inhibitors or GLP-1 receptor agonists were identified and enrolled from 2012 to 2018. Subjects were then propensity-score matched 1:1 based on age, sex, and index date. Major osteoporotic fractures (MOF) were defined as hip, vertebral, humerus, or forearm fractures. A Cox proportional hazards model was utilized to estimate hazard rate ratios (HR) for MOF, and survival curves were plotted using the Kaplan-Meier estimator.

RESULTS

In total, 27,543 individuals treated with either combination were identified and included. After matching, 18,390 individuals were included in the main analysis (9,190 in each group). Median follow-up times were 355 [interquartile range (IQR) 126-780] and 372 [IQR 136-766] days in the SGLT2 inhibitor and GLP-1 receptor agonist group, respectively. We found a crude HR of 0.77 [95% CI 0.56-1.04] for MOF with SGLT2 inhibitors compared to GLP-1 receptor agonists. In the fully adjusted model, we obtained an unaltered HR of 0.77 [95% CI 0.56-1.05]. Results were similar across subgroup- and sensitivity analyses.

CONCLUSION

These results suggest that SGLT2 inhibitors have no effect on fracture risk when compared to GLP-1 receptor agonists. This is in line with results from previous studies.

Fractures and Osteoporosis in Patients With Diabetes With Charcot Foot

OBJECTIVE

Charcot foot is a serious complication of diabetes, with degeneration of the bones and joints in the foot and ankle. It is unknown whether patients with diabetes with a Charcot foot have an increased risk of osteoporosis and fractures. The aim of this study was to investigate whether patients with diabetes with a Charcot foot have an increased risk of fracture and/or osteoporosis compared with patients with diabetes without Charcot foot.

RESEARCH DESIGN AND METHODS

A Danish register-based, nationwide population-based matched cohort study was conducted. During 1995-2018, we identified 1,602 patients with diabetes with Charcot foot and matched them on sex and date of diagnosis of diabetes with 16,296 patients with diabetes without Charcot foot. We used logistic regression to estimate odds ratios (ORs) with 95% CIs for fracture and osteoporosis. Information about exposure, outcome, and comorbidities was retrieved from the Danish National Patient Register.

RESULTS

Diabetes patients with Charcot foot had higher risk of fractures compared with those without Charcot foot (i.e., ORs for any fracture, lower-leg fracture, foot fracture, and osteoporotic fracture were 1.8 [95% CI 1.6-2.0], 2.4 [2.0-2.8], 2.9 [2.6-3.3], and 1.3 [1.1-1.4], respectively). Furthermore, patients with diabetes with Charcot foot had higher risk of osteoporosis compared with the patients without Charcot foot, with an OR of 1.3 (95% CI 1.1-1.5).

CONCLUSIONS

Patients with diabetes with a Charcot foot have an increased risk of fractures and osteoporosis compared with patients with diabetes without a Charcot foot.

Management of bone fragility in type 2 diabetes: Perspective from an interdisciplinary expert panel

AIM

Bone fragility is increasingly recognized as a relevant complication of type 2 diabetes (T2D) and diabetic patients with fragility fractures have higher mortality rates than non diabetic individuals or diabetic patients without fractures. However, current diagnostic approaches for fracture risk stratification, such as bone mineral density measurement or the use of risk assessment algorithms, largely underestimate fracture risk in T2D patients. A multidisciplinary expert panel was established in order to in order to formulate clinical consensus recommendations on bone health assessment and management of fracture risk in patients with T2D.

DATA SYNTHESIS

The following key questions were addressed: a) which are the risk factors for bone fragility in T2D?, b) which diagnostic procedures can be currently used to stratify fracture risk in T2D patients?, c) which are the effects of antidiabetic treatments on bone?, and d) how to prevent and treat bone fragility in T2D patients? Based on the available data members of this panel suggest that the stratification of fracture risk in patients with diabetes should firstly rely on the presence of a previous fragility fracture and on the individual risk profile, with the inclusion of T2D-specific risk factors (namely T2D duration above 10 yrs, presence of chronic T2D complications, use of insulin or thiazolidinediones and persistent HbA1c levels above 8% for at least 1 year). Two independent diagnostic approaches were then suggested in the presence or the absence of a prevalent fragility fracture, respectively.

CONCLUSIONS

Clinical trials in T2D patients at risk for fragility fractures are needed to determine the efficacy and safety of available antiresorptive and anabolic agents in this specific setting.

Risk Factors for Incident Fracture in Older Adults With Type 2 Diabetes: The Framingham Heart Study

OBJECTIVE

To identify risk factors for fracture in type 2 diabetes.

RESEARCH DESIGN AND METHODS

This prospective study included members of the Framingham Original and Offspring Cohorts. Type 2 diabetes was defined as fasting plasma glucose >125 mg/dL or use of type 2 diabetes therapy. We used repeated-measures Cox proportional hazards regression to calculate hazard ratios (HRs) and 95% CIs for associations between potential predictors and incidence of fragility fracture.

RESULTS

Participants included 793 individuals with type 2 diabetes. Mean ± SD age was 70 ± 10 years; 45% were women. A total of 106 incident fractures occurred over 1,437 observation follow-up intervals. Fracture incidence increased with age (adjusted HRs 1.00, 1.44 [95% CI 0.65, 3.16], and 2.40 [1.14, 5.04] for <60, 60-70, and >70 years, respectively; P _trend = 0.02), female sex (2.23 [1.26, 3.95]), HbA_1c (1.00, 2.10 [1.17, 3.75], and 1.29 [0.69, 2.41] for 4.45-6.46% [25-47 mmol/mol], 6.50-7.49% [48-58 mmol/mol], and 7.50-13.86% [58-128 mmol/mol]; P _trend =0.03), falls in past year (1.00, 1.87 [0.82, 4.28], and 3.29 [1.34, 8.09] for no falls, one fall, and two or more falls; P _trend =0.03), fracture history (2.05 [1.34, 3.12]), and lower grip strength (0.82 [0.69, 0.99] per 5-kg increase). Femoral neck bone mineral density, BMI, smoking, physical function, chronic diseases, medications, and physical function were not associated with fracture incidence.

CONCLUSIONS

Prior falls, fractures, low grip strength, and elevated HbA_1c are risk factors for fractures in older adults with type 2 diabetes. Evaluation of these factors may improve opportunities for early intervention and reduce fractures in this high-risk group.

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.

Bone mineral density and trabecular bone score in elderly type 2 diabetes Southeast Asian patients with severe osteoporotic hip fractures

INTRODUCTION

Studies show trabecular bone score (TBS) may provide information regarding bone quality independent of bone mineral density (BMD) in type 2 diabetes (DM2) patients. We analyzed our Southeast Asian severe osteoporotic hip fracture patients to study these differences.

METHODS

We conducted a retrospective cross-sectional analysis of subjects admitted to Changi General Hospital, Singapore with severe osteoporotic hip fractures from 2014-2017 who had BMD performed. Electronic records were reviewed and subjects were classified as having diabetes according to the WHO 2019 criteria. DM2 patients were classified according to their HbA1c into well controlled (HbA1c < 7%) and poorly controlled (HbA1c ≥ 7%) DM2.

RESULTS

Elderly patients with hip fractures present with average femur neck T scores at the osteoporotic range, however those with DM2 had higher BMD and TBS values compared to non DM2 patients. These differences were statistically significant in elderly women-poorly controlled elderly DM2 women with hip fracture had the highest total hip T-score (-2.57 ± 0.86) vs (-2.76 ± 0.96) in well controlled DM2 and (-3.09 ± 1.01) in non DM2 women with hip fracture, p < 0.001. In contrast, TBS scores were lower in poorly controlled DM2 women with hip fracture compared to well controlled DM2 women with hip fracture (1.22 ± 0.11) vs (1.24 ± 0.09), but these were still significantly higher compared to non DM2 women with hip fracture (1.19 ± 0.10), p < 0.001. In elderly men with hip fractures, univariate analysis showed no statistically significant differences in TBS or hip or LS BMD between those with poorly controlled DM2, well controlled DM2 and non DM2. The differences in TBS and BMD remained significant in all DM2 women with hip fractures even after adjustments for potential confounders. Differences in TBS and BMD in poorly controlled DM2 men with hip fractures only became significant after accounting for potential confounders. However, upon inclusion of LS BMD into the multivariate model these differences were attenuated and remained significant only between elderly women with well controlled DM2 and non DM2 women with hip fractures.

CONCLUSIONS

Elderly patients with DM2 and severe osteoporosis present with hip fractures at a higher BMD and TBS values compared to non DM2 patients. These differences were significant after adjustment for confounders in all DM2 women and poorly controlled DM2 men with hip fractures, TBS differences were attenuated with the inclusion LS BMD. Further studies are needed to ascertain differences in BMD and TBS in older Southeast Asian DM2 patients with variable glycemic control and severe osteoporosis.

Diabetes mellitus and risk of low-energy fracture: a meta-analysis

BACKGROUND

Low-energy fracture risk is significantly increased in diabetes mellitus, the purpose of this article is to systematically evaluate the association between diabetes mellitus and risk for low-energy fracture.

METHODS

We conducted a systematic literature search of Medline, Embase, Science Citation Index, Wiley Online Library database through January 2019. Pooled relative risks (RR) with corresponding 95% confidence intervals (95% CI) were calculated with random-effects model to assess the strength of association.

RESULTS

Thirty-seven studies met the inclusion criteria, which included 3,123,382 participants. The pooled RR of any fracture in people with diabetes mellitus was 1.5 (95% CI 1.3-1.8; P < 0.05). The significant association not found in subgroup analysis of prospective design, follow-up period ≥ 10 year (all P > 0.05). The pooled RR of hip fracture in people with diabetes mellitus was 2.0 (95% CI 1.8-2.3; P < 0.05). In addition, subgroup analysis shown higher risk of hip fracture in type 1 diabetes (RR: 5.3). The pooled RR of vertebral fracture with diabetes mellitus was 1.4 (95% CI 0.9-2.2; P = 0.196). Subgroup analysis by type of diabetes showed that the RR of vertebral fracture for patients with unknown-type diabetes was 2.4 (95% CI 1.4-4.0; P < 0.05). Diabetes mellitus was associated with fractures at other sites, and effect estimates was statically significant.

CONCLUSIONS

Diabetes mellitus is an independent risk factor for low-energy fracture, and this relationship is more pronounced in hip fracture.

Increased Risk of Falls, Fall-related Injuries and Fractures in People with Type 1 and Type 2 Diabetes - A Nationwide Cohort Study

INTRODUCTION

People with diabetes could have an increased risk of falls as they show more complications, morbidity and use of medication compared to the general population. This study aimed to estimate the risk of falls and to identify risk factors associated with falls in people with diabetes. The second aim was to estimate fall-related injuries, such as lesions and fractures, including their anatomic localization in people with diabetes compared with the general population.

METHODS

From the Danish National Patient Register, we identified people with Type 1 Diabetes (T1D) (n=12,975) Type 2 Diabetes (T2D) (n=407,009). The cohort was divided into two groups, with respective control groups matched on age and sex (1:1). All episodes of people hospitalized with a first fall from 1996 to 2017 were analyzed using a Cox proportional-hazards model. Risk factors such as age, sex, diabetic complications, a history of alcohol abuse and the use of medication were included in an adjusted analysis. The incidence rate, incidence rate difference and incidence rate ratio (IRR) of falls and the anatomic localization of fall-related injuries as lesions and fractures were identified.

RESULTS AND DISCUSSION

The cumulative incidence, of falls requiring hospital treatment, was 13.3% in T1D, 11.9% in T2D. In the adjusted analysis, T1D and T2D were associated with a higher risk of falls [T1D, Hazard Ratio (HR): 1.33 (95% CI: 1.25 - 1.43), T2D, HR: 1.19 (95% CI:1.16 - 1.22), respectively]. Women [group 1, HR 1.21 (CI:95%:1.13 - 1.29), group 2, HR 1.61 (CI:95%:1.58-1.64)], aged >65 years [groups 1, HR 1.52 (CI:95%:1.39 - 1.61), group 2, HR 1.32 (CI:95%:1.58-1.64)], use of selective serotonin receptor inhibitors (SSRI) [group 1, HR 1.35 (CI:95%:1.1.30 - 1.40), group 2, HR 1.32 (CI:95%:1.27-1.38)], opioids [group 1, HR 1.15 (CI:95%:1.12 - 1.19), group 2, HR 1.09 (CI:95%:1.05-1.12)] and a history of alcohol abuse [group 1, HR 1.77 (CI:95%:1.17 - 2.15), group 2, HR 1.88 (CI:95%:1.65-2.15)] were significantly associated with an increased risk of falls in both groups. The IRR of fall-related injuries as hip, radius, humerus and skull/facial fractures were higher in people with T2D than controls [IRR 1.02 (CI:95%:1.01-1.04), IRR 1.39 (CI:95%: 1.18-1.61), IRR 1.24 (CI:95%: 1.12-1.37) and IRR 1.15 (CI:95%:1.07-1.24)]. People with T1D had a higher IRR of hip fractures than controls [IRR: 1.11 (CI:95%:1.02 - 1.23)].

CONCLUSION

People with diabetes have an increased risk of first fall and a higher incidence of fall- related injuries, including fractures. Advanced aging and sex are non-modifiable risk factors, whereas diabetes, the use of SSRIs and opioids and alcohol abuse could be potentially modifiable risk factors for falls. Gaining information on risk factors for falls could guide the management of diabetes treatment, i.e., choice of drugs, which enables us to improve treatment, particularly in people with a high risk of falls and fractures associated with high mortality.

Diabetes and fractures: new evidence of atypical femoral fractures?

Patients with diabetes have an increased risk of fractures. In this study, subtrochanteric and femoral shaft fractures were increased in patients with type 1 diabetes compared with the general population. In the light of this, more evidence points towards an association between diabetes and atypical femoral fractures.

INTRODUCTION

Patients with diabetes have an increased risk of femoral fractures, but little is known about the risk of atypical femoral fractures (AFFs). The aim of this study was to identify the risk of subtrochanteric and femoral shaft (ST/FS) fractures and estimate the risk of AFFs in patients with type 1 (T1D) and type 2 diabetes (T2D).

METHODS

From the nationwide Danish National Patient Register, we identified patients with T1D (n = 19,896), T2D (n = 312,188), and sex- and aged-matched controls without diabetes (n = 996,252) from the general population and all ST/FS fractures (n = 7509). Data were analyzed using a Cox proportional-hazards model and the incidence rate and rate ratio of ST/FS fractures were estimated.

RESULTS

The incidence rate of ST/FS fractures in T1D was 52.14 events per 100,000 person years and 73.21 per 100,000 person years in T2D. T1D was associated with an increased risk of ST/FS (HR 2.07 (95% CI 1.68-2.56)), whereas T2D was not (HR 0.99 (95% CI 0.94-1.10)). Previous ST/FS fractures were associated with an increased risk of subsequent ST/FS fractures (HR 6.95 (95% CI 6.00-8.05)) and the use of bisphosphonates with an increased risk of ST/FS fractures (HR 1.72 (95% CI 1.54-1.91)).

CONCLUSION

Patients with T1D have a higher risk of ST/FS fractures compared with sex- and age-matched controls. Since a proportion of ST/FS fractures are classified as AFFs, this could point towards the fact that AFFs also are increased in patients with T1D, but not T2D.

Lipid Profile and Risk of Bone Fracture: A Systematic Review and Meta-Analysis of Observational Studies

Purpose: Earlier studies have linked lipid profile to osteoporotic fractures; however, to our knowledge, no study had summarized available data on this relationship. We aimed to summarize the current evidence on the association between lipid profile and bone fractures. Material and Methods: A systematic search of PubMed and Scopus was done to find relevant published studies until March 2018. To combine effect sizes, we applied fixed- or random-effects analysis, where appropriate. Cochran's Q test and I² were used to assess between-study heterogeneity. Results: Overall, 11 studies (seven prospective, three cross-sectional and one case-control studies) were included in the current systematic review. Out of them, 10 studies with a total sample size of 60,484 individuals, aged 25 years or more, were used in the meta-analysis. The results showed that total cholesterol concentration was positively associated with risk of bone fracture; such that a 50-mg/dl increase in plasma level of TC was associated with 15% greater odds of bone fracture (combined effect size: 1.15, 95% CI: 1.02-1.30, P = .02). Furthermore, we found that individuals with a decreased level of HDL (<40 mg/dl) had a lower risk of bone fracture compared with those with a normal level (≥40 mg/dl) (combined effect size: 0.82, 95% CI: 0.71-0.96, P = .01). No significant association was found between plasma level of TG and LDL with the risk of bone fractures either in prospective or cross-sectional studies. Conclusions: We found that plasma levels of total cholesterol were positively associated with bone fractures. In addition, decreased levels of HDL were associated with an increased risk of osteoporotic fractures. Abbreviations: TG: triglycerides, TC: total cholesterol, HDL: high-density lipoprotein, LDL: low-density lipoprotein, OR: odds ratio, RR: relative risk, HR: hazard ratio, DXA: dual-energy X-ray absorptiometry, ICD: International Classification of Diseases, SD: standard deviation.

Glycemic Control and Insulin Treatment Alter Fracture Risk in Older Men With Type 2 Diabetes Mellitus

Diabetes mellitus among older men has been associated with increased bone mineral density but paradoxically increased fracture risk. Given the interactions among medication treatment, glycemic control, and diabetes-associated comorbidities, the relative effects of each factor remains unclear. This retrospective study includes 652,901 male veterans aged ≥65 years with diabetes and baseline hemoglobin A1c (HbA1c) value. All subjects received primary care in the Veterans Health Administration (VHA) from 2000 to 2010. Administrative data included ICD9 diagnoses and pharmacy records and was linked to Medicare fee-for-service data. Hazard ratios (HR) for any clinical fracture and hip fracture were calculated using competing risk hazards models, adjusted for fracture risk factors including age, race/ethnicity, body mass index (BMI), alcohol and tobacco use, rheumatoid arthritis, corticosteroid use, as well as diabetes-related comorbidities including cardiovascular disease, chronic kidney disease, and peripheral neuropathy. HbA1c <6.5% was associated with a higher risk of any clinical fracture (HR = 1.08, 95% confidence interval [CI] 1.06-1.11) compared with the reference HbA1c of 7.5% to 8.5%. Fracture risk was not increased among those with A1c ≥8.5%, nor among those with A1c 6.5% to 7.5%. Use of insulin was independently associated with greater risk of fracture (HR = 1.10, 95% CI 1.07-1.12). There was a significant interaction between insulin use and HbA1c level, (p < 0.001), such that those using insulin with HbA1c <6.5% had HR = 1.23 and those with HbA1c 6.5% to 7.5% had HR = 1.15. Metformin use was associated with decreased fracture risk (HR = 0.88, 95% CI 0.87-0.90). We conclude that among older men with diabetes, those with HbA1c lower than 6.5% are at increased risk for any clinical and hip fracture. Insulin use is associated with higher fracture risk, especially among those with tight glycemic control. Our findings demonstrate the importance of the treatment regimen and avoiding hypoglycemia for fracture prevention in older men with diabetes. © 2019 American Society for Bone and Mineral Research.

Bone health in diabetes and prediabetes

Bone fragility has been recognized as a complication of diabetes, both type 1 diabetes (T1D) and type 2 diabetes (T2D), whereas the relationship between prediabetes and fracture risk is less clear. Fractures can deeply impact a diabetic patient’s quality of life. However, the mechanisms underlying bone fragility in diabetes are complex and have not been fully elucidated. Patients with T1D generally exhibit low bone mineral density (BMD), although the relatively small reduction in BMD does not entirely explain the increase in fracture risk. On the contrary, patients with T2D or prediabetes have normal or even higher BMD as compared with healthy subjects. These observations suggest that factors other than bone mass may influence fracture risk. Some of these factors have been identified, including disease duration, poor glycemic control, presence of diabetes complications, and certain antidiabetic drugs. Nevertheless, currently available tools for the prediction of risk inadequately capture diabetic patients at increased risk of fracture. Aim of this review is to provide a comprehensive overview of bone health and the mechanisms responsible for increased susceptibility to fracture across the spectrum of glycemic status, spanning from insulin resistance to overt forms of diabetes. The management of bone fragility in diabetic patient is also discussed.

Hypoglycaemia and type 1 diabetes are associated with an increased risk of fractures

People with diabetes have an increased risk of fractures, and in this study, the effect of hypoglycaemia and insulin on this risk was investigated. Type 1 diabetes and hypoglycaemia did increase the fracture risk, and prevention of hypoglycaemia is thus an important focus area in the prevention of fractures.

INTRODUCTION

Studies have shown that type 1 diabetes (T1D) and type 2 diabetes (T2D) are associated with increased risk of fractures. Especially, subjects with T1D have an increased risk of fractures. The purpose of this study was to investigate the association of T1D, hypoglycaemia and insulin on fracture risk.

METHODS

A cohort study with T1D subjects (n = 19,896) and T2D subjects (n = 312,188) matched with subjects from the general populated (n = 996,252) and a nested case-control study with T1D subjects with fracture (n = 895) as cases and T1D subjects without (n = 2685) as controls were conducted based on subjects from the Danish National Patient Registry (DNPR).

RESULTS

T1D (HR = 2.47, 95% CI 2.37 to 2.59), age (HR = 1.05, 95% CI 1.05 to 1.05), previous fracture (HR = 1.95, 95% CI 1.92 to 1.99) and being female (HR = 2.06, 95% CI 2.04 to 2.09) increased the risk of fractures. Also, T2D (HR = 1.14, 95% CI 1.11 to 1.18) increased the risk of proximal upper arm and shoulder fractures. T1D (HR = 2.41, 95% CI 2.20 to 2.65) increased the risk of hip and femoral region fractures. Hypoglycaemia (OR = 1.58, 95% CI 1.27 to 1.97) increased the risk of fractures, whereas insulin use did not change the risk.

CONCLUSIONS

Hypoglycaemic episodes are associated with increased fracture risk, and the frequency of hypoglycaemic episodes leading to hospital admission was above 16% for T1D subjects. Prevention of hypoglycaemia is thus an important focus area in the prevention of fractures.

Diabetes and bone

Bone disease is a serious complication to diabetes. Patients with type 1 diabetes (T1D) and type 2 diabetes (T2D) suffer from an increased risk of fracture, most notably at the hip, compared with patients without diabetes. Confounders such as patient sex, age, body mass index, blood glucose status, fall risk, and diabetes medications may influence the fracture risk. Different underlying mechanisms contribute to bone disease in patients with diabetes. Bone quality is affected by low bone turnover in T1D and T2D, and furthermore, incorporation of advanced glycation end-products, changes in the incretin hormone response, and microvascular complications contribute to impaired bone quality and increased fracture risk. Diagnosis of bone disease in patients with diabetes is a challenge as current methods for fracture prediction such as bone mineral density T-score and fracture risk assessment tools underestimate fracture risk for patients with T1D and T2D. This review focuses on bone disease and fracture risk in patients with diabetes regarding epidemiology, underlying disease mechanisms, and diagnostic methods, and we also provide considerations regarding the management of diabetes patients with bone disease in terms of an intervention threshold and different treatments.

Self-reported low-energy fractures and associated risk factors in people with diabetes: A national population-based study

AIMS

Clinical risk factors and bone mineral densitometry underestimate low-energy fracture (LEF) risk in people with diabetes. We aim to estimate the prevalence of LEF in diabetics, compare with nondiabetics; and evaluate possible predictors of LEF in people with diabetes.

METHODS

Cross-sectional, population-based study in Portuguese subjects over 40 years-old. Estimates computed as weighted proportions/means, considering sample design. Multivariate logistic regression models to evaluate the association of diabetes and LEF; and predictors of LEF in diabetics.

RESULTS

7675 subjects were analysed, of which 1173 reported diabetes. Diabetics were older (mean age 66.0 ± 11.49y), more frequently reported osteoporosis and falls in the previous 12 months (32.4% vs. 22.9%). Prevalence of self-reported LEF was 16.2% (95% CI:13.68-19.13) among diabetics (vs. 13.3%, 95% CI:12.14-14.57, in nondiabetics); OR for the association diabetes and LEF:1.26, 95% CI:1.01-1.58, p = 0.045 (in women, adjusted OR:1.41, 95% CI:1.05-1.89, p = 0.02). Thirty percent of diabetics reported at least one major LEF and 70% in other sites. In diabetics, LEF was independently associated with self-reported osteoporosis and falls in the previous 12 months.

CONCLUSION

People with diabetes reported more falls and had higher prevalence of self-reported LEF. Self-reported osteoporosis and falls were associated with LEF in diabetics. Our findings emphasize the need for fracture and falls preventive measures in diabetics.

Type 1 Diabetes and Bone Fragility: Links and Risks

Type 1 diabetes (T1D) is associated with an increased fracture risk, which is present at young and old age. Reductions in bone mineral density do not explain the increased fracture risk. Novel scanning modalities suggest that structural deficits may contribute to the increased fracture risk. Furthermore, T1D may due to insulinopenia be a state of low bone turnover. However, diabetes complications and comorbidities may influence fracture risk. Patients with T1D are fearful of falls. The diabetes related complications, hypoglycemic events, and antihypertensive treatment may all lead to falls. Thus, the increased fracture risk in T1D seems to be multifactorial, and earlier intervention with antiosteoporotic medication and focus on fall prevention is needed. This systematic review addresses the epidemiology of fractures and osteoporosis in patients with T1D and the factors that influence fracture risk.

Using Human 'Experiments of Nature' to Predict Drug Safety Issues: An Example with PCSK9 Inhibitors

INTRODUCTION

When a new drug enters the market, its full array of side effects remains to be defined. Current surveillance approaches targeting these effects remain largely reactive. There is a need for development of methods to predict specific safety events that should be sought for a given new drug during development and postmarketing activities.

OBJECTIVE

We present here a safety signal identification approach applied to a new set of drug entities, inhibitors of the serine protease proprotein convertase subtilisin/kexin type 9 (PCSK9).

METHODS

Using phenome-wide association study (PheWAS) methods, we analyzed available genotype and clinical data from 29,722 patients, leveraging the known effects of changes in PCSK9 to identify novel phenotypes in which this protein and its inhibitors may have impact.

RESULTS

PheWAS revealed a significantly reduced risk of hypercholesterolemia (odds ratio [OR] 0.68, p = 7.6 × 10^-4) in association with a known loss-of-function variant in PCSK9, R46L. Similarly, laboratory data indicated significantly reduced beta mean low-density lipoprotein cholesterol (- 14.47 mg/dL, p = 2.58 × 10^-23) in individuals carrying the R46L variant. The R46L variant was also associated with an increased risk of spina bifida (OR 5.90, p = 2.7 × 10^-4), suggesting that further investigation of potential connections between inhibition of PCSK9 and neural tube defects may be warranted.

CONCLUSION

This novel methodology provides an opportunity to put in place new mechanisms to assess the safety and long-term tolerability of PCSK9 inhibitors specifically, and other new agents in general, as they move into human testing and expanded clinical use.

Skeletal Fragility in Type 2 Diabetes Mellitus

Type 2 diabetes (T2D) is associated with an increased risk of fracture, which has been reported in several epidemiological studies. However, bone mineral density in T2D is increased and underestimates the fracture risk. Common risk factors for fracture do not fully explain the increased fracture risk observed in patients with T2D. We propose that the pathogenesis of increased fracture risk in T2D is due to low bone turnover caused by osteocyte dysfunction resulting in bone microcracks and fractures. Increased levels of sclerostin may mediate the low bone turnover and may be a novel marker of increased fracture risk, although further research is needed. An impaired incretin response in T2D may also affect bone turnover. Accumulation of advanced glycosylation endproducts may also impair bone strength. Concerning antidiabetic medication, the glitazones are detrimental to bone health and associated with increased fracture risk, and the sulphonylureas may increase fracture risk by causing hypoglycemia. So far, the results on the effect of other antidiabetics are ambiguous. No specific guideline for the management of bone disease in T2D is available and current evidence on the effects of antiosteoporotic medication in T2D is sparse. The aim of this review is to collate current evidence of the pathogenesis, detection and treatment of diabetic bone disease.

Analysis of Fractures in Patients With Type 2 Diabetes Treated With Empagliflozin in Pooled Data From Placebo-Controlled Trials and a Head-to-Head Study Versus Glimepiride

OBJECTIVE

To assess the effect of empagliflozin on bone fractures and bone mineral density in patients with type 2 diabetes in pooled placebo-controlled trial data and a head-to-head study versus glimepiride.

RESEARCH DESIGN AND METHODS

Pooled data were analyzed from patients who were randomized 1:1:1 to empagliflozin 10 mg, empagliflozin 25 mg, or placebo in phase I-III clinical trials. Data were also analyzed from the EMPA-REG H2H-SU trial in which patients received empagliflozin 25 mg or glimepiride as an add-on to metformin for 104 weeks with a 104-week extension. Bone fracture adverse events (AEs) were evaluated through a search of investigator-reported (nonadjudicated) events.

RESULTS

In the pooled analysis, bone fracture AEs were reported in 119 of 4,221 (2.8%), 105 of 4,196 (2.5%), and 123 of 4,203 (2.9%) patients in the empagliflozin 10 mg, empagliflozin 25 mg, and placebo groups, respectively (rates of 1.55, 1.36, and 1.69/100 patient-years, respectively). In the EMPA-REG H2H-SU trial, bone fracture AEs were reported in 31 of 765 (4.1%) patients receiving empagliflozin 25 mg and in 33 of 780 (4.2%) patients receiving glimepiride (rates of 1.28 and 1.40/100 patient-years, respectively).

CONCLUSIONS

Empagliflozin did not increase the risk of bone fracture compared with placebo in a pooled analysis of >12,000 patients or compared with glimepiride in a 4-year head-to-head study.

The serum 25-hydroxyvitamin D levels and hip fracture risk: a meta-analysis of prospective cohort studies

Hip fracture has increasingly become a social and economic burden. The relationship between serum 25-hydroxyvitamin D levels and the risk of hip fracture reported by previous studies remains controversial. We searched Pubmed and Embase to identify studies reporting the relationship between serum 25-hydroxyvitamin D levels and risk of hip fracture. Fifteen prospective cohort studies with a total of 51239 participants and 3386 hip fracture cases were included. By pooling the Relative Risk of the lowest vs. the highest categories indicated that lower levels of serum 25-hydroxyvitamin D were more likely to be a risk factor for hip fracture with adjusted Relative Risk (95%Confidence Interval) of 1.58 (1.41, 1.77). Subgroup meta-analysis examining the stability of the primary results achieved the same results. A dose-response meta-analysis showed that the risk of hip fracture was a descending curve below the line of RR=1. The descending trend was obvious when serum 25-hydroxyvitamin D levels were less than 60 nmol/L and was flat when serum 25-hydroxyvitamin D levels were more than 60 nmol/L. We found that individuals with low levels of serum 25-hydroxyvitamin D have an increased risk of hip fracture, and this effect was evident when the serum 25-hydroxyvitamin D levels were less than 60 nmol/L.

The effect of insulin on bone mineral density among women with type 2 diabetes: a SWAN Pharmacoepidemiology study

This was a longitudinal study examining the effects of insulin use on bone mineral density loss. Insulin use was found to be associated with greater bone mineral density loss at the femoral neck among women with diabetes mellitus.

INTRODUCTION

Women with diabetes mellitus (DM) have higher bone mineral density (BMD) and experience slower BMD loss but have an increased risk of fracture. The data regarding the effect of insulin treatment on BMD remains conflicted. We examined the impact of insulin initiation on BMD.

METHODS

We investigated the annual changes in BMD associated with the new use of insulin among women with DM in the Study of Women's Health Across the Nation (SWAN). Propensity score (PS) matching, which is a statistical method that helps balance the baseline characteristics of women who did and did not initiate insulin, was used. Covariates with a potential impact on bone health were included in all models. Mixed model regression was used to test the change in BMD between the two groups. Median follow-up time was 5.4 years.

RESULTS

The cohort consisted of 110 women, mean age, 53.6 years; 49% white and 51% black. Women using insulin (n = 55) were similar on most relevant characteristics to the 55 not using insulin. Median diabetes duration for the user group was 10 vs. 5.0 years for the non-user group. There was a greater loss of BMD at the femoral neck among insulin users (- 1.1%) vs non-users (- 0.77%) (p = 0.04). There were no differences in BMD loss at the spine - 0.30% vs - 0.32% (p = 0.85) or at the total hip - 0.31% vs - 0.25 (p = 0.71), respectively.

CONCLUSIONS

Women with T2DM who initiated insulin experienced a more rapid BMD loss at the femoral neck as compared to women who did use insulin.

Molecular Modulation of Osteoblasts and Osteoclasts in Type 2 Diabetes

Diabetes is a common disease affecting majority of populations worldwide. Since 1980, there has been an increase in the number of people diagnosed as prediabetic and diabetic. Diabetes is characterized by high levels of circulating glucose and leads to most microvascular and macrovascular complications such as retinopathy, nephropathy, neuropathy, stroke, and myocardial infarction. Bone marrow vascular disruption and increased adiposity are also linked to various complications in type II diabetes mellitus. In addition to these complications, type 2 diabetic patients also have fragile bones caused by faulty mineralization mainly due to increased adiposity among diabetic patients that affects both osteoblast and osteoclast functions. Other factors that increase fracture risk in diabetic patients are increased oxidative stress, inflammation, and drugs administered to diabetic patients. This review reports the modulation of different pathways that affect bone metabolism in diabetic conditions.

Can LDL cholesterol be too low? Possible risks of extremely low levels

Following the continuous accumulation of evidence supporting the beneficial role of reducing low-density lipoprotein cholesterol (LDL-C) levels in the treatment and prevention of atherosclerotic cardiovascular disease and its complications, therapeutic possibilities now exist to lower LDL-C to very low levels, similar to or even lower than those seen in newborns and nonhuman species. In addition to the important task of evaluating potential side effects of such treatments, the question arises whether extremely low LDL-C levels per se may provoke adverse effects in humans. In this review, we summarize information from studies of human cellular and organ physiology, phenotypic characterization of rare genetic diseases of lipid metabolism, and experience from clinical trials. Specifically, we emphasize the importance of the robustness of the regulatory systems that maintain balanced fluxes and levels of cholesterol at both cellular and organismal levels. Even at extremely low LDL-C levels, critical capacities of steroid hormone and bile acid production are preserved, and the presence of a cholesterol blood-brain barrier protects cells in the central nervous system. Apparent relationships sometimes reported between less pronounced low LDL-C levels and disease states such as cancer, depression, infectious disease and others can generally be explained as secondary phenomena. Drug-related side effects including an increased propensity for development of type 2 diabetes occur during statin treatment, whilst further evaluation of more potent LDL-lowering treatments such as PCSK9 inhibitors is needed. Experience from the recently reported and ongoing large event-driven trials are of great interest, and further evaluation including careful analysis of cognitive functions will be important.

The changing epidemiology of fall-related fractures in adults

There has been very little analysis of the epidemiology of adult fall-related fractures outwith the osteoporotic population. We have analysed all in-patient and out-patient fall-related fractures in a one-year period in a defined population and documented their epidemiology. The overall prevalence of non-spinal fall-related fractures is 63.1% with 40.7% and 82.7% occurring in males and females respectively. In females aged 20-29 years >50% of fractures follow falls, the equivalent age range in males being 50-59 years. Analysis of fall-related fractures in two one-year periods in 2000 and 2010/11 shows a significant increase in almost all age ranges up to 60-69 years with a decreased incidence in 90+ patients. In males there is a significant increase in 30-39year males but also in males >80years. In females the greatest increase in incidence is in 16-19year females but all age ranges show a significant increase up to 60-69 years. There is a decreased incidence in 90+ females. The reasons for the increase in the incidence of fall-related are multifactorial but they are probably contributed to by the inherently weaker bone of younger females and by the increased incidence of conditions such as obesity and diabetes.

Epidemiology of Fractures in Diabetes

Diabetes mellitus is associated with an increased risk of fracture. The risk of a hip fracture is up to sevenfold increased in patients with type 1 diabetes and about 1.3-fold increased in patients with type 2 diabetes. However, these relative risk estimates may depend on the age and gender distribution of the population in question. Bone mineral density and the fracture risk assessment tool do not explain the increased fracture risk in patients with diabetes. Shared risk factors as pancreatitis, alcohol use, smoking and oral glucocorticoids may influence the observed fracture risk in patients with diabetes. This review examines the association between diabetes and fracture and attempts to disentangle the tight connection between diabetes per se, diabetes-related complications, comorbidities and shared risk factors. This is of great importance as the number of diabetes patients' increases with growing and aging populations and putting even more at risk of fracture.