Fracture risk in patients treated with amiodarone or digoxin for cardiac arrhythmias: a nation-wide case-control study

Interleukin-17 plays a role in dental pulp inflammation mediated by zoledronic acid: a mechanism unrelated to the Th17 immune response?

OBJECTIVE

To evaluate the influence of RORγT inhibition by digoxin on inflammatory changes related to interleukin-17 (IL-17) in the pulp of rats treated with zoledronate (ZOL).

METHODOLOGY

Forty male Wistar rats were divided into a negative control group (NCG) treated with saline solution, a positive control group (PCG) treated with ZOL (0.20 mg/kg), and three groups treated with ZOL and co-treated with digoxin 1, 2, or 4 mg/kg (DG1, 2, and 4). After four intravenous administrations of ZOL or saline solution in a 70-day protocol, the right molars were evaluated by histomorphometry (number of blood vessels, blood vessels/µm2, cells/µm2, total blood vessel area, and average blood vessel area) and immunohistochemistry (IL-17, TNF-α, IL-6, and TGF-β). The Kruskal-Wallis/Dunn test was used for statistical analysis.

RESULTS

PCG showed an increase in total blood vessel area (p=0.008) and average blood vessel area (p=0.014), and digoxin treatment reversed these changes. DG4 showed a reduction in blood vessels/µm2 (p<0.001). In PCG odontoblasts, there was an increase in IL-17 (p=0.002) and TNF-α (p=0.002) immunostaining, and in DG4, these changes were reversed. Odontoblasts in the digoxin-treated groups also showed an increase in IL-6 immunostaining (p<0.001) and a reduction in TGF-β immunostaining (p=0.002), and all ZOL-treated groups showed an increase in IL-17 (p=0.011) and TNF-α (p=0.017) in non-odontoblasts cells.

CONCLUSION

ZOL induces TNF-α- and IL-17-dependent vasodilation and ectasia, and the classical Th17 response activation pathway does not seem to participate in this process.

Role of Na+, K+-ATPase ion pump in osteoinduction

Porous biphasic calcium phosphate bioceramic (BCP) possesses osteoinductivity to induce the osteoblastic commitment of mesenchymal stem cells (MSCs) and ectopic bone formation. However, the underlying mechanism remains enigmatic. We performed a gene array analysis of MSCs cocultured with BCP to screen for candidate osteoinductive modulators. Na⁺, K⁺-ATPase (NKA), an ion transporter, therefore was identified as a crucial ion transporter in regulating the osteogenesis of the cells. NKA activator, a polyclonal antibody, enriched the cytomembrane abundance of NKA and lead to an enhanced osteogenic effect of BCP. As indicated in gene array analysis and suggested by co-immunoprecipitation assay, protein phosphatase 2A (PP2A) was elevated by BCP to dephosphorylate NKA and prevent its endocytosis. The inhibition of NKA by ouabain resulted in an adverse effect on osteoinductivity of BCP. We further altered NKA activity in mice implanted with BCP and found that the intensity and incidence of osteoinduction was increased by the NKA activator. We went one step further by investigating the potential of targeting NKA in osteoporotic bone regeneration. Activating NKA upregulated osteogenic gene expression and calcium deposition ability of osteoporotic osteoblasts. Furthermore, activation of NKA in mice ameliorated estrogen-deficiency induced bone loss, in terms of increased bone mass and improved bending strength. With this osteoinductive bioceramic derived ion transporter target, we demonstrate that the activation of NKA has significant potential to revolutionize the regeneration of bone. STATEMENT OF SIGNIFICANCE: In this study, we identified an important role of Na⁺, K⁺-ATPase (NKA) have played in osteoinductivity of biphasic calcium phosphate bioceramic (BCP). Furthermore, we demonstrated the therapeutic potential of targeting NKA in osteoporotic bone regeneration. Numerous gene and protein targets to treat osteoporosis were discovered every year, mainly obtained by genomic and proteomic screenings of a large population. In contrast, our study identified an unrevealed bone regenerating target from the upregulated genes induced by an osteoinductive biomaterial. The approach was cost-saving since it did not require a large sample pool. Furthermore, the target derived from this approach was proven to be anabolic. Identification of an anabolic agent holds significant value since most of the current anti-osteoporotic therapies are antiresorptive.

Rate or Rhythm Control in Older Atrial Fibrillation Patients: Risk of Fall-Related Injuries and Syncope

OBJECTIVES

Management of atrial fibrillation (AF) with rate and/or rhythm control could lead to fall-related injuries and syncope, especially in the older AF population. We aimed to determine the association of rate and/or rhythm control with fall-related injuries and syncope in a real-world older AF cohort.

DESIGN

A retrospective cohort study.

SETTING

Danish nationwide administrative registries from 2000 to 2015.

PARTICIPANTS

A total of 100 935 patients with AF aged 65 years or older claiming prescription of rate-lowering drugs (RLDs) and/or anti-arrhythmic drugs (AADs) were included. We compared the use of rate-lowering monotherapy with rate-lowering dual therapy, AAD monotherapy, and AAD combined with rate-lowering therapy.

MEASUREMENTS

Outcomes were fall-related injuries and syncope as a composite end point (primary) or separate end point (secondary).

RESULTS

In this population, the median age was 78 years (interquartile range [IQR] = 72-84 y), and 53 481 (53.0%) were women. During a median follow-up of 2.1 years (IQR = 1.0-5.1), 17 132 (17.0%) experienced a fall-related injury, 5745 (5.7%) had a syncope, and 21 093 (20.9%) experienced either. Compared with rate-lowering monotherapy, AADs were associated with a higher risk of fall-related injuries and syncope. The incidence rate ratio (IRR) for the composite end point was 1.29 (95% confidence interval [CI]: 1.17-1.43) for AAD monotherapy and 1.46 [95% CI = 1.34-1.58] for AAD combined with rate-lowering therapy. When stratifying by individual drugs, amiodarone significantly increased the risk of fall-related injuries and syncope (IRR = 1.40 [1.26-1.55]). Compared with more than 180 days of rate-lowering monotherapy, a higher risk of all outcomes was seen in the first 90 days of any treatment; however, the greatest risk was in the first 14 days for those treated with AADs.

CONCLUSION

In AF patients aged 65 years and older, AAD use was associated with a higher risk of fall-related injuries and syncope, and the risk was highest within the first 14 days for those treated with AADs. Only amiodarone use was associated with a higher risk. J Am Geriatr Soc 67:2023-2030, 2019.

Atherosclerosis and Osteoporosis. Common Targets for the Effects of Cardiovascular and Anti-osteoporotic Drugs (Part I). The Effect of Cardiovascular Drugs on Bone Strength

Daily use of antihypertensive and lipid-lowering drugs in clinical practice dictates the need for knowledge of their pleiotropic effects. The article presents the results of studies of the effect of cardiovascular drugs, such as statins, beta-blockers, ACE inhibitors, diuretics, calcium antagonists and nitrates on bone mineral density and fractures associated with osteoporosis. The mechanisms of action of drugs on bone mass, markers of bone metabolism, the frequency of fractures in osteoporosis are discussed. Most studies show that the use of cardiac drugs along with a positive effect on the vascular wall, slow bone resorption and increase bone mass. Knowledge of the additional effect on bone metabolism of drugs used in cardiovascular diseases allows to choose an adequate therapy and improve the prognosis of both diseases.

Increased 1-year mortality rates among elderly hip fracture patients with atrial fibrillation

BACKGROUND AND AIMS

Prediction of factors associated with survival following hip fracture is important. We studied crude and adjusted survival rates in elderly hip fracture patients with and without atrial fibrillation (AF) to assess possible risk of death associated with AF.

METHODS

A historical prospective cohort study, comprising 1114 consecutive patients with hip fractures. Subjects were divided into three groups: patients with sinus rhythm (SR), paroxysmal atrial fibrillation (PAF) or chronic atrial fibrillation (CAF). The main outcome measures were crude and adjusted survival rates at 30, 90 and 365 days, and end of follow-up.

RESULTS

AF patients differed from SR patients by gender (p=0.0018), age (p=0.008), heart failure (p<0.001), ischemic heart disease (p<0.001) and history of a stroke (p<0.001). The lowest death rates were observed among SR and PAF patients, whereas CAF patients had the highest rates at each follow-up time point. CAF (but not PAF or SR) patients were at a significantly higher risk of death at both 365 days and at the end of the study (HR 1.786, CI 1.011- 3.155 and HR 1.835, CI 1.302-2.585, respectively). Older age (HR 1.301, CI 1.135-1.491 and HR 1.321, CI 1.321-1.415) and male gender (HR 1.879, CI 1.271- 2.779 and HR 1.545, CI 1.251-1.909) also predicted higher risk of death at both 365 days and at the end of the study.

CONCLUSIONS

Atrial fibrillation cannot be considered to adversely affect short-term survival of hip fracture patients. After 365 day, CAF was associated with a significantly higher risk of death.

Heart drugs that affect bone

There have been important developments in our understanding of the mechanisms underlying the development of osteoporosis, and several of these mechanisms also underlie atherosclerosis. Drugs given to treat cardiovascular disease may impact on bone health in either a beneficial or a harmful way. There is evidence that nitrates are beneficial to bone, but evidence for the benefit of statins, thiazide diuretics, and β-blockers is weaker. By contrast, it is likely to be that some drugs such as loop-acting diuretics are harmful to bone, whereas evidence for harm caused by drugs such as warfarin is weaker. These observations point towards opportunities for new drug development for bone diseases, and possibly the development of treatments that will benefit more than one disease.

Levothyroxine dose and risk of fractures in older adults: nested case-control study

OBJECTIVE

To quantify the effect of levothyroxine dose on risk of fractures in older adults.

DESIGN

Nested case-control study.

SETTING

Population based health databases, Ontario, Canada.

PARTICIPANTS

Adults aged 70 or more prescribed levothyroxine between 1 April 2002 and 31 March 2007 and followed for fractures until 31 March 2008. Cases were cohort members admitted to hospital for any fracture, matched with up to five controls from within the cohort who had not yet had a fracture.

MAIN OUTCOME MEASURE

Primary outcome was fracture (wrist or forearm, shoulder or upper arm, thoracic spine, lumbar spine and pelvis, hip or femur, or lower leg or ankle) in relation to levothyroxine use (current, recent past, remote). Risk among current users was compared between those prescribed high, medium, and low cumulative levothyroxine doses in the year before fracture.

RESULTS

Of 213,511 prevalent levothyroxine users identified, 22,236 (10.4%) experienced a fracture over a mean 3.8 years of follow-up, 18,108 (88%) of whom were women. Compared with remote levothyroxine use, current use was associated with a significantly higher risk of fracture (adjusted odds ratio 1.88, 95% confidence interval 1.71 to 2.05), despite adjustment for numerous risk factors. Among current users, high and medium cumulative doses (>0.093 mg/day and 0.044-0.093 mg/day) were associated with a significantly increased risk of fracture compared with low cumulative doses (<0.044 mg/day): 3.45 (3.27 to 3.65) and 2.62 (2.50 to 2.76), respectively.

CONCLUSION

Among adults aged 70 or more, current levothyroxine treatment was associated with a significantly increased risk of fracture, with a strong dose-response relation. Ongoing monitoring of levothyroxine dose is important to avoid overtreatment in this population.

Hypertension is a risk factor for fractures

To study the effects of hypertension and other cardiovascular risk factors on risk of fractures, we carried out a case-control study including 124,655 fracture cases and 373,962 age- and gender-matched controls. The main exposure was hypertension, stroke, acute myocardial infarction, ischemic heart disease, atrial fibrillation, peripheral arterial disease, and deep venous thromboembolism, and the main confounders were use of diuretics, antihypertensive drugs, organic nitrates, vitamin K antagonists, and cholesterol lowering drugs along with other confounders. Hypertension and stroke were the only significant risk factors in both the short-term (OR = 1.27, 95% CI = 1.20-1.34 and 1.24, and 95% CI = 1.16-1.31 for < or = 3 years since diagnosis of hypertension and stroke, respectively) and the long-term (OR = 1.11, 95% CI = 1.00-1.23 and 1.09, and 95% CI = 1.02-1.18 for > 6 years since diagnosis of hypertension and stroke, respectively) perspective. Acute myocardial infarction, atrial fibrillation, and deep venous thromboembolism were all associated with a transient increase in the risk of fractures within the first 3 years following diagnosis. Peripheral arterial disease and ischemic heart disease were not associated with an increased risk of fractures. In conclusion, hypertension and stroke seem to be the major cardiovascular risk factors for fractures, whereas acute myocardial infarction, atrial fibrillation, and deep venous thromboembolism seem to be only minor risk factors. The fracture risk in hypertension may explain why antihypertensive drugs as a class effect are associated with a decreased risk of fractures. These drugs may counter some of the deleterious effects of high blood pressure.