Thiazide diuretic agents and the incidence of hip fracture

Incident Diuretic Use and Subsequent Risk of Bone Fractures: A Large Nationwide Observational Study of US Veterans

OBJECTIVE

To investigate the association of incident use of diuretics with subsequent risk of incident bone fractures.

PATIENTS AND METHODS

In a nationwide cohort of 863,339 US veterans receiving care from the VA health care system between October 1, 2004, and September 30, 2006, with follow-up through June 30, 2018, we examined the association of incident diuretic use (overall, and separately by thiazide, loop, and potassium-sparing diuretics) with subsequent risk of incident bone fractures using multivariable Cox regression models while minimizing confounding by indication using a target trial emulation approach.

RESULTS

Patients were 63.3±12.9 years old; 93.5% (n=807,180) were male; and 27.1% (n=233,996) were diabetic. Their baseline estimated glomerular filtration rate was 84.4±16.5 mL/min per 1.73 m2. Among 863,339 patients, 424,386 (49.2%) newly initiated diuretics, of which 77.4% (n=328,524), 22.5% (n=95,457), and 0.1% (n=405) were thiazide, loop, and potassium-sparing diuretic users, respectively. After multivariable adjustments, incident diuretic use (vs non-use) was significantly associated with higher risk of incident fracture (adjusted HR [aHR], 1.14; 95% CI, 1.11 to 1.16). The association was most pronounced for loop diuretics (aHR, 1.39; 95% CI, 1.35 to 1.44) but less evident for thiazide diuretics (aHR, 1.08; 95% CI, 1.06 to 1.10) and was not significant for potassium-sparing diuretics (aHR, 0.97; 95% CI, 0.62 to 1.52). The diuretic-fracture association was more evident in younger (vs older) patients, those with (vs without) corticosteroid use, and those with lower (vs higher) serum sodium levels.

CONCLUSION

Incident use of diuretics, particularly loop diuretics, was independently associated with higher risk of incident bone fractures. Our findings suggest distinct pathophysiologic contributions of diuretics to bone metabolism and the need for careful attention to skeletal outcomes when initiating diuretics.

Thiazide diuretics and primary hyperparathyroidism

Thiazide diuretics exert a natriuretic and diuretic effect by inhibiting sodium reabsorption in the distal convoluted tubule. Furthermore, thiazide diuretics affect renal calcium handling by increasing calcium reabsorption, leading to hypocalciuria. The effect that thiazide diuretics exert on parathyroid hormone secretion is controversial. Some studies found parathyroid hormone levels were suppressed with the use of thiazide diuretics, while others found that thiazides were associated with initial parathyroid hormone suppression followed by raised parathyroid hormone levels. This makes the relationship between thiazide diuretics and primary hyperparathyroidism interesting. If a patient is taking thiazide diuretics, this may make it harder to establish the aetiology of hypercalcaemia and may unmask normocalcaemic or mild primary hyperparathyroidism. Thiazide diuretics may have a beneficial role in the diagnosis of patients with concomitant hyperparathyroidism and hypercalciuria by distinguishing secondary hyperparathyroidism caused by hypercalciuria from normocalcaemic primary hyperparathyroidism. In addition, thiazide diuretics may have a role in managing patients with primary hyperparathyroidism who have an indication for parathyroidectomy in view of significant hypercalciuria, but are unfit for surgery.

Design and application of a knowledge network for automatic prioritization of drug mechanisms

MOTIVATION

Drug repositioning is an attractive alternative to de novo drug discovery due to reduced time and costs to bring drugs to market. Computational repositioning methods, particularly non-black-box methods that can account for and predict a drug's mechanism, may provide great benefit for directing future development. By tuning both data and algorithm to utilize relationships important to drug mechanisms, a computational repositioning algorithm can be trained to both predict and explain mechanistically novel indications.

RESULTS

In this work, we examined the 123 curated drug mechanism paths found in the drug mechanism database (DrugMechDB) and after identifying the most important relationships, we integrated 18 data sources to produce a heterogeneous knowledge graph, MechRepoNet, capable of capturing the information in these paths. We applied the Rephetio repurposing algorithm to MechRepoNet using only a subset of relationships known to be mechanistic in nature and found adequate predictive ability on an evaluation set with AUROC value of 0.83. The resulting repurposing model allowed us to prioritize paths in our knowledge graph to produce a predicted treatment mechanism. We found that DrugMechDB paths, when present in the network were rated highly among predicted mechanisms. We then demonstrated MechRepoNet's ability to use mechanistic insight to identify a drug's mechanistic target, with a mean reciprocal rank of 0.525 on a test set of known drug-target interactions. Finally, we walked through repurposing examples of the anti-cancer drug imatinib for use in the treatment of asthma, and metolazone for use in the treatment of osteoporosis, to demonstrate this method's utility in providing mechanistic insight into repurposing predictions it provides.

AVAILABILITY AND IMPLEMENTATION

The Python code to reproduce the entirety of this analysis is available at: https://github.com/SuLab/MechRepoNet (archived at https://doi.org/10.5281/zenodo.6456335).

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Antihypertensive drugs demonstrate varying levels of hip fracture risk: A systematic review and meta-analysis

OBJECTIVE

By aggregating the literature, we evaluated the association between use of specific antihypertensive drugs and the risk of hip fractures compared with nonuse.

STUDY DESIGN AND SETTING

We systematically searched the Pubmed, Embase, and Cochrane databases from inception of each database until July 30, 2020 to identify articles including patients 18 years of age or older reporting on the association between antihypertensive drugs and the risk of hip fracture. Antihypertensive drugs were restricted to thiazides; beta-blockers; calcium-channel blockers; angiotensin-converting enzyme (ACE) inhibitors; and angiotensin receptor blockers. Nonusers encompass all patients that are not using the specific antihypertensive drug that has been reported. Unadjusted odds ratios with 95% confidence intervals (CIs) of the association between antihypertensive drug use and hip fractures were reported. Meta-analysis was performed when a minimum of five studies were identified for each antihypertensive drug class. Quality assessment was done using ROBINS-I tool. The GRADE approach was used to evaluate the certainty of the evidence.

RESULTS

Of 962 citations, 22 observational studies were included; 9 studies had a cohort design and 13 studies were case-control studies. No randomized controlled trials were identified. We found very low certainty of evidence that both thiazides (pooled odds ratio: 0.85, 95% CI 0.73 to 0.99, p = 0.04) as well as beta-blockers (pooled odds ratio: 0.88, 95% CI 0.79 to 0.98, p = 0.02) were associated with a reduced hip fracture risk as compared to specific nonuse. One study, reporting on angiotensin receptor blockers, also suggested a protective effect for hip fractures, whereas we found conflicting findings in four studies for calcium-channel blockers and in two studies for ACE inhibitors.

CONCLUSION

Among 22 observational studies, we found very low certainty of evidence that, compared to specific nonuse of antihypertensive drugs, use of thiazides, beta-blockers, and angiotensin receptor blockers were associated with a reduced protective hip fracture risk, while conflicting findings for calcium-channel blockers and ACE inhibitors were found. Given the low quality of included studies, further research -randomized controlled trials- are needed to definitively assess the causal relationship between specific antihypertensive drug classes and (relatively infrequent) hip fractures.

Thiazide Use and Fracture Risk: An updated Bayesian Meta-Analysis

The association between thiazide use and fracture risk is still controversial. We conducted an updated meta-analysis on the association between thiazide use and fracture risk. We systematically searched PubMed, Embase, and Cochrane library databases for all types of human studies, including observational and experimental studies that were published up until July 2019. We also manually searched the reference lists of relevant studies. The pooled relative risks (RRs) with 95% credible interval (CrI) were calculated using a Bayesian hierarchical random effect model. A total of 19 case-control (N = 496,568 subjects) and 21 cohort studies (N = 4,418,602 subjects) were included in this meta-analysis. The pooled RR for fractures associated with thiazide use was 0.87 (95% CrI: 0.70–0.99) in case-control and 0.95 (95% CrI: 0.85–1.08) in cohort studies. The probabilities that thiazide use reduces any fracture risk by more than 0% were 93% in case-control studies and 72% in cohort studies. Significant heterogeneity was found for both case-control (p < 0.001, I² = 75%) and cohort studies (p < 0.001, I² = 97.2%). Thiazide use was associated with reduced fracture risk in case-control studies, but not in cohort studies. The associations demonstrated in case-control studies might be driven by inherent biases, such as selection bias and recall bias. Thus, thiazide use may not be a protective factor for fractures.

Thiazide Diuretics and the Incidence of Osteoporotic Fracture: A Systematic Review and Meta-Analysis of Cohort Studies

Background: Thiazide diuretics may improve bone mineral density. However, results are inconsistent for studies evaluating the association between thiazides and risk of osteoporotic fracture. We performed an updated meta-analysis of cohort studies to determine the association between thiazides use and fracture risk.

Methods: Relevant studies were identified via systematic search of PubMed and Embase. A random-effect model was used for meta-analysis. Subgroup analyses were performed to explore the potential influences of study characteristics on the outcome.

Results: Seventeen cohort studies with 3,537,504 participants were included. The pooled results showed that use of thiazide diuretics at baseline did not significantly affect the risk of overall osteoporotic fracture incidence as compared with controls (risk ratio [RR]: 0.96, 95% confidence interval [CI]: 0.83 to 1.09, p = 0.51) with significant heterogeneity (p for Cochrane’s Q test < 0.001, I² = 90%). Results of subgroup analyses indicated that general status of the participants may be an important determinant for the association between thiazide diuretics and subsequent risk of osteoporotic fracture. Use of thiazide diuretics was associated with significantly reduced risk of fracture in patients with acute status including new-onset stroke or spinal cord injury (RR: 0.70, 95% CI: 0.57 to 0.86, p < 0.001), but not in those with good conditions such as community-dwelling population or hypertensive patients (p for subgroup difference = 0.02).

Conclusions: Use of thiazide diuretics is not associated with significantly affected risk of overall osteoporotic fracture. However, the association may be different according to the general status of the participants.

Association between diuretic use and the risk of vertebral fracture after stroke: a population-based retrospective cohort study

Background

Stroke is a major risk factor for osteoporosis and fractures. No study has evaluated the association between diuretic use and risk of vertebral fracture in stroke patients, although a considerable proportion of stroke patients are prescribed diuretics for hypertension. Our study aimed to investigate whether treatment with thiazides or loop diuretics affects the risk of vertebral fracture after stroke.

Methods

A population-based propensity score-matched retrospective cohort study was conducted using the Taiwan National Health Insurance Research Database. Patients with a new diagnosis of stroke between 2000 and 2011 were included. After propensity score matching, 9468 patients were included in the analysis of the effect of thiazides, of who 4734 received thiazides within 2 years after stroke. To analyze the loop diuretic effect, 4728 patients were included, of who 2364 received loop diuretics. Cox proportional hazards regression models were used to calculate hazard ratios (HRs) of vertebral fractures among patients according to thiazide or loop diuretic use within 2 years following stroke. Sensitivity analyses based on the duration of thiazide or loop diuretic use were further conducted.

Results

There was no significant difference in vertebral fracture risk between thiazide users and non-users (adjusted HR [aHR] = 1.14, 95% confidence interval [CI] = 0.88–1.47, p = 0.316). Loop diuretic users had a significantly higher vertebral fracture risk than non-users (aHR = 1.45, 95% CI = 1.06–1.98, p = 0.019). However, the sensitivity analysis revealed that short-term thiazide use (exposure duration < 90 days within 2 years after stroke) significantly increased the risk of vertebral fracture versus non-use (aHR = 1.38, 95% CI = 1.02–1.88, p = 0.039). Only short-term loop diuretic users had significantly higher risk of vertebral fracture (aHR = 1.56, 95% CI = 1.11–2.20, p = 0.011). The other two subgroups with longer exposure duration in analyses for both thiazides and loop diuretics revealed no significant effect.

Conclusions

Short-term thiazide or loop diuretic use was associated with an increased risk of vertebral fracture after stroke. Further prospective clinical trials are required to confirm this finding.

Transplantation of a Gitelman Syndrome Kidney Ameliorates Hypertension: A Case Report

Gitelman syndrome is caused by inactivating mutations of the gene that encodes the renal sodium/chloride cotransporter (NCC; encoded by SLC12A3), resulting in hypokalemia, hypomagnesemia, hypocalciuria, and metabolic alkalosis. Renal salt wasting commonly provokes mild hypotension. The paucity of previous kidney transplants from donors with known tubulopathies suggests that such conditions may be considered contraindications to donation. A 76-year-old man received a live unrelated kidney transplant from a donor with known Gitelman syndrome secondary to a pathogenic mutation of SLC12A3. Immediate graft function preceded the emergence of the Gitelman syndrome biochemical phenotype and blood pressure subsequently improved. The recipient developed unexpected hyponatremia. Potential causes are discussed, including the possibility that it paralleled the physiologic changes seen in the high-volume state of thiazide-induced hyponatremia. Transplanted kidneys are subject to nephrotoxicity from the use of calcineurin inhibitors. Acquired Gitelman syndrome may confer a potential long-term advantage to the recipient through both improved blood pressure control and protection against the calcineurin inhibitor-induced side-effect profile caused by NCC overactivation. Both the donor and recipient remain well. In conclusion, Gitelman syndrome need not preclude kidney donation and transference of the phenotype may have benefits for the recipient.

Thiazide diuretic usage and risk of fracture: a meta-analysis of cohort studies

Inconsistent findings in regard to association between thiazide diuretic use and the risk of fracture have been reported during the past decade. This updated meta-analysis, which pooled data from 11 qualified prospective designed studies, found that thiazides have a significant protective effect on fracture risk.

INTRODUCTION

An updated comprehensive meta-analysis examine the association between thiazide diuretic use and therisk of fracture is needed.

METHODS

Cohort studies regarding thiazide diuretic exposure and the risk of fracture, published from inception to May 1 2017, were identified through MEDLINE, EMBASE, SCOPUS, and the Cochrane Database of Systematic Reviews. The literature search, study selection, study appraisal, and data extraction were pre-defined in the protocol and were independently conducted by two investigators. Due to the heterogeneity of the original studies, a random effects model was used to pool the confounder-adjusted relative risk (RR).

RESULTS

Eleven eligible cohort studies involving 2,193,160 participants were included for analysis. Overall, thiazide diuretic users, as compared with non-users, had a significant 14% reduction in the risk of all fractures (relative risk [RR], 0.86; 95% confidence interval [CI], 0.80-0.93; p = 0.009) and an 18% reduction in the risk of hip fracture (RR, 0.82; 95%CI, 0.80-0.93; p = 0.009). However, the effect size associated with thiazide use became slightly weaker when the analysis was limited to only high-quality original studies (quality score > 8) (RR, 0.89; 95%CI, 0.80-0.99; p = 0.005), studies with a larger sample size (> 10,000) (RR, 0.90; 95%CI, 0.80-1.00; p = 0.002), and studies published after 2007 (RR, 0.92; 95%CI, 0.82-1.02; p = 0.001).

CONCLUSION

Our findings indicate that thiazide diuretic use may convey a decreased risk of fracture and as such, the protective effect of this class of medicine should be considered when prescribing thiazide diuretics in clinical practice.

The Impact of Antihypertensive Medications on Bone Mineral Density and Fracture Risk

PURPOSE OF REVIEW

This review summarizes the impact of thiazide diuretics on fracture risk in older hypertensive individuals.

RECENT FINDINGS

We performed a post hoc evaluation of the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial, a randomized, prospective, double blind hypertension study comparing a thiazide-like diuretic, a calcium channel blocker (CCB), and an angiotensin converting enzyme inhibitor (ACEi). We examined the risk of hip and pelvic fractures during the in-trial period (n = 22,180 participants; mean 4.9-year follow-up) and during the post-trial period using national data bases (n = 16,622 participants) (mean total follow-up 7.8 years). During the trial, participants randomized to the thiazide diuretic versus the CCB or the ACEi had a lower risk of fracture on adjusted analyses (HR 0.79 [95% CI, 0.63, 0.98], p = 0.04). Risk of fracture was significantly lower in participants randomized to the diuretic as compared to those randomized to the ACEi (HR 0.75 [95% CI, 0.58, 0.98]; p = 0.04), but not significantly different compared to the CCB (HR 0.87 [95% CI, 0.71, 1.09]; p = 0.17). Over the entire trial and post-trial period of follow-up, the cumulative incidence of fractures was non-significantly lower in participants assigned to the diuretic vs assignment to the ACEi or the CCB (HR 0.87 [0.74-1.03], p = 0.10) and versus each medication separately. These findings establish a benefit for thiazide diuretic treatment for the prevention of fractures versus other commonly used antihypertensive medications using prospective, randomized data. The effects of the thiazide diuretic on bone appear to be long lasting.

Thiazides in the management of hypertension in older adults - a systematic review

Background

Thiazides are commonly prescribed to older people for the management of hypertension. The objective of this study was to identify the evidence on the risks and benefits of their use among adults aged ≥65 years and to develop recommendations to reduce potentially inappropriate use.

Methods

Systematic review (SR) of the literature covering six databases. We applied a staged search approach, where each search was undertaken only if the previous one did not yield high quality results. Searches 1 and 2 identified relevant SRs and meta-analyses published up to December 2015 from all databases. Search 3 identified additional individual interventional studies (IS) and observational studies (OS) not identified by the preceding searches. We included all studies evaluating the effect of thiazides on patient-relevant outcomes in the management of hypertension with a sufficient number of participants aged ≥65 years or a subgroup analysis based on age. Two independent reviewers extracted data and carried out quality appraisal. Recommendations were developed using the GRADE methodology.

Results

Searches 1 to 3 were performed. We included 34 articles reporting on 12 IS and 4 OS. Mean ages ranged from 59 to 83.8 years. Four studies had performed a subgroup analysis by age. Information on comorbidity, polypharmacy and frailty of the participants was scarce or not available. The IS compared thiazides to placebo or other antihypertensive drugs and evaluated cardiovascular endpoints or all-cause-mortality as primary outcomes. The OS investigated the association between thiazide use and the risk of gout, fractures and adverse effects. Our results suggest that thiazides are efficacious in preventing cardiovascular events for this population group. Low-dose regimens of thiazides may be safer than high-dose (low quality of evidence), and a history of gout may increase the risk of adverse events (low quality of evidence). Three recommendations were developed.

Conclusions

The use of low dose treatment with thiazides for the management of hypertension in adults aged 65 and older seems justified, unless a history of gout is present. The quality of the evidence is low and studies rarely describe characteristics of the participants such as polypharmacy and frailty. Further good quality studies are needed.

Electronic supplementary material

The online version of this article (doi:10.1186/s12877-017-0576-3) contains supplementary material, which is available to authorized users.

Adverse bone effects of medications used to treat non-skeletal disorders

There is a growing list of medications used to treat non-skeletal disorders that cause bone loss and/or increase fracture risk. This review discusses glucocorticoids, drugs that reduce sex steroids, antidiabetic agents, acid-reducing drugs, selective serotonin reuptake inhibitors, and heparin. A number of drugs are known to cause bone loss, increase fracture risk, or both. These drugs should be used in the lowest dose necessary to achieve the desired benefit and for the shortest time necessary, but in many cases, long-term treatment is required. Effective countermeasures are available for some.

Thiazide diuretics and the risk of hip fracture after stroke: a population-based propensity-matched cohort study using Taiwan's National Health Insurance Research Database

OBJECTIVES

This study aimed to investigate the association between thiazide use and the risk of hip fracture after stroke.

SETTING

A population-based, propensity-matched cohort study was conducted on the basis of Taiwan's National Health Insurance Research Database.

PARTICIPANTS

Patients with newly diagnosed ischaemic stroke between 2000 and 2011 were included. After propensity score matching, 7470 patients were included, of whom 3735 received thiazides and 3735 did not.

OUTCOME MEASURES

HRs for developing hip fractures within 2 years after stroke were calculated using Cox proportional hazards regression model with adjustments for sociodemographic and coexisting medical conditions.

RESULTS

Overall, patients using thiazides after stroke had a lower risk of hip fracture than those not using thiazides (8.5 vs 13.9 per 1000 person-years, adjusted HR=0.64, 95% CI 0.46 to 0.89, p=0.007). Further sensitivity analysis based on the duration of thiazide use revealed that the risk of hip fracture tended to decrease as the duration of exposure of thiazides increased. However, the effect was significant only in patients with long-term use of thiazides (using thiazides for >365 days within 2 years after stroke), with a 59% reduction in the risk of hip fracture when compared with patients not using thiazide (adjusted HR=0.41, 95% CI 0.22 to 0.79, p=0.008).

CONCLUSIONS

The long-term use of thiazides is associated with a decreased risk of hip fracture after stroke.

Primary and secondary osteoporotic fractures prophylaxis: evaluation of a prospective cohort

OBJECTIVE

To measure the prevalence of primary drug prevention of fractures due to osteoporosis in patients admitted to a tertiary teaching hospital, in a medium-sized city, admitted with osteoporotic fractures. Moreover, to identify the incidence of prescribing secondary prophylaxis after the first fracture event. At the same time, the prevalence of risk factors for such fractures as described in the literature was measured.

METHODS

This longitudinal prospective study was based on a cohort of patients admitted in a tertiary teaching hospital from October 2015 to January 2016. Patients with low energy or fragility fractures were included in the study regardless of gender or race, over the age of 50 years. All patients who did not have these characteristics were excluded. The follow-up lasted four months. Serial questionnaires were applied at admission and in the follow-up consultations at four to eight weeks and at 16 weeks.

RESULTS

Only one patient reported receiving treatment with specific drugs for the disease before hospital admission, resulting in a prevalence of primary chemoprophylaxis of only 2.27%. No patient was prescribed medication for the treatment of osteoporosis after the fracture. The prevalence of risk factors was similar to those found in the literature review.

CONCLUSION

In the present study, the frequency of primary and secondary osteoporosis chemoprophylaxis in patients who were admitted with fragility fractures was low, as well as the early indication of drug treatment after the first fracture. The prevalence of fragility fracture risk factors is similar to those reported in the literature.

Gout and Risk of Fracture in Women: A Prospective Cohort Study

OBJECTIVE

Uric acid may be linked to bone health through its antioxidant or prooxidant effects, thereby affecting bone resorption and formation, or through its dual inhibition of vitamin D activation and parathyroid hormone production. Results of prior studies on the relationship between uric acid and bone mineral density have been conflicting. This prospective study was undertaken to examine the relationship between gout, a disease characterized by hyperuricemia and inflammation, and risk of hip or wrist fracture in women.

METHODS

We conducted a prospective observational study of gout and risk of incident wrist and hip fracture in women participating in the Nurses' Health Study (n = 103,799 at baseline, with 14 years of follow-up for the wrist fracture analysis and 22 years of follow-up for the hip fracture analysis). Gout history and incident cases of wrist and hip fracture were assessed by biennial questionnaire. Cox proportional hazards models were used to simultaneously adjust for potential confounders.

RESULTS

In this cohort, there were 3,769 incident wrist fractures (1990-2004) and 2,147 incident hip fractures (1990-2012), with 107 wrist fractures and 117 hip fractures occurring in participants with gout. In those women with a history of gout compared with women without gout, the multivariable-adjusted relative risk of wrist fracture was 1.12 (95% confidence interval [95% CI] 0.92-1.36) and the multivariable-adjusted relative risk of hip fracture was 1.38 (95% CI 1.14-1.68).

CONCLUSION

In women, a history of gout is associated with a modestly increased risk of hip fracture, but not significantly associated with a risk of wrist fracture.

Long-term Effects of Antihypertensive Drug Use and New-onset Osteoporotic Fracture in Elderly Patients: A Population-based Longitudinal Cohort Study

Background:

Antihypertensive drugs have been linked to new-onset osteoporotic fracture (NOF), and different classes of antihypertensive drugs may alter the risk for the development of NOF; however, the classic effect of different antihypertensive drugs on the development of NOF in the elderly has not been well studied during long-term follow-up.

Methods:

In this study, we investigated the association between different classic antihypertensives and the development of NOF in the elderly. This was a longitudinal cohort study performed using data from claim forms submitted to the Taiwan Bureau of National Health Insurance in Central Taiwan, China including case patients with NOF aged 65–80 years from January 2002 to December 2012 and non-NOF controls. Prescriptions for antihypertensives before the index date were retrieved from a prescription database. We estimated the hazard ratios (HRs) of NOF associated with antihypertensive use. Non-NOF controls served as the reference group.

Results:

A total of 128 patients with NOF were identified from among 1144 patients with hypertension during the study period. The risk of NOF after adjusting age, sex, comorbidities, and concurrent medications was higher among the users of angiotensin-converting enzyme (ACE) inhibitors (HR, 1.64; 95% confidence interval [CI], 1.01–2.66) than among nonusers. Patients who took calcium channel blockers (CCBs) (HR, 0.70; 95% CI, 0.49–0.99) were at a lower risk of developing NOF than nonusers. Loop diuretics, thiazide diuretics, angiotensin receptor blocker, beta-blocker, and alpha-blocker were not associated with the risk of NOF.

Conclusions:

Elderly with hypertension who take CCBs are at a lower risk of NOF and that the use of ACE inhibitors was associated with a significantly increased risk of developing NOF during the 11-year follow-up.

Diuretic Use and Risk of Vertebral Fracture in Women

BACKGROUND

Vertebral fracture is the most common type of osteoporotic fracture. While thiazide diuretics, which are commonly prescribed for the treatment of hypertension, decrease calciuria, they may also induce hyponatremia, which has been associated with increased vertebral fracture risk. Loop diuretics increase calciuria, which would reduce bone mineral density and increase vertebral fracture risk, but they rarely cause hyponatremia. Recent studies on diuretics and fractures did not include or specifically examine vertebral fracture. The few studies of diuretics and vertebral fracture have been limited by cases defined by self-report or administrative data, relatively small number of cases, study design that was not prospective, and lack of long-term follow-up with updated information on diuretic use.

METHODS

We conducted a prospective cohort study of thiazide diuretic use, loop diuretic use, and risk of incident clinical vertebral fracture in 55,780 women, 55-82 years of age, participating in the Nurses' Health Study, without a prior history of any fracture. Diuretic use was assessed by questionnaire every 4 years. Self-reported vertebral fracture was confirmed by medical record review. Cox proportional-hazards models were used to simultaneously adjust for potential confounders.

RESULTS

Our analysis included 420 incident vertebral fracture cases documented between 2002 and 2012. The multivariate-adjusted relative risk of clinical vertebral fracture for women taking thiazides compared with women not taking thiazides was 1.47 (95% confidence interval, 1.18-1.85). The multivariate adjusted relative risk of vertebral fracture for women taking loop diuretics compared with women not taking loop diuretics was 1.59 (95% confidence interval, 1.12-2.25).

CONCLUSION

Thiazide diuretics and loop diuretics are each independently associated with increased risk of vertebral fracture in women.

Optimal age of commencing and discontinuing thiazide therapy to protect against fractures

A study of national Danish patient data with regard to thiazide diuretics vs. non-treatment. We find that after age 83 years, thiazides increase the 10-year risk of major fractures. We also find that thiazides can be stopped after 63 years old to possibly protect against fracture occurrence.

INTRODUCTION

The purpose of this study was to retrospectively examine the optimal age for commencing and discontinuing thiazide therapy to protect from osteoporotic fractures.

METHODS

A population-based, retrospective matched cohort study was done using national data of 2.93 million Danish subjects. Ten-year crude and adjusted age-grouped hazard ratios (HRs) of fracture occurrence were stratified by age of commencing thiazides compared to non-exposure. Separate analyses were done on Anatomical Therapeutic Chemical Classification System (ATC) codes C03AA and C03AA + C03AB compiled. Ten-year crude HRs of fracture occurrence for discontinuing vs. continuing thiazides were estimated and stratified by age for the two groups.

RESULTS

For C03AB alone (97.1 % of thiazide prescriptions), adjusted 10-year HRs of fracture occurrence were significantly increased for thiazide commencement after age 83 years and comparable to non-exposure for commencement between ages 50 and 83 years. For C03AA + C03AB, 10-year adjusted HRs of fracture occurrence were significantly increased from ages 73 years and upwards. Crude 10-year HRs of fracture occurrence were significantly decreased for discontinuing vs. continuing thiazides at or after age 63 years for C03AB and age 77 years for C03AA + C03AB.

CONCLUSIONS

No significantly protective effect of thiazides was found on fracture occurrence compared to non-users, but evidence that thiazides increase the 10-year adjusted HR risk of fractures if prescribed after the age of 83 years for C03AB and 73 years for C03AA + C03AB. Discontinuing thiazides at or after age 63 years for C03AB or 77 years for C03AA & C03AB significantly decreases the 10-year risk of fractures compared to continuing thiazides. Further prospective studies are warranted.

Pathophysiological Mechanisms and Correlates of Therapeutic Pharmacological Interventions in Essential Arterial Hypertension

Treating arterial hypertension (HT) remains a hard task. The hypertensive patient is often a subject with several comorbidities and metabolic abnormalities. Clinicians everyday have to choose the right drug for the single patient among the different classes of antihypertensives. Apart from lowering blood pressure, a main therapeutic target should be that of counteracting all the possible pathophysiological mechanisms involved in HT itself and in existing/potential comorbidities. All the ancillary positive and negative effects of the administered drugs should be considered: in particular, since hypertensive patients are often glucose intolerant/diabetic, carrier of serum lipids disorder, have already developed atherosclerotic diseases and endothelial dysfunction, they should not be treated with drugs negatively interfering with these conditions but with molecules that, if possible, improve them. The main pathophysiological mechanisms and correlates of therapeutic pharmacological interventions in essential HT are reviewed here.

Personalizing the diuretic treatment of hypertension: the need for more clinical and research attention

Neither randomized controlled trials nor efforts to identify genetic markers have been helpful with regard to the goal of individualizing diuretic therapy in the treatment of hypertension, a goal that receives little clinical or research attention. This review will examine, and bring attention to, the considerable yet overlooked information relevant to individualizing diuretic therapy. It will bring attention to clinical, biochemical, and pharmacological clues that can be helpful in identifying who is likely to respond to a diuretic, who needs a stronger diuretic regimen, which diuretic to prescribe, and how to minimize adverse effects. New directions for clinical research aimed at individualizing use in hypertension will be explored. Research and clinical attention to the goal of individualizing diuretic treatment in hypertension need to be renewed, to help us achieve greater hypertension control with fewer adverse effects and lower costs.

[Pharmacogenic osteoporosis beyond cortisone. Proton pump inhibitors, glitazones and diuretics]

BACKGROUND

[corrected] There are many drugs which can cause osteoporosis or at least favor its initiation. The effect of hormones and drugs with antihormonal activity, such as glucocorticoids and aromatase inhibitors, on initiation of osteoporosis is well known. In addition, proton pump inhibitors, glitazones and diuretics also influence the formation of osteoporosis.

MATERIAL AND METHODS

The results of currently available studies on the correlation between proton pump inhibitors, glitazones and diuretics on formation of osteoporosis were evaluated and summarized.

RESULTS

Proton pump inhibitors and glitazones increase the risk for osteoporotic fractures. Loop diuretics may slightly increase fracture risk, whereas thiazides were shown to be osteoprotective by reducing fracture probability on a relevant scale.

CONCLUSION

Proton pump inhibitors should not be prescribed without serious consideration and then only as long as necessary. Alternatively, the administration of the less effective H2 antagonists should be considered when possible due to the reduction of acid secretion. Because the long-term intake of thiazides is associated with a clinically relevant reduction in the risk of fractures and they are economic and well-tolerated, prescription can be thoroughly recommended within the framework of differential diagnostic considerations in an appropriate clinical context. The briefly increased risk of falling immediately after starting diuretic therapy is the only point which needs to be considered.

Preventing Hip Fracture After Stroke

Hip fracture after stroke is a frequently occurring and costly complication. The bone quality of stroke survivors is affected by decreased mobility, asymmetric weight bearing, and impaired vitamin D stores. Simultaneously, the risk of falling after stroke is often increased by various impairments. Yet, attempts to limit falls are not enough to prevent fractures. Closer attention to bone health is also needed. Bone markers, which reflect the dynamics of bone remodeling, are becoming more available. Activity is necessary for bone health, but there are no clear guidelines for the type and amount of therapeutic exercise. New metrics for studying bone mineral density and exercise are on the horizon. Finally, there appears to be a role for bisphosphonate prophylaxis in a yet-to-be-defined at-risk population of stroke survivors. The purpose of this review is to discuss the setting for hip fracture after stroke and assess emerging treatments and technologies that may be used to combat the problem.

Risk of fracture in urolithiasis: a population-based cohort study using the health improvement network

BACKGROUND AND OBJECTIVES

Studies have shown decreased bone mineral density in individuals with urolithiasis, but their burden of fracture remains unclear. This study sought to determine whether urolithiasis is associated with increased fracture risk across the lifespan and to delineate sex effects.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A population-based retrospective cohort study using The Health Improvement Network was performed. The median calendar year for the start of the observation period was 2004 (1994-2012). This study identified 51,785 participants with ≥1 of 87 diagnostic codes for urolithiasis and 517,267 randomly selected age-, sex-, and practice-matched participants. Cox regression was used to estimate the hazard ratio (HR) for first fracture. Fractures identified using diagnostic codes were classified by anatomic site.

RESULTS

Median age was 53 years, and 67% of participants were men, confirming their greater urolithiasis burden. Median time from urolithiasis diagnosis to fracture was 10 years. The HR for fracture associated with urolithiasis differed by sex and age (P for interactions, P≤0.003). In men, the adjusted HR was greatest in adolescence (1.55; 95% confidence interval [95% CI], 1.07 to 2.25) with an overall HR of 1.10 (95% CI, 1.05 to 1.16). Urolithiasis was associated with higher fracture risk in women aged 30-79 years (HR, 1.17-1.52), and was highest in women aged 30-39 years (HR, 1.52; 95% CI, 1.23 to 1.87). Peak background fracture rates were highest in boys aged 10-19 years and in women aged 70-79 years. The incidence per 10,000 person-years in participants with versus without urolithiasis was 392 versus 258 in male participants aged 10-19 years, and 263 versus 218 in women aged 70-79 years. Distribution of fracture site within sex did not differ between participants with versus without urolithiasis.

CONCLUSIONS

Urolithiasis was associated with higher incident fracture risk. The significantly higher risk at times of peak background fracture incidence in adolescent boys and elderly women has profound public health implications.

Possible way to reduce fracture rates in patients with traumatic spinal cord injury?

Lower extremity fractures in men with spinal cord injury (SCI) are a major problem. The use of thiazide diuretics, a simple and safe intervention, may be effective in reducing the risk of fracture in patients with traumatic SCI. Furthermore, thiazide diuretics have an added benefit of reducing kidney stone formation.

Which components of a primary care affiliated home visiting nurse program are associated with disability maintenance/improvement?

A process evaluation of a primary care affiliated home visiting nurse intervention was performed to determine which intervention components were associated with disability maintenance/improvement. This secondary analysis (N = 238) used data recorded in intervention databases and patient interviews among community-dwelling elders with disability. Intervention components were examined in descriptive, correlational, bivariate, and logistic regression analyses. Results demonstrated that two structure components--physician-patient-family-nurse conference visits and intervention (education) materials--and three process components--disease management activities, goal setting, and medication management activities--were linked to maintaining/improving activities of daily living disability status. Confirmation of these findings may help home care nurses to delay disability worsening.

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.

Metabolic complications associated with use of diuretics

Diuretics are commonly used therapeutic agents that act to inhibit sodium transport systems along the length of the renal tubule. The most effective diuretics are inhibitors of sodium chloride transport in the thick ascending limb of Henle. Loop diuretics mobilize large amounts of sodium chloride and water and produce a copious diuresis with a sharp reduction of extracellular fluid volume. As the site of action of diuretics moves downstream (thiazide and potassium-sparing diuretics), their effectiveness declines because the transport systems they inhibit have low transport capacity. Depending on the site of action diuretics can influence the renal handling of electrolyte-free water, calcium, potassium, protons, sodium bicarbonate, and uric acid. As a result, electrolyte and acid-base disorders commonly accompany diuretic use. Glucose and lipid abnormalities also can occur, particularly with the use of thiazide diuretics. This review focuses on the biochemical complications associated with the use of diuretics. The development of these complications can be minimized with careful monitoring, dosage adjustment, and replacement of electrolyte losses.

Association of hypertension and bone mineral density in an elderly African American female population

BACKGROUND

Recent studies have shown that hypertension is inversely correlated with bone mineral density (BMD) as determined by dual energy x-ray absorptiometery (DXA) in different ethnic groups. But in most published studies, either the sample size was small or the study was limited by different measurement methods. These limitations leave this association controversial and inconclusive. The current study utilizes a sample of African American females referred for clinical screening of osteoporosis in our center to find out if any association of high blood pressure and BMD in this ethnic group exists. The secondary endpoint was to determine the effect of thiazide diuretics on BMD of the elderly African American females because, theoretically, thiazides are considered to have a positive impact on BMD.

METHODS

In this retrospective, cross-sectional study, 10 years of data were reviewed from 1113 medical records of African American females aged 65 years and older whose BMD values were measured by DXA at the lumbar spine (L1-L4) and both femoral necks (the standard sites for BMD determination) along with their T scores and Z scores (used to determine osteopenia vs osteoporosis). Our exclusion criteria included patients who: (1) were current smokers, (2) had a previous oophorectomy, (3) had a history of corticosteroid use, (4) had a history of biphosphonate use, (5) were on hormone replacement therapy, and (6) were diabetic and taking either pioglitazones or roziglitazones. A total of 148 patients were excluded from the analysis due to either incomplete data or exclusion criteria. The remaining sample was then divided into 2 groups based on their hypertensive status. For the subanalysis, the hypertensive group was further divided into 2 additional groups based on their thiazide usage.

RESULTS

We had complete data on 965 participants, of which 631 (65.3%) had a history of hypertension and 334 (34.7%) did not. Out of 631 hypertensive patients, 173 were found to be using thiazide diuretics as antihypertensive medication, while 458 were without thiazide diurectic use. The proportion of patients with both osteopenia and osteoporosis was similar in those with and without hypertension (50% vs 50%, p = .95 for osteopenia; 18% vs 19%, p = .95 for osteoporosis). There was no significant difference between the BMD at the lumbar spine, and right and left femoral necks between patients with and without hypertension. This lack of association held true when comparing the mean T scores and Z scores at the above sites. Within patients with a history of hypertension, there were no significant differences in the BMD, T score or Z score at any site with and without a history of thiazide diuretic use.

CONCLUSION

Hypertension in elderly African American females aged at least 65 years was not found to be correlated with low BMD at either the lumbar spine (L1-L4) or both femoral necks when confounding factors were taken into consideration. Mean BMD of the hypertensive cohort taking thiazide diuretics was found lower at the lumbar spine as compared to the hypertensive patients not taking thiazide diuretics.

Thiazide diuretics and the risk of hip fracture

BACKGROUND

Thiazide diuretics are one of the most commonly prescribed antihypertensive agents worldwide. Thiazides reduce urinary calcium excretion. Chronic ingestion of thiazides is associated with higher bone mineral density. It has been suggested that thiazides may prevent hip fracture. However, there are concerns that diuretics, by increasing the risk of fall in elderly, could potentially negate its beneficial effects on hip fracture.

OBJECTIVES

To assess any association between the use of thiazide diuretics and the risk of hip fracture in adults.

SEARCH STRATEGY

We searched eligible studies up to December 2008 in MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), the Cumulative Index to Nursing and Allied Health Literature (CINAHL), International Pharmaceutical Abstracts, the Database of Abstracts of Review of Effects (DARE) and reference lists of previous reviews and included studies.

SELECTION CRITERIA

All randomized controlled trials and observational studies, which assessed the association between thiazide diuretic use and hip fracture.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied the selection criteria, extracted data and assessed risk of bias of each study selected.  The results were summarized descriptively and quantitatively. Cohort studies and case control studies were analysed separately.

MAIN RESULTS

No randomized control trials were found. Twenty-one observational studies with nearly four hundred thousand participants were included. Six of them were cohort studies and 15 were case-control studies. Two cohort studies appear to involve the same cohort so there were only 5 unique ones. The risk of bias was assessed with the Newcastle-Ottawa Scale (NOS). Five cohort studies had low risk of bias and one had moderate risk of bias. Seven case control studies had low risk of bias and 8 had moderate risk of bias. Meta-analysis of cohort studies showed that thiazide use was associated with a reduction in risk of hip fracture by 24%, pooled RR 0.76 (95% CI 0.64-0.89; p = 0.0009). We chose not to provide a pooled summary statistics for case-control studies because of high heterogeneity (Tau(2) = 0.03, I(2) = 62%, p = 0.0008).

AUTHORS' CONCLUSIONS

Thiazides appear to reduce the risk of hip fracture based on observational studies. Randomized controlled trials are needed to confirm these findings.  

A review of thiazide-induced hyponatraemia

There are numerous reports of thiazide-induced hyponatraemia (TIH) and its incidence is growing as a result of increasing prescription after guidelines recommending thiazides as first-line treatment of essential hypertension have been introduced. Thiazide diuretics are a common cause of severe hyponatraemia that is usually induced within two weeks of starting the thiazide diuretic, but it can occur any time and very rapidly in susceptible patients. Despite several relevant reports and years of clinical experience, TIH remains a very common clinical scenario. Although its impact has recently been reviewed, little attention has been given to the practical approach for preventing this medical complication. In the present review, the epidemiology, pathogenesis, clinical presentation and management of TIH are discussed, and an approach to its prevention suggested in the hope that increased awareness and understanding will reduce the incidence and complications of this potentially life-threatening condition.

A cross-species analysis of a mouse model of breast cancer-specific osteolysis and human bone metastases using gene expression profiling

Background

Breast cancer is the second leading cause of cancer-related death in women in the United States. During the advanced stages of disease, many breast cancer patients suffer from bone metastasis. These metastases are predominantly osteolytic and develop when tumor cells interact with bone. In vivo models that mimic the breast cancer-specific osteolytic bone microenvironment are limited. Previously, we developed a mouse model of tumor-bone interaction in which three mouse breast cancer cell lines were implanted onto the calvaria. Analysis of tumors from this model revealed that they exhibited strong bone resorption, induction of osteoclasts and intracranial penetration at the tumor bone (TB)-interface.

Methods

In this study, we identified and used a TB microenvironment-specific gene expression signature from this model to extend our understanding of the metastatic bone microenvironment in human disease and to predict potential therapeutic targets.

Results

We identified a TB signature consisting of 934 genes that were commonly (among our 3 cell lines) and specifically (as compared to tumor-alone area within the bone microenvironment) up- and down-regulated >2-fold at the TB interface in our mouse osteolytic model. By comparing the TB signature with gene expression profiles from human breast metastases and an in vitro osteoclast model, we demonstrate that our model mimics both the human breast cancer bone microenvironment and osteoclastogenesis. Furthermore, we observed enrichment in various signaling pathways specific to the TB interface; that is, TGF-β and myeloid self-renewal pathways were activated and the Wnt pathway was inactivated. Lastly, we used the TB-signature to predict cyclopenthiazide as a potential inhibitor of the TB interface.

Conclusion

Our mouse breast cancer model morphologically and genetically resembles the osteoclastic bone microenvironment observed in human disease. Characterization of the gene expression signature specific to the TB interface in our model revealed signaling mechanisms operative in human breast cancer metastases and predicted a therapeutic inhibitor of cancer-mediated osteolysis.

Opioid analgesics and the risk of fractures in older adults with arthritis

OBJECTIVES

To compare the risk of fracture associated with initiating opioids with that of nonsteroidal anti-inflammatory drugs (NSAIDs) and the variation in risk according to opioid dose, duration of action, and duration of use.

DESIGN

Retrospective cohort study.

SETTING

Two statewide pharmaceutical benefit programs for persons aged 65 and older.

PARTICIPANTS

Twelve thousand four hundred thirty-six initiators of opioids and 4,874 initiators of NSAIDs began treatment between January 1, 1999, and December 31, 2006. Mean age at initiation of analgesia was 81; 85% of participants were female, and all had arthritis.

MEASUREMENTS

Cox proportional hazards models, adjusted for several potential confounders, quantified fracture risk. Study outcomes were fractures of the hip, humerus or ulna, or wrist, identified using a combination of diagnosis (International Classification of Diseases, Ninth Revision, Clinical Modification) and procedure (Common Procedural Terminology) codes.

RESULTS

There were 587 fracture events among the participants initiating opioids (120 fractures per 1,000 person-years) and 38 fracture events among participants initiating NSAIDs (25 fractures per 1,000 person-years) (hazard ratio (HR)=4.9, 95% confidence interval (CI)=3.5-6.9). Fracture risk was greater with higher opioid dose. Risk was greater for short-acting opioids (HR=5.1, 95% CI=3.7-7.1) than for long-acting opioids (HR=2.6, 95% CI=1.5-4.4), even in participants taking equianalgesic doses, with differential fracture risk apparent for the first 2 weeks after starting opioids but not thereafter.

CONCLUSION

Older people with arthritis who initiate therapy with opioids are more likely to experience a fracture than those who initiate NSAIDs. For the first 2 weeks after initiating opioid therapy, but not thereafter, short-acting opioids are associated with a greater risk of fracture than are long-acting opioids.

Effects of low-dose hydrochlorothiazide on urolithiasis and bone metabolism in severely disabled individuals: a pilot study

To clarify the effects of hydrochlorothiazide (HCT) on calcium metabolism in subjects with severe motor and intellectual disabilities (SMID), we examined four patients (16-48years old) with a history of urolithiasis and/or bone fracture and increased urinary calcium/creatinine ratio (U-Ca/Cr). U-Ca/Cr, blood markers of bone turnover, and bone-mineral density (BMD) were measured before and after administration of low-dose HCT (0.25-0.5mg/kg/day). Three months after the initiation of HCT, U-Ca/Cr decreased in all patients, but this effect was less evident at 9-18months. Bone-turnover marker of bone-specific alkaline phosphatase also showed a tendency to decrease, but BMD remained unchanged during the follow-up period. In SMID patients, HCT is beneficial for the treatment of hypercalciuria but its effects can be transient in certain cases. HCT may also ameliorate the increase in bone turnover, but its effects on the prevention of bone fractures remain uncertain. Hyponatremia is the most frequent and significant adverse effect of HCT, for which a close observation is mandatory in HCT application for patients with SMID.

Diuretics, calciuria and secondary hyperparathyroidism in the Chronic Renal Insufficiency Cohort

BACKGROUND

Secondary hyperparathyroidism is a common complication of chronic kidney disease (CKD) that is associated with bone disease, cardiovascular disease and death. Pathophysiological factors that maintain secondary hyperparathyroidism in advanced CKD are well-known, but early mechanisms of the disease that can be targeted for its primary prevention are poorly understood. Diuretics are widely used to control volume status and blood pressure in CKD patients but are also known to have important effects on renal calcium handling, which we hypothesized could alter the risk of secondary hyperparathyroidism.

METHODS

We examined the relationship of diuretic treatment with urinary calcium excretion, parathyroid hormone (PTH) levels and prevalence of secondary hyperparathyroidism (PTH ≥ 65 pg/mL) in a cross-sectional study of 3616 CKD patients in the Chronic Renal Insufficiency Cohort.

RESULTS

Compared with no diuretics, treatment with loop diuretics was independently associated with higher adjusted urinary calcium (55.0 versus 39.6 mg/day; P < 0.001), higher adjusted PTH [67.9, 95% confidence interval (CI) 65.2-70.7 pg/mL, versus 52.8, 95% CI 51.1-54.6 pg/mL, P < 0.001] and greater odds of secondary hyperparathyroidism (odds ratio 2.1; 95% CI 1.7-2.6). Thiazide monotherapy was associated with lower calciuria (25.5 versus 39.6 mg/day; P < 0.001) but only modestly lower PTH levels (50.0, 95% CI 47.8-52.3, versus 520.8, 95% CI 51.1-54.6 pg/mL, P = 0.04) compared with no diuretics. However, coadministration of thiazide and loop diuretics was associated with blunted urinary calcium (30.3 versus 55.0 mg/day; P <0.001) and odds of hyperparathyroidism (odds ratio 1.3 versus 2.1; P for interaction = 0.05) compared with loop diuretics alone.

CONCLUSIONS

Loop diuretic use was associated with greater calciuria, PTH levels and odds of secondary hyperparathyroidism compared to no treatment. These associations were attenuated in patients who were coadministered thiazides. Diuretic choice is a potentially modifiable determinant of secondary hyperparathyroidism in CKD.

Nephrolithiasis-associated bone disease: pathogenesis and treatment options

Nephrolithiasis remains a formidable health problem in the United States and worldwide. A very important but underaddressed area in nephrolithiasis is the accompanying bone disease. Epidemiologic studies have shown that osteoporotic fractures occur more frequently in patients with nephrolithiasis than in the general population. Decreased bone mineral density and defects in bone remodeling are commonly encountered in patients with calcium nephrolithiasis. The pathophysiologic connection of bone defects to kidney stones is unknown. Hypercalciuria and hypocitraturia are two important risk factors for stone disease, and treatments with thiazide diuretics and alkali, respectively, have been shown to be useful in preventing stone recurrence in small prospective trials. However, no studies have examined the efficacy of these agents or other therapies in preventing continued bone loss in calcium stone formers. This manuscript reviews the epidemiology, pathophysiology, and potential treatments of bone disease in patients with nephrolithiasis.

High dose vitamin D3 attenuates the hypocalciuric effect of thiazide in hypercalciuric rats

Thiazide is known to decrease urinary calcium excretion. We hypothesized that thiazide shows different hypocalciuric effects depending on the stimuli causing hypercalciuria. The hypocalciuric effect of hydrochlorothiazide (HCTZ) and the expression of transient receptor potential vanilloid 5 (TRPV5), calbindin-D(28K), and several sodium transporters were assessed in hypercalciuric rats induced by high calcium diet and vitamin D(3). Urine calcium excretion and the expression of transporters were measured from 4 groups of Sprague-Dawley rats; control, HCTZ, high calcium-vitamin D, and high calcium-vitamin D with HCTZ groups. HCTZ decreased urinary calcium excretion by 51.4% in the HCTZ group and only 15% in the high calcium-vitamin D with HCTZ group. TRPV5 protein abundance was not changed by HCTZ in the high calcium-vitamin D with HCTZ group compared to the high calcium-vitamin D group. Protein abundance of NHE3, SGLT1, and NKCC2 decreased in the hypercalciuric rats, and only SGLT1 protein abundance was increased by HCTZ in the hypercalciuric rats. The hypocalciuric effect of HCTZ is attenuated in high calcium and vitamin D-induced hypercalciuric rats. This attenuation seems to have resulted from the lack of HCTZ's effect on protein abundance of TRPV5 in severe hypercalciuric condition induced by high calcium and vitamin D.

Effects of thiazide on the expression of TRPV5, calbindin-D28K, and sodium transporters in hypercalciuric rats

TRPV5 is believed to play an important role in the regulation of urinary calcium excretion. We assessed the effects of hydrochlorothiazide (HCTZ) on the expression of TRPV5, calbindin-D(28K), and several sodium transporters in hypercalciuric rats. Sprague-Dawley rats were divided into 4 groups; control, HCTZ, high salt, and high salt with HCTZ group in experiment 1; control, HCTZ, high calcium (Ca), and high Ca with HCTZ group in experiment 2. To quantitate the expression of TRPV5, calbindin-D(28K), and sodium transporters, western blotting was performed. In both experiments, HCTZ significantly decreased urinary calcium excretion. TRPV5 protein abundance decreased in all hypercalciuric rats, and restored by HCTZ in both high salt with HCTZ and high Ca with HCTZ group. Calbindin-D(28K) protein abundance increased in the high salt and high salt with HCTZ groups, but did not differ among groups in experiment 2. Protein abundance of NHE3 and NKCC2 decreased in all hypercalciuric rats, and were restored by HCTZ in only high Ca-induced hypercalciuric rats. In summary, protein abundance of TRPV5, NHE3, and NKCC2 decreased in all hypercalciuric rats. The hypocalciuric effect of HCTZ is associated with increased protein abundance of TRPV5 in high salt or calcium diet-induced hypercalciuric rats.