Oral bisphosphonate use in the elderly is not associated with acute kidney injury

The Efficacy and Safety of Bisphosphonate Therapy for Osteopenia/Osteoporosis in Patients With Chronic Kidney Disease: A Systematic Review and Individual Patient-Level Meta-Analysis of Placebo-Controlled Randomized Trials

Background

The efficacy and safety of bisphosphonate therapy for the treatment of osteoporosis and osteopenia in the setting of chronic kidney disease (CKD) is unclear.

Objective

To determine the effect of bisphosphonate therapy on fractures, bone mineral density (BMD), and adverse events in adults across the spectrum of CKD and dialysis.

Design

Systematic review and individual patient-level meta-analysis.

Setting

Searches of Ageline, CINAHL, the Cochrane Library, EMBASE, and Medline from inception to August 25, 2016, supplemented with manual screening and clinicalstudydatarequest.com. Authors were contacted for individual patient-level data.

Patients

Randomized, placebo-controlled trials with 100 or more participants that evaluated the treatment of primary osteoporosis/osteopenia in adult men and women with bisphosphonate therapy.

Measurements

Study characteristics, quality, and data were assessed independently by 2 reviewers. Outcome measures were fractures, BMD, and adverse events including decline in estimated glomerular filtration rate (eGFR) and hypocalcemia (calcium <2.00 mmol/L).

Methods

Single-stage individual patient-level meta-analysis.

Results

Of 39 eligible studies, individual patient-level data was available for 7 studies, all of which were studies of ibandronate. Of 7428 participants (5010 ibandronate, 2418 placebo), 100% were female, 98.6% were white, the mean body mass index was 25.7 kg/m2 (SD 3.9), 18.9% were smokers and there were 740 fracture events. The mean eGFR was 69.1 mL/min/1.73 m2 (SD 15.9) including 14.5%, 54.9%, 27.5%, 3.0%, and 0.2% stages G1, G2, G3A, G3B, and G4 CKD. Ibandronate increased hip and lumbar spine BMD and decreased the risk of fracture in the overall population (hazard ratio (HR) 0.871, 95% confidence interval (CI) 0.746, 1.018) but in patients with stage G3B CKD, it increased the risk of fracture (HR 3.862, 95% CI 1.156, 12.903). Ibandronate did not impact eGFR over 12 months but increased the risk of hypocalcemia (HR 1.324, 95% CI 1.056, 1.660) with no evidence of any effect modification by CKD stage (all tests of interaction p > 0.05).

Limitations

Clinically significant heterogeneity among studies, lack of long-term follow-up and bone biopsy results, limited representation of stage G4 and G5 CKD patients.

Conclusions

Chronic kidney disease potentially modifies the efficacy but not the safety of bisphosphonate therapy in osteopenia and osteoporosis.

Registration

PROSPERO CRD42020145613.

Oral Bisphosphonates Are Associated With Increased Risk of Severe Acute Kidney Injury in Elderly Patients With Complex Health Needs: A Self-Controlled Case Series in the United Kingdom

Although oral bisphosphonates (BP) are commonly used, there is conflicting evidence for their safety in the elderly. Safety concerns might trump BP use in older patients with complex health needs. Our study evaluated the safety of BP, focusing on severe acute kidney injury (AKI), gastrointestinal ulcer (GI ulcer), osteonecrosis of the jaw (ONJ), and femur fractures. We used UK primary care data (Clinical Practice Research Datalink [CPRD GOLD]), linked to hospital (Hospital Episode Statistics [HES] inpatient) and ONS mortality data. We included all patients aged >65 with complex health needs and no BP use in the year before study start (January 1, 2010). Complex health needs were defined in three cohorts: an electronic frailty index score ≥3 (frailty cohort), one or more unplanned hospitalization/s (hospitalization cohort); and prescription of ≥10 different medicines in 2009 (polypharmacy cohort). Incidence rates were calculated for all outcomes. Subsequently, all individuals who experienced AKI or GI ulcer anytime during follow-up were included for Self-Controlled Case Series (SCCS) analyses. Incidence rate ratios (IRRs) were estimated separately for AKI and GI ulcer, comparing event rates between BP-exposed and unexposed time windows. No SCCS were conducted for ONJ and femur fractures. We identified 94,364 individuals in the frailty cohort, as well as 78,184 and 95,621 persons in the hospitalization and polypharmacy cohorts. Of those, 3023, 1950, and 2992 individuals experienced AKI and 1403, 1019, and 1453 had GI ulcer/s during follow-up, respectively. Age-adjusted SCCS models found evidence of increased risk of AKI associated with BP use (frailty cohort: IRR 1.65; 95% confidence interval [CI], 1.25-2.19), but no association with GI ulcers (frailty cohort: IRR 1.24; 95% CI, 0.86-1.78). Similar results were obtained for the hospitalization and polypharmacy cohorts. Our study found a 50% to 65% increased risk of AKI associated with BP use in elderly patients with complex health needs. Future studies should further investigate the risk-benefit of BP use in these patients. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Association between Anti-Osteoporotic Drugs and Risk of Acute Kidney Injury: A Cross-Sectional Study Using Disproportional Analysis and a Pharmacovigilance Database

The number of fractures related to osteoporosis is expected to increase. Therefore, clarifying the risk of acute kidney injury (AKI) associated with each type of anti-osteoporotic drug may avoid discontinuation of osteoporosis pharmacotherapy due to onset of AKI. This cross-sectional study using disproportional analysis and a pharmacovigilance database assessed the risk of AKI with various anti-osteoporotic drugs by analyzing data entered into the US Food and Drug Administration's Adverse Event Reporting System (FAERS) from April 2014 to March 2021 and the Medical Data Vision (MDV) database in Japan in November 2021. All anti-osteoporotic drugs were investigated, including bisphosphonates, selective estrogen receptor modulators, denosumab, romosozumab, abaloparatide, and teriparatide. In the analysis of FAERS data, disproportionality for decreasing AKI was observed for oral ibandronate [reporting odds ratios (ROR) 0.22, 95% confidence interval (CI) 0.09-0.45, P < 0.01], bazedoxifene (ROR 0.26, 95% CI 0.05-0.77, P = 0.01), and intravenous ibandronate (ROR 0.39, 95% CI 0.14-0.86, P = 0.01). In the analysis of the MDV data, the incidence of AKI was lower in patients taking intravenous ibandronate [odds ratio (OR) 0.22, 95% CI 0.06-0.89, P = 0.03], and the incidence of AKI was higher in patients taking oral alendronate (OR 2.40, 95% CI 2.08-2.77, P < 0.01). Risk of AKI may differ even among oral anti-osteoporotic drugs, and the evidence of this association should be assessed further in future drug safety studies. This article is protected by copyright. All rights reserved.

Bone and Mineral Disease in Kidney Transplant Recipients

After kidney transplantation, mineral and bone disorders are associated with higher risk of fractures and consequent morbidity and mortality. Disorders of calcium and phosphorus, vitamin D deficiency, and hyperparathyroidism are also common. The epidemiology of bone disease has evolved over the past several decades due to changes in immunosuppressive regimens, mainly glucocorticoid minimization or avoidance. The assessment of bone disease in kidney transplant recipients relies on risk factor recognition and bone mineral density assessment. Several drugs have been trialed for the treatment of post-transplant mineral and bone disorders. This review will focus on the epidemiology, effect, and treatment of metabolic and skeletal derangements in the transplant recipient.

Effects of bisphosphonates on long-term kidney transplantation outcomes

BACKGROUND

Bisphosphonates are administered to post-transplantation patients with mineral and bone disorders; however, the association between bisphosphonate therapy and long-term renal graft survival remains unclear.

METHODS

This nested case-control study investigated the effects of bisphosphonates on long-term graft outcomes after kidney transplantation. We enrolled 3836 kidney transplant recipients treated from April 1979 to June 2016 and matched patients with graft failure to those without (controls). Annual post-transplant bone mineral density assessments were performed and recipients with osteopenia or osteoporosis received bisphosphonate therapy. The associations between bisphosphonate use and long-term graft outcomes and graft survival were analyzed using conditional logistic regression and landmark analyses, respectively.

RESULTS

A landmark analysis demonstrated that death-censored graft survival was significantly higher in bisphosphonate users than in non-users in the entire cohort (log-rank test, P < 0.001). In the nested case-control matched cohort, bisphosphonate users had a significantly reduced risk of graft failure than did non-users (odds ratio = 0.38; 95% confidence interval 0.30-0.48). Bisphosphonate use, increased cumulative duration of bisphosphonate use >1 year and increased cumulative bisphosphonate dose above the first quartile were associated with a reduced risk of graft failure, after adjustments.

CONCLUSIONS

Bisphosphonates may improve long-term graft survival in kidney transplant recipients.

Bisphosphonate nephropathy: A case series and review of the literature

From rat studies, human case reports and cohort studies, bisphosphonates seem to impair renal function. However, when critically reviewing the literature, zoledronate and pamidronate are more frequently involved in renal deterioration than other bisphosphonates. When bisphosphonate nephropathy occurs, zoledronate more frequently induces tubular toxicity whereas pamidronate typically induces focal segmental glomerulosclerosis. Thus, although bisphosphonates are highly effective in preventing complications for patients with osseous metastases and are highly effective in preventing fractures for patients with osteoporosis, renal function should be monitored closely after initiation of these drugs.

Bisphosphonates to reduce bone fractures in stage 3B+ chronic kidney disease: a propensity score-matched cohort study

BACKGROUND

Bisphosphonates are contraindicated in patients with stage 4+ chronic kidney disease. However, they are widely used to prevent fragility fractures in stage 3 chronic kidney disease, despite a lack of good-quality data on their effects.

OBJECTIVES

The aims of each work package were as follows. Work package 1: to study the relationship between bisphosphonate use and chronic kidney disease progression. Work package 2: to study the association between using bisphosphonates and fracture risk. Work package 3: to determine the risks of hypocalcaemia, hypophosphataemia, acute kidney injury and upper gastrointestinal events associated with using bisphosphonates. Work package 4: to investigate the association between using bisphosphonates and changes in bone mineral density over time.

DESIGN

This was a new-user cohort study design with propensity score matching.

SETTING AND DATA SOURCES

Data were obtained from UK NHS primary care (Clinical Practice Research Datalink GOLD database) and linked hospital inpatient records (Hospital Episode Statistics) for work packages 1-3 and from the Danish Odense University Hospital Databases for work package 4.

PARTICIPANTS

Patients registered in the data sources who had at least one measurement of estimated glomerular filtration rate of < 45 ml/minute/1.73 m2 were eligible. A second estimated glomerular filtration rate value of < 45 ml/minute/1.73 m2 within 1 year after the first was requested for work packages 1 and 3. Patients with no Hospital Episode Statistics linkage were excluded from work packages 1-3. Patients with < 1 year of run-in data before index estimated glomerular filtration rate and previous users of anti-osteoporosis medications were excluded from work packages 1-4.

INTERVENTIONS/EXPOSURE

Bisphosphonate use, identified from primary care prescriptions (for work packages 1-3) or pharmacy dispensations (for work package 4), was the main exposure.

MAIN OUTCOME MEASURES

Work package 1: chronic kidney disease progression, defined as stage worsening or starting renal replacement. Work package 2: hip fracture. Work package 3: acute kidney injury, hypocalcaemia and hypophosphataemia identified from Hospital Episode Statistics, and gastrointestinal events identified from Clinical Practice Research Datalink or Hospital Episode Statistics. Work package 4: annualised femoral neck bone mineral density percentage change.

RESULTS

Bisphosphonate use was associated with an excess risk of chronic kidney disease progression (subdistribution hazard ratio 1.12, 95% confidence interval 1.02 to 1.24) in work package 1, but did not increase the probability of other safety outcomes in work package 3. The results from work package 2 suggested that bisphosphonate use increased fracture risk (hazard ratio 1.25, 95% confidence interval 1.13 to 1.39) for hip fractures, but sensitivity analyses suggested that this was related to unresolved confounding. Conversely, work package 4 suggested that bisphosphonates improved bone mineral density, with an average 2.65% (95% confidence interval 1.32% to 3.99%) greater gain in femoral neck bone mineral density per year in bisphosphonate users than in matched non-users.

LIMITATIONS

Confounding by indication was a concern for the clinical effectiveness (i.e. work package 2) data. Bias analyses suggested that these findings were due to inappropriate adjustment for pre-treatment risk. work packages 3 and 4 were based on small numbers of events and participants, respectively.

CONCLUSIONS

Bisphosphonates were associated with a 12% excess risk of chronic kidney disease progression in participants with stage 3B+ chronic kidney disease. No other safety concerns were identified. Bisphosphonate therapy increased bone mineral density, but the research team failed to demonstrate antifracture effectiveness.

FUTURE WORK

Randomised controlled trial data are needed to demonstrate antifracture efficacy in patients with stage 3B+ chronic kidney disease. More safety analyses are needed to characterise the renal toxicity of bisphosphonates in stage 3A chronic kidney disease, possibly using observational data.

STUDY REGISTRATION

This study is registered as EUPAS10029.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 17. See the NIHR Journals Library website for further project information. The project was also supported by the National Institute for Health Research Biomedical Research Centre, Oxford.

The association between renal function and BMD response to bisphosphonate treatment: Real-world cohort study using linked national registers

BACKGROUND

Management of osteoporosis given reduced renal function is one of the largest challenges in the bone clinic.

OBJECTIVES

Identify the cut-off for renal function below which there would be no overall BMD benefit associated with bisphosphonate use. Track safety outcomes resulting in hospital encounters.

METHODS

Population-based, observational register-linked study of BMD trajectories in adults from the island of Funen (pop 465,000) as a function of estimated creatinine clearance (CKD-epi), treatment and adherence to oBP. One laboratory performed all the biochemical analyses for the area while all DXA scans were in a central facility. For inclusion, patients were required to have both a DXA scan and an eGFR measurement (CKD-EPI) within 1 year prior to their study index date. Medication Possession Ratio (MPR) was calculated from national data.

RESULTS

Out of 6176 incident BP users, 1789 had eGFR and DXA measurements at appropriate timepoints for the planned analysis, while this was the case for 3908 of 29,336 non-users. Users of oBPs exhibited progressively smaller gains in BMD with decreasing renal function. However, for CKD stage 3A and better, the annual change in BMD was significantly more positive than in the non-user group at similar levels of renal function. In non-users, the average annual change in BMD was negative but largely unaffected by renal function down to stage 3B. There were no new cases of acute renal injury, glomerulonephritis or dialysis. The rate of new kidney transplantation was zero in non-users and 0.26 per 1000 PY in the BP user population. Hypocalcaemia encounters did not differ significantly from that seen in non-users.

CONCLUSIONS

The BMD changes observed in real-world users of oBP in this population based single-clinic are consistent with those observed in the original RCTs of alendronate. We noted a gradual decrease in the absolute gains in BMD in oBP users with decreasing renal function though there was no significant interaction - largely explained by low numbers of treated patients with poor renal function - between CKD stage and adherence driven BMD change. There were no cases of acute renal injury resulting in hospital encounters. More data is needed on the efficacy and safety of bisphosphonates in CKD stage 3B to 5 and prescribers should reconsider the low use of DXA in patients with renal function impairment now that a wider range of treatment options are available.

Oral Bisphosphonate Use and All-Cause Mortality in Patients With Moderate-Severe (Grade 3B-5D) Chronic Kidney Disease: A Population-Based Cohort Study

Oral bisphosphonates (oBPs) have been associated with reduced fractures and mortality. However, their risks and benefits are unclear in patients with moderate-severe CKD. This study examined the association between oBPs and all-cause mortality in G3B-5D CKD. This is a population-based cohort study including all subjects with an estimated glomerular filtration rate (eGFR) <45/mL/min/1.73 m² (G3B: eGFR <45/mL/min/1.73 m² G4: eGFR 15-29/mL/min/1.73 m² G5: eGFR <15/mL/min/1.73 m² G5D: hemodialysis) aged 40+ years from the UK Clinical Practice Research Datalink (CPRD) and the Catalan Information System for Research in Primary Care (SIDIAP). Previous and current users of other anti-osteoporosis drugs were excluded. oBP use was modeled as a time-varying exposure to avoid immortal time bias. Treatment episodes in oBP users were created by concatenating prescriptions until patients switched or stopped therapy or were censored or died. A washout period of 180 days was added to (date of last prescription +180 days). Propensity scores (PSs) were calculated using prespecified predictors of mortality including age, gender, baseline eGFR, socioeconomic status, comorbidities, previous fracture, co-medications, and number of hospital admissions in the previous year. Cox models were used for PS adjustment before and after PS trimming (the first and last quintiles). In the CPRD, of 19,351 oBP users and 210,954 non-oBP users, 5234 (27%) and 85,105 (40%) deaths were recorded over 45,690 and 915,867 person-years of follow-up, respectively. oBP users had 8% lower mortality risk compared to non-oBP users (hazard ratio [HR] 0.92; 95% CI, 0.89 to 0.95). Following PS trimming, this became nonsignificant (HR 0.98; 95% CI, 0.94 to 1.04). In the SIDIAP, of 4146 oBP users and 86,127 non-oBP users, 1330 (32%) and 36,513 (42%) died, respectively. oBPs were not associated with mortality in PS adjustment and trimming (HR 1.04; 95% CI, 0.99 to 1.1 and HR 0.95; 95% CI, 0.89 to 1.01). In this observational, patient-based cohort study, oBPs were not associated with increased mortality among patients with moderate-severe CKD. However, further studies are needed on other effects of oBPs in CKD patients. © 2020 American Society for Bone and Mineral Research.

Bisphosphonate therapy in CKD: the current state of affairs

PURPOSE OF REVIEW

Chronic kidney disease (CKD) is associated with the development of mineral and bone disorders (MBD), including renal osteodystrophy (ROD). ROD is a global disorder of bone strength that is associated with an increased fracture risk. The use of bisphosphonates for fracture risk reduction in CKD remains controversial. This review provides a synopsis of the state-of-the literature regarding the safety and potential antifracture benefits of bisphosphonates in CKD patients.

RECENT FINDINGS

In preclinical studies of animals with CKD 3-4 and evidence of CKD-MBD, bisphosphonates resulted in changes in bone quality that improve bone strength. Bone turnover was generally reduced to a similar extent in animals with and without CKD. Post hoc analyses of randomized trials in patients with CKD 3-4 reported increases in bone mineral density (BMD) and fracture reduction that were similar in patients with and without CKD. There are no primary clinical trial data in patients with CKD-MBD.

SUMMARY

In patients with CKD without evidence of CKD-MBD, the use of bisphosphonates should follow general population guidelines. The lack of data for patients with CKD 4-5D and evidence of CKD-MBD makes treatment decisions challenging. Clinical studies are urgently needed to provide data on the safety and antifracture benefits of bisphosphonates in these cohorts.

Nephrology comanagement and the quality of antibiotic prescribing in primary care for patients with chronic kidney disease: a retrospective cross-sectional study

BACKGROUND

In primary care, patients with chronic kidney disease (CKD) are frequently prescribed excessive doses of antibiotics relative to their kidney function. We examined whether nephrology comanagement is associated with improved prescribing in primary care.

METHODS

In a retrospective propensity score-matched cross-sectional study, we studied the appropriateness of antibiotic prescriptions by primary care physicians to Ontarians ≥66 years of age with CKD Stages 4 and 5 (estimated glomerular filtration rate <30 mL/min/1.73 m2 not receiving dialysis) from 1 April 2003 to 31 March 2014. Comanagement was defined as having at least one outpatient visit with a nephrologist within the year prior to antibiotic prescription date. We compared the rate of appropriately dosed antibiotics in primary care between 3937 patients who were comanaged by a nephrologist and 3937 patients who were not.

RESULTS

Only 1184 (30%) of 3937 noncomanaged patients had appropriately dosed antibiotic prescriptions prescribed by a primary care physician. Nephrology comanagement was associated with an increased likelihood that an appropriately dosed prescription was prescribed by a primary care physician; however, the magnitude of the effect was modest [1342/3937 (34%); odds ratio 1.20 (95% confidence interval 1.09-1.32); P < 0.001].

CONCLUSION

The majority of antibiotics prescribed by primary care physicians are inappropriately dosed in CKD patients, whether or not a nephrologist is comanaging the patient. Nephrologists have an opportunity to increase awareness of appropriate dosing of medications in primary care through the patients they comanage.

Skeletal levels of bisphosphonate in the setting of chronic kidney disease are independent of remodeling rate and lower with fractionated dosing

BACKGROUND

Chronic kidney disease (CKD) results in a dramatic increase in skeletal fracture risk. Bisphosphates (BP) are an effective treatment for reducing fracture risk but they are not recommended in advanced CKD. We have recently shown higher acute skeletal accumulation of fluorescently-tagged zoledronate (ZOL) in the setting of CKD but how this accumulation is retained/lost over time is unclear. Furthermore, it is unknown if alternative dosing approaches can modulate accumulation in the setting of CKD.

METHODS

To address these two questions normal (NL) and Cy/+ (CKD) rats were divided into control groups (no dosing), a single dose of a fluorescent-tagged ZOL (FAM-ZOL), a single dose of non-labelled zoledronate (ZOL) or ten weekly doses of FAM-ZOL each at 1/10th the dose of the single dose group. Half of the CKD animals in each group were provided water with 3% calcium in drinking water (CKD + Ca) to suppress PTH and remodeling. At 30 or 35 weeks of age, serum, tibia, ulna, radius, vertebra, femora, and mandible were collected and subjected to assessment methods including biochemistry, dynamic histomorphometry and multi-spectral fluorescence levels (using IVIS SpectrumCT).

RESULTS

FAM-ZOL did not significantly reduce bone remodeling in either NL or CKD animals while Ca supplementation in CKD produced remodeling levels comparable to NL. At five- and ten-weeks post-dosing, both CKD and CKD + Ca groups had higher levels of FAM-ZOL in most, but not all, skeletal sites compared to NL with no difference between the two CKD groups suggesting that the rate of remodeling did not affect skeletal retention of FAM-ZOL. Fractionating the FAM-ZOL into ten weekly doses led to 20-32% less (p < 0.05) accumulation/retention of compound in the vertebra, radius, and ulna compared to administration as a single dose.

CONCLUSIONS

The rate of bone turnover does not have significant effects on levels of FAM-ZOL accumulation/retention in animals with CKD. A lower dose/more frequent administration paradigm results in lower levels of accumulation/retention over time. These data provide information that could better inform the use of bisphosphonates in the setting of CKD in order to combat the dramatic increase in fracture risk.

Fracture risk and treatment in chronic kidney disease

PURPOSE OF REVIEW

Chronic kidney disease (CKD) is associated with the development of mineral bone disorder (MBD), osteoporosis, and fragility fractures. The purpose of this review is to provide an update on recent findings in the diagnosis and treatment of osteoporosis in patients with CKD.

RECENT FINDINGS

Multiple observational studies have shown that bone mineral density measurement using DEXA is equally predictive in CKD stages 1-3, as in the general population. Post hoc analyses from randomized trials of bisphosphonates, SERM, RANKL inhibitors and PTH agonists all suggest equal efficacy in mild-moderate CKD. A recent systematic review also found evidence for efficacy of bisphosphonates in patients with a kidney transplant.

SUMMARY

Bone mineral density measurement using DEXA is accurate in patients with CKD stages 1-3 and should be considered to guide treatment of osteoporosis. Current treatments are unaffected by mild-to-moderate decline in kidney function, and physicians should use bisphosphonates and other osteoporosis treatments in this population, whenever indicated. Studies evaluating the optimal diagnostic and management strategy in patients with CKD stages (G4-5D) are needed.

Population-Based Study of Risk of AKI with Levetiracetam

BACKGROUND AND OBJECTIVES

Regulatory agencies warn about the risk of AKI with levetiracetam use on the basis of information from case reports. We conducted this study to determine whether new levetiracetam use versus nonuse is associated with a higher risk of AKI.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a population-based retrospective cohort study of adults with epilepsy in Ontario, Canada. Patients who received a new outpatient prescription for levetiracetam between January 1, 2004 and March 1, 2017 were matched to two nonusers on stage of CKD, recorded seizure in the prior 90 days, and logit of a propensity score for levetiracetam use. The primary outcome was a hospital encounter (emergency department visit or hospitalization) with AKI within 30 days of cohort entry. Secondary outcomes were AKI within 180 days and change in the concentration of serum creatinine. We assessed the primary outcome using health care diagnosis codes. We evaluated the change in the concentration of serum creatinine in a subpopulation with laboratory measurements.

RESULTS

We matched 3980 levetiracetam users to 7960 nonusers (mean age 55 years, 51% women). Levetiracetam use was not significantly associated with a higher risk of AKI within 30 days (13 [0.33%] events in levetiracetam users and 21 [0.26%] events in nonusers [odds ratio, 1.24; 95% confidence interval, 0.62 to 2.47]). Similarly, there was no significant association with AKI within 180 days (odds ratio, 0.70; 95% confidence interval, 0.43 to 1.13). The change in the concentration of serum creatinine did not significantly differ between levetiracetam users and nonusers.

CONCLUSIONS

In this population-based study levetiracetam use was not associated with a higher risk of AKI.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2018_12_11_Yau_Podcast.mp3.

Side effects of drugs for osteoporosis and metastatic bone disease

Osteoporosis is a common condition that leads to substantial morbidity and mortality and affects an increasing number of persons worldwide. Several pharmacological therapies that inhibit bone resorption, promote bone formation, or both, are available for the treatment of osteoporosis. The osteoanabolic treatment spectrum was recently expanded by the introduction of a novel bone-forming agent in the United States, and clinical trials indicate that a new class of bone anabolic therapy may become available. Both antiresorptive and bone anabolic therapies are associated with common and rare adverse effects, which are particularly important to address as these drugs are used for long-term treatment in numerous patients with a large proportion being elderly and/or having multimorbidity. In addition, antiresorptive drugs are used to inhibit bone resorption in patients with malignant hypercalcaemia or to prevent skeletal events in cancer patients, and bisphosphonates have been repurposed as a cancer preventive therapy. However, therapeutic doses are generally higher when antiresorptive drugs are used in the oncological setting, which influence the prevalence of adverse effects significantly. This review highlights key issues and controversies regarding adverse effects of currently available and emerging drugs used for osteoporosis and metastatic bone diseases.

Skeletal accumulation of fluorescently tagged zoledronate is higher in animals with early stage chronic kidney disease

This work examines the skeletal accumulation of fluorescently tagged zoledronate in an animal model of chronic kidney disease. The results show higher accumulation in 24-h post-dose animals with lower kidney function due to greater amounts of binding at individual surfaces.

INTRODUCTION

Chronic kidney disease (CKD) patients suffer from increased rates of skeletal-related mortality from changes driven by biochemical abnormalities. Bisphosphonates are commonly used in reducing fracture risk in a variety of diseases, yet their use is not recommended in advanced stages of CKD. This study aimed to characterize the accumulation of a single dose of fluorescently tagged zoledronate (FAM-ZOL) in the setting of reduced kidney function.

METHODS

At 25 weeks of age, FAM-ZOL was administered to normal and CKD rats. Twenty-four hours later, multiple bones were collected and assessed using bulk fluorescence imaging, two-photon imaging, and dynamic histomorphometry.

RESULTS

CKD animals had significantly higher levels of FAM-ZOL accumulation in the proximal tibia, radius, and ulna, but not in lumbar vertebral body or mandible, based on multiple measurement modalities. Although a majority of trabecular bone surfaces were covered with FAM-ZOL in both normal and CKD animals, the latter had significantly higher levels of fluorescence per unit bone surface in the proximal tibia.

CONCLUSIONS

These results provide new data regarding how reduced kidney function affects drug accumulation in rat bone.

Risk of Ventricular Arrhythmia with Citalopram and Escitalopram: A Population-Based Study

Background

The risk of ventricular arrhythmia with citalopram and escitalopram is controversial. In this study we investigated the association between these two drugs and the risk of ventricular arrhythmia.

Methods

We conducted a population-based retrospective cohort study of older adults (mean age 76 years) from 2002 to 2012 in Ontario, Canada, newly prescribed citalopram (n = 137 701) or escitalopram (n = 38 436), compared to those prescribed referent antidepressants sertraline or paroxetine (n = 96 620). After inverse probability of treatment weighting using a propensity score, the baseline characteristics of the comparison groups were similar. The primary outcome was a hospital encounter with ventricular arrhythmia within 90 days of a new prescription, assessed using hospital diagnostic codes. The secondary outcome was all-cause mortality within 90 days.

Results

Citalopram was associated with a higher risk of a hospital encounter with ventricular arrhythmia compared with referent antidepressants (0.06% vs. 0.04%, relative risk [RR] 1.53, 95% confidence intervals [CI]1.03 to 2.29), and a higher risk of mortality (3.49% vs. 3.12%, RR 1.12, 95% CI 1.06 to 1.18). Escitalopram was not associated with a higher risk of ventricular arrhythmia compared with the referent antidepressants (0.03% vs. 0.04%, RR 0.84, 95% CI 0.42 to 1.68), but was associated with a higher risk of mortality (2.86% vs. 2.63%, RR 1.09, 95% CI 1.01 to 1.18).

Conclusion

Among older adults, initiation of citalopram compared to two referent antidepressants was associated with a small but statistically significant increase in the 90-day risk of a hospital encounter for ventricular arrhythmia.

Determination of pKa values of alendronate sodium in aqueous solution by piecewise linear regression based on acid-base potentiometric titration

As a mono-sodium salt form of alendronic acid, alendronate sodium presents multi-level ionization for the dissociation of its four hydroxyl groups. The dissociation constants of alendronate sodium were determined in this work by studying the piecewise linear relationship between volume of titrant and pH value based on acid-base potentiometric titration reaction. The distribution curves of alendronate sodium were drawn according to the determined pKa values. There were 4 dissociation constants (pKa₁=2.43, pKa₂=7.55, pKa₃=10.80, pKa₄=11.99, respectively) of alendronate sodium, and 12 existing forms, of which 4 could be ignored, existing in different pH environments.

Statin Safety in Chinese: A Population-Based Study of Older Adults

Background

Compared to Caucasians, Chinese achieve a higher blood concentration of statin for a given dose. It remains unknown whether this translates to increased risk of serious statin-associated adverse events amongst Chinese patients.

Methods

We conducted a population-based retrospective cohort study of older adults (mean age, 74 years) newly prescribed a statin in Ontario, Canada between 2002 and 2013, where 19,033 Chinese (assessed through a validated surname algorithm) were matched (1:3) by propensity score to 57,099 non-Chinese. This study used linked healthcare databases.

Findings

The follow-up observation period (mean 1.1, maximum 10.8 years) was similar between groups, as were the reasons for censoring the observation period (end of follow-up, death, or statin discontinuation). Forty-seven percent (47%) of Chinese were initiated on a higher than recommended statin dose. Compared to non-Chinese, Chinese ethnicity did not associate with any of the four serious statin-associated adverse events assessed in this study [rhabdomyolysis hazard ratio (HR) 0.61 (95% CI 0.28 to 1.34), incident diabetes HR 1.02 (95% CI 0.80 to 1.30), acute kidney injury HR 0.90 (95% CI 0.72 to 1.13), or all-cause mortality HR 0.88 (95% CI 0.74 to 1.05)]. Similar results were observed in subgroups defined by statin type and dose.

Conclusions

We observed no higher risk of serious statin toxicity in Chinese than matched non-Chinese older adults with similar indicators of baseline health. Regulatory agencies should review available data, including findings from our study, to decide if a change in their statin dosing recommendations for people of Chinese ethnicity is warranted.

Macrolide antibiotics and the risk of ventricular arrhythmia in older adults

BACKGROUND

Many respiratory tract infections are treated with macrolide antibiotics. Regulatory agencies warn that these antibiotics increase the risk of ventricular arrhythmia. We examined the 30-day risk of ventricular arrhythmia and all-cause mortality associated with macrolide antibiotics relative to nonmacrolide antibiotics.

METHODS

We conducted a population-based retrospective cohort study involving older adults (age > 65 yr) with a new prescription for an oral macrolide antibiotic (azithromycin, clarithromycin or erythromycin) in Ontario from 2002 to 2013. Our primary outcome was a hospital encounter with ventricular arrhythmia within 30 days after a new prescription. Our secondary outcome was 30-day all-cause mortality. We matched patients 1:1 using propensity scores to patients prescribed nonmacrolide antibiotics (amoxicillin, cefuroxime or levofloxacin). We used conditional logistic regression to measure the association between macrolide exposure and outcomes, and repeated the analysis in 4 subgroups defined by the presence or absence of chronic kidney disease, congestive heart failure, coronary artery disease and concurrent use of a drug known to prolong the QT interval.

RESULTS

Compared with nonmacrolide antibiotics, macrolide antibiotics were not associated with a higher risk of ventricular arrhythmia (0.03% v. 0.03%; relative risk [RR] 1.06, 95% confidence interval [CI] 0.83-1.36) and were associated with a lower risk of all-cause mortality (0.62% v. 0.76%; RR 0.82, 95% CI 0.78-0.86). These associations were similar in all subgroups.

INTERPRETATION

Among older adults, macrolide antibiotics were not associated with a higher 30-day risk of ventricular arrhythmia than nonmacrolide antibiotics. These findings suggest that current warnings from the US Food and Drug Administration may be overstated.

Pharmacology of Bisphosphonates in Patients with Chronic Kidney Disease

Bisphosphonates are medications which bind strongly to mineral. They are ingested by osteoclasts and inhibit an enzyme necessary for bone resorption. The gastrointestinal absorption is poor and the only method of excretion is renal. Therefore, in patients with CKD the body accumulates a higher percentage of a dose of bisphosphonate. These medications remain attached to bone mineral for many years. Although the primary action is to inhibit bone resorption, secondarily bone formation is also inhibited, and in patients with CKD bisphosphonate use often leads to adynamic bone. In some experimental models in animals, the bisphosphonates can inhibit vascular calcification but this effect has not been seen in humans. Intravenous bisphosphonates may cause renal damage but oral doses do not reduce creatinine clearance. In stage 3 CKD, in patients who still have normal PTH, calcium, and alkaline phosphatase, randomized trials show similar benefits as in patients without CKD. Data from stage 4 and 5 CKD are very limited and no clear benefit has been shown.

The risk of pancreatitis with sitagliptin therapy in older adults: a population-based cohort study

BACKGROUND

The risk of pancreatitis with sitagliptin use in routine care remains to be established in older patients. We aimed to determine this risk in older adults who were newly prescribed sitagliptin versus an alternative hypoglycemic agent in the outpatient setting.

METHODS

In a population-based retrospective cohort study in Ontario from 2010 until 2012 involving adults aged 66 years and older, we studied those who were newly prescribed sitagliptin or an alternative hypoglycemic agent. Our primary outcome of interest was a hospital encounter (emergency department visit or hospital admission) with acute pancreatitis within 90 days. We used inverse probability of treatment weighting to balance the 2 groups and logistic regression with a robust variance estimate to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

A total of 57 689 patients (mean age 74 yr) were newly prescribed sitagliptin, and 83 405 patients (mean age 75 yr) were given an alternative hypoglycemic agent (metformin, glyburide, gliclazide or insulin) during the study period. After weighting, there were no significant differences in measured baseline characteristics between groups. In the weighted sample, sitagliptin was not associated with an increased risk of a hospital encounter with pancreatitis compared with alternative hypoglycemic agents (weighted total 46 of 57 689 patients taking sitagliptin [0.08%] v. 48 of 55 705 patients taking alternative hypoglycemic agents [0.09%], absolute risk difference -0.01% [95% CI -0.05% to 0.02%], OR 0.92 [95% CI 0.55 to 1.55]).

INTERPRETATION

Older adults newly prescribed sitagliptin in routine care were not at a substantially higher risk of pancreatitis than those prescribed alternative hypoglycemic agents. These findings are reassuring for those who use or prescribe sitagliptin in the management of type 2 diabetes.

Treatment of osteoporosis in renal insufficiency

Patients with osteoporosis often have chronic kidney disease (CKD). CKD is associated with bone and mineral disturbances, renal osteodystrophy, which like osteoporosis leads to a higher risk of fractures. Bisphosphonates are first-line therapy for osteoporosis; however, these are contra-indicated in patients with a GFR <30 ml/min. In this article, we have reviewed the diagnosis and treatment of osteoporosis in moderate to severe renal failure from data of clinical trials. Results have shown that osteoporosis patients and severe CKD with no signs of renal osteodystrophy, oral bisphosphonates (risedronate) seem to be a safe choice. Renal function and PTH should subsequently be monitored strictly. Denosumab, with regularly monitoring of calcium and adequate vitamin D levels or raloxifene are a possible second choice. In any case, one should be certain that there is no adynamic bone before treatment can be started. If there is any doubt, bone biopsies should be taken.

Risk of adverse events among older adults following co-prescription of clarithromycin and statins not metabolized by cytochrome P450 3A4

BACKGROUND

The cytochrome P450 3A4 (CYP3A4) inhibitor clarithromycin may also inhibit liver-specific organic anion-transporting polypeptides (OATP1B1 and OATP1B3). We studied whether concurrent use of clarithromycin and a statin not metabolized by CYP3A4 was associated with an increased frequency of serious adverse events.

METHODS

Using large health care databases, we studied a population-based cohort of older adults (mean age 74 years) who were taking a statin not metabolized by CYP3A4 (rosuvastatin [76% of prescriptions], pravastatin [21%] or fluvastatin [3%]) between 2002 and 2013 and were newly prescribed clarithromycin (n=51,523) or azithromycin (n=52,518), the latter an antibiotic that inhibits neither CYP3A4 nor OATP1B1 and OATP1B3. Outcomes were hospital admission with a diagnostic code for rhabdomyolysis, acute kidney injury or hyperkalemia, and all-cause mortality. All outcomes were assessed within 30 days after co-prescription.

RESULTS

Compared with the control group, patients co-prescribed clarithromycin and a statin not metabolized by CYP3A4 were at increased risk of hospital admission with acute kidney injury (adjusted relative risk [RR] 1.65, 95% confidence interval [CI] 1.31 to 2.09), admission with hyperkalemia (adjusted RR 2.17, 95% CI 1.22 to 3.86) and all-cause mortality (adjusted RR 1.43, 95% CI 1.15 to 1.76). The adjusted RR for admission with rhabdomyolysis was 2.27 (95% CI 0.86 to 5.96). The absolute increase in risk for each outcome was small and likely below 1%, even after we considered the insensitivity of some hospital database codes.

INTERPRETATION

Among older adults taking a statin not metabolized by CYP3A4, co-prescription of clarithromycin versus azithromycin was associated with a modest but statistically significant increase in the 30-day absolute risk of adverse outcomes.

Altered mental status in older adults with histamine2-receptor antagonists: a population-based study

BACKGROUND

Standard doses of histamine2-receptor antagonists (H2RAs) may induce altered mental status in older adults, especially in those with chronic kidney disease (CKD).

METHODS

Population-based cohort study of older adults who started a new H2RA between 2002 and 2011 was conducted. Ninety percent received the current standard H2RA dose in routine care. There was no significant difference in 27 baseline patient characteristics. The primary outcome was hospitalization with an urgent head computed tomography (CT) scan (proxy for altered mental status), and the secondary outcome was all-cause mortality also within 30days of a new H2RA prescription.

RESULTS

Standard vs. low H2RA dose was associated with a higher risk of hospitalization with an urgent head CT scan (0.98% vs. 0.74%, absolute risk difference 0.24% [95% CI 0.11% to 0.36%], relative risk 1.33 [95% CI 1.12 to 1.58]). This risk was not modified by the presence of CKD (interaction P value=0.71). Standard vs. low H2RA dose was associated with a higher risk of mortality (1.07% vs.0.74%; absolute risk difference 0.34% [95% CI 0.20% to 0.46%], relative risk 1.46 [95% CI 1.23 to 1.73]).

INTERPRETATION

Compared to a lower dose, initiation of the current standard dose of H2RA in older adults is associated with a small absolute increase in the 30-day risk of altered mental status (using neuroimaging as a proxy), even in the absence of CKD. This risk may be avoided by initiating older adults on low doses of H2RAs for gastroesophogeal reflux disease, and increasing dosing as necessary for symptom control.

Higher dose versus lower dose of antiviral therapy in the treatment of herpes zoster infection in the elderly: a matched retrospective population-based cohort study

Background

Higher versus lower doses of antiviral drugs used to treat herpes zoster infection may lead to more adverse drug events in older adults, particularly those with chronic kidney disease.

Methods

We conducted a matched retrospective population-based cohort study of older adults (mean 77 years) in Ontario, Canada who initiated in the outpatient setting a higher (n = 23,256) or lower (n = 3,876) dose of one of three oral antivirals for the treatment of herpes zoster between 2002 and 2011. The primary outcome was hospitalization within 30 days with evidence of a computed tomography (CT) scan of the head (a proxy for acute neurotoxicity). The secondary outcome was 30-day all-cause mortality.

Results

A higher compared to lower dose of antiviral drug was not associated with an increased risk of hospitalization with an urgent CT scan of the head (247 [1.06%] events with higher dose versus 43 [1.11%] events with lower dose, relative risk 0.96, 95% confidence interval 0.69 to 1.33, p-value 0.79) and was not associated with a higher risk of all-cause mortality (63 [0.27%] events versus 15 [0.39%] events, relative risk 0.70, 95% confidence interval 0.40 to 1.23, p-value 0.21). Results were consistent in all subgroups, including those with and without chronic kidney disease.

Conclusions

Initiating a higher compared to a lower dose of an antiviral drug for the treatment of herpes zoster was not associated with an increased risk of adverse drug events. The findings support the safety of these drugs in older adults as currently prescribed in routine care.

Kidney function and population-based outcomes of initiating oral atenolol versus metoprolol tartrate in older adults

BACKGROUND

Atenolol and metoprolol tartrate are commonly prescribed β-blockers. Atenolol elimination depends on kidney function, whereas metoprolol tartrate does not. We hypothesized that compared to metoprolol tartrate, initiating oral atenolol treatment would be associated with more adverse events in older adults, with the association most pronounced in patients with lower baseline estimated glomerular filtration rates (eGFRs).

STUDY DESIGN

Population-based matched retrospective cohort study.

SETTING & PARTICIPANTS

Older adults (mean age, 75 years) in Ontario, Canada, prescribed oral atenolol versus metoprolol tartrate from April 2002 through December 2011. The 2 groups were well matched (n=75,257 in each group), with no difference in 31 measured baseline characteristics. Patients with end-stage renal disease were ineligible, and 4.6% of patients had chronic kidney disease (median eGFR, 38mL/min/1.73m(2) assessed through a database algorithm).

PREDICTORS

β-Blocker type and eGFR.

OUTCOMES

A composite outcome of hospitalization with bradycardia or hypotension and all-cause mortality were assessed in 90-day follow-up.

RESULTS

Compared to metoprolol tartrate, initiating atenolol treatment was not associated with higher risk of hospitalization with bradycardia or hypotension (incidence, 0.71% vs 0.79%; relative risk, 0.90; 95%CI, 0.80-1.01). Atenolol treatment initiation was associated with lower 90-day risk of mortality than metoprolol tartrate (incidence, 0.97% vs 1.44%; relative risk, 0.68; 95%CI, 0.61-0.74). Lower eGFR did not modify either association (P for interaction=0.5 and 0.6, respectively).

LIMITATIONS

Heart rate and blood pressure were not available in our data sources, and effects ascertained from observational studies are subject to residual confounding.

CONCLUSIONS

Contrary to our expectation, we found that atenolol versus metoprolol tartrate was associated with lower 90-day risk of mortality in patients regardless of eGFR, with no difference in risk of hospitalization with bradycardia or hypotension.

Higher anti-depressant dose and major adverse outcomes in moderate chronic kidney disease: a retrospective population-based study

BACKGROUND

Many older patients have chronic kidney disease (CKD), and a lower dose of anti-depressants paroxetine, mirtazapine and venlafaxine is recommended in patients with CKD to prevent drug accumulation from reduced elimination. Using information available in large population-based healthcare administrative databases, we conducted this study to determine if ignoring the recommendation and prescribing a higher versus lower dose of anti-depressants associates with a higher risk of adverse events.

METHODS

We conducted a population-based cohort study to describe the 30-day risk of delirium in older adults who initiated a higher vs. lower dose of these three anti-depressants in routine care. We defined delirium using the best proxy available in our data sources - hospitalization with an urgent head computed tomography (CT) scan. We determined if CKD status modified the association between anti-depressant dose and outcome, and examined the secondary outcome of 30 day all-cause mortality. We used multivariable logistic regression analyses to estimate adjusted odds ratios (relative risk (RR)) and 95% confidence intervals.

RESULTS

We identified adults (mean age 75) in Ontario who started a new study anti-depressant at a higher dose (n=36,651; 31%) or lower dose (n=81,160; 69%). Initiating a higher vs. lower dose was not associated with an increased risk of hospitalization with head CT (1.09% vs. 1.27% (adjusted RR 0.90; 95% CI, 0.80 to 1.02), but was associated with a lower risk of all-cause mortality (0.76% vs. 0.97% RR 0.82; 95% CI, 0.71 to 0.95). Neither of these relative risks were modified by the presence of CKD (p=0.16, 0.68, respectively).

CONCLUSIONS

We did not observe an increase in two adverse outcomes when study anti-depressants were initiated at a higher dose in elderly patients with moderate CKD. Contrary to our hypothesis, the 30-day risk of mortality was lower when a higher versus lower dose of anti-depressant was initiated in these patients, a finding which requires corroboration and further study.

Association between angiotensin converting enzyme inhibitor or angiotensin receptor blocker use prior to major elective surgery and the risk of acute dialysis

Background

Some studies but not others suggest angiotensin converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) use prior to major surgery associates with a higher risk of postoperative acute kidney injury (AKI) and death.

Methods

We conducted a large population-based retrospective cohort study of patients aged 66 years or older who received major elective surgery in 118 hospitals in Ontario, Canada from 1995 to 2010 (n = 237,208). We grouped the cohort into ACEi/ARB users (n = 101,494) and non-users (n = 135,714) according to whether the patient filled at least one prescription for an ACEi or ARB (or not) in the 120 days prior to surgery. Our study outcomes were acute kidney injury treated with dialysis (AKI-D) within 14 days of surgery and all-cause mortality within 90 days of surgery.

Results

After adjusting for potential confounders, preoperative ACEi/ARB use versus non-use was associated with 17% lower risk of post-operative AKI-D (adjusted relative risk (RR): 0.83; 95% confidence interval (CI): 0.71 to 0.98) and 9% lower risk of all-cause mortality (adjusted RR: 0.91; 95% CI: 0.87 to 0.95). Propensity score matched analyses provided similar results. The association between ACEi/ARB and AKI-D was significantly modified by the presence of preoperative chronic kidney disease (CKD) (P value for interaction < 0.001) with the observed association evident only in patients with CKD (CKD - adjusted RR: 0.62; 95% CI: 0.50 to 0.78 versus No CKD: adjusted RR: 1.00; 95% CI: 0.81 to 1.24).

Conclusions

In this cohort study, preoperative ACEi/ARB use versus non-use was associated with a lower risk of AKI-D, and the association was primarily evident in patients with CKD. Large, multi-centre randomized trials are needed to inform optimal ACEi/ARB use in the peri-operative setting.

Renal safety in patients treated with bisphosphonates for osteoporosis: a review

Bisphosphonates are widely used for the treatment of osteoporosis and are generally well tolerated. However, the United States Food and Drug Administration safety reports have highlighted the issue of renal safety in bisphosphonate-treated patients. All bisphosphonates carry labeled "warnings" or a contraindication for use in patients with severe renal impairment (creatinine clearance <30 or <35 mL/min). Data from pivotal trials and their extension studies of bisphosphonates approved for the management of osteoporosis were obtained via PubMed, and were reviewed with support from published articles available on PubMed. Renal safety analyses of pivotal trials of oral alendronate, risedronate, and ibandronate for postmenopausal osteoporosis showed no short-term or long-term effects on renal function. Transient postinfusion increases in serum creatinine have been reported in patients receiving intravenous ibandronate and zoledronic acid; however, studies showed that treatment with these agents did not result in long-term renal function deterioration in clinical trial patients with osteoporosis. All bisphosphonate therapies have "warnings" for use in patients with severe renal impairment. Clinical trial results have shown that even in elderly, frail, osteoporotic patients with renal impairment, intravenous bisphosphonate therapy administration in accordance with the prescribing information did not result in long-term renal function decline. Physicians should follow guidelines for bisphosphonate therapies administration at all times.

Bisphosphonate safety and efficacy in chronic kidney disease

A new population-based study of elderly patients hospitalized for a fracture and treated with an oral bisphosphonate finds no increased risk of acute kidney injury. The safety and efficacy of bisphosphonates may be different in patients with chronic kidney disease (CKD). The effects on vascular calcifications need further study, because low bone turnover might exacerbate vascular calcifications in patients with CKD. Even if bisphosphonates prove safe, their efficacy in this population is uncertain.

Comparing two types of macrolide antibiotics for the purpose of assessing population-based drug interactions

OBJECTIVE

Clarithromycin strongly inhibits enzyme cytochrome P450 3A4, preventing the metabolism of some other drugs, while azithromycin is a weak inhibitor. Accordingly, blood concentrations of other drugs increase with clarithromycin coprescription leading to adverse events. These macrolide antibiotics also differ on other properties that may impact outcomes. In this study, we compared outcomes in two groups of macrolide antibiotic users in the absence of potentially interacting drugs.

DESIGN

Population-based retrospective cohort study.

SETTING

Ontario, Canada, from 2003 to 2010.

PATIENTS

Patients (mean 74 years) prescribed clarithromycin (n=52 251) or azithromycin (referent group, n=46 618).

MAIN OUTCOMES

The primary outcomes were hospital admission within 30 days of a new antibiotic prescription with any of the 12 conditions examined separately (acute kidney injury, acute myocardial infarction, neuroimaging (proxy for delirium), hypotension, syncope, hyperkalaemia, hyponatraemia, hyperglycaemia, arrhythmia, ischaemic stroke, gastrointestinal bleeding and sepsis). The secondary outcome was mortality.

RESULTS

The baseline characteristics of the two groups, including patient demographics, comorbid conditions, infection type and prescribing physician specialty, were nearly identical. The median daily dose was 1000 mg for clarithromycin and 300 mg for azithromycin and the median duration of dispensing antibiotics was 10 and 5 days, respectively. There was no difference between the groups in the risk of hospitalisation for any condition studied (relative risk ranged from 0.67 to 1.23). Compared with azithromycin, clarithromycin was associated with a slightly higher risk of all-cause mortality (0.46% vs 0.37%, relative risk 1.25, 95% CI 1.03 to 1.52).

CONCLUSIONS

Clarithromycin can be used to assess drug interactions in population-based studies with azithromycin serving as a control group. However, any differences in mortality observed between the two antibiotic groups in the setting of other drug use may be partially attributable to factors beyond the inhibition of drug metabolising enzymes and transporters, as the difference for this outcome was significant.

Cardiovascular disease after Escherichia coli O157:H7 gastroenteritis

BACKGROUND

Escherichia coli O157:H7 is one cause of acute bacterial gastroenteritis, which can be devastating in outbreak situations. We studied the risk of cardiovascular disease following such an outbreak in Walkerton, Ontario, in May 2000.

METHODS

In this community-based cohort study, we linked data from the Walkerton Health Study (2002-2008) to Ontario's large healthcare databases. We included 4 groups of adults: 3 groups of Walkerton participants (153 with severe gastroenteritis, 414 with mild gastroenteritis, 331 with no gastroenteritis) and a group of 11 263 residents from the surrounding communities that were unaffected by the outbreak. The primary outcome was a composite of death or first major cardiovascular event (admission to hospital for acute myocardial infarction, stroke or congestive heart failure, or evidence of associated procedures). The secondary outcome was first major cardiovascular event censored for death. Adults were followed for an average of 7.4 years.

RESULTS

During the study period, 1174 adults (9.7%) died or experienced a major cardiovascular event. Compared with residents of the surrounding communities, the risk of death or cardiovascular event was not elevated among Walkerton participants with severe or mild gastroenteritis (hazard ratio [HR] for severe gastroenteritis 0.74, 95% confidence interval [CI] 0.38-1.43, mild gastroenteritis HR 0.64, 95% CI 0.42-0.98). Compared with Walkerton participants who had no gastroenteritis, risk of death or cardiovascular event was not elevated among participants with severe or mild gastroenteritis.

INTERPRETATION

There was no increase in the risk of cardiovascular disease in the decade following acute infection during a major E. coli O157:H7 outbreak.