Baclofen and the risk of fall and fracture in older adults: A real-world cohort study.

BACKGROUND: The growth of oral muscle relaxant prescriptions among older adults in the United States is concerning due to the drugs' adverse sedative effects. Baclofen is a gamma-aminobutyric acid agonist muscle relaxant that is associated with encephalopathy. We characterized the risk of fall and fracture associated with oral baclofen against other muscle relaxants (tizanidine or cyclobenzaprine) in older adults. METHODS: We designed a new-user, active-comparator study using tertiary health system data from Geisinger Health, Pennsylvania (January 2005 through December 2018). Older adults (aged ≥65 years) newly treated with baclofen, tizanidine, or cyclobenzaprine were included. Propensity score-based inverse probability of treatment weighting (IPTW) was used to balance the treatment groups on 58 baseline characteristics. Fine-Gray competing risk regression was used to estimate the risk of fall and fracture. RESULTS: The study cohort comprised of 2205 new baclofen users, 1103 new tizanidine users, and 9708 new cyclobenzaprine users. During a median follow-up of 100 days, baclofen was associated with a higher risk of fall compared to tizanidine (IPTW incidence rate, 108.4 vs. 61.9 per 1000 person-years; subdistribution hazard ratio [SHR], 1.68 [95% CI, 1.20-2.36]). The risk of fall associated with baclofen was comparable to cyclobenzaprine (SHR, 1.17 [95% CI, 0.93-1.47]) with a median follow-up of 106 days. The risk of fracture was similar among patients treated with baclofen versus tizanidine (SHR, 0.85 [95% CI, 0.63-1.14]) or cyclobenzaprine (SHR, 0.85 [95% CI, 0.67-1.07]). CONCLUSIONS: The risk of fall associated with baclofen was greater than tizanidine, but not compared to cyclobenzaprine in older adults. The risk of fracture was comparable among the older users of baclofen, tizanidine, and cyclobenzaprine. Our findings may inform risk-benefit considerations in the increasingly common clinical encounters where oral muscle relaxants are prescribed.

Risk of Major Bleeding Associated with Concomitant Direct-Acting Oral Anticoagulant and Clopidogrel Use: A Retrospective Cohort Study.

BACKGROUND AND AIM: Combined anticoagulant-antiplatelet therapy is often indicated in adults with cardiovascular disease and atrial fibrillation or venous thromboembolism. The study aim was to assess the comparative risk of bleeding between rivaroxaban and apixaban when combined with clopidogrel. METHODS: We conducted a retrospective cohort study of commercially insured US adults newly treated with a combination of rivaroxaban+clopidogrel or apixaban+clopidogrel (2015-2018) using Merative™ Marketscan Research Databases. We used propensity score-based inverse probability of treatment weighting (IPTW) to balance the treatment groups. Weighted Cox proportional hazards regression was used to estimate the risk of major bleeding. RESULTS: The study cohort included 2895 rivaroxaban+clopidogrel users and 3628 apixaban+clopidogrel users. The median (range) duration of follow up was 61 (73) days. Rivaroxaban+clopidogrel users had a similar risk of major bleeding compared with apixaban+clopidogrel users (IPTW incidence rate per 100 person-years 7.96 vs 7.38; IPTW hazard ratio [HR] 1.13 [95% CI 0.78-1.63]). In the subcohort of adults who were treated with DOAC or clopidogrel monotherapy prior to the combined therapy, the risk of major bleeding did not differ by the drug of monotherapy (IPTW HR for rivaroxaban+clopidogrel group: 0.66 [95% CI 0.33-1.32]; IPTW HR for apixaban+clopidogrel group: 1.10 [95% CI 0.55-2.23]) CONCLUSIONS: In our study of commercially insured US adults, the concomitant use of rivaroxaban+clopidogrel and apixaban+clopidogrel conferred a similar risk of major bleeding. DOAC versus clopidogrel monotherapy prior to the concomitant therapy did not influence the risk of major bleeding.

Baclofen and the Risk of Encephalopathy: A Real-World, Active-Comparator Cohort Study.

OBJECTIVE: To quantify the risk of encephalopathy associated with oral baclofen compared with other muscle relaxants-tizanidine or cyclobenzaprine. PATIENTS AND METHODS: We conducted a new-user, active-comparator study of 2 pairwise cohorts using tertiary health system data from Geisinger Health in Pennsylvania (January 1, 2005, through December 31, 2018). Adults (aged ≥18 years) newly treated with baclofen or tizanidine were included in cohort 1. Adults newly treated with baclofen or cyclobenzaprine were included in cohort 2. Propensity score-based inverse probability of treatment weighting (IPTW) was used to balance the respective cohorts on 45 patient characteristics. Fine-Gray competing risk regression was used to estimate the risk of encephalopathy. RESULTS: Cohort 1 included 16,192 new baclofen users and 9782 new tizanidine users. The 30-day risk of encephalopathy was higher in patients treated with baclofen vs tizanidine (IPTW incidence rate, 64.7 vs 28.3 per 1000 person-years) with an IPTW subdistribution hazard ratio (SHR) of 2.29 (95% CI, 1.43 to 3.67). This risk persisted through 1 year (SHR, 1.32 [95% CI, 1.07 to 1.64]). Similarly in cohort 2, baclofen vs cyclobenzaprine was associated with a greater risk of encephalopathy at 30 days (SHR, 2.35 [95% CI, 1.59 to 3.48]) that persisted through the first year of treatment (SHR, 1.94 [95% CI, 1.56 to 2.40]). CONCLUSION: The risk of encephalopathy was greater with baclofen vs tizanidine or cyclobenzaprine use. The elevated risk was apparent as early as 30 days and persisted through the first year of treatment. Our findings from routine care settings may inform shared treatment decisions between patients and prescribers.

Glucose-Lowering Agents and the Risk of Hypoglycemia: a Real-world Study.

BACKGROUND: Sodium-glucose cotransporter-2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP1RA) are increasingly recommended in type 2 diabetes. Hypoglycemia is a serious adverse effect of glucose-lowering agents. Real-world comparison of hypoglycemic risks among SGLT2i, GLP1RA, dipeptidyl peptidase-4 inhibitor (DPP4i), and sulfonylureas is limited. OBJECTIVE: Quantify the risk of hypoglycemia associated with SGLT2i, GLP1RA, DPP4i, and sulfonylureas (the primary reference group). DESIGN: Retrospective cohort study conducted using electronic health records from Geisinger Health, Pennsylvania (2015-2019). PARTICIPANTS: A total of 10,713 patients with type 2 diabetes who newly received SGLT2i (n=1487), GLP1RA (n=1241), DPP4i (n=2938), or sulfonylureas (n=5047). Propensity score-based inverse probability of treatment weighting was used to balance patient characteristics across four treatment groups simultaneously. MAIN MEASURES: Hypoglycemia was defined as capillary blood glucose <70 mg/dL; severe hypoglycemia was defined as capillary blood glucose <54 mg/dL. A weighted Cox proportional hazards regression model was used to estimate the risk of outcomes for pairwise comparisons of SGTL2i, GLP1RA, DPP4i, and sulfonylureas. KEY RESULTS: Median follow-up was 21.3 months. Compared with sulfonylureas, the risk of hypoglycemia was lower with SGLT2i (hazard ratio 0.60 [95% confidence interval 0.48-0.75]), GLP1RA (0.49 [0.34-0.69]), and DPP4i (0.60 [0.48-0.78]). The risk of severe hypoglycemia was also lower with SGLT2i (0.43 [0.35-0.74]), GLP1RA (0.50 [0.28-0.87]), and DPP4i (0.64 [0.46-0.90]) compared to sulfonylureas. The risks of hypoglycemia and severe hypoglycemia were similar across the SGLT2i, GLP1RA, and DPP4i groups (SGLT2i vs. DPP4i: 0.95 [0.67-1.34]; GLP1RA vs. DPP4i: 0.81 [0.55-1.19]; SGLT2i vs. GLP1RA: 1.17 [0.76-1.82] for hypoglycemia). CONCLUSION: SGLT2i and GLP1RA confer a lower risk of hypoglycemia compared with sulfonylureas and similar risk compared with DPP4i. Given the known cardiovascular benefits associated with SGLT2i and GL1PRA, our results suggesting the safety of SGLT2i and GL1PRA further support their use.

Trimethoprim-sulfamethoxazole and the risk of a hospital encounter with hyperkalemia: a matched population-based cohort study.

BACKGROUND: Trimethoprim-sulfamethoxazole (TMP-SMX) can cause hyperkalemia by reducing renal potassium excretion. We assessed the risk of hyperkalemia after initiating TMP-SMX versus amoxicillin and determined if this risk is modified by a patient's baseline kidney function [estimated glomerular filtration rate (eGFR)]. METHODS: We conducted a population-based cohort study in Ontario, Canada involving adults ≥66 years of age newly treated with TMP-SMX (n = 58 999) matched 1:1 with those newly treated with amoxicillin (2008-2020). The primary outcome was a hospital encounter with hyperkalemia defined by a laboratory serum potassium value ≥5.5 mmol/L within 14 days of antibiotic treatment. Secondary outcomes included a hospital encounter with acute kidney injury (AKI) and all-cause hospitalization. Risk ratios (RRs) were obtained using a modified Poisson regression. RESULTS: A hospital encounter with hyperkalemia occurred in 269/58 999 (0.46%) patients treated with TMP-SMX versus 80/58 999 (0.14%) in those treated with amoxicillin {RR 3.36 [95% confidence interval (CI) 2.62-4.31]}. The absolute risk of hyperkalemia in patients treated with TMP-SMX versus amoxicillin increased progressively with decreasing eGFR (risk difference of 0.12% for an eGFR ≥60 ml/min/1.73 m2, 0.42% for eGFR 45-59, 0.85% for eGFR 30-44 and 1.45% for eGFR <30; additive interaction P < .001). TMP-SMX versus amoxicillin was associated with a higher risk of a hospital encounter with AKI [RR 3.15 (95% CI 2.82-3.51)] and all-cause hospitalization [RR 1.43 (95% CI 1.34-1.53)]. CONCLUSIONS: The 14-day risk of a hospital encounter with hyperkalemia was higher in patients newly treated with TMP-SMX versus amoxicillin and the risk was highest in patients with a low eGFR.

Risk of Hospitalization and Death Associated With Pimavanserin Use in Older Adults With Parkinson Disease.

BACKGROUND AND OBJECTIVES: To determine the risk of hospitalization and death associated with pimavanserin use. METHODS: We conducted a retrospective cohort study of adults 65 years and older with Parkinson disease between November 1, 2015, and December 31, 2018, using an administrative dataset on residents of Medicare-certified long-term care facilities and linked Medicare claims data. Propensity score-based inverse probability of treatment weighting (IPTW) was used to balance pimavanserin users and nonusers on 24 baseline characteristics. Fine-Gray competing risk and Cox proportional hazards regression models were used to estimate the risk of hospitalization and death up to 1 year, respectively. RESULTS: The study cohort included 2,186 pimavanserin users and 18,212 nonusers. There was a higher risk of 30-day hospitalization with pimavanserin use vs nonuse (IPTW-adjusted hazard ratio [aHR] 1.24, 95% confidence intervals [CI] 1.06-1.43). There was no association of pimavanserin use with 90-day hospitalization (aHR 1.10, CI 0.99-1.24) or with 30-day mortality (aHR 0.76, CI 0.56-1.03). Pimavanserin use vs nonuse was associated with increased 90-day mortality (aHR 1.20, CI 1.02-1.41) that persisted after 180 days (aHR 1.28, CI 1.13-1.45) and 1 year (aHR 1.56, CI 1.42-1.72). DISCUSSION: Pimavanserin use vs nonuse in older adults was associated with an increased risk of hospitalization at 1 month of initiation and a higher risk of death for up to 1 year following initiation. These findings, in a large real-world cohort within long-term care facilities, may help to inform decisions regarding its risk/benefit balance among patients with Parkinson disease. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that in patients with Parkinson disease who are 65 or older and residing in Medicare-certified long-term care facilities, pimavanserin is associated with an increased risk of 30-day hospitalization and higher 90-, 180-, and 365-day mortality.

The risk of fall and fracture with the initiation of a prostate-selective α antagonist: a population based cohort study.

STUDY QUESTION: Do men starting treatment with prostate-specific α antagonists have increased risk of fall and fracture? METHODS: Administrative datasets from the province of Ontario, Canada, that contain patient level data were used to generate a cohort of 147,084 men aged ≥ 66 years who filled their first outpatient prescription for prostate-specific α antagonists tamsulosin, alfuzosin, or silodosin between June 2003 and December 2013 (exposed men) plus an equal sized cohort matched 1:1 (using a propensity score model) who did not initiate α antagonist therapy. The primary outcome was a hospital emergency room visit or inpatient admission for a fall or fracture in the 90 days after exposure. STUDY ANSWER AND LIMITATIONS: The men exposed to prostate-specific α antagonist had significantly increased risks of falling (odds ratio 1.14 (95% CI 1.07 to 1.21), absolute risk increase 0.17% (0.08 to 0.25%)) and of sustaining a fracture (odds ratio 1.16 (1.04 to 1.29), absolute risk increase 0.06% (0.02 to 0.11%)) compared with the unexposed cohort. This increased risk was not observed in the period before α antagonist use. Secondary outcomes of hypotension and head trauma were also significantly increased in the exposed cohort (odds ratios 1.80 (1.59 to 2.03) and 1.15 (1.04 to 1.27) respectively). The two cohorts were similar across 98 different covariates including demographics, comorbid conditions, medication use, healthcare use, and prior medical investigation. Potential unmeasured confounders, such as physical deconditioning, mobility impairment, and situational risk factors, may exist. The data used to identify the primary outcomes had limited sensitivity, so the absolute risks of the outcomes are probably underestimates. The study only included men ≥ 66 years old, and 84% of exposed men were prescribed tamsulosin, so results may not be generalizable to younger men, and there may not be statistical power to show small differences in outcomes between the drugs. WHAT THIS STUDY ADDS: Prostate-specific α antagonists are associated with a small but significant increased risk of fall, fracture, and head trauma, probably as a result of induced hypotension. FUNDING, COMPETING INTERESTS, DATA SHARING: This project was conducted at the Institute for Clinical Evaluative Sciences (ICES) Western Site through the Kidney, Dialysis, and Transplantation (KDT) research program. BW has received a research grant from Astellas, and L-AF does consultancy for Amgen.

Assessment of healthcare quality metrics: Length-of-stay, 30-day readmission, and 30-day mortality for radical nephrectomy with inferior vena cava thrombectomy.

INTRODUCTION: Length-of-stay (LOS), 30-day readmission, and 30-day mortality are metrics used to assess quality of care and provider reimbursement. Therefore, we investigated patient- and hospital-level characteristics associated with the three healthcare quality metrics for radical nephrectomy with inferior vena cava (IVC) thrombectomy. METHODS: Using the National Cancer Data Base, we established a cohort of patients who received radical nephrectomy following the diagnosis of renal cell carcinoma (RCC) stage cT3b between 1998 and 2011. We then assessed the associations between patient- or hospital-level characteristics and LOS using multivariable negative binomial regression. We used multivariable logistic regression to determine the associations between the characteristics and 30-day readmission or 30-day mortality. RESULTS: During the study period, 5768 patients were diagnosed with RCC stage cT3b and underwent radical nephrectomy. LOS ≤2 days and ≥9 days were associated with a higher likelihood of 30-day readmission (respective odds ratio [OR] 1.61 and 1.58) and 30-day mortality (respective OR 11.62 and 11.87). Older patients (60-79 years vs. <50 years) were less likely to experience 30-day readmission (OR 0.46-0.52). Older patients (≥80 years vs. <50 years, OR 3.67) and patients with a high index of comorbidity (Charlson comorbidity score ≥ 2 vs. 0, OR 1.95) were more likely to suffer 30-day mortality. CONCLUSIONS: LOS is an important predictor of short-term readmission and mortality following radical nephrectomy with IVC thrombectomy. Older age and a high index of comorbidity also predict short-term mortality after the surgery.

Atypical antipsychotic drugs and the risk for acute kidney injury and other adverse outcomes in older adults: a population-based cohort study.

BACKGROUND: Several adverse outcomes attributed to atypical antipsychotic drugs, specifically quetiapine, risperidone, and olanzapine, are known to cause acute kidney injury (AKI). Such outcomes include hypotension, acute urinary retention, and the neuroleptic malignant syndrome or rhabdomyolysis. OBJECTIVE: To investigate the risk for AKI and other adverse outcomes associated with use of atypical antipsychotic drugs versus nonuse. DESIGN: Population-based cohort study. SETTING: Ontario, Canada, from 2003 to 2012. PATIENTS: Adults aged 65 years or older who received a new outpatient prescription for an oral atypical antipsychotic drug (n=97,777) matched 1:1 with those who did not receive such a prescription. MEASUREMENTS: The primary outcome was hospitalization with AKI (assessed by using a hospital diagnosis code and, in a subpopulation, serum creatinine levels) within 90 days of prescription for atypical antipsychotic drugs. RESULTS: Atypical antipsychotic drug use versus nonuse was associated with a higher risk for hospitalization with AKI (relative risk [RR], 1.73 [95% CI, 1.55 to 1.92]). This association was consistent when AKI was assessed in a subpopulation for which information on serum creatinine levels was available (5.46% vs. 3.34%; RR, 1.70 [CI, 1.22 to 2.38]; absolute risk increase, 2.12% [CI, 0.80% to 3.43%]). Drug use was also associated with hypotension (RR, 1.91 [CI, 1.60 to 2.28]), acute urinary retention (RR, 1.98 [CI, 1.63 to 2.40]), and all-cause mortality (RR, 2.39 [CI, 2.28 to 2.50]). LIMITATION: Only older adults were included in the study. CONCLUSION: Atypical antipsychotic drug use is associated with an increased risk for AKI and other adverse outcomes that may explain the observed association with AKI. The findings support current safety concerns about the use of these drugs in older adults. PRIMARY FUNDING SOURCE: Academic Medical Organization of Southwestern Ontario.

Statin toxicity from macrolide antibiotic coprescription: a population-based cohort study.

BACKGROUND: Clarithromycin and erythromycin, but not azithromycin, inhibit cytochrome P450 isoenzyme 3A4 (CYP3A4), and inhibition increases blood concentrations of statins that are metabolized by CYP3A4. OBJECTIVE: To measure the frequency of statin toxicity after coprescription of a statin with clarithromycin or erythromycin. DESIGN: Population-based cohort study. SETTING: Ontario, Canada, from 2003 to 2010. PATIENTS: Continuous statin users older than 65 years who were prescribed clarithromycin (n = 72,591) or erythromycin (n = 3267) compared with those prescribed azithromycin (n = 68,478). MEASUREMENTS: The primary outcome was hospitalization with rhabdomyolysis within 30 days of the antibiotic prescription. RESULTS: Atorvastatin was the most commonly prescribed statin (73%) followed by simvastatin and lovastatin. Compared with azithromycin, coprescription of a statin with clarithromycin or erythromycin was associated with a higher risk for hospitalization with rhabdomyolysis (absolute risk increase, 0.02% [95% CI, 0.01% to 0.03%]; relative risk [RR], 2.17 [CI, 1.04 to 4.53]) or with acute kidney injury (absolute risk increase, 1.26% [CI, 0.58% to 1.95%]; RR, 1.78 [CI, 1.49 to 2.14]) and for all-cause mortality (absolute risk increase, 0.25% [CI, 0.17% to 0.33%]; RR, 1.56 [CI, 1.36 to 1.80]). LIMITATIONS: Only older adults were included in the study. The absolute risk increase for rhabdomyolysis may be underestimated because the codes used to identify it were insensitive. CONCLUSION: In older adults, coprescription of clarithromycin or erythromycin with a statin that is metabolized by CYP3A4 increases the risk for statin toxicity. PRIMARY FUNDING SOURCE: Academic Medical Organization of Southwestern Ontario.

Validity of the International Classification of Diseases, Tenth Revision code for acute kidney injury in elderly patients at presentation to the emergency department and at hospital admission.

OBJECTIVE: To evaluate the validity of the International Classification of Diseases, Tenth Revision (ICD-10) code N17x for acute kidney injury (AKI) in elderly patients in two settings: at presentation to the emergency department and at hospital admission. DESIGN: A population-based retrospective validation study. SETTING: Southwestern Ontario, Canada, from 2003 to 2010. PARTICIPANTS: Elderly patients with serum creatinine measurements at presentation to the emergency department (n=36 049) or hospital admission (n=38 566). The baseline serum creatinine measurement was a median of 102 and 39 days prior to presentation to the emergency department and hospital admission, respectively. MAIN OUTCOME MEASURES: Sensitivity, specificity and positive and negative predictive values of ICD-10 diagnostic coding algorithms for AKI using a reference standard based on changes in serum creatinine from the baseline value. Median changes in serum creatinine of patients who were code positive and code negative for AKI. RESULTS: The sensitivity of the best-performing coding algorithm for AKI (defined as a ≥2-fold increase in serum creatinine concentration) was 37.4% (95% CI 32.1% to 43.1%) at presentation to the emergency department and 61.6% (95% CI 57.5% to 65.5%) at hospital admission. The specificity was greater than 95% in both settings. In patients who were code positive for AKI, the median (IQR) increase in serum creatinine from the baseline was 133 (62 to 288) µmol/l at presentation to the emergency department and 98 (43 to 200) µmol/l at hospital admission. In those who were code negative, the increase in serum creatinine was 2 (-8 to 14) and 6 (-4 to 20) µmol/l, respectively. CONCLUSIONS: The presence or absence of ICD-10 code N17× differentiates two groups of patients with distinct changes in serum creatinine at the time of a hospital encounter. However, the code underestimates the true incidence of AKI due to a limited sensitivity.