Mara, Kristin C

IMPORTANCE: Meropenem dosing is typically guided by creatinine-based estimated glomerular filtration rate (eGFR), but creatinine is a suboptimal GFR marker in the critically ill. OBJECTIVES: This study aimed to develop and qualify a population pharmacokinetic model for meropenem in critically ill adults and to determine which eGFR equation based on creatinine, cystatin C, or both biomarkers best improves model performance. DESIGN, SETTING, AND PARTICIPANTS: This single-center study evaluated adults hospitalized in an ICU who received IV meropenem from 2018 to 2022. Patients were excluded if they had acute kidney injury, were on kidney replacement therapy, or were treated with extracorporeal membrane oxygenation. Two cohorts were used for population pharmacokinetic modeling: a richly sampled development cohort (n = 19) and an opportunistically sampled qualification cohort (n = 32). MAIN OUTCOMES AND MEASURES: A nonlinear mixed-effects model was developed using parametric methods to estimate meropenem serum concentrations. RESULTS: The best-fit structural model in the richly sampled development cohort was a two-compartment model with first-order elimination. The final model included time-dependent weight normalized to a 70-kg adult as a covariate for volume of distribution (Vd) and time-dependent eGFR for clearance. Among the eGFR equations evaluated, eGFR based on creatinine and cystatin C expressed in mL/min best-predicted meropenem clearance. The mean (se) Vd in the final model was 18.2 (3.5) liters and clearance was 11.5 (1.3) L/hr. Using the development cohort as the Bayesian prior, the opportunistically sampled cohort demonstrated good accuracy and low bias. CONCLUSIONS AND RELEVANCE: Contemporary eGFR equations that use both creatinine and cystatin C improved meropenem population pharmacokinetic model performance compared with creatinine-only or cystatin C-only eGFR equations in adult critically ill patients.

Abstract Introduction Although there are studies assessing reasons for antidepressant discontinuation, little is known about the impact of sex differences or cytochrome P450 phenotypes. Our objective is to assess discontinuation rates between males and females and whether CYP450 phenotype influences discontinuation. Methods This is a retrospective review of patients previously enrolled in the Right Drug, Right Dose, Right Time: Using Genomic Data to Individualize Treatment database with major depressive disorder. Patients were evaluated for antidepressants trialed between January 1, 2009, and September 30, 2019. Survival analyses with competing risks were used to analyze discontinuation reasons. A Kaplan-Meier estimation method was used to assess the time to discontinuation and discontinuation rates. Analyses were also completed to assess discontinuation between men and women by phenotypic groups. All tests were two-sided, and p-values ≤ .05 were considered statistically significant. Results There were 620 antidepressant discontinuation events discovered from 1015 antidepressant trials included. Overall, the median time to discontinuation for males was 2.6 years and 1.9 years for females (hazard ratio [HR] 0.97 [95% confidence interval (CI): 0.80, 1.19], p = .77). The risk of discontinuation was not different between males and females in any of the phenotype groups, which was consistent in the multivariable analyses. Concomitant use of medications that inhibited or induced antidepressant metabolism increased the overall risk of discontinuation (HR 1.45, 95% CI [1.06, 1.99], p = .020) in a time-dependent analysis. Discussion We did not detect a significant difference in risk of antidepressant discontinuation rates between males and females even when accounting for cytochrome P450 phenotype. Future studies should account for whether medications that inhibit or induce antidepressant metabolism may be a crucial factor in antidepressant discontinuation.

AbstractStudy ObjectiveTo develop and validate a model for predicting acute kidney injury (AKI) after high‐dose methotrexate (HDMTX) exposure.DesignRetrospective analysis.SettingMultisite integrated health system throughout Minnesota and Wisconsin.PatientsAdult patients with lymphoma who received HDMTX as a 4‐h infusion.Measurements and Main ResultsLASSO methodology was used to identify factors available at the outset of therapy that predicted incident AKI within 7 days following HDMTX. The model was then validated in an independent cohort. The incidence of AKI within 7 days following HDMTX was 21.6% (95% confidence interval (CI) 18.4%‐24.8%) in the derivation cohort (435 unique patients who received a total of 1642 doses of HDMTX) and 15.6% (95% CI 5.3%‐24.8%) in the validation cohort (55 unique patients who received a total of 247 doses of HDMTX). Factors significantly associated with AKI after HDMTX in the multivariable model included age ≥ 55 years, male sex, and lower HDMTX dose number. Other factors that were not found to be significantly associated with AKI on multivariable analysis, but were included in the final model, were body surface area, Charlson Comorbidity Index, and estimated glomerular filtration rate. The c‐statistic of the model was 0.72 (95% CI 0.69‐0.75) in the derivation cohort and 0.72 (95% CI 0.60‐0.84) in the validation cohort.ConclusionThis model utilizing identified sociodemographic and clinical factors is predictive of AKI following HDMTX administration in adult patients with lymphoma.

IMPORTANCE: The outcomes of critically ill adults with obesity on continuous renal replacement therapy (CRRT) are poorly characterized. The impact of CRRT dose on these outcomes is uncertain. OBJECTIVES: This study aimed to determine if obesity conferred a survival advantage for critically ill adults with acute kidney injury (AKI) on CRRT. Secondarily, we evaluated whether the dose of CRRT predicted mortality in this population. DESIGN, SETTING, AND PARTICIPANTS: A retrospective, observational cohort study performed at an academic medical center in Minnesota. The study population included critically ill adults with AKI managed with CRRT. MAIN OUTCOMES AND MEASURES: The primary outcome of 30-day mortality was compared between obese (body mass index [BMI] ≥ 30 kg/m2) and nonobese (BMI < 30 kg/m2) patients. Multivariable regression assessed was used to assess CRRT dose as a predictor of outcomes. An analysis included dose indexed according to actual body weight (ABW), adjusted body weight (AdjBW), or ideal body weight (IBW). RESULTS: Among 1033 included patients, the median (interquartile range) BMI was 26 kg/m2 (23–28 kg/m2) in the nonobese group and 36 kg/m2 (32–41 kg/m2) in the obese group. Mortality was similar between groups at 30 days (54% vs. 48%; p = 0.06) but lower in the obese group at 90 days (62% vs. 55%; p = 0.02). CRRT dose predicted an increase in mortality when indexed according to ABW or AdjBW (hazard ratio [HR], 1.2–1.16) but not IBW (HR, 1.04). CONCLUSIONS AND RELEVANCE: In critically ill adults with AKI requiring CRRT, short-term mortality appeared lower in obese patients compared with nonobese patients. Among weight calculations, IBW appears to be preferred to promote safe CRRT dosing in obese patients.

ABSTRACT Cefepime exhibits highly variable pharmacokinetics in critically ill patients. The purpose of this study was to develop and qualify a population pharmacokinetic model for use in the critically ill and investigate the impact of various estimated glomerular filtration rate (eGFR) equations using creatinine, cystatin C, or both on model parameters. This was a prospective study of critically ill adults hospitalized at an academic medical center treated with intravenous cefepime. Individuals with acute kidney injury or on kidney replacement therapy or extracorporeal membrane oxygenation were excluded. A nonlinear mixed-effects population pharmacokinetic model was developed using data collected from 2018 to 2022. The 120 included individuals contributed 379 serum samples for analysis. A two-compartment pharmacokinetic model with first-order elimination best described the data. The population mean parameters (standard error) in the final model were 7.84 (0.24) L/h for CL1 and 15.6 (1.45) L for V1. Q was fixed at 7.09 L/h and V2 was fixed at 10.6 L, due to low observed interindividual variation in these parameters. The final model included weight as a covariate for volume of distribution and the eGFR cr-cysC (mL/min) as a predictor of drug clearance. In summary, a population pharmacokinetic model for cefepime was created for critically ill adults. The study demonstrated the importance of cystatin C to prediction of cefepime clearance. Cefepime dosing models which use an eGFR equation inclusive of cystatin C are likely to exhibit improved accuracy and precision compared to dosing models which incorporate an eGFR equation with only creatinine.

IMPORTANCE: Protein binding of valproate varies among ICU patients, altering the biologically active free valproate concentration (VPAC). Free VPAC is measured at few laboratories and is often discordant with total VPAC. Existing equations to predict free VPAC are either not validated or are inaccurate in ICU patients. OBJECTIVES: We designed this study to derive and validate a novel equation to predict free VPAC using data from ICU patients and to compare its performance to published equations. DESIGN: Retrospective cohort study. SETTING: Two academic medical centers. PARTICIPANTS: Patients older than 18 years old with concomitant free and total VPACs measured in the ICU were included in the derivation cohort if admitted from 2014 to 2018, and the validation cohort if admitted from 2019 to 2022. MAIN OUTCOMES AND MEASURES: Multivariable linear regression was used to derive an equation to predict free VPAC. Modified Bland-Altman plots and the rate of therapeutic concordance between the measured and predicted free VPAC were compared. RESULTS: Demographics, median free and total VPACs, and valproate free fractions were similar among 115 patients in the derivation cohort and 147 patients in the validation cohort. The Bland-Altman plots showed the new equation performed better (bias, 0.3 [95% limits of agreement, –13.6 to 14.2]) than the Nasreddine (–9.2 [–26.5 to 8.2]), Kodama (–9.7 [–30.0 to 10.7]), Conde Giner (–7.9 [–24.9 to 9.1]), and Parent (–9.9 [–30.7 to 11.0]) equations, and similar to Doré (–2.0 [–16.0 to 11.9]). The Doré and new equations had the highest therapeutic concordance rate (73%). CONCLUSIONS AND RELEVANCE: For patients at risk of altered protein binding such as ICU patients, existing equations to predict free VPAC are discordant with measured free VPAC. A new equation had low bias but was imprecise. External validation should be performed to improve its precision and generalizability. Until then, monitoring free valproate is recommended during critical illness.

Abstract Objective Adverse childhood experiences (ACEs) are reported in more than half of the women in the United States and have been shown to negatively impact the menopause experience. The objective of this study was to evaluate the association between ACEs and age at natural menopause. Methods This is a cross-sectional study conducted among participants of the Data Registry on the Experiences of Aging, Menopause, and Sexuality (DREAMS). The registry included women who were seen for consultations in the women's health clinic at Mayo Clinic, Rochester, between May 2015 and December 2016. Only postmenopausal women were included in this analysis. Childhood adversity was assessed with the validated ACE questionnaire. Age at natural menopause was self-reported. The association between ACEs and age at menopause was evaluated using a multivariable linear regression model adjusting for multiple confounders. Results A total of 350 women were evaluated. The mean age was 59.2 years, and a majority were White (92.9%), married/partnered (82%), and educated (91.2% with at least some college education). Women with a history of at least four ACEs were estimated to reach natural menopause 1.3 years sooner than women with no ACE in multivariable analysis, but the results were not statistically significant (95% confidence interval, −3.2 to 0.6; P = 0.18). Conclusions Although stressful life experiences such as ACEs may negatively influence health for midlife women, this study did not find an association with the age at natural menopause.

Background: Data are controversial regarding nephrotoxicity risk with vancomycin plus piperacillin–tazobactam (VPT) compared to vancomycin alone or in combination with other beta-lactams (BLs) in acute care use. Furthermore, data are lacking on the incidence of acute kidney injury (AKI) with long-term use of VPT including outpatient parenteral antimicrobial therapy (OPAT). Methods: This retrospective study included 826 adult patients on an intravenous vancomycin plus BL for ⩾2 weeks, including cefepime, piperacillin/tazobactam, ertapenem, or meropenem, from August 2017 to January 2022. The primary outcome was incidence of AKI. Univariate and multivariable Cox proportional hazard regression analyses were conducted to adjust for confounding variables. A secondary analysis based on the propensity score (PS)-matched cohort was performed. Results: AKI occurred in 14.4% of patients in the VPT group ( n = 15/104) compared to 5.5% in the other BL group ( n = 40/722) ( p < 0.001). Average time to AKI from start of combination therapy was 9.4 (1.7–12.0) days in the VPT group and 10.9 (5–22.7) days in the other BL group ( p = 0.20). The median duration of vancomycin and BL in the overall cohort was approximately 1 month. Beyond BL selection, patient characteristics were not associated with AKI other than the receipt of concomitant acyclovir [hazard ratio (HR) 2.48 (95% confidence interval (CI): 1.33–4.65), p = 0.004]. In the PS-matched cohort, AKI occurred in 14.4% of patients in the VPT group ( n = 15/104) and 5.3% in the other BL group ( n = 11/208) ( p = 0.006). Receipt of VPT [HR: 2.55 (1.36–4.78), p = 0.004] and acyclovir [HR: 2.38 (1.19–4.74), p = 0.014) remained significantly associated with AKI in the multivariable model. Conclusion: Clinicians should exercise caution when using VPT for >2 weeks, including in the OPAT setting, even when no renal dysfunction is observed during the initial week of combination therapy.

Background: Underweight patients may be at an increased risk of bleeding while receiving venous thromboembolism (VTE) prophylaxis. Additional evidence is needed to identify patient-specific factors associated with bleeding. The objective of the study was to describe the incidence and identify risk factors associated with bleeding in low-weight (⩽ 60 kg) adult patients receiving subcutaneous unfractionated heparin (SQH) for VTE prophylaxis. Methods: This was a single-center, retrospective, nested case–control study of low-weight patients receiving SQH for VTE prophylaxis for ⩾ 48 hours. Cases, patients with clinically relevant bleeding while receiving SQH, and controls, patients without a bleeding event, were matched in a 1:3 ratio for age, sex, primary service (surgical or medical), and time at risk of bleeding on SQH to determine factors associated with bleeding. Results: A total of 3761 patients met the inclusion criteria, of which 38 cases of clinically relevant bleeding were identified. The bleeding incidence was 1% at hospital day 6 and 2.8% at hospital day 14. Most patients in this study (69%) received SQH 5000 units three times daily. ICU admission at SQH start was associated with bleeding, OR 2.97 (95% CI 1.21–7.29). Conclusion: Bleeding in low-weight patients on prophylactic SQH was uncommon. Patients admitted to the ICU at time of SQH start may be at a higher risk of bleeding. Further studies are needed to detect additional risk factors associated with bleeding and investigate the effects of reduced dosing in this population.

AbstractBackgroundInfertility has been linked with an increased risk of sexual dysfunction in reproductive-aged women, with longer periods of infertility associated with a greater risk.AimThe study’s aim was to examine whether a history of infertility treatment in women is linked to sexual dysfunction during midlife.MethodsThe cross-sectional study was conducted among sexually active women, between the ages of 45 and 65 years, who sought consultation at the women’s health clinics at a US tertiary care center. History of infertility treatment was assessed with a single question that asked participants if they were treated for infertility in the past. The association between a history of infertility treatment and sexual dysfunction—which was diagnosed by a combination of Female Sexual Function Index score ≤26.55 and Female Sexual Distress Scale–Revised score ≥11—was assessed in a multivariable logistic regression model that adjusted for multiple confounders.OutcomesThe primary outcome was sexual dysfunction in midlife women.ResultsThe analysis included 5912 women, with a mean age of 54.1 years. Nearly 16% of women reported receiving treatment for infertility. More than half the women (55%) had sexual dysfunction: 56.3% of those with previous fertility treatments and 54.4% of those without any fertility treatment (P = .3). Receiving treatment for infertility in the younger years did not significantly increase the odds of sexual dysfunction in midlife in univariate (odds ratio, 1.08; 95% CI, 0.94-1.24; P = .3) and multivariable analyses (odds ratio, 1.11; 95% CI, 0.96-1.29; P = .17).Clinical ImplicationsWhile infertility is known to be predictive of sexual dysfunction in women during their reproductive years, there was no association between a history of infertility treatment and sexual dysfunction in midlife women in the current study.Strengths and LimitationsThe study used validated questionnaires accounting for sexual complaints and distress and adjusted for multiple confounding factors. Limitations include the selection bias introduced by the study of women presenting for evaluation of sexual dysfunction, which may have been a result of factors stronger than the influence of infertility. Other limitations include the study’s cross-sectional nature with suboptimal racial and ethnic representation.ConclusionAlthough infertility is commonly associated with female sexual dysfunction in women of reproductive age, the association was not present in midlife women in the current study.