Use of E-values for addressing confounding in observational studies-an empirical assessment of the literature

The atherogenic index of plasma increases the risk of incident kidney stones: a nested case-control study in Chinese adults

OBJECTIVE

To investigate the association between atherogenic index of plasma (AIP) and risk of incident kidney stones.

METHODS

A nested case-control study was conducted using data from the Shanghai Kidney Stone Cohort from December 2018 to February 2023. Kidney stones were ascertained by ultrasound. Propensity score matching selected 2,550 patients with incident kidney stones and 5,100 controls from a total of 64,121 adults. Baseline fasting plasma samples were collected to measure the AIP, defined as the logarithm of the ratio triglycerides to high-density lipoprotein cholesterol. A multivariable conditional logistic regression model and restricted cubic spline were applied to examine the association between the AIP and the risk of incident kidney stones.

RESULTS

The baseline AIP values of the incident kidney stone patients and controls were 0.98 (0.67) and 0.91 (0.65), respectively. Patients with incident kidney stones had much higher baseline AIP levels than controls (p < 0.001). Participants in the highest AIP quartile had a 29% greater risk of developing kidney stones. Moreover, each increase in the standard deviation of the AIP was associated with a 10% greater risk of nephrolithiasis. A restricted cubic spline showed a significant positive and linear correlation between the AIP and the risk of developing kidney stones (P-overall = 0.040, P-nonlinear = 0.923). These findings remained robust in sensitivity analyses.

CONCLUSIONS

A higher AIP is associated with a greater risk of incident kidney stones.

Association of urinary perchlorate, nitrate and thiocyanate with pregnancy loss risk among reproductive-aged women

Environmental pollution is recognized as a critical contributor to pregnancy loss. However, there is currently a paucity of evidence concerning the potential impact of perchlorate, thiocyanate and nitrate, which are known as sodium iodine symporter inhibitors. This study was therefore designed to investigate the potential association between urinary perchlorate, thiocyanate and nitrate concentration and the risk of pregnancy loss. Based on the National Health and Nutrition Examination Survey 2001-2002 and 2005-2020 cycles, a total of 3249 reproductive-aged women were enrolled, of whom 1729 (53.22 %) had a history of pregnancy loss encompassing miscarriages, stillbirths, ectopic pregnancies, or abortions. Logistic regression analyses revealed that urinary perchlorate levels were significantly associated with increased pregnancy loss prevalence. In the weighted quantile sum and Bayesian kernel machine regression models, co-exposure to three anions were also significantly associated with higher pregnancy loss odds, with perchlorate identified as the primary contributor. Additionally, the mediation analysis suggested that insulin resistance, represented by the triglyceride-glucose index, accounted for 6.08 % of the perchlorate-associated risk. In summary, our study revealed a potential role of perchlorate exposure in pregnancy loss. Further prospective studies are needed to confirm our findings and elucidate the underlying causative mechanistic links.

Ikigai and suicidal ideation in Japan during the COVID-19 pandemic

BACKGROUND

Ikigai i.e., a Japanese concept relating to purpose in life but that is somewhat broader, has been associated with better physical and mental health. However, little is known about its association with suicidality. This study examined the association between ikigai and suicidal ideation in the Japanese general population during the COVID-19 pandemic.

METHODS

Data were analyzed from 3371 adults aged ≥18 who participated in an online survey in March 2023. Information on ikigai and pandemic-related suicidal ideation was obtained from self-reports. Logistic regression was used to examine associations.

RESULTS

In a fully adjusted analysis, compared to those with ikigai, individuals who did not know if they had ikigai (OR: 1.96, 95 % CI: 1.36-2.82) or did not have ikigai (OR: 2.50, 95 % CI: 1.74-3.57) had significantly higher odds of suicidal ideation. In sex- and age-stratified analyses, not having ikigai was associated with significantly higher odds of suicidal ideation in all population subgroups with the highest odds being observed in individuals aged ≥60 (OR: 6.27, 95 % CI: 2.02-19.45).

CONCLUSIONS

An absence of ikigai was associated with higher odds of suicidal ideation during the COVID-19 pandemic. Future research should examine the association between ikigai and suicidal behavior as well as explore the potential mechanisms linking ikigai and suicidality.

Breaking Down Bias: A Methodological Primer on Identifying, Evaluating, and Mitigating Bias in Cardiovascular Research

Systematic error, often referred to as bias is an inherent challenge in observational cardiovascular research, and has the potential to profoundly influence the design, conduct, and interpretation of study results. If not carefully considered and managed, bias can lead to spurious results, which can misinform clinical practice or public health initiatives and compromise patient outcomes. This methodological primer offers a concise introduction to identifying, evaluating, and mitigating bias in observational cardiovascular research studies that examine the causal association between an exposure (or treatment) and an outcome. Using high-profile examples from the cardiovascular literature, this review provides a theoretical overview of 3 main types of bias-selection bias, information bias, and confounding-and discusses the implications of specialized types of biases commonly encountered in longitudinal cardiovascular research studies, namely, competing risks, immortal time bias, and confounding by indication. Furthermore, strategies and tools that can be used to minimize and assess the influence of bias are highlighted, with a specific focus on using the target trial framework, directed acyclic graphs, quantitative bias analysis, and formal risk of bias assessments. This review aims to assist researchers and health care professionals in designing observational studies and selecting appropriate methodologies to reduce bias, ultimately enhancing the estimation of causal associations in cardiovascular research.

Analysis of demographic variation and childhood correlates of financial well-being across 22 countries

Using nationally representative data from 202,898 participants in the Global Flourishing Study, this work examines factors associated with financial well-being across 22 countries. We investigate how demographic factors-including age, gender, marital status, employment status, education, religious service attendance and immigration status-are correlated with financial well-being (as assessed through four dimensions). Additionally, we analyse associations between recalled early-life conditions, such as parental marital status and childhood health, with financial well-being in adulthood. Our findings reveal cross-national differences in levels of financial well-being and its demographic correlates. Early-life conditions were also consistently associated with adult financial well-being, although these associations varied substantially across countries. These results suggest that understanding financial well-being should encompass both current sociodemographic factors and early-life experiences within the unique cultural and socioeconomic contexts of different populations.

The Impact of Neuroanesthesia Fellowship Training and Anesthesiologist-Surgeon Dyad Volume on Patient Outcomes in Adult Spine Surgery: A Population-Based Study

INTRODUCTION

Extensive research has explored the impact of surgeons' characteristics on patient outcomes; however, the influence of anesthesiologists remains understudied. We performed a population-based retrospective cohort study to investigate the impact of anesthesiologists' characteristics on in-hospital morbidity after spine surgery.

METHODS

Adult patients who underwent spine surgery at the London Health Science Centre, Ontario, Canada between January 1, 2010 and June 30, 2023 were included in this study. Data was extracted from the local administrative database. Five anesthesiologists' characteristics (neuroanesthesia fellowship and residency training backgrounds, surgeon familiarity, annual case volume, and sex) were examined as primary exposures. The primary outcome was composite in-hospital morbidity, encompassing 141 complications. Multivariable logistic regression was performed to assess the association between anesthesiologists' characteristics and postoperative morbidity with adjustment of patients' sex, Charlson Comorbidities Index, surgical complexity, and surgeon characteristics.

RESULTS

A total of 7692 spine surgeries were included in the analysis. Being a neuroanesthesia fellowship-trained anesthesiologist and high anesthesiologist-surgeon annual dyad volume were associated with reduction in in-hospital comorbidity; adjusted odds ratio (95% CI) of 0.58 (0.49-0.69; P <0.001) and 0.93 (0.91-0.95; P <0.001), respectively. Conversely, anesthesiologist annual case volume, characteristics of residency training and anesthesiologist sex showed only nuanced associations with outcomes.

CONCLUSIONS

Neuroanesthesia fellowship training and high surgeon-anesthesiologist dyad familiarity was associated with a reduction in in-hospital morbidity following spine surgery. These findings underscore the superiority of structured fellowship education over case exposure experience alone, advocate for dedicated neuroanesthesia teams with high surgeon-anesthesiologist dyad volume and recognize neuroanesthesia as a crucial subspecialty in spine surgery.

Real Effect or Bias? Good Practices for Evaluating the Robustness of Evidence From Comparative Observational Studies Through Quantitative Sensitivity Analysis for Unmeasured Confounding

The assumption of "no unmeasured confounders" is a critical but unverifiable assumption required for causal inference yet quantitative sensitivity analyses to assess robustness of real-world evidence remains under-utilized. The lack of use is likely in part due to complexity of implementation and often specific and restrictive data requirements for application of each method. With the advent of methods that are broadly applicable in that they do not require identification of a specific unmeasured confounder-along with publicly available code for implementation-roadblocks toward broader use of sensitivity analyses are decreasing. To spur greater application, here we offer a good practice guidance to address the potential for unmeasured confounding at both the design and analysis stages, including framing questions and an analytic toolbox for researchers. The questions at the design stage guide the researcher through steps evaluating the potential robustness of the design while encouraging gathering of additional data to reduce uncertainty due to potential confounding. At the analysis stage, the questions guide quantifying the robustness of the observed result and providing researchers with a clearer indication of the strength of their conclusions. We demonstrate the application of this guidance using simulated data based on an observational fibromyalgia study, applying multiple methods from our analytic toolbox for illustration purposes.

Application of methodological strategies to address unmeasured confounding in real-world vaccine safety and effectiveness study: a systematic review

OBJECTIVES

Uses of real-world data to evaluate vaccine safety and effectiveness are often challenged by unmeasured confounding. The study aimed to review the application of methods to address unmeasured confounding in observational vaccine safety and effectiveness research.

STUDY DESIGN AND SETTING

We conducted a systematic review (PROSPERO: CRD42024519882), and searched PubMed, Web of Science, Embase, and Scopus for epidemiological studies investigating influenza and COVID-19 vaccines as exposures, and respiratory and cardiovascular diseases as outcomes, published between January 1, 2017, and December 31, 2023. Data on study design and statistical analyses were extracted from eligible articles.

RESULTS

A total of 913 studies were included, of which 42 (4.6%, 42/913) accounted for unmeasured confounding through statistical correction (31.0%, 13/42) or confounding detection or quantification (78.6%, 33/42). Negative control was employed in 24 (57.1%, 24/42) studies-2 (8.3%, 2/24) for confounding correction and 22 (91.7%, 22/24) for confounding detection or quantification-followed by E-value (31.0%, 13/42), prior event rate ratio (11.9%, 5/42), regression discontinuity design (7.1%, 3/42), instrumental variable (4.8%, 2/42), and difference-in-differences (2.4%, 1/42). A total of 871 (95.4%, 871/913) studies did not address unmeasured confounding, but 38.9% (355/913) reported it as study limitation.

CONCLUSION

Unmeasured confounding in real-world vaccine safety and effectiveness studies remains underexplored. Current research primarily employed confounding detection or quantification, notably negative control and E-value, which did not yield adjusted effect estimates. While some studies used correction methods like instrumental variable, regression discontinuity design, and negative control, challenges arise from the stringent assumptions. Future efforts should prioritize developing valid methodologies to mitigate unmeasured confounding.

Use of sensitivity analyses to assess uncontrolled confounding from unmeasured variables in observational, active comparator pharmacoepidemiologic studies: a systematic review

Understanding the potential for, and direction and magnitude of uncontrolled confounding is critical for generating informative real-world evidence. Many sensitivity analyses are available to assess robustness of study results to residual confounding, but it is unclear how researchers are using these methods. We conducted a systematic review of published active-comparator cohort studies of drugs or biologics to summarize use of sensitivity analyses aimed at assessing uncontrolled confounding from an unmeasured variable. We reviewed articles in 5 medical and 7 epidemiologic journals published between January 1, 2017, and June 30, 2022. We identified 158 active-comparator cohort studies: 76 from medical and 82 from epidemiologic journals. Residual, unmeasured, or uncontrolled confounding was noted as a potential concern in 93% of studies, but only 84 (53%) implemented at least 1 sensitivity analysis to assess uncontrolled confounding from an unmeasured variable. The most common analyses were E-values among medical journal articles (21%) and restriction on measured variables among epidemiologic journal articles (22%). Researchers must rigorously consider the role of residual confounding in their analyses and the best sensitivity analyses for assessing this potential bias. This article is part of a Special Collection on Pharmacoepidemiology.

Exposure to perchlorate and cardiovascular disease in China: A community-based cross-sectional study and benchmark dose estimation

The association between exposure to perchlorate, which inhibits thyroidal iodine uptake, and cardiovascular disease (CVD) is unclear in China. Moreover, the point of departure (POD) for perchlorate based on observed adverse health effect in Chinese populations remains absent. A total of 2355 adults (mean age 50.4 years and 39.2% male) from four communities in Shenzhen were included in analyses. Spot urine specimens were collected to measure urinary perchlorate concentrations, which were applied to estimate daily intakes of perchlorate. Multivariable logistic regression model was applied to examine the association between perchlorate and CVD. The roles of cardiometabolic risk factors, including obesity, abdominal obesity, hypertension, diabetes, and hyperlipidemia, were evaluated with mediation analyses. We further employed Bayesian benchmark dose (BMD) modeling to derive the POD for risk assessment. Comparing extreme tertiles, subjects in the highest perchlorate tertile had a significantly elevated risk of prevalent CVD (OR: 2.16; 95% CI: 1.28, 3.65). Multivariable-adjusted ORs for hypertension, diabetes, and hyperlipidemia associated with per doubling in urinary perchlorate concentration were 1.11 (95% CI: 1.01, 1.21), 1.15 (95% CI: 1.02, 1.28), and 1.11 (95% CI: 1.01, 1.20), respectively. Hypertension, diabetes, and hyperlipidemia partially mediated the perchlorate-CVD association (mediated proportion ranged from 7.75% to 11.30%). Given a benchmark response of 5% and 10%, the model-averaged BMD lower bounds (BMDLs) of perchlorate exposure on CVD were 0.15 and 0.40 μg/kg-bw day, respectively. Our estimated POD for perchlorate was lower than those recommended by other groups. These findings call for stricter regulations on perchlorate contamination to promote cardiovascular health in China.

Predicting higher risk factors for COVID-19 short-term reinfection in patients with rheumatic diseases: a modeling study based on XGBoost algorithm

BACKGROUND

Corona virus disease 2019 (COVID-19) reinfection, particularly short-term reinfection, poses challenges to the management of rheumatic diseases and may increase adverse clinical outcomes. This study aims to develop machine learning models to predict and identify the risk of short-term COVID-19 reinfection in patients with rheumatic diseases.

METHODS

We developed four prediction models using explainable machine learning to assess the risk of short-term COVID-19 reinfection in 543 patients with rheumatic diseases. Psychological health was evaluated using the Functional Assessment of Chronic Illness Therapy Fatigue (FACIT-F) scale, the Patient Health Questionnaire-9 (PHQ-9), the Generalized Anxiety Disorder 7-item (GAD-7) questionnaire, and the Pittsburgh Sleep Quality Index (PSQI) scale. Health status and disease activity were assessed using the EuroQol-5 Dimension-3 Level (EQ-5D-3L) descriptive system and the Visual Analogue Score (VAS) scale. The model performance was assessed by Area Under the Receiver Operating Characteristic Curve (AUC), Area Under the Precision-Recall Curve (AUPRC), and the geometric mean of sensitivity and specificity (G-mean). SHapley Additive exPlanations (SHAP) analysis was used to interpret the contribution of each predictor to the model outcomes.

RESULTS

The eXtreme Gradient Boosting (XGBoost) model demonstrated superior performance with an AUC of 0.91 (95% CI 0.87-0.95). Significant factors of short-term reinfection included glucocorticoid taper (OR = 2.61, 95% CI 1.38-4.92), conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) taper (OR = 2.97, 95% CI 1.90-4.64), the number of symptoms (OR = 1.24, 95% CI 1.08-1.42), and GAD-7 scores (OR = 1.07, 95% CI 1.02-1.13). FACIT-F scores were associated with a lower likelihood of short-term reinfection (OR = 0.95, 95% CI 0.93-0.96). Besides, we found that the GAD-7 score was one of the most important predictors.

CONCLUSION

We developed explainable machine learning models to predict the risk of short-term COVID-19 reinfection in patients with rheumatic diseases. SHAP analysis highlighted the importance of clinical and psychological factors. Factors included anxiety, fatigue, depression, poor sleep quality, high disease activity during initial infection, and the use of glucocorticoid taper were significant predictors. These findings underscore the need for targeted preventive measures in this patient population.

Association between triglyceride-glucose index and risk of kidney stone: a Chinese population-based case-control study

OBJECTIVE

To investigate the association between the triglyceride-glucose (TyG) index, a surrogate marker of insulin resistance and the risk of kidney stones (KSs) in a Chinese population.

DESIGN

Case-control study.

SETTING

Three Physical Examination Centers in Shanghai, China, between January 2020 and December 2022.

PARTICIPANTS

A total of 117 757 Chinese adults underwent health check-ups during the study period.

PRIMARY AND SECONDARY OUTCOME MEASURES

The association between the TyG index and the risk of KS was assessed using multivariable logistic regression analysis. The dose-response relationship between the TyG index and KS risk was evaluated with a restricted cubic spline (RCS) analysis. Stratified analyses were conducted to explore whether factors such as age, sex, obesity, hypertension and diabetes modify the association between the TyG index and KS risk.

RESULTS

Out Of the 117 757 participants, 11 645 (9.9%) were diagnosed with KS using ultrasound. Individuals with KS had significantly higher TyG values than controls (p<0.001). The multivariable-adjusted ORs for KS increased across TyG quartiles, with the highest quartile showing an OR of 1.28 (95% CI 1.20 to 1.36) compared with the lowest quartile. Each SD increase in the TyG index was associated with a 10% higher risk of KS (OR: 1.10, 95% CI 1.08 to 1.13). RCS analysis revealed a significant positive and linear association between TyG index and KS (p overall<0.001, p non-linear=0.136). The positive association persisted across the subgroup and sensitivity analyses.

CONCLUSIONS

The TyG index was positively associated with the risk of prevalent KS, suggesting that insulin resistance may be a risk factor for KS in the Chinese population.

Remnant cholesterol increases the risk of incident kidney stones: a nested case-control study in Chinese adults

Kidney stones pose a significant healthcare burden worldwide. Dyslipidemia is a risk factor for kidney stones, but the relationship between remnant cholesterol (RC) and kidney stone risk is unknown. We aimed to investigate the association between RC and the risk of incident kidney stones. We conducted a nested case-control study based on data from Shanghai Kidney Stone Cohort conducted in Shanghai from December 2018 to February 2023. Propensity score matching was used to select 2550 incident kidney stone cases and 7650 controls from a total of 60,158 adults. Baseline fasting plasma samples were collected to measure RC, which was calculated as total cholesterol minus high-density lipoproteins cholesterol and low-density lipoproteins cholesterol. Multivariable conditional logistic regression and a restricted cubic spline were used to estimate the association between tertiles of RC and kidney stone risk. Subgroup and sensitivity analyses were also performed. The baseline RC of incident kidney stone cases and controls were 0.58 (0.57) and 0.54 (0.55), respectively. Incident kidney stones had much higher baseline RC levels than controls (P < 0.001). Higher baseline RC levels were significantly associated with increased kidney stone risk after adjustment for potential confounders (highest vs. lowest tertile: OR 1.16, 95% CI 1.04-1.30; per 1 mmol/L increase: OR 1.16, 95% CI 1.07-1.26). Restricted cubic spline showed a significant positive and linear dose-response relationship between RC and the risk of developing kidney stones (P-overall = 0.005, P-nonlinear = 0.482). Sensitivity analyses yielded consistent results. Elevated RC levels are associated with a greater risk of incident kidney stones in Chinese adults.

Potential causal links of long-term exposure to PM2.5 and its chemical components with the risk of nasopharyngeal carcinoma recurrence: A 10-year cohort study in South China

There is a lack of evidence from cohort studies on the causal association of long-term exposure to ambient fine particulate matter (PM2.5) and its chemical components with the risk of nasopharyngeal carcinoma (NPC) recurrence. Based on a 10-year prospective cohort of 1184 newly diagnosed NPC patients, we comprehensively evaluated the potential causal links of ambient PM2.5 and its chemical components including black carbon (BC), organic matter (OM), sulfate (SO4 2-), nitrate (NO3 -), and ammonium (NH4 +) with the recurrence risk of NPC using a marginal structural Cox model adjusted with inverse probability weighting. We observed 291 NPC patients experiencing recurrence during the 10-year follow-up and estimated a 33% increased risk of NPC recurrence (hazard ratio [HR]: 1.33, 95% confidence interval [CI]: 1.02-1.74) following each interquartile range (IQR) increase in PM2.5 exposure. Each IQR increment in BC, NH4 +, OM, NO3 -, and SO4 2- was associated with HRs of 1.36 (95%CI: 1.13-1.65), 1.35 (95%CI: 1.07-1.70), 1.33 (95%CI: 1.11-1.59), 1.32 (95%CI: 1.06-1.64), 1.31 (95%CI: 1.08-1.57). The elderly, patients with no family history of cancer, no smoking history, no drinking history, and those with severe conditions may exhibit a greater likelihood of NPC recurrence following exposure to PM2.5 and its chemical components. Additionally, the effect estimates of the five components are greater among patients who were exposed to high concentration than in the full cohort of patients. Our study provides solid evidence for a potential relationship between long-term exposure to PM2.5 and its components and the risk of NPC recurrence.

The Methodological Quality of Observational Studies Examining the Risk of Pregnancy Drug Use on Congenital Malformations Needs Substantial Improvement: A Cross-Sectional Survey

BACKGROUND AND OBJECTIVE

An increasing number of observational studies have investigated the risk of using drugs during pregnancy on congenital malformations. However, the credibility of the causal relationships drawn from these studies remains uncertain. This study aims to evaluate the potential methodological issues in existing observational studies.

METHODS

We used a stepwise approach to investigate this issue. First, we identified observational studies published in 2020 that examined the risk of congenital malformations associated with medication use during pregnancy. We assessed the methodological characteristics for establishing causality, including study design, confounding control, and sensitivity analysis, and compared them between "core clinical journals" and "general journals." For studies reporting an increased risk of congenital malformations in core clinical journals, we searched for subsequent studies addressing the same research question published between January 2021 and May 2023 to assess the consistency of the literature.

RESULTS

A total of 40 eligible studies were published in 2020, primarily focused on the safety of vitamin B12 and folic acid (n = 4), antidepressants (n = 4), and others (n = 32). Our findings suggest that only two (5.00%) studies used causal models to guide the identification of confounding, and only eight (20.00%) studies assessed the potential dose-response relationship. In all, 15 (37.50%) studies used propensity score analysis strategy to achieve "mimic-randomization." In addition, 22 studies (55.00%) performed sensitivity analyses, while 10 (45.45%) showed inconsistency with the primary outcome. Furthermore, 5 studies reported positive outcomes, whereas only 1 out of 11 studies demonstrated a positive correlation between drug usage during pregnancy and major malformations in subsequent studies.

CONCLUSION

A significant portion of the studies has failed to sufficiently consider the essential methodological characteristics required to improve the credibility of causal inferences. The increased risk of congenital malformations documented in core clinical journal was not adequately replicated in subsequent studies.

Association between remnant cholesterol and risk of kidney stones: a case-control study in Chinese adults

Remnant cholesterol (RC), a key indicator of dyslipidemia, has been validated as a contributing factor to metabolic and cardiovascular diseases, both of which are closely associated with kidney stones (KS). This study aimed to investigate the association between RC and the risk of KS in Chinese adults. A total of 8,576 KS cases (mean age 55.87, 69.37% male) and 137,523 controls (mean age 54.57, 51.62% male) were included in this case-control study. RC was calculated using the formula: RC = TC-HDL-LDL. KS was ascertained with ultrasound by well-trained physicians. Multivariable logistic and restricted cubic spline (RCS) were applied to investigate the relationship between RC and KS. A total of 146,099 subjects (weighted mean age 54.64 years and 52.66% male) were included with mean RC = 0.8 for controls and RC = 0.72 for KS cases (P < 0.001). The multivariable-adjusted OR for KS occurrence across consecutive quartiles was 1.00 (reference), 1.05 (0.98-1.12), 1.15 (1.07-1.22), and 1.44 (1.35-1.53), respectively. Moreover, each standard deviation increment of RC was associated with a 15% (OR:1.15, 95% CI: 1.12-1.19) higher risk of KS occurrence. RCS showed significant and linear dose-response relationships between RC and KS occurrence (P-overall < 0.001, P-nonlinear = 0.270). The positive associations between RC and KS risk persisted in sensitivity analyses, suggesting the robustness of the results. In this case-control study of Chinese adults, elevated RC was associated with the occurrence of KS.

Glucose-albumin ratio (GAR) as a novel biomarker of postoperative urinary tract infection in elderly hip fracture patients

Purpose

Postoperative urinary tract infections (UTIs) worsen the prognosis of elderly patients with hip fractures. This study aimed to assess the predictive ability of blood-based biomarkers, specifically the glucose-albumin ratio (GAR), in predicting postoperative UTIs.

Methods

A retrospective observational study of 1,231 patients from a Level I trauma center was conducted. We evaluated the prognostic and predictive value of 15 biomarkers, including the glucose-albumin ratio, in elderly patients with hip fractures. The primary outcome measure was the incidence of postoperative UTIs.

Results

The glucose to albumin ratio transformed into GAR was superior to any other biomarker in predicting postoperative UTIs in elderly hip fracture patients (AUC = 0.756, p < 0.001). Elevated GAR (using the best cut-off value of 0.18) was independently associated with postoperative UTIs (OR 3.20, 95% CI 2.23-4.58). Further analysis dividing GAR levels into four groups according to quartiles showed that compared to patients with GAR levels of Q1 (< 0.14), GAR levels of Q2 (0.14-0.17; OR 2.11, 95% CI 1.07-4.15), Q3 (0.17-0.21; OR 3.36, 95% CI 1.74-6.52) and Q4 (> 0.21; OR 7.55, 95% CI 3.84-14.83) patients had significantly higher odds of UTIs.

Conclusion

GAR holds potential as a novel biomarker for predicting postoperative UTIs in elderly patients with hip fractures.

Characterizing the impact of thermoregulation in patients after cardiac arrest: a retrospective cohort study

PURPOSE

Core body temperature has been extensively investigated as a thereuptic target in care after cardiac arrest. Nevertheless, the integrity of thermoregulation in patients after cardiac arrest has not been well studied. We sought to evaluate whether low spontaneous body temperature after cardiac arrest is associated with increased death and a worse neurologic outcome, and whether patients with low spontaneous body temperature exhibit features suggestive of impaired thermoregulation.

METHODS

We conducted a single-centre retrospective cohort study. We included all adult patients who underwent temperature control with hypothermia after cardiac arrest between 1 January 2014 and 30 June 2020. The primary exposure was low spontaneous core body temperature (< 35 °C) at initiation of hypothermia therapy. The primary outcome was in-hospital death and the secondary outcome was poor neurologic outcomes at discharge.

RESULTS

Five hundred and ninety-seven adult patients, comprising both in- and out-of-hospital cardiac arrests, were included. Patients with low spontaneous body temperature also had slightly lower average temperature, and more frequent transient but controlled breakthrough fever episodes in the first 24 hr. In the multivariable logistic regression analysis, low spontaneous body temperature was associated with higher odds of in-hospital death (odds ratio, 2.9; 95% confidence interval, 1.9 to 4.2; P < 0.001).

CONCLUSION

In this single-centre retrospective cohort study, low spontaneous core body temperature was associated with poor outcomes in patients after cardiac arrest. Patients with low spontaneous body temperature also exhibited features suggestive of impaired thermoregulation. Further research is needed to determine whether body temperature upon presentation reflects the robustness of the patient's underlying physiology and severity of brain insult after a cardiac arrest.

Effectiveness of oseltamivir in reducing COVID-19-related in-hospital deaths: A pharmacoepidemiological study

BACKGROUND

Oseltamivir is a low-cost antiviral agent that could support or complement treatment of COVID-19. This study assessed whether oseltamivir is effective in reducing COVID-19-related mortality.

METHODS

This retrospective cohort study evaluated real-world data from a nationwide database of hospitalisation due to severe acute respiratory syndrome in Brazil. Propensity score matching was used to mimic a randomised controlled trial with 'oseltamivir' and 'no antivirals at all' as the intervention and control groups, respectively.

RESULTS

A total of 21 480 and 268 486 patients admitted between February 2020 and January 2023 were included in the intervention and control groups, respectively. After matching, the odds ratio (OR) for death was 0.901 (95% confidence interval [CI] 0.873-0.930). The OR (95% CI) for death in patients who were admitted to the ICU, and on non-invasive or invasive ventilation was 0.868 (0.821-0.917), 0.935 (0.893-0.980), and 0.883 (0.814-0.958), respectively.

CONCLUSIONS

Overall, the use of oseltamivir was associated with an attributable risk reduction of 2.50% (95% CI 1.77-3.29). Similar results were observed in patients who were admitted to the ICU, and on non-invasive or invasive ventilation. Oseltamivir is a low-cost potential antiviral treatment for COVID-19.

Childhood maltreatment and health in the UK Biobank: triangulation of outcome-wide and polygenic risk score analyses

BACKGROUND

Childhood maltreatment is common globally and impacts morbidity, mortality, and well-being. Our understanding of its impact is constrained by key substantive and methodological limitations of extant research, including understudied physical health outcomes and bias due to unmeasured confounding. We address these limitations through a large-scale outcome-wide triangulation study.

METHODS

We performed two outcome-wide analyses (OWAs) in the UK Biobank. First, we examined the relationship between self-reported maltreatment exposure (number of maltreatment types, via Childhood Trauma Screener) and 414 outcomes in a sub-sample of 157,316 individuals using generalized linear models ("observational OWA"). Outcomes covered a broad range of health themes including health behaviors, cardiovascular disease, digestive health, socioeconomic status, and pain. Second, we examined the relationship between a polygenic risk score for maltreatment and 298 outcomes in a non-overlapping sample of 243,006 individuals ("genetic OWA"). We triangulated results across OWAs based on differing sources of bias.

RESULTS

Overall, 23.8% of the analytic sample for the observational OWA reported at least one maltreatment type. Of 298 outcomes examined in both OWAs, 25% were significant in both OWAs and concordant in the direction of association. Most of these were considered robust in the observational OWA according to sensitivity analyses and included outcomes such as marital separation (OR from observational OWA, ORo = 1.25 (95% CI: 1.21, 1.29); OR from genetic OWA, ORg = 1.06 (1.03, 1.08)), major diet changes due to illness (ORo = 1.27 (1.24, 1.29); ORg = 1.01 (1.00, 1.03)), certain intestinal diseases (ORo = 1.14 (1.10, 1.18); ORg = 1.03 (1.01, 1.06)), hearing difficulty with background noise (ORo = 1.11 (1.11, 1.12); ORg = 1.01 (1.00, 1.01)), knee arthrosis (ORo = 1.13 (1.09, 1.18); ORg = 1.03 (1.01, 1.05)), frequent sleeplessness (ORo = 1.21 (1.20, 1.23); ORg = 1.02 (1.01, 1.03)), and low household income (ORo = 1.28 (1.26, 1.31); ORg = 1.02 (1.01, 1.03)). Approximately 62% of results were significant in the observational OWA but not the genetic OWA, including numerous cardiovascular outcomes. Only 6 outcomes were significant in the genetic OWA and null in the observational OWA; these included diastolic blood pressure and glaucoma. No outcomes were statistically significant in opposite directions in the two analyses, and 11% were not significant in either OWA.

CONCLUSIONS

Our findings underscore the far-reaching negative effects of childhood maltreatment in later life and the utility of an outcome-wide triangulation design with sensitivity analyses for improving causal inference.

High Mechanical Power and Driving Pressures are Associated With Postoperative Respiratory Failure Independent From Patients' Respiratory System Mechanics

OBJECTIVES

High mechanical power and driving pressure (ΔP) have been associated with postoperative respiratory failure (PRF) and may be important parameters guiding mechanical ventilation. However, it remains unclear whether high mechanical power and ΔP merely reflect patients with poor respiratory system mechanics at risk of PRF. We investigated the effect of mechanical power and ΔP on PRF in cohorts after exact matching by patients' baseline respiratory system compliance.

DESIGN

Hospital registry study.

SETTING

Academic hospital in New England.

PATIENTS

Adult patients undergoing general anesthesia between 2008 and 2020.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

The primary exposure was high (≥ 6.7 J/min, cohort median) versus low mechanical power and the key-secondary exposure was high (≥ 15.0 cm H 2 O) versus low ΔP. The primary endpoint was PRF (reintubation or unplanned noninvasive ventilation within seven days). Among 97,555 included patients, 4,030 (4.1%) developed PRF. In adjusted analyses, high intraoperative mechanical power and ΔP were associated with higher odds of PRF (adjusted odds ratio [aOR] 1.37 [95% CI, 1.25-1.50]; p < 0.001 and aOR 1.45 [95% CI, 1.31-1.60]; p < 0.001, respectively). There was large variability in applied ventilatory parameters, dependent on the anesthesia provider. This facilitated matching of 63,612 (mechanical power cohort) and 53,260 (ΔP cohort) patients, yielding identical baseline standardized respiratory system compliance (standardized difference [SDiff] = 0.00) with distinctly different mechanical power (9.4 [2.4] vs 4.9 [1.3] J/min; SDiff = -2.33) and ΔP (19.3 [4.1] vs 11.9 [2.1] cm H 2 O; SDiff = -2.27). After matching, high mechanical power and ΔP remained associated with higher risk of PRF (aOR 1.30 [95% CI, 1.17-1.45]; p < 0.001 and aOR 1.28 [95% CI, 1.12-1.46]; p < 0.001, respectively).

CONCLUSIONS

High mechanical power and ΔP are associated with PRF independent of patient's baseline respiratory system compliance. Our findings support utilization of these parameters for titrating mechanical ventilation in the operating room and ICU.

Venous Thromboembolism in Total Hip and Total Knee Arthroplasty

Importance

The optimal pharmacologic thromboprophylaxis agent after total hip and total knee arthroplasty is uncertain and consensus is lacking. Quantifying the risk of postoperative venous thromboembolism (VTE) and bleeding and evaluating comparative effectiveness and safety of the thromboprophylaxis strategies can inform care.

Objective

To quantify risk factors for postoperative VTE and bleeding and compare patient outcomes among pharmacological thromboprophylaxis agents used after total hip and knee arthroplasty.

Design, Setting, and Participants

This retrospective cohort study used data from a large health care claims database. Participants included patients in the United States with hip or knee arthroplasty and continuous insurance enrollment 3 months prior to and following their surgical procedure. Patients were excluded if they received anticoagulation before surgery, received no postsurgical pharmacological thromboprophylaxis, or had multiple postsurgery thromboprophylactic agents. In a propensity-matched analysis, patients receiving a direct oral anticoagulant (DOAC) were matched with those receiving aspirin.

Exposures

Aspirin, apixaban, rivaroxaban, enoxaparin, or warfarin.

Main Outcomes and Measures

The primary outcome was 30-day cumulative incidence of postdischarge VTE. Other outcomes included postdischarge bleeding.

Results

Among 29 264 patients included in the final cohort, 17 040 (58.2%) were female, 27 897 (95.2%) had inpatient admissions with median (IQR) length of stay of 2 (1-2) days, 10 948 (37.4%) underwent total hip arthroplasty, 18 316 (62.6%) underwent total knee arthroplasty; and median (IQR) age was 59 (55-63) years. At 30 days, cumulative incidence of VTE was 1.19% (95% CI, 1.06%-1.32%) and cumulative incidence of bleeding was 3.43% (95% CI, 3.22%-3.64%). In the multivariate analysis, leading risk factors associated with increased VTE risk included prior VTE history (odds ratio [OR], 5.94 [95% CI, 4.29-8.24]), a hereditary hypercoagulable state (OR, 2.64 [95% CI, 1.32-5.28]), knee arthroplasty (OR, 1.65 [95% CI, 1.29-2.10]), and male sex (OR, 1.34 [95% CI, 1.08-1.67]). In a propensity-matched cohort of 7844 DOAC-aspirin pairs, there was no significant difference in the risk of VTE in the first 30 days after the surgical procedure (OR, 1.14 [95% CI, 0.82-1.59]), but postoperative bleeding was more frequent in patients receiving DOACs (OR, 1.36 [95% CI, 1.13-1.62]).

Conclusions and Relevance

In this cohort study of patients who underwent total hip or total knee arthroplasty, underlying patient risk factors, but not choice of aspirin or DOAC, were associated with postsurgical VTE. Postoperative bleeding rates were lower in patients prescribed aspirin. These results suggest that thromboprophylaxis strategies should be patient-centric and tailored to individual risk of thrombosis and bleeding.

Prevention of Hip Fractures: Trade-off between Minor Benefits to Individuals and Large Benefits to the Community

Goeffrey Rose postulated that a population-based measure bringing a small benefit to each individual can yield large benefits to the community. We aimed to test this axiom by quantifying the relationship between change in bone mineral density (BMD) and hip fracture incidence between two prospective cohorts separated by ~10 years. In this prospective population-based Dubbo Osteoporosis Epidemiology Study (DOES), the participants aged 60+ were recruited in two waves: the initial cohort (1311 women, 842 men) in 1989 to 1992 and the second cohort (974 women, 544 men) in 1999 to 2001. The incident hip fracture was radiologically ascertained. Femoral neck BMD was measured biannually. Multivariable-adjusted Cox's proportional hazards models were adjusted for the predefined covariates such as age, BMI, lifestyle factors, falls, and prior fracture. Compared with the initial cohort, the second cohort had a higher femoral neck BMD by ~0.04 g/cm2 in women and 0.03 g/cm2 in men. However, the prevalence of osteoporosis in the second cohort was halved (prevalence ratio 0.51, 95% CI 0.36 to 0.73 in women; 0.45, 0.24 to 0.84 in men), and its hip fracture incidence was significantly reduced (hazard ratio 0.54, 95% CI, 0.38 to 0.78 in women; 0.39, 0.19 to 0.80 in men). Sensitivity analyses indicated that the "effect" was unlikely due to unmeasured confounders. These findings suggest that a population-wide strategy aimed at enhancing BMD across the entire population could lead to a substantial decrease in the incidence of hip fractures. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Correlation between admission hypoalbuminemia and postoperative urinary tract infections in elderly hip fracture patients

PURPOSE

This study aimed to evaluate the correlation between hypoalbuminemia upon admission and the incidence of postoperative urinary tract infections (UTIs) in elderly patients with hip fractures.

METHODS

A retrospective analysis was performed on the medical records of elderly patients who underwent surgical treatment for hip fractures at a level I trauma center from 2013 to 2023. Serum albumin levels were measured upon admission, and hypoalbuminemia was defined as a total albumin level < 35 g/L. Multivariable logistic regression and propensity score matching analysis were utilized to control and reduce potential confounding factors, aiming to obtain adjusted odds ratios (ORs) and 95% confidence intervals (CI) for UTIs to determine the strength of the association.

RESULTS

This observational cohort study included 1279 patients, among whom 298 (23.3%) developed UTIs. Patients with albumin levels < 35 g/L had significantly greater odds of developing UTIs compared to those with albumin levels ≥ 35 g/L (OR 1.86, 95% CI 1.28-2.70). Further analysis, dividing albumin levels into quartiles, demonstrated that patients in the Q2 group (38.0-40.9 g/L; OR 1.38, 95% CI 0.88-2.17), Q3 group (35.0-37.9 g/L; OR 1.69, 95% CI 1.06-2.71), and Q4 group (15.3-34.9 g/L; OR 2.67, 95% CI 1.61-4.43) had notably higher odds of developing UTIs compared to those in the Q1 group (41.0-52.0 g/L).

CONCLUSIONS

The presence of hypoalbuminemia upon admission in elderly patients undergoing hip fracture surgery is strongly correlated with the occurrence of postoperative UTIs. Furthermore, this association exhibits a clear dose-response relationship.

Comparison of lower extremity bypass and peripheral vascular intervention for chronic limb-threatening ischemia in the Medicare-linked Vascular Quality Initiative

OBJECTIVE

There is a relative lack of comparative effectiveness research on revascularization for patients with chronic limb-threatening ischemia (CLTI). We examined the association between lower extremity bypass (LEB) vs peripheral vascular intervention (PVI) for CLTI and 30-day and 5-year all-cause mortality and 30-day and 5-year amputation.

METHODS

Patients undergoing LEB and PVI of the below-the-knee popliteal and infrapopliteal arteries between 2014 and 2019 were queried from the Vascular Quality Initiative, and outcomes data were obtained from the Medicare claims-linked Vascular Implant Surveillance and Interventional Outcomes Network database. Propensity scores were calculated on 15 variables using a logistic regression model to control for imbalances between treatment groups. A 1:1 matching method was used. Kaplan-Meier survival curves and hierarchical Cox proportional hazards regression with a random intercept for site and operator nested in site to account for clustered data compared 30-day and 5-year all-cause mortality between groups. Thirty-day and 5-year amputation were subsequently compared using competing risk analysis to account for the competing risk of death.

RESULTS

There was a total of 2075 patients in each group. The overall mean age was 71 ± 11 years, 69% were male, and 76% were white, 18% were black, and 6% were of Hispanic ethnicity. Baseline clinical and demographic characteristics in the matched cohort were balanced between groups. There was no association between all-cause mortality over 30 days and LEB vs PVI (cumulative incidence, 2.3% vs 2.3% by Kaplan Meier; log-rank P-value = .906; hazard ratio [HR], 0.95; 95% confidence interval [CI], 0.62-1.44; P-value = .80). All-cause mortality over 5 years was lower for LEB vs PVI (cumulative incidence, 55.9% vs 60.1% by Kaplan Meier; log-rank P-value < .001; HR, 0.77; 95% CI, 0.70-0.86; P-value < .001). Accounting for competing risk of death, amputation over 30 days was also lower in LEB vs PVI (cumulative incidence function, 1.9% vs 3.0%; Fine and Gray P-value = .025; subHR, 0.63; 95% CI, 0.42-0.95; P-value = .025). There was no association between amputation over 5 years and LEB vs PVI (cumulative incidence function, 22.6% vs 23.4%; Fine and Gray P-value = .184; subHR, 0.91; 95% CI, 0.79-1.05; P-value = .184).

CONCLUSIONS

In the Vascular Quality Initiative-linked Medicare registry, LEB vs PVI for CLTI was associated with a lower risk of 30-day amputation and 5-year all-cause mortality. These results will serve as a foundation to validate recently published randomized controlled trial data, and to broaden the comparative effectiveness evidence base for CLTI.

Associations of grip strength and walking pace with mortality in stroke survivors: A prospective study from UK Biobank

INTRODUCTION

Although stroke is an emerging cause of disability and mortality globally, associations between physical capability markers and mortality in stroke survivors are elusive. This study investigated the individual and combined associations of walking pace and grip strength with all-cause and stroke mortality in stroke survivors.

METHODS

Individual and combined associations of walking pace and grip strength with stroke deaths and all-cause mortality were investigated using Cox proportional-hazard models adjusted for sociodemographic, lifestyle, and health-related variables.

RESULTS

Seven thousand four hundred eighty-six stroke survivors from the UK Biobank study (aged 40-70 years; 42.4% women) were included in this prospective study. Over a median follow-up of 12.6 (IQR: 11.9-13.3) years, 1490 (19.9%) participants died, of whom 222 (3.0%) died from stroke. After adjusting for confounding factors, and compared to individuals in the average/brisk walking pace category, those who reported a slow walking pace had 2.00 (95% CI: 1.50-2.68) and 1.99 (95% CI: 1.78-2.23) times higher risk of stroke mortality and all-cause mortality, respectively. Similar associations were identified for participants with low grip strength compared with those with normal levels. For combined associations, those with both slow walking pace and low grip strength showed the highest risk of stroke mortality (hazard ratio: 2.86 [95% CI: 1.93-4.22]). Similar results were found for all-cause mortality.

CONCLUSIONS

Low grip strength and slow walking pace were associated with a higher risk of stroke and all-cause mortality in stroke survivors. If these associations are causal, improving physical capability among stroke survivors might potentially prolong survival.

Charlson Comorbidity Index is correlated with all-cause readmission within six months in patients with heart failure: a retrospective cohort study in China

BACKGROUND

Charlson Comorbidity Index (CCI) is positively associated with all-cause readmission in patients with heart failure (HF) in western countries. However, there is a scarcity of strong scientific evidence supporting the correlation in China. This study aimed at testing this hypothesis in Chinese.   METHODS: We conducted a secondary analysis of 1,946 patients with HF in Zigong Fourth People's Hospital in China between December 2016 to June 2019. Logistic regression models were used to study the hypotheses, with adjustments for the four regression models. We also explore the linear trend and possible nonlinear relationship between CCI and readmission within six months. We further conducted subgroup analysis and tests for interaction to examine the possible interaction between CCI and the endpoint. Additionally, CCI alone and several combinations of variables based on CCI were used to predict the endpoint. Under the curve (AUC), sensitivity and specificity were reported to evaluate the performance of the predicted model.

RESULTS

In the adjusted II model, CCI was an independent prognostic factor for readmission within six months in patients with HF (OR = 1.14, 95% CI: 1.03-1.26, P = 0.011). Trend tests revealed that there was a significant linear trend for the association. A nonlinear association was identified between them and the inflection point of CCI was 1. Subgroup analyses and tests for interaction indicated that cystatin played an interactive role in the association. ROC analysis indicated neither CCI alone nor combinations of variables based on CCI were adequate for prediction.

CONCLUSION

CCI was independently positively correlated with readmission within six months in patients with HF in Chinese population. However, CCI has limited value on predicting readmission within six months in patients with HF.

Adverse childhood experiences, alcohol consumption, and the modifying role of social participation: population-based study of adults in southwestern Uganda

Background

Adverse childhood experiences (ACEs) include multiple forms of child maltreatment, including abuse and neglect, as well as other forms of household dysfunction. Studies from Uganda have revealed a high prevalence of child abuse, as well as one of the highest levels of alcohol consumption in Africa. Few population-based studies from Africa have estimated associations between ACEs and adult alcohol use, or assessed the potential buffering effects of social participation.

Methods

This cross-sectional, population-based study was conducted in a rural parish in southwestern Uganda between 2016 and 2018. We assessed self-reported ACEs using a modified version of the Adverse Childhood Experiences - International Questionnaire (ACE-IQ) scale. We measured heavy alcohol consumption using a 3-item scale previously validated in this population. We measured social participation using a 10-item scale eliciting participants' membership and participation in different community groups over the past two months. We fitted multivariable Poisson regression models to estimate the associations between ACEs and heavy alcohol consumption, and to assess for the potential buffering effects of social participation.

Results

We estimated statistically significant associations between the total ACE score and heavy alcohol consumption (adjusted relative risk [ARR] per ACE=1.17; 95% CI, 1.09-1.25; P ≤0.001). Social participation had a statistically significant moderating effect on the association between total ACE score and heavy alcohol consumption (P=0.047 for interaction): the estimated association between total ACE score and heavy alcohol consumption among study participants who did not participate in a community group was larger, with a narrower confidence interval (ARR=1.21 per ACE; 95% CI, 1.11-1.33; P<0.001), while the estimated association among study participants who did participate in a community group was smaller and less precisely estimated (ARR=1.12 per ACE; 95% CI, 1.02-1.24; P=0.02).

Conclusions

Our findings demonstrate an association between ACEs and heavy alcohol consumption behavior among adults in rural Uganda. The adverse effects of ACEs were buffered in part by social participation. To prevent or reduce harmful alcohol use behaviors among adults, it is important to address the chronic stress caused by ACEs.

Does coprescribing nonsteroidal anti-inflammatory drugs and oral anticoagulants increase the risk of major bleeding, stroke and systemic embolism?

AIMS

To examine the risk of gastrointestinal (GI) bleeding, major bleeding, stroke and systemic embolism associated with prescribing nonsteroidal anti-inflammatory drugs (NSAIDs) to adults receiving oral anticoagulant (OAC) therapy.

METHODS

We conducted a population-based cohort study in adults receiving OAC therapy using linked primary care (Clinical Practice Research Datalink GOLD) and hospital (Hospital Episodes Statistics) electronic health records. We used cause-specific Cox regression models with time-dependent NSAID treatment in a propensity score matched population to estimate the increased risk of GI bleeding, stroke, major bleeding and systemic embolism associated with NSAID use.

RESULTS

The matched cohort contained 3177 patients with OAC therapy alone and 3177 with at least 1 concomitant NSAID prescription. Compared with OAC therapy alone, concomitant prescription of NSAIDs with OACs was associated with increased risk of GI bleeding (hazard ratio [HR] 3.01, 95% confidence interval [CI] 1.63 to 5.55), stroke (HR 2.71, 95% CI 1.48 to 4.96) and major bleeding (HR 2.77, 95% CI 1.84 to 4.19). The association with systemic embolism did not reach statistical significance (HR 3.02, 95% CI 0.82 to 11.07). Sensitivity analyses indicated that the results were robust to changes in exclusion criteria and the choice of potential confounding variables.

CONCLUSION

When OACs are coprescribed with NSAIDs, the risk of adverse bleeding events increases and, simultaneously, the protective effect of OACs to prevent strokes reduces. There is a need for interventions that reduce hazardous prescribing of NSAIDs in people receiving OAC therapy.

Impact of Integrating Machine Learning in Comparative Effectiveness Research of Oral Anticoagulants in Patients with Atrial Fibrillation

We aimed to compare the ability to balance baseline covariates and explore the impact of residual confounding between conventional and machine learning approaches to derive propensity scores (PS). The Health Insurance Review and Assessment Service database (January 2012-September 2019) was used. Patients with atrial fibrillation (AF) who initiated oral anticoagulants during July 2015-September 2018 were included. The outcome of interest was stroke/systemic embolism. To estimate PS, we used a logistic regression model (i.e., a conventional approach) and a generalized boosted model (GBM) which is a machine learning approach. Both PS matching and inverse probability of treatment weighting were performed. To evaluate balance achievement, standardized differences, p-values, and boxplots were used. To explore residual confounding, E-values and negative control outcomes were used. In total, 129,434 patients were identified. Although all baseline covariates were well balanced, the distribution of continuous variables seemed more similar when GBM was applied. E-values ranged between 1.75 and 2.70 and were generally higher in GBM. In the negative control outcome analysis, slightly more nonsignificant hazard ratios were observed in GBM. We showed GBM provided a better ability to balance covariates and had a lower impact of residual confounding, compared with the conventional approach in the empirical example of comparative effectiveness analysis.

Unmeasured confounding in nonrandomized studies: quantitative bias analysis in health technology assessment

Evidence generated from nonrandomized studies (NRS) is increasingly submitted to health technology assessment (HTA) agencies. Unmeasured confounding is a primary concern with this type of evidence, as it may result in biased treatment effect estimates, which has led to much criticism of NRS by HTA agencies. Quantitative bias analyses are a group of methods that have been developed in the epidemiological literature to quantify the impact of unmeasured confounding and adjust effect estimates from NRS. Key considerations for application in HTA proposed in this article reflect the need to balance methodological complexity with ease of application and interpretation, and the need to ensure the methods fit within the existing frameworks used to assess nonrandomized evidence by HTA bodies.

The role of physical environmental characteristics and intellectual disability in conduct problem trajectories across childhood: A population-based Cohort study

BACKGROUND

The paucity of research investigating the role of the physical environment in the developmental progression of conduct problems and the potential moderating effects of intellectual disability (ID) is surprising, given the clinical relevance of elucidating environmental determinants of disruptive behaviours.

AIMS

To use data from a large UK cohort study to assess associations between physical environmental exposures, ID, and conduct problem trajectories.

METHOD

The sample included 8168 Millennium Cohort Study children (1.9% with ID). Multilevel growth curve modelling was used to examine the role of physical environment characteristics in the developmental trajectories of conduct problems after adjustments for ID status.

RESULTS

Exposure to external environmental domains was not associated with differences in children's conduct problems across development. Alternatively, internal aspects of the household environment: spatial density (b = 0.40, p < .001) and damp problems (b = 0.14, p < .001) were both significantly associated with increased trajectories. Various individual and familial covariates were positively associated with conduct problems over time, including: presence of ID (b = 0.96, p < .001), autism spectrum disorder (b = 1.18, p < .001), male sex (b = 0.26, p < .001), poverty (b = 0.19, p < .001), maternal depression (b = 0.65, p < .001), and non-nuclear family structure (b = 0.35, p < .001). Positive ID status appeared to moderate the effects of internal household spatial density, reporting a non-linear negative association with spatial density and conduct problems across development (b = -1.08, p < .01).

CONCLUSIONS

Our findings highlight the potential harmful consequences of poor internal residential conditions on children's development of disruptive behaviours.

Systematic Review of Physical Activity Trajectories and Mortality in Patients With Coronary Artery Disease

BACKGROUND

The role of lifestyle physical activity (PA) trajectories in the mortality risk of patients with coronary heart disease (CHD) remains unclear.

OBJECTIVES

The purpose of this study was to determine the association of longitudinal PA trajectories with all-cause and cardiovascular disease (CVD) mortality in patients with CHD.

METHODS

Longitudinal cohorts reporting the association of PA trajectories with mortality in patients with CHD were identified in April 2021 by searching 5 databases without language restrictions. Published HRs and 95% CIs were pooled using random effects models and bias assessed by Egger regression.

RESULTS

A total of 9 prospective cohorts included 33,576 patients. The mean age was 62.5 years. The maximum follow-up was 15.7 years. All of the studies assessed PA through validated questionnaires, and mortality was well documented. Changes in PA defined 4 nominal PA trajectories. Compared with always-inactive patients, the risk of all-cause mortality was 50% lower in those who remained active (HR: 0.50; 95% CI: 0.39-0.63); 45% lower in those who were inactive but became active (HR: 0.55; 95% CI: 0.44-0.7); and 20% lower in those who were active but became inactive (HR: 0.80; 95% CI: 0.64-0.99). Similar results were observed for CVD mortality, except for the category of decreased activity (HR: 0.91; 95% CI: 0.67-1.24). The overall risk of bias was low. No evidence of publication bias was found. Multiple sensitivity analyses provided consistent results.

CONCLUSIONS

This study illustrates how patients with CHD may benefit by preserving or adopting an active lifestyle. The observation that the benefits of past activity can be weakened or lost if PA is not maintained may be confounded by disease progression.

Association Between Left Ventricular Relative Wall Thickness and Acute Kidney Injury After Noncardiac Surgery

BACKGROUND

Acute kidney injury (AKI) after major noncardiac surgery is commonly attributed to cardiovascular dysfunction. Identifying novel associations between preoperative cardiovascular markers and kidney injury may guide risk stratification and perioperative intervention. Increased left ventricular relative wall thickness (RWT), routinely measured on echocardiography, is associated with myocardial dysfunction and long-term risk of heart failure in patients with preserved left ventricular ejection fraction (LVEF); however, its relationship to postoperative complications has not been studied. We evaluated the association between preoperative RWT and AKI in high-risk noncardiac surgical patients with preserved LVEF.

METHODS

Patients ≥18 years of age having major noncardiac surgery (high-risk elective intra-abdominal or noncardiac intrathoracic surgery) between July 1, 2016, and June 30, 2018, who had transthoracic echocardiography in the previous 12 months were eligible. Patients with preoperative creatinine ≥2 mg/dL or reduced LVEF (<50%) were excluded. The association between RWT and AKI, defined as an increase in serum creatinine by 0.3 mg/dL from baseline within 48 hours or by 50% within 7 days after surgery, was assessed using multivariable logistic regression adjusted for preoperative covariates. An additional model adjusted for intraoperative covariates, which are strongly associated with AKI, especially hypotension. RWT was modeled continuously, associating the change in odds of AKI for each 0.1 increase in RWT.

RESULTS

The study included 1041 patients (mean ± standard deviation [SD] age 62 ± 15 years; 59% female). A total of 145 subjects (13.9%) developed AKI within 7 days. For RWT quartiles 1 through 4, respectively, 20 of 262 (7.6%), 40 of 259 (15.4%), 39 of 263 (14.8%), and 46 of 257 (17.9%) developed AKI. Log-odds and proportion with AKI increased across the observed RWT values. After adjusting for confounders (demographics, American Society of Anesthesiologists [ASA] physical status, comorbidities, baseline creatinine, antihypertensive medications, and left ventricular mass index), each RWT increase of 0.1 was associated with an estimated 26% increased odds of developing AKI (odds ratio [OR]; 95% confidence interval [CI]) of 1.26 (1.09-1.46; P = .002). After adjusting for intraoperative covariates (length of surgery, presence of an arterial line, intraoperative hypotension, crystalloid administration, transfusion, and urine output), RWT remained independently associated with the odds of AKI (OR; 95% CI) of 1.28 (1.13-1.47; P = .001). Increased RWT was also independently associated with hospital length of stay and adjusted hazard ratio (HR [95% CI]) of 0.94 (0.89-0.99; P = .018).

CONCLUSIONS

Left ventricular RWT is a novel cardiovascular factor associated with AKI within 7 days after high-risk noncardiac surgery among patients with preserved LVEF. Application of this commonly available measurement of risk stratification or perioperative intervention warrants further investigation.

Albumin levels predict mortality in sepsis patients with acute kidney injury undergoing continuous renal replacement therapy: a secondary analysis based on a retrospective cohort study

BACKGROUND

Albumin (ALB) levels are negatively associated with mortality in patients with sepsis. However, among sepsis patients with acute kidney injury (AKI) undergoing continuous renal replacement therapy (CRRT), there has been no similar study on the correlation between ALB levels and mortality alone. This study tested the hypothesis that ALB levels are negatively associated with mortality among such patients.

METHODS

We conducted a secondary analysis of 794 septic patients who were diagnosed with AKI and underwent CRRT in South Korea. For the Kaplan-Meier survival analysis, Cox proportional hazards models were used to study the hypotheses, with adjustments for the pertinent covariables. We also explore the possible nonlinear relationship and conducted sensitivity analyses including subgroup analyses and tests for interactions to investigate the association further. Additionally, ALB was used to construct model and we then compared the performance of ALB with that of APACHE II and SOFA in predicting mortality.

RESULTS

The ALB level was an independent prognostic factor for death at 28 and 90 days after CRRT initiation (HR = 0.75, 95% CI: 0.62-0.90, P = 0.0024 for death at 28 days and HR = 0.73, 95% CI: 0.63-0.86, P < 0.0001 for death at 90 days). A nonlinear association was not identified between ALB levels and the endpoints. Subgroup analyses and tests for interactions indicated that HCO₃ and CRP played an interactive role in the association. ROC analysis indicated ALB, SOFA and APACHE-II were separately inadequate for clinical applications.

CONCLUSION

A 1 g/dL increase in ALB levels was independently associated with a 25 and 27% decrease in the risk of death at 28 and 90 days, respectively. However, this conclusion needs to be taken with caution as this study has several limitations.

Cancer and COVID-19 Susceptibility and Severity: A Two-Sample Mendelian Randomization and Bioinformatic Analysis

The clinical management of patients with COVID-19 and cancer is a Gordian knot that has been discussed widely but has not reached a consensus. We introduced two-sample Mendelian randomization to investigate the causal association between a genetic predisposition to cancers and COVID-19 susceptibility and severity. Moreover, we also explored the mutation landscape, expression pattern, and prognostic implications of genes involved with COVID-19 in distinct cancers. Among all of the cancer types we analyzed, only the genetic predisposition to lung adenocarcinoma was causally associated with increased COVID-19 severity (OR = 2.93, β = 1.074, se = 0.411, p = 0.009) with no obvious heterogeneity (Q = 17.29, p = 0.24) or symmetry of the funnel plot. In addition, the results of the pleiotropy test demonstrated that instrument SNPs were less likely to affect COVID-19 severity via approaches other than lung adenocarcinoma cancer susceptibility (p = 0.96). Leave-one-out analysis showed no outliers in instrument SNPs, whose elimination rendered alterations in statistical significance, which further supported the reliability of the MR results. Broad mutation and differential expression of these genes were also found in cancers, which may provide valuable information for developing new treatment modalities for patients with both cancer and COVID-19. For example, ERAP2, a risk factor for COVID-19-associated death, is upregulated in lung squamous cancer and negatively associated with patient prognosis. Hence, ERAP2-targeted treatment may simultaneously reduce COVID-19 disease severity and restrain cancer progression. Our results highlighted the importance of strengthening medical surveillance for COVID-19 deterioration in patients with lung adenocarcinoma by showing their causal genetic association. For these patients, a delay in anticancer treatment, such as chemotherapy and surgery, should be considered.

An approach to quantifying the potential importance of residual confounding in systematic reviews of observational studies: A GRADE concept paper

Small relative effect sizes are common in observational studies of exposure in environmental and public health. However, such effects can still have considerable policy importance when the baseline rate of the health outcome is high, and many persons are exposed. Assessing the certainty of the evidence based on these effect sizes is challenging because they can be prone to residual confounding due to the non-randomized nature of the evidence. When applying GRADE, a precise relative risk >2.0 increases the certainty in an existing effect because residual confounding is unlikely to explain the association. GRADE also suggests rating up when opposing plausible residual confounding exists for other effect sizes. In this concept paper, we propose using the E-value, defined as the smallest effect size of a confounder that still can reduce an observed RR to the null value, and a reference confounder to assess the likelihood of residual confounding. We propose a 4-step approach. 1. Assess the association of interest for relevant exposure levels. 2. Calculate the E-value for this observed association. 3. Choose a reference confounder with sufficient strength and information and assess its effect on the observed association using the E-value. 4. Assess how likely it is that residual confounding will still bias the observed RR. We present three case studies and discuss the feasibility of the approach.

Multiple-bias Sensitivity Analysis Using Bounds

Confounding, selection bias, and measurement error are well-known sources of bias in epidemiologic research. Methods for assessing these biases have their own limitations. Many quantitative sensitivity analysis approaches consider each type of bias individually, although more complex approaches are harder to implement or require numerous assumptions. By failing to consider multiple biases at once, researchers can underestimate-or overestimate-their joint impact. We show that it is possible to bound the total composite bias owing to these three sources and to use that bound to assess the sensitivity of a risk ratio to any combination of these biases. We derive bounds for the total composite bias under a variety of scenarios, providing researchers with tools to assess their total potential impact. We apply this technique to a study where unmeasured confounding and selection bias are both concerns and to another study in which possible differential exposure misclassification and confounding are concerns. The approach we describe, though conservative, is easier to implement and makes simpler assumptions than quantitative bias analysis. We provide R functions to aid implementation.

The Importance of Making Assumptions in Bias Analysis

Quantitative bias analyses allow researchers to adjust for uncontrolled confounding, given specification of certain bias parameters. When researchers are concerned about unknown confounders, plausible values for these bias parameters will be difficult to specify. Ding and VanderWeele developed bounding factor and E-value approaches that require the user to specify only some of the bias parameters. We describe the mathematical meaning of bounding factors and E-values and the plausibility of these methods in an applied context. We encourage researchers to pay particular attention to the assumption made, when using E-values, that the prevalence of the uncontrolled confounder among the exposed is 100% (or, equivalently, the prevalence of the exposure among those without the confounder is 0%). We contrast methods that attempt to bound biases or effects and alternative approaches such as quantitative bias analysis. We provide an example where failure to make this distinction led to erroneous statements. If the primary concern in an analysis is with known but unmeasured potential confounders, then E-values are not needed and may be misleading. In cases where the concern is with unknown confounders, the E-value assumption of an extreme possible prevalence of the confounder limits its practical utility.

Bias Analysis Gone Bad

Quantitative bias analysis comprises the tools used to estimate the direction, magnitude, and uncertainty from systematic errors affecting epidemiologic research. Despite the availability of methods and tools, and guidance for good practices, few reports of epidemiologic research incorporate quantitative estimates of bias impacts. The lack of familiarity with bias analysis allows for the possibility of misuse, which is likely most often unintentional but could occasionally include intentional efforts to mislead. We identified 3 examples of suboptimal bias analysis, one for each common bias. For each, we describe the original research and its bias analysis, compare the bias analysis with good practices, and describe how the bias analysis and research findings might have been improved. We assert no motive to the suboptimal bias analysis by the original authors. Common shortcomings in the examples were lack of a clear bias model, computed example, and computing code; poor selection of the values assigned to the bias model's parameters; and little effort to understand the range of uncertainty associated with the bias. Until bias analysis becomes more common, community expectations for the presentation, explanation, and interpretation of bias analyses will remain unstable. Attention to good practices should improve quality, avoid errors, and discourage manipulation.

Invited Commentary: Dealing With the Inevitable Deficiencies of Bias Analysis-and All Analyses

Lash et al. (Am J Epidemiol. 2021;190(8):1604-1612) have presented detailed critiques of 3 bias analyses that they identify as "suboptimal." This identification raises the question of what "optimal" means for bias analysis, because it is practically impossible to do statistically optimal analyses of typical population studies-with or without bias analysis. At best the analysis can only attempt to satisfy practice guidelines and account for available information both within and outside the study. One should not expect a full accounting for all sources of uncertainty; hence, interval estimates and distributions for causal effects should never be treated as valid uncertainty assessments-they are instead only example analyses that follow from collections of often questionable assumptions. These observations reinforce those of Lash et al. and point to the need for more development of methods for judging bias-parameter distributions and utilization of available information.

On the use of the E-value for sensitivity analysis in epidemiologic studies

This study illustrates the use of a recently developed sensitivity index, the E-value, helpful in strengthening causal inferences in observational epidemiological studies. The E-value aims to determine the minimum required strength of association between an unmeasured confounder and an exposure/outcome to explain the observed association as non-causal. Such parameter is defined as E - v a l u e = R R + R R R R - 1 , where RR is the risk ratio between the exposure and the outcome. Our work illustrates the E-value using observational data from a recently published study on the relationship between indicators of prenatal care adequacy and the outcome low birthweight. The E-value ranged between 1.45 and 5.63 according to the category and prenatal care index evaluated, showing the highest value for the "no prenatal care" category of the GINDEX index and the minimum value for "intermediate prenatal care" of the APNCU index. For "inappropriate prenatal care" (all indexes), the E-value ranged between 2.76 (GINDEX) and 4.99 (APNCU). These findings indicate that only strong confounder/low birthweight associations (more than 400% increased risk) would be able to fully explain the prenatal care vs. low birthweight association observed. The E-value is a useful, intuitive sensitivity analysis tool that may help strengthening causal inferences in epidemiological observational studies.

Confounding and effect measure modification in reproductive medicine research

The majority of research within reproductive and gynecologic health, or investigating ART, is observational in design. One of the most critical challenges for observational studies is confounding, while one of the most important for discovery and inference is effect modification. In this commentary, we explain what confounding and effect modification are and why they matter. We present examples illustrating how failing to adjust for a confounder leads to invalid conclusions, as well as examples where adjusting for a factor that is not a confounder also leads to invalid or imprecise conclusions. Careful consideration of which factors may act as confounders or modifiers of the association of interest is critical to conducting sound research, particularly with complex observational studies in reproductive medicine.

Childhood trauma, major depressive disorder, suicidality, and the modifying role of social support among adolescents living with HIV in rural Uganda

BACKGROUND

Childhood trauma is associated with mental health problems among adolescents living with HIV (ALHIV) in sub-Saharan Africa, but little is known about potential moderating factors.

METHODS

We enrolled 224 ALHIV aged 13-17 years and collected information on childhood trauma, major depressive disorder, and suicidality. We used modified multivariable Poisson regression to estimate the association between the mental health outcome variables and childhood trauma, and to assess for effect modification by social support.

RESULTS

Major depressive disorder had a statistically significant association with emotional abuse (adjusted relative risk [ARR] 2.57; 95% CI 1.31-5.04; P=0.006) and physical abuse (ARR 2.16; 95% CI 1.19-3.89; P=0.01). The estimated association between any abuse and major depressive disorder was statistically significant among those with a low level of social support (ARR 4.30; 95% CI 1.64-11.25; P=0.003) but not among those with a high level of social support (ARR 1.30; 95% CI 0.57-2.98; P=0.52). Suicidality also had a statistically significant association with emotional abuse (ARR 2.03; 95% CI 1.05-3.920; P=0.03) and physical abuse (ARR 3.17; 95% CI 1.60-6.25.; P=0.001), but no differences by social support were noted.

LIMITATIONS

Corporal punishment is used widely in schools and homes as a form of discipline in Uganda; this cultural practice could have biased reporting about physical abuse.

CONCLUSIONS

Childhood trauma is associated with poor mental health among ALHIV, but its effects may be moderated by social support. More research is needed to develop social support interventions for ALHIV with adverse childhood experiences for improved mental health outcomes.