Doubly robust adaptive LASSO for effect modifier discovery

Effect modification occurs when the effect of a treatment on an outcome differsaccording to the level of some pre-treatment variable (the effect modifier). Assessing an effect modifier is not a straight-forward task even for a subject matter expert. In this paper, we propose a two-stageprocedure to automatically selecteffect modifying variables in a Marginal Structural Model (MSM) with a single time point exposure based on the two nuisance quantities (the conditionaloutcome expectation and propensity score). We highlight the performance of our proposal in a simulation study. Finally, to illustrate tractability of our proposed methods, we apply them to analyze a set of pregnancy data. We estimate the conditional expected difference in the counterfactual birth weight if all women were exposed to inhaled corticosteroids during pregnancy versus the counterfactual birthweight if all women were not, using data from asthma medications during pregnancy.

Donor Death Category Is an Effect Modifier Between Cold Ischemia Time and Post-transplant Graft Function in Deceased-Donor Kidney Transplant Recipients

Objectives: We aimed to analyze the effect of cold ischemia time (CIT) on post-transplant graft function through mixed-effect model analysis to reduce the bias caused by paired mate kidneys.Methods: We reviewed all kidney transplantation records from 2015 to 2019 at our center. After applying the exclusion criteria, 561 cases were included for analysis. All donor characteristics, preservation and matching information, and recipient characteristics were collected. Transplant outcomes included delayed graft function (DGF) and estimated glomerular filtration rate (eGFR). Generalized linear mixed models were applied for analysis. We also explored potential effect modifiers, namely, donor death category, expanded criteria donors, and donor death causes.Results: Among the 561 cases, 79 DGF recipients developed DGF, and 15 recipients who died after surgery were excluded from the eGFR estimation. The median stable eGFR of the 546 recipients was 60.39 (47.63, 76.97) ml/min/1.73 m2. After adjusting for confounding covariates, CIT had a negative impact on DGF incidence [odds ratio = 1.149 (1.006, 1.313), P = 0.041]. In the evaluation of the impact on eGFR, the regression showed that CIT had no significant correlation with eGFR [β = −0.287 (−0.625, 0.051), P = 0.096]. When exploring potential effect modifiers, only the death category showed a significant interaction with CIT in the effect on eGFR (Pinteraction = 0.027). In the donation after brain death (DBD) group, CIT had no significant effect on eGFR [β = 0.135 (−0.433, 0.702), P = 0.642]. In the donation after circulatory death/donation after brain death followed by circulatory death (DCD/DBCD) group, CIT had a significantly negative effect on eGFR [β= −0.700 (−1.196, −0.204), P = 0.006]. Compared to a CIT of 0–6 h, a CIT of 6–8 or 8–12 h did not decrease the post-transplant eGFR. CIT over 12 h (12–16 h or over 16 h) significantly decreased eGFR. With the increase in CIT, the regenerated eGFR worsened (Ptrend = 0.011).Conclusion: Considering the effect of paired mate kidneys, the risk of DGF increased with prolonged CIT. The donor death category was an effect modifier between CIT and eGFR. Prolonged CIT did not reduce the eGFR level in recipients from DBDs but significantly decreased the eGFR in recipients from DCDs/DBCDs. This result indicates the potential biological interaction between CIT and donor death category.

The Interplay between Anticholinergic Burden and Anemia in Relation to 1-Year Mortality among Older Patients Discharged from Acute Care Hospitals

Anticholinergic burden (ACB) and anemia were found associated with an increased risk of death among older patients. Additionally, anticholinergic medications may contribute to the development of anemia. Therefore, we aimed at investigating the prognostic interplay of ACB and anemia among older patients discharged from hospital. Our series consisted of 783 patients enrolled in a multicenter observational study. The outcome of the study was 1 year mortality. ACB was assessed by an Anticholinergic Cognitive Burden score. Anemia was defined as hemoglobin < 13 g/dL in men and <12 g/dL in women. The association between study variables and mortality was investigated by Cox regression analysis. After adjusting for several potential confounders, ACB score = 2 or more was significantly associated with the outcome in anemic patients (HR = 1.93, 95%CI = 1.13–3.40), but not non anemic patients (HR = 1.51, 95%CI = 0.65–3.48). An additive prognostic interaction between ACB and anemia was observed (p = 0.02). Anemia may represent a relevant effect modifier in the association between ACB and mortality.

Mental Health Outcomes in Barcelona: The Interplay between Gentrification and Greenspace

Greenspace is widely related to mental health benefits, but this relationship may vary by social group. Gentrification, as linked to processes of unequal urban development and conflict, potentially impacts health outcomes. This study explores the relationships between greenspace and mental health and between gentrification and mental health associations. It also further examines gentrification as an effect modifier in the greenspace–mental health association and SES as an effect modifier in the gentrification-mental health association. We used cross-sectional Barcelona (Spain) data from 2006, which included perceived mental health status and self-reported depression/anxiety from the Barcelona Health Survey. Greenspace exposure was measured as residential access to (1) all greenspace, (2) greenways and (3) parks in 2006. Census-tract level gentrification was measured using an index including changes in sociodemographic indicators between 1991 and 2006. Logistic regression models revealed that only greenways were associated with better mental health outcomes, with no significant relationship between mental health and parks or all greenspace. Living in gentrifying neighborhoods was protective for depression/anxiety compared to living in non-gentrifying neighborhoods. However, only residents of gentrifiable census tracts benefited from the exposure to greenways. SES was not found to be an effect modifier in the association between gentrification and mental health. Future research should tackle this study’s limitations by incorporating a direct measure of displacement in the gentrification status indicator, accounting for qualitative aspects of greenspace and user’s perceptions. Gentrification may undermine the health benefits provided by greenspace interventions.

682Do job stressor—mental health relationships vary by migrant status? An Australian comparative analysis

Background Migrants may be more likely to experience occupational health inequities (OHIs) than native-born workers due to higher occupational exposure, higher vulnerability to exposure-associated health impacts, or both. This study explores migrant status-related differences in vulnerability to job stressor exposures in terms of mental health in Australia. Methods Data were from wave 14 of the Household Income and Labour Dynamics in Australia Survey. Migrant status was defined by country of birth (COB), the dominant language of COB, and the years since arrival in Australia. Job stressors included skill discretion, decision authority, and job insecurity. Mental health was assessed using the Mental Health Inventory-5 score (MHI-5). Data were analysed using linear regression, adjusting for gender, age, and education. Migrant status was analysed as the effect modifier of job stressor—mental health relationships. Results As expected, skill discretion and decision authority were positively, while job insecurity was negatively associated with the MHI-5 score. However, there was no statistical evidence of migrant status acting as an effect modifier of job stressor—mental health relationships even though the dominant language of COB and years since arrival in Australia have been taken into account. Conclusions The magnitudes of job stressor—mental health relationships do not differ between migrant workers and Australia-born workers. Key messages Differential exposure rather than differential vulnerability is a more important mechanism for generating occupational mental health inequities between migrants and Australian-born workers. Reducing job stressor exposures could reduce the OHIs among migrant workers in Australia.

Horizontal Aorta in Transcatheter Self-Expanding Valves: Insights From the HORSE International Multicentre Registry

Background: An increased degree of aortic angulation (AA) represents a challenging feature for bioprosthesis positioning. Whether AA has an impact on procedural outcomes of contemporary self-expanding valves remains unsettled. The aim of this study was to evaluate the impact of AA on procedural outcomes of transcatheter aortic valve replacement with contemporary self-expanding valves. Methods: The HORSE (Horizontal Aorta in Transcatheter Self-Expanding Valves) is an international, retrospective registry including 3862 consecutive patients undergoing transcatheter aortic valve replacement with either Evolut R/PRO (n=1959) or ACURATE neo (n=1903) devices. Patients undergoing Evolut R 34 mm implantation were excluded as no comparable prosthesis size for ACURATE neo is available. AA was evaluated with preprocedural computed tomography, and its impact on device success was evaluated. Results: In the overall population, AA did not have any impact upon device success, also when adjusting for in-study outcome predictors (odds ratio for 1° increment, 0.99 [95% CI, 0.98–1.01], P =0.306). However, increased AA was associated with lower device success with use of the Evolut R/PRO valves (odds ratio, 0.97 [95% CI, 0.95–0.99]; P =0.004), but not the ACURATE neo valves (odds ratio, 1.00 [95% CI, 0.98–1.03], P =0.304). The best AA cutoff value predicting device success was 49° (47% of the study cohort). Among patients with AA≥49°, Evolut R/PRO valves were associated with lower device success as compared to the ACURATE neo valve (inverse probability weighting odds ratio, 0.62 [95% CI, 0.46–0.83]; P =0.002). Conclusions: Horizontal aorta, as defined by an AA ≥49°, is a common feature among transcatheter aortic valve replacement candidates and predicts device failure of the Evolut R/PRO valves, but not of the ACURATE neo valve. AA may be an effect modifier of the association between self-expanding valve type and device success.

Simple models to include influenza vaccination history when evaluating the effect of influenza vaccination

Background Most reports of influenza vaccine effectiveness consider current-season vaccination only. Aim We evaluated a method to estimate the effect of influenza vaccinations (EIV) considering vaccination history. Methods We used a test-negative design with well-documented vaccination history to evaluate the average EIV over eight influenza seasons (2011/12–2018/19; n = 10,356). Modifying effect was considered as difference in effects of vaccination in current and previous seasons and current-season vaccination only. We also explored differences between current-season estimates excluding from the reference category people vaccinated in any of the five previous seasons and estimates without this exclusion or only for one or three previous seasons. Results The EIV was 50%, 45% and 38% in people vaccinated in the current season who had previously received none, one to two and three to five doses, respectively, and it was 30% and 43% for one to two and three to five prior doses only. Vaccination in at least three previous seasons reduced the effect of current-season vaccination by 12 percentage points overall, 31 among outpatients, 22 in 9–65 year-olds, and 23 against influenza B. Including people vaccinated in previous seasons only in the unvaccinated category underestimated EIV by 9 percentage points on average (31% vs 40%). Estimates considering vaccination of three or five previous seasons were similar. Conclusions Vaccine effectiveness studies should consider influenza vaccination in previous seasons, as it can retain effect and is often an effect modifier. Vaccination status in three categories (current season, previous seasons only, unvaccinated) reflects the whole EIV.