Improving the causal treatment effect estimation with propensity scores by the bootstrap

AbstractWhen observational studies are used to establish the causal effects of treatments, the estimated effect is affected by treatment selection bias. The inverse propensity score weight (IPSW) is often used to deal with such bias. However, IPSW requires strong assumptions whose misspecifications and strategies to correct the misspecifications were rarely studied. We present a bootstrap bias correction of IPSW (BC-IPSW) to improve the performance of propensity score in dealing with treatment selection bias in the presence of failure to the ignorability and overlap assumptions. The approach was motivated by a real observational study to explore the potential of anticoagulant treatment for reducing mortality in patients with end-stage renal disease. The benefit of the treatment to enhance survival was demonstrated; the suggested BC-IPSW method indicated a statistically significant reduction in mortality for patients receiving the treatment. Using extensive simulations, we show that BC-IPSW substantially reduced the bias due to the misspecification of the ignorability and overlap assumptions. Further, we showed that IPSW is still useful to account for the lack of treatment randomization, but its advantages are stringently linked to the satisfaction of ignorability, indicating that the existence of relevant though unmeasured or unused covariates can worsen the selection bias

A Qualitative Approach Using Diaries and Interviews

1. Nadia Rania[1][1][⇑][2] 2. Laura Migliorini[1][1] 3. Stefania Rebora[1][1] 4. Paola Cardinali[1][1] 1. 1DISFOR, Department of Education Science, University of Genoa, Italy 1. Nadia Rania, DISFOR, Department of Education Science, University of Genoa, C.so A. Podesta, 2, 16121 Genoa, Italy. Email: nadia.rania{at}unige.it This study compares Italian mothers' and Ecuadorian immigrant mothers' daily family routines. Thirty mothers took part in this investigation: 15 Italians ( M = 37.5 years, with ages ranging from 30 to 42 years) and 15 Ecuadorians ( M = 36.1 years, with ages ranging from 18 to 46 years and having lived in Italy for an average of 15 years), with children ranging in age from 4 to 8 years. The objective is to highlight the differences and similarities between the daily routines and family relations that characterize the lives of each of the two groups of participants. The instruments employed in service of these aims were in-depth interviews and diaries. The results showed similarities regarding the routines of Italian and Ecuadorian families. However, a relevant difference emerged regarding their perceptions of social support. Specifically, Italians receive more social support from their parents than do Ecuadorians, who are supported more by other relatives or by friends. [1]: #aff-1 [2]: #corresp-

Clinical and Socio-Demographic Determinants of Self-Care Behaviours in Patients with Heart Failure and Diabetes Mellitus: A Multicentre Cross-Sectional Study

Background Self-care is vital for patients with heart failure to maintain health and quality of life, and it is even more vital for those who are also affected by diabetes mellitus, since they are at higher risk of worse outcomes. The literature is unclear on the influence of diabetes on heart failure self-care as well as on the influence of socio-demographic and clinical factors on self-care. Objectives (1) To compare self-care maintenance, self-care management and self-care confidence of patients with heart failure and diabetes versus those heart failure patients without diabetes; (2) to estimate if the presence of diabetes influences self-care maintenance, self-care management and self-care confidence of heart failure patients; (3) to identify socio-demographic and clinical determinants of self-care maintenance, self-care management and self-care confidence in patients with heart failure and diabetes. Design Secondary analysis of data from a multicentre cross-sectional study. Setting Outpatient clinics from 29 Italian provinces. Participants 1192 adults with confirmed diagnosis of heart failure. Methods Socio-demographic and clinical data were abstracted from patients’ medical records. Self-care maintenance, self-care management and self-care confidence were measured with the Self-Care of Heart Failure Index Version 6.2; each scale has a standardized score from 0 to 100, where a score \u3c70 indicates inadequate self-care. Multiple linear regression analyses were performed. Results Of 1192 heart failure patients, 379 (31.8%) had diabetes. In these 379, heart failure self-care behaviours were suboptimal (means range from 53.2 to 55.6). No statistically significant differences were found in any of the three self-care measures in heart failure patients with and without diabetes. The presence of diabetes did not influence self-care maintenance (p = 0.12), self-care management (p = 0.21) or self-care confidence (p = 0.51). Age (p = 0.04), number of medications (p = 0.01), presence of a caregiver (p = 0.04), family income (p = 0.009) and self-care confidence (p \u3c 0.001) were determinants of self-care maintenance. Gender (p = 0.01), number of medications (p = 0.004) and self-care confidence (p \u3c 0.001) were significant determinants of self-care management. Number of medications (p = 0.002) and cognitive function (p \u3c 0.001) were determinants of self-care confidence. Conclusions Self-care was poor in heart failure patients with diabetes mellitus. This population needs more intensive interventions to improve self-care. Determinants of self-care in heart failure patients with diabetes mellitus should be systematically assessed by clinicians to identify patients at risk of inadequate self-care

MOTIVATional intErviewing to Improve Self-Care in Heart Failure Patients (MOTIVATE-HF): Study Protocol of a Three-Arm Multicenter Randomized Controlled Trial

Aims Heart Failure (HF) self-care improves patient outcomes but trials designed to improve HF self-care have shown inconsistent results. Interventions may be more effective in improving self-care if they mobilize support from providers, promote self-efficacy, increase understanding of HF, increase the family involvement, and are individualized. All of these elements are emphasized in motivational interviewing (MI); few trials have been conducted using MI in HF patients and rarely have caregivers been involved in MI interventions. The aim of this study will be to evaluate if MI improves self-care maintenance in HF patients, and to determine if MI improves the following secondary outcomes: a) in HF patients: self-care management, self-care confidence, symptom perception, quality of life, anxiety/depression, cognition, sleep quality, mutuality with caregiver, hospitalizations, use of emergency services, and mortality; b) in caregivers: caregiver contribution to self-care, quality of life, anxiety/depression, sleep, mutuality with patient, preparedness, and social support. Methods A three-arm randomized controlled trial will be conducted in a sample of 240 HF patients and caregivers. Patients and caregivers will be randomized to the following arms: 1) MI intervention to patients only; 2) MI intervention to patients and caregivers; 3) standard of care to patients and caregivers. The primary outcome will be measured in patients 3 months after enrollment. Primary and secondary outcomes also will be evaluated 6, 9 and 12 months after enrollment. Conclusion This study will contribute to understand if MI provided to patients and caregivers can improve self-care. Because HF is rising in prevalence, findings can be useful to reduce the burden of the disease

Glutathione S-transferase homozygous deletions and relapse in childhood acute lymphoblastic leukemia: a novel study design in a large Italian AIEOP cohort

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Delirium symptoms duration and mortality in SARS-COV2 elderly: results of a multicenter retrospective cohort study

BACKGROUND: Since the occurrence of the SARS-COV2 pandemic, there has been an increasing interest in investigating the epidemiology of delirium. Delirium is frequent in SARS-COV2 patients and it is associated with increased mortality; however, no information is available on the association between delirium duration in SARS-COV2 patients and related outcomes. AIMS: The aim of this study is to investigate the association between the duration of delirium symptoms and in-hospital mortality in older patients with SARS-COV2 infection. METHODS: Retrospective cohort study of patients 65 years of age and older with SARS-CoV 2 infection admitted to two acute geriatric wards and one rehabilitation ward. Delirium symptoms duration was assessed retrospectively with a chart-based validated method. In-hospital mortality was ascertained via medical records. RESULTS: A total of 241 patients were included. The prevalence of delirium on admission was 16%. The median number of days with delirium symptoms was 4 (IQR 2–6.5) vs. 0 (IQR 0–2) in patients with and without delirium on admission. In the multivariable Cox regression model, each day with a delirium symptom in a patient with the same length of stay was associated with a 10% increase in in-hospital mortality (Hazard ratio 1.1, 95% Confidence interval 1.01–1.2; p = 0.03). Other variables associated with increased risk of in-hospital death were age, comorbidity, CPAP, CRP levels and total number of drugs on admission. CONCLUSIONS: The study supports the necessity to establish protocols for the monitoring and management of delirium during emergency conditions to allow an appropriate care for older patients. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40520-021-01899-8

Crude incidence in two-phase designs in the presence of competing risks.

BackgroundIn many studies, some information might not be available for the whole cohort, some covariates, or even the outcome, might be ascertained in selected subsamples. These studies are part of a broad category termed two-phase studies. Common examples include the nested case-control and the case-cohort designs. For two-phase studies, appropriate weighted survival estimates have been derived; however, no estimator of cumulative incidence accounting for competing events has been proposed. This is relevant in the presence of multiple types of events, where estimation of event type specific quantities are needed for evaluating outcome.MethodsWe develop a non parametric estimator of the cumulative incidence function of events accounting for possible competing events. It handles a general sampling design by weights derived from the sampling probabilities. The variance is derived from the influence function of the subdistribution hazard.ResultsThe proposed method shows good performance in simulations. It is applied to estimate the crude incidence of relapse in childhood acute lymphoblastic leukemia in groups defined by a genotype not available for everyone in a cohort of nearly 2000 patients, where death due to toxicity acted as a competing event. In a second example the aim was to estimate engagement in care of a cohort of HIV patients in resource limited setting, where for some patients the outcome itself was missing due to lost to follow-up. A sampling based approach was used to identify outcome in a subsample of lost patients and to obtain a valid estimate of connection to care.ConclusionsA valid estimator for cumulative incidence of events accounting for competing risks under a general sampling design from an infinite target population is derived

Association Between Sex Hormone Levels and Clinical Outcomes in Patients With COVID-19 Admitted to Hospital: An Observational, Retrospective, Cohort Study

Understanding the cause of sex disparities in COVID-19 outcomes is a major challenge. We investigate sex hormone levels and their association with outcomes in COVID-19 patients, stratified by sex and age. This observational, retrospective, cohort study included 138 patients aged 18 years or older with COVID-19, hospitalized in Italy between February 1 and May 30, 2020. The association between sex hormones (testosterone, estradiol, progesterone, dehydroepiandrosterone) and outcomes (ARDS, severe COVID-19, in-hospital mortality) was explored in 120 patients aged 50 years and over. STROBE checklist was followed. The median age was 73.5 years [IQR 61, 82]; 55.8% were male. In older males, testosterone was lower if ARDS and severe COVID-19 were reported than if not (3.6 vs. 5.3 nmol/L, p =0.0378 and 3.7 vs. 8.5 nmol/L, p =0.0011, respectively). Deceased males had lower testosterone (2.4 vs. 4.8 nmol/L, p =0.0536) and higher estradiol than survivors (40 vs. 24 pg/mL, p = 0.0006). Testosterone was negatively associated with ARDS (OR 0.849 [95% CI 0.734, 0.982]), severe COVID-19 (OR 0.691 [95% CI 0.546, 0.874]), and in-hospital mortality (OR 0.742 [95% CI 0.566, 0.972]), regardless of potential confounders, though confirmed only in the regression model on males. Higher estradiol was associated with a higher probability of death (OR 1.051 [95% CI 1.018, 1.084]), confirmed in both sex models. In males, higher testosterone seems to be protective against any considered outcome. Higher estradiol was associated with a higher probability of death in both sexes.The research was funded by Italian Ministry of Health “Fondi Ricerca Corrente, Project L1P5” for IRCCS Sacro Cuore Don Calabria Hospital. The funding source had no role in the collection, analysis, or interpretation of data, the study design, or the writing of the paper.Peer reviewe

The validation service of the hydrological SAF geostationary and polar satellite precipitation products

Abstract. The development phase (DP) of the EUMETSAT Satellite Application Facility for Support to Operational Hydrology and Water Management (H-SAF) led to the design and implementation of several precipitation products, after 5 yr (2005–2010) of activity. Presently, five precipitation estimation algorithms based on data from passive microwave and infrared sensors, on board geostationary and sun-synchronous platforms, function in operational mode at the H-SAF hosting institute to provide near real-time precipitation products at different spatial and temporal resolutions. In order to evaluate the precipitation product accuracy, a validation activity has been established since the beginning of the project. A Precipitation Product Validation Group (PPVG) works in parallel with the development of the estimation algorithms with two aims: to provide the algorithm developers with indications to refine algorithms and products, and to evaluate the error structure to be associated with the operational products. In this paper, the framework of the PPVG is presented: (a) the characteristics of the ground reference data available to H-SAF (i.e. radar and rain gauge networks), (b) the agreed upon validation strategy settled among the eight European countries participating in the PPVG, and (c) the steps of the validation procedures. The quality of the reference data is discussed, and the efforts for its improvement are outlined, with special emphasis on the definition of a ground radar quality map and on the implementation of a suitable rain gauge interpolation algorithm. The work done during the H-SAF development phase has led the PPVG to converge into a common validation procedure among the members, taking advantage of the experience acquired by each one of them in the validation of H-SAF products. The methodology is presented here, indicating the main steps of the validation procedure (ground data quality control, spatial interpolation, up-scaling of radar data vs. satellite grid, statistical score evaluation, case study analysis). Finally, an overview of the results is presented, focusing on the monthly statistical indicators, referred to the satellite product performances over different seasons and areas