Evaluating sources of bias in observational studies

Sex differences in clinical characteristics and outcomes in patients hospitalized with cellulitis in Spain (2016-2022)

PURPOSE

To estimate hospitalization rates, analyze sex-specific clinical characteristics, assess in-hospital mortality and its risk factors, and measure the economic burden of cellulitis hospitalizations.

MATERIALS AND METHODS

This retrospective population-based study included adults aged ≥15 years hospitalized for cellulitis in Spain from 2016 to 2022. Multivariable logistic regression was used to identify factors associated with in-hospital mortality (IHM).

RESULTS

A total of 194,673 cellulitis hospitalizations were recorded (90,828 women and 103,845 men). The mean hospitalization rates per 1000 admissions and per 100,000 inhabitants were lower in women than men (6.0 vs. 7.6 and 63 vs. 76, respectively). In women, cellulitis was more common in those aged 65-75 and ≥80 years and in those with hypertension, dyslipidemia, heart failure, or hypothyroidism. Women had a higher crude IHM (7.4%) than men (5.9%), but sex was not significantly associated with mortality after adjustment (AOR: 1.02; 95% CI: 0.93-1.07). The strongest predictors of mortality were similar in both women and men. These included leukemia (AOR: 4.45 vs. 3.15), age ≥80 years (AOR: 3.96 vs. 4.39), sepsis (AOR: 3.59 vs. 2.95), neoplasia (AOR: 3.44 vs. 3.47), and cirrhosis (AOR: 2.49 vs. 2.41). The total hospitalization cost for women was €451.8 million, with a median cost of €3,653 per admission.

CONCLUSIONS

The clinical profile and outcomes of cellulitis differ by sex. In women, advanced age, comorbidities, and complications like sepsis significantly increased mortality risk.

A national population-based study of mortality and risk factors in COVID-19-hospitalized patients in Spain (2020-2021)

Objectives

The study aimed to analyze in-hospital mortality (IHM) among all COVID-19 patients hospitalized in Spain between March 1, 2020, and December 31, 2021, and to compare two distinct periods: the prevaccination period (March 1, 2020, to January 31, 2021) and the vaccination period (February 1, 2021, to December 31, 2021). The objective was to assess the impact of vaccination on IHM and identify associated risk factors, using data from Spain's national hospitalization registry.

Methods

This retrospective analysis used data from the Spanish National Surveillance System for Hospital Data. The primary outcome was in-hospital mortality (IHM). Multivariate logistic regression identified risk factors across the overall study period, as well as during the prevaccination and vaccination periods. Risk factors included age (in 20-year intervals), sex, comorbidities (e.g., hypertension, diabetes, chronic kidney failure, obesity, neurodegenerative disorders, and others), and admission to the intensive care unit.

Results

A total of 524,314 COVID-19 hospitalizations were recorded in Spain, with 329,690 during the prevaccination period and 194,624 during the vaccination period. Hospitalization rates dropped from 697/100,000 people to 411/100,000, and in-hospital mortality (IHM) decreased from 16.2 to 11.5% (adjusted odds ratio [AOR]: 0.71, 95% CI: 0.70-0.73, p < 0.001). IHM rose with age, from 0.8% in patients aged 18-39 to 31.7% in those ≥80 years (p < 0.001), but significant decreases were observed across all age groups after vaccination, especially in those ≥80 years (AOR: 0.76, 95% CI: 0.75-0.79, p < 0.001). Risk factors for IHM remained consistent, with leukemia, neoplasm, and lymphoma posing the highest risks, while female sex (AOR: 0.75, 95% CI: 0.74-0.77, p < 0.001) and dyslipidemia (AOR: 0.85, 95% CI: 0.32-0.86, p < 0.001) were protective factors.

Conclusion

During the vaccination period, the risk of in-hospital mortality (IHM) was 29% lower than in the prevaccination period, after adjusting for sex, age, and comorbidities. This reduced risk was observed across sexes, age groups, and comorbidities. The risk factors for IHM remained consistent between the two periods, with age as the main risk factor, while female sex and dyslipidemia were identified as protective factors.

Causal pathways in preeclampsia: a Mendelian randomization study in European populations

Purpose

Our study utilizes Mendelian Randomization (MR) to explore the causal relationships between a range of risk factors and preeclampsia, a major contributor to maternal and perinatal morbidity and mortality.

Methods

Employing the Inverse Variance Weighting (IVW) approach, we conducted a comprehensive multi-exposure MR study analyzing genetic variants linked to 25 risk factors including metabolic disorders, circulating lipid levels, immune and inflammatory responses, lifestyle choices, and bone metabolism. We applied rigorous statistical techniques such as sensitivity analyses, Cochran's Q test, MR Egger regression, funnel plots, and leave-one-out sensitivity analysis to address potential biases like pleiotropy and population stratification.

Results

Our analysis included 267,242 individuals, focusing on European ancestries and involving 2,355 patients with preeclampsia. We identified strong genetic associations linking increased preeclampsia risk with factors such as hyperthyroidism, BMI, type 2 diabetes, and elevated serum uric acid levels. Conversely, no significant causal links were found with gestational diabetes, total cholesterol, sleep duration, and bone mineral density, suggesting areas for further investigation. A notable finding was the causal relationship between systemic lupus erythematosus and increased preeclampsia risk, highlighting the significant role of immune and inflammatory responses.

Conclusion

This extensive MR study sheds light on the complex etiology of preeclampsia, underscoring the causal impact of specific metabolic, lipid, immune, lifestyle, and bone metabolism factors. Our findings advocate for a multidimensional approach to better understand and manage preeclampsia, paving the way for future research to develop targeted preventive and therapeutic strategies.

Everolimus plus endocrine therapy beyond CDK4/6 inhibitors progression for HR+ /HER2- advanced breast cancer: a real-world evidence cohort

PURPOSE

Everolimus in combination with endocrine therapy (ET) was formerly approved as 2nd-line therapy in HR(+)/HER2(-) advanced breast cancer (aBC) patients (pts) progressing during or after a non-steroidal aromatase inhibitor (NSAI). Since this approval, the treatment landscape of aBC has changed dramatically, particularly with the arrival of CDK 4-6 inhibitors. Endocrine monotherapy after progression to CDK4/6 inhibitors has shown a limited progression-free survival (PFS), below 3 months. Evidence of the efficacy of everolimus plus ET after CDK4/6 inhibitors is scarce.

METHODS

A retrospective observational study of patients with aBC treated with everolimus and ET beyond CDK4/6-i progression compiled from February 2015 to December 2022 in 4 Spanish hospitals was performed. Clinical and demographic data were collected from medical records. The main objective was to estimate the median progression-free survival (mPFS). Everolimus adverse events (AE) were registered. Quantitative variables were summarized with medians; qualitative variables with proportions and the Kaplan-Meier method were used for survival estimates.

RESULTS

One hundred sixty-one patients received everolimus plus ET (exemestane: 96, fulvestrant: 54, tamoxifen: 10, unknown: 1) after progressing on a CDK4/6 inhibitor. The median follow-up time was 15 months (interquartile range: 1-56 months). The median age at diagnosis was 49 years (range: 35-90 years). The estimated mPFS was 6.0 months (95%CI 5.3-7.8 months). PFS was longer in patients with previous CDK4/6 inhibitor therapy lasting for > 18 months (8.7 months, 95%CI 6.6-11.3 months), in patients w/o visceral metastases (8.0 months, 95%CI 5.8-10.5 months), and chemotherapy-naïve in the metastatic setting (7.2 months, 95%CI 5.9-8.4 months).

CONCLUSION

This retrospective analysis cohort of everolimus plus ET in mBC patients previously treated with a CDK4/6 inhibitor suggests a longer estimated mPFS when compared with the mPFS with ET monotherapy obtained from current randomized clinical data. Everolimus plus ET may be considered as a valid control arm in novel clinical trial designs.

Coronavirus disease 2019 and cardiovascular complications: focused clinical review

The coronavirus disease 2019 (COVID-19) may cause not only an acute respiratory distress syndrome (ARDS) but also multiple organ damage and failure requiring intensive care and leading to death. Male sex, advanced age, chronic lung disease, chronic kidney disease and cardiovascular disease, such as hypertension, diabetes and obesity have been identified as risk factors for the COVID-19 severity. Presumably, as these three cardiovascular risk factors are associated with a high prevalence of multiorgan damage. In the present focused clinical review, we will discuss the cardiovascular complications of COVID-19 including acute cardiovascular syndrome (acute cardiac injury/COVID cardiomyopathy, thromboembolic complications and arrhythmias) and post-COVID-19 sequelae. Preliminary data shows that the cause of acute cardiovascular syndrome may be multifactorial and involve direct viral invasion of the heart and vascular system, as well as through the immune and inflammation-mediated systemic cytokine storm. COVID-19 survivors may also show persistently elevated blood pressure and sinus tachycardia at rest. Furthermore, poor diabetic control, persistent renal damage and cerebral sequelae, such as persistent cognitive and neuropsychiatric alterations are also frequently reported. A particular attention should be paid towards cardiovascular protection in COVID-19 patients who develop acute cardiovascular syndromes during hospitalization, and/or permanent/semipermanent sequelae after recovery from COVID-19. These conditions may require careful clinical assessment, treatment and close follow-up to avoid short-term and long-term complications.