Tag: statistics

Cardiol Ther. 2021 Sep 4. doi: 10.1007/s40119-021-00239-1. Online ahead of print.

ABSTRACT

INTRODUCTION: Hypertension is a progressive cardiovascular condition arising from complex aetiologies. Progression is strongly associated with functional and structural abnormalities that lead to multi-organ dysfunction. Stroke and myocardial infarction are two of the major complications of hypertension in India. Various anti-hypertensive drugs, such as calcium channel blockers (CCBs), beta-blockers, diuretics, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, have been the medications of choice for disease management and are known to be effective in reducing the complications of hypertension. CCBs, such as amlodipine, are also currently being used and proven to be effective, although their beneficial effects in the management of complications of hypertension like stroke and myocardial infarction (MI) have yet to be proven. Therefore, the aim of this systematic review was to evaluate the effect of amlodipine on stroke and MI in hypertensive patients.

METHODS: A systematic search of English electronic databases was performed for studies with sufficient statistical power that were published between 2000 andl 30 August 2020, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. A total of 676 papers were screened, and 13 were found eligible to be included in the meta-analysis. Studies that included patients who suffered from MI or stroke and were under amlodipine treatment were included in the analysis. The odds ratio and the risk ratio of amlodipine compared to active control/placebo were noted from the studies and statistically analyzed.

RESULTS: Amlodipine had a significant effect in reducing stroke and MI in hypertensive patients. Similar to results published in reports, this systematic review proved that the hazard ratio for amlodipine was < 1 for stroke (0.69-1.04) and MI (0.77-0.98), showing that amlodipine accounted for better prevention of stroke and MI.

CONCLUSION: In the pooled analysis of data from 12 randomised controlled trials and one double-blinded cohort study measuring the effect of CCBs, we found that the CCB amlodipine reduced the risk of stroke and MI in hypertensive patients. Superior results for amlodipine were found in ten of the 13 studies included in this meta-analysis.

PMID:34480745 | DOI:10.1007/s40119-021-00239-1

Biometrics. 2021 Sep 4. doi: 10.1111/biom.13556. Online ahead of print.

ABSTRACT

An accelerated failure time (AFT) model assuming a log-linear relationship between failure time and a set of covariates can be either parametric or semiparametric, depending on the distributional assumption for the error term. Both classes of AFT models have been popular in the analysis of censored failure time data. The semiparametric AFT model is more flexible and robust to departures from the distributional assumption than its parametric counterpart. However, the semiparametric AFT model is subject to producing biased results for estimating any quantities involving an intercept. Estimating an intercept requires a separate procedure. Moreover, a consistent estimation of the intercept requires stringent conditions. Thus, essential quantities such as mean failure times might not be reliably estimated using semiparametric AFT models, which can be naturally done in the framework of parametric AFT models. Meanwhile, parametric AFT models can be severely impaired by misspecifications. To overcome this, we propose a new type of AFT model using a nonparametric Gaussian scale mixture distribution. We also provide feasible algorithms to estimate the parameters and mixing distribution. The finite sample properties of the proposed estimators are investigated via an extensive stimulation study. The proposed estimators are illustrated using a real data set.

PMID:34480750 | DOI:10.1111/biom.13556

Genetica. 2021 Sep 4. doi: 10.1007/s10709-021-00129-3. Online ahead of print.

ABSTRACT

Reducing false discoveries caused by population stratification (PS) has always been a challenge in genome-wide association studies (GWAS). The current literature established several single marker approaches including genomic control (GC), EIGENSTRAT and generalized linear mixed model association test (GMMAT) and multi-marker methods such as LASSO mixed model (LASSOMM). However, the single-marker methods require prespecifying an arbitrary p value threshold in the selection process, likely resulting in suboptimal precision or recall. On the other hand, it appears that LASSOMM is extremely computationally intensive and may not suitable for large-scale GWAS. In this paper, we proposed a simple multi-marker approach (PCA-LASSO) combining principal component analysis (PCA) and least absolute shrinkage and selection operator (LASSO). We utilize PCA to correct for the confounding effects of PS and LASSO with built-in cross-validation for a data-driven selection. Compared to the current single-marker approaches, the proposed PCA-LASSO provides optimal balance between precision and recall, and consequently superior F₁ scores. Similarly, compared to LASSOMM, PCA-LASSO markedly increases the precision while minimizing the loss of recall, and therefore improves the overall F₁ score in presence of PS. More importantly, PCA-LASSO drastically reduces the computational time by > 1000 times when compared to LASSOMM. We applied PCA-LASSO to a real dataset of Alzheimer’s disease and successfully identified SNP rs429358 (Gene APOE4) which has been widely reported to be associated with the onset and elevated risk of Alzheimer’s disease. In conclusion, PCA-LASSO is a simple, fast, but accurate approach for GWAS in presence of latent PS.

PMID:34480683 | DOI:10.1007/s10709-021-00129-3

Environ Sci Pollut Res Int. 2021 Sep 4. doi: 10.1007/s11356-021-15100-0. Online ahead of print.

ABSTRACT

Inspired by a circular economy paradigm, an evolving momentum of policies and legislations aims to close the loop of product lifecycles through improved level of recycling, remanufacturing, and reuse, with the objective of adding value to the economy while not endangering the environment. However, the trade-off between the environmental and economic sustainability of designing business processes is inevitable. To address this trade-off in the supply chain context, competing objectives regarding both cost minimization and reduction in carbon emission should be simultaneously considered and integrated into a comprehensive model. This complexity is however elevated when uncertainty of demand is taken into consideration. In this study, the design of a closed-loop supply chain is investigated where competing objectives of cost and sustainability of supply chain operations are evaluated under demand uncertainty. Augmented Weighted Tchebycheff (AWT) and ε-constraint methods are employed to address the multi-objectivity of the problem while a robust optimization approach is applied to deal with the demand uncertainty. The results confirm that the proposed approach provides efficient solutions for designing a green closed-loop supply chain network.

PMID:34480699 | DOI:10.1007/s11356-021-15100-0

Tech Coloproctol. 2021 Sep 4. doi: 10.1007/s10151-021-02508-6. Online ahead of print.

ABSTRACT

BACKGROUND: Anastomotic leak following elective sigmoidectomy performed due to sigmoid volvulus (SV) is a devastating complication. The aim of this study was to identify the incidence and risk factors associated with leak in this specific group of patients.

METHODS: A retrospective study was performed at two university-affiliated tertiary centres in Israel. All consecutive patients between January 2014 and April 2020 treated for SV with elective sigmoidectomy and primary anastomosis were reviewed and those suffering from anastomotic leak identified. Factors associated with this complication were assessed using univariate analysis and odds ratios subsequently calculated.

RESULTS: Of the 99 patients initially identified, 58 were included in the study group [45 males and 13 females (77.6% versus 22.4% respectively) mean age 67.4 years, range 13-97]. There were 10 anastomotic leaks identified (17.2%). On univariate analysis recurrent decompression (OR 8.28, p = 0.027), age > 80-years (OR 6.88, p = 0.027), open rather than laparoscopic surgery (OR = 5.83, p = 0.005) and ASA grade 3/4 (OR 0.132, p = 0.023) were significantly associated with anastomotic leak. Male sex approached but not reach statistical significance.

CONCLUSIONS: Recurrent endoscopic decompression, age > 80 years, open surgery and ASA grade 3/4 are associated with anastomotic leak and these patients should be considered for formation of a colostomy instead. If an anastomosis is performed, patients should be appropriately counselled and monitored in the perioperative period.

PMID:34480672 | DOI:10.1007/s10151-021-02508-6

Cancer Causes Control. 2021 Sep 4. doi: 10.1007/s10552-021-01483-5. Online ahead of print.

ABSTRACT

OBJECTIVE: The aim of this study was to analyze the influence of social determinants on changes in dietary habits before and after diagnosis of breast cancer in women (Barcelona, 2003-2013).

METHODS: We performed a cohort study with 2,235 women diagnosed with breast cancer. The information was obtained from an ad hoc questionnaire based on recommendations from the Spanish Society of Community Nutrition. We conducted a descriptive bivariate analysis and fit logistic regression models. The dependent variable was the change in dietary habits (food groups) and the independent variables were a selection of social and clinical variables (age, social class, cohabitation, years since diagnosis, history of replaces, and treatment with chemotherapy).

RESULTS: While 5.8% of women followed a healthy diet (consumption of vegetables, fruits, farinaceous, lean meat, and seafood) before diagnosis, 9.5% did so after diagnosis. We observed statistically significant changes in consumption of all food groups (p < 0.001) after diagnosis. The greatest change in consumption patterns was observed in women aged < 50 years and those from non-manual classes (high classes) [e.g., legume consumption: OR_{<50 years/>65 years} = 2.9 (95% CI 1.78-4.81); OR_{non-manual/manual} = 2.5 (95% CI 1.38-4.36)]. The occurrence of relapses and chemotherapy was associated with greater changes in dietary habits.

CONCLUSION: Women with breast cancer change their eating habits after diagnosis, and these changes are conditioned by social and clinical determinants.

PMID:34480675 | DOI:10.1007/s10552-021-01483-5

Clin Oral Investig. 2021 Sep 4. doi: 10.1007/s00784-021-04159-1. Online ahead of print.

ABSTRACT

OBJECTIVE: The aim of the present study was to evaluate the regenerative potential of permanent necrotic mature teeth with different apical foramen diameters in comparison to conventional endodontic treatment.

METHODS: Pulp necrosis and periapical pathosis were induced in premolars (144 roots) in six mongrel dogs. The infected teeth were divided into six groups; conventional root canal treatment (RCT) group prepared up to apical preparation sizes #F3 ProTaper file, regenerative endodontic therapy (RET) groups; groups RET-F3, RET-F4, and RET-F5 where regenerative endodontic procedures were applied after apical preparation up to sizes #F3, F4, and F5 ProTaper file, respectively, control groups; and positive (P) and negative (N) groups included infected and healthy teeth respectively. Each group (12 teeth with 24 roots each) was further subdivided into two subgroups (6 teeth with 12 roots each) according to the evaluation periods 1 and 3 months; each group was equally randomized in the upper and lower jaws during each evaluation period.

RESULTS: The inflammatory cell counts for the RCT group were statistically significantly higher than that of all RET groups at the first period and only significantly higher than RET-F5 at the second period. The enlargement of the apical foramen to #F5 showed no statistically significant difference with #F4 regarding the inflammatory cell count, tissue in-growth inside the root canal, and percentage of bone resorption. The tissue formed after RET was not true pulp tissue and is considered tissue repair with connective tissue, dilated blood vessels, and cementum-like structures.  CONCLUSION: Increasing the apical size diameter was associated with less inflammatory cell count, less percentage of bone resorption, more tissue ingrowth, and more percentage of new hard tissue formation inside root canal. The minimum apical diameter that should be enlarged for RET is 0.4 mm.

CLINICAL RELEVANCE: RET could be used as an alternative procedure to RCT for the treatment of mature teeth with necrotic pulp and apical periodontitis.

PMID:34480644 | DOI:10.1007/s00784-021-04159-1

Gastric Cancer. 2021 Sep 4. doi: 10.1007/s10120-021-01230-4. Online ahead of print.

ABSTRACT

BACKGROUND: The phase 3 ATTRACTION-2 study demonstrated that nivolumab monotherapy was superior to placebo for patients with pretreated advanced gastric or gastroesophageal junction cancer, but early progression of tumors in some patients was of concern.

METHODS: This post hoc analysis statistically explored the baseline characteristics of the ATTRACTION-2 patients and extracted a single-factor and double-factor combinations associated with early disease progression or early death. In the extracted patient subgroups, the 3-year restricted mean survival times of progression-free survival and overall survival were compared between the nivolumab and placebo arms.

RESULTS: Two single factors (age and peritoneal metastasis) were extracted as independent predictors of early progression, but none of them, as a single factor, stratified patients into two subgroups with significant differences in restricted mean survival time. In contrast, two double-factor combinations (serum sodium level and white blood cell count; serum sodium level and neutrophil-lymphocyte ratio) stratifying patients into two subgroups with significant differences in the restricted mean survival time were extracted. Additional exploratory analysis of a triple-factor combination showed that patients aged < 60 years with peritoneal metastasis and low serum sodium levels (approximately 7% of all patients) might receive less benefit from nivolumab, and patients aged ≥ 60 years with no peritoneal metastasis and normal serum sodium levels might receive higher benefit.

CONCLUSIONS: A combination of age, peritoneal metastasis, and serum sodium level might predict benefit from nivolumab as salvage therapy in advanced gastric or gastroesophageal junction cancer patients, especially less benefit for patients having all three risk factors.

PMID:34480657 | DOI:10.1007/s10120-021-01230-4

Arch Virol. 2021 Sep 4. doi: 10.1007/s00705-021-05214-8. Online ahead of print.

ABSTRACT

Adenovirus, respiratory syncytial virus, and influenza virus are common causes of respiratory infections. The COVID-19 pandemic had a significant impact on their prevalence. The aim of this study was to analyze the epidemic changes of common respiratory viruses in the Affiliated Hospital of Hangzhou Normal University in Hangzhou, China, from October of 2017 to February of 2021. We collected statistics from 121,529 patients in the outpatient and inpatient departments of the hospital who had throat or nose swabs collected for testing for four virus antigens by the colloidal gold method. Of these, 13,200 (10.86%) were positive for influenza A virus, 8,402 (6.91%) were positive for influenza B virus, 6,056 (4.98%) were positive for adenovirus, and 4,739 (3.90%) were positive for respiratory syncytial virus. The positivity rates of the influenza A virus (0-14 years old, P = 0.376; over 14 years old, P = 0.197) and respiratory syncytial virus (0-14 years old, P = 0.763; over 14 years old, P = 0.465) did not differ significantly by gender. After January of 2020, influenza virus infection decreased significantly. The positivity rate of respiratory syncytial virus remained high, and its epidemic season was similar to before. Strict respiratory protection and regulation of crowd activities have a great impact on the epidemic characteristics of viruses. After major changes in the public health environment, virus epidemics and their mutations should be monitored closely, extensively, and continuously.

PMID:34480636 | DOI:10.1007/s00705-021-05214-8

Eur J Pediatr. 2021 Sep 4. doi: 10.1007/s00431-021-04250-5. Online ahead of print.

ABSTRACT

To identify predictors for home death among children using socio-demographic factors and cause of death. It is a nationwide registry study. A cohort of children (1-17 years) who died between 1 January 2006 and 31 December 2016. It was set in Denmark, Europe. Predictors for home death were assessed: age, gender, diagnosis, region of residence, urbanicity, household income and immigrant status. Of 938 deceased children included, causes of death were solid tumours (17.3%), haematological cancers (8.5%) and non-cancerous conditions (74.2%). A total of 25% died at home. Compared to the lowest quartile, the groups with higher household income did not have a higher probability of dying at home (adjusted odds ratio (adj-OR) 0.8 (95% CI 0.5-1.2/1.3)). Dying of haematological cancers (adj-OR 0.3 (95% CI 0.2-0.7)) and non-cancerous conditions (adj-OR 0.5 (95% CI 0.3-0.7)) was associated with lower odds for home death compared to dying of solid tumours. However, being an immigrant was negatively associated with home death (adj-OR 0.6 (95% CI 0.4-0.9)). Moreover, a tendency was also found that being older, male, living outside the capital and in more urban areas were notable in relation to home death, however, not statistically significant.Conclusions: The fact that household income was not associated with dying at home may be explained by the Danish tax-financed healthcare system. However, having haematological cancers, non-cancerous conditions or being an immigrant were associated with lower odds for home death. Cultural differences along with heterogeneous trajectories may partly explain these differences, which should be considered prospectively. What is Known: • Prior studies have shown disparities in place-of-death of terminally ill children with diagnosis, ethnicity and socio-economic position as key factors. • Danish healthcare is tax-financed and in principle access to healthcare is equal; however, disparities have been found in the intensity of treatment of terminally ill children. What is New: • In a tax-financed, equal-access healthcare system, children died just as frequently at home in families with low as high household income. • Disparities in home death were related to diagnosis and immigrant status.

PMID:34480639 | DOI:10.1007/s00431-021-04250-5