Category: Statistics

Bull Math Biol. 2024 May 8;86(6):70. doi: 10.1007/s11538-024-01304-1.

ABSTRACT

Practical limitations of quality and quantity of data can limit the precision of parameter identification in mathematical models. Model-based experimental design approaches have been developed to minimise parameter uncertainty, but the majority of these approaches have relied on first-order approximations of model sensitivity at a local point in parameter space. Practical identifiability approaches such as profile-likelihood have shown potential for quantifying parameter uncertainty beyond linear approximations. This research presents a genetic algorithm approach to optimise sample timing across various parameterisations of a demonstrative PK-PD model with the goal of aiding experimental design. The optimisation relies on a chosen metric of parameter uncertainty that is based on the profile-likelihood method. Additionally, the approach considers cases where multiple parameter scenarios may require simultaneous optimisation. The genetic algorithm approach was able to locate near-optimal sampling protocols for a wide range of sample number (n = 3-20), and it reduced the parameter variance metric by 33-37% on average. The profile-likelihood metric also correlated well with an existing Monte Carlo-based metric (with a worst-case r > 0.89), while reducing computational cost by an order of magnitude. The combination of the new profile-likelihood metric and the genetic algorithm demonstrate the feasibility of considering the nonlinear nature of models in optimal experimental design at a reasonable computational cost. The outputs of such a process could allow for experimenters to either improve parameter certainty given a fixed number of samples, or reduce sample quantity while retaining the same level of parameter certainty.

PMID:38717656 | DOI:10.1007/s11538-024-01304-1

Rev Sci Instrum. 2024 May 1;95(5):053503. doi: 10.1063/5.0203259.

ABSTRACT

We report a Bidirectional Electrode Control Arm Assembly (BECAA) for precisely manipulating dust clouds levitated above the powered electrode in RF plasmas. The reported techniques allow the creation of perfectly 2D dust layers by eliminating off-plane particles by moving the electrode from outside the plasma chamber without altering the plasma conditions. The tilting and moving of electrodes using BECAA also allows the precise and repeatable elimination of dust particles one by one to achieve any desired number of grains N without trial and error. Simultaneously acquired top and side view images of dust clusters show that they are perfectly planar or 2D. A demonstration of clusters with N = 1-28 without changing the plasma conditions is presented to show the utility of BECAA for complex plasma and statistical physics experimental design. Demonstration videos and 3D printable part files are available for easy reproduction and adaptation of this new method to repeatably produce 2D clusters in existing RF plasma chambers.

PMID:38717655 | DOI:10.1063/5.0203259

Lifetime Data Anal. 2024 May 8. doi: 10.1007/s10985-024-09628-9. Online ahead of print.

ABSTRACT

The added value of candidate predictors for risk modeling is routinely evaluated by comparing the performance of models with or without including candidate predictors. Such comparison is most meaningful when the estimated risk by the two models are both unbiased in the target population. Very often data for candidate predictors are sourced from nonrepresentative convenience samples. Updating the base model using the study data without acknowledging the discrepancy between the underlying distribution of the study data and that in the target population can lead to biased risk estimates and therefore an unfair evaluation of candidate predictors. To address this issue assuming access to a well-calibrated base model, we propose a semiparametric method for model fitting that enforces good calibration. The central idea is to calibrate the fitted model against the base model by enforcing suitable constraints in maximizing the likelihood function. This approach enables unbiased assessment of model improvement offered by candidate predictors without requiring a representative sample from the target population, thus overcoming a significant practical challenge. We study theoretical properties for model parameter estimates, and demonstrate improvement in model calibration via extensive simulation studies. Finally, we apply the proposed method to data extracted from Penn Medicine Biobank to inform the added value of breast density for breast cancer risk assessment in the Caucasian woman population.

PMID:38717617 | DOI:10.1007/s10985-024-09628-9

Biochem Genet. 2024 May 8. doi: 10.1007/s10528-024-10813-6. Online ahead of print.

ABSTRACT

Infection by the recent SARS-CoV-2 virus causes the COVID-19 disease with variable clinical manifestations ranging from asymptomatic or mild respiratory symptoms to severe respiratory distress and multiorgan failure. The renin-angiotensin system, responsible for maintaining homeostasis and governing several critical processes, has been considered the main system involved in the pathogenesis and progression of COVID-19. Here, we aimed to assess the possible association between variants in the RAS-related genes and COVID-19 susceptibility and severity in a sample of the Moroccan population. A total of 325 individuals were recruited in this study, with 102 outpatients, 105 hospitalized patients, and 118 healthy controls negative for SARS-CoV-2 infection, and subjected to NGS gene panel sequencing containing eleven RAS pathway genes. A total of 65 functional variants were identified, including 63 missenses, 1 splice, and 1 INDEL. Most of them were rare, with 47 (72%) found in a single individual. According to the common disease/common variant hypothesis, five common candidate variants with MAF > 10% were identified (ACE2 rs2285666, TMPRSS2 rs12329760, AGT rs699 genes, ACE rs4341, and ACE rs4343). Statistical analysis showed that the ACE rs4343 AA genotype was associated with a 2.5-fold increased risk of severe COVID-19 (p = 0.026), and the T genotype of the ACE2 rs2285666 variant showed a borderline association with susceptibility to SARS-CoV-2 in males (p = 0.097). In conclusion, our results showed that the RAS pathway genes are highly conserved among Moroccans, and most of the identified variants are rare. Among the common variants, the ACE rs4343 polymorphism would lead to a genetic predisposition for severe COVID-19.

PMID:38717614 | DOI:10.1007/s10528-024-10813-6

Geospat Health. 2024 May 7;19(1). doi: 10.4081/gh.2024.1249.

ABSTRACT

Community food environments (CFEs) have a strong impact on child health and nutrition and this impact is currently negative in many areas. In the Republic of Argentina, there is a lack of research evaluating CFEs regionally and comprehensively by tools based on geographic information systems (GIS). This study aimed to characterize the spatial patterns of CFEs, through variables associated with its three dimensions (political, individual and environmental), and their association with the spatial distribution in urban localities in Argentina. CFEs were assessed in 657 localities with ≥5,000 inhabitants. Data on births and CFEs were obtained from nationally available open-source data and through remote sensing. The spatial distribution and presence of clusters were assessed using hotspot analysis, purely spatial analysis (SaTScan), Moran’s Index, semivariograms and spatially restrained multivariate clustering. Clusters of low risk for LBW, macrosomia, and preterm births were observed in the central-east part of the country, while high-risk clusters identified in the North, Centre and South. In the central-eastern region, low-risk clusters were found coinciding with hotspots of public policy coverage, high night-time light, social security coverage and complete secondary education of the household head in areas with low risk for negative outcomes of the birth variables studied, with the opposite with regard to households with unsatisfied basic needs and predominant land use classes in peri-urban areas of crops and herbaceous cover. These results show that the exploration of spatial patterns of CFEs is a necessary preliminary step before developing explanatory models and generating novel findings valuable for decision-making.

PMID:38716709 | DOI:10.4081/gh.2024.1249

Hypertension. 2024 May 8. doi: 10.1161/HYPERTENSIONAHA.124.22832. Online ahead of print.

ABSTRACT

BACKGROUND: Systolic blood pressure (BP) is a key predictor of cardiovascular events, but patients with peripheral artery disease (PAD) are rarely included in hypertension trials. The VALUE trial (Valsartan Antihypertensive Long-Term Use Evaluation) investigated the long-term effects of valsartan- or amlodipine-based treatments on cardiovascular outcomes in patients with hypertension with a high cardiovascular risk. The aim of this subanalysis was to clarify the relationship between achieved BP on treatment and cardiovascular outcomes in patients with hypertension with PAD.

METHODS: Patients were followed for 4 to 6 years, and BP was measured regularly. The primary end point was time to the first major adverse cardiovascular event, including myocardial infarction, stroke, cardiovascular death, and heart failure requiring hospitalization. Statistical analyses were performed using Cox regression, adjusting for various baseline covariates.

RESULTS: Of the 13 803 participants, 1898 (13.8%) had PAD. During a median follow-up of 4.5 years, patients with PAD had a 23% increased risk of major adverse cardiovascular events compared with patients without PAD. Patients with an achieved systolic BP <130 mm Hg and 130 to 139 mm Hg, compared with those with systolic BP ≥140 mm Hg, were associated with a decreased risk of a major adverse cardiovascular event (hazard ratio, 0.65 [95% CI, 0.43-0.97]; P=0.037; 0.85 [95% CI, 0.74-0.97]; P=0.016, respectively). Additionally, systolic BP <130 mm Hg was associated with a decreased risk of cardiovascular death (hazard ratio, 0.33 [95% CI, 0.12-0.92]; P=0.034). The incidence of the primary outcome did not differ between antihypertensive treatment regimens (P=0.365).

CONCLUSIONS: Our results indicate that more intensive BP control is associated with a reduction in cardiovascular morbidity and mortality in patients with hypertensive PAD.

PMID:38716657 | DOI:10.1161/HYPERTENSIONAHA.124.22832

Microsurgery. 2024 May;44(4):e31185. doi: 10.1002/micr.31185.

ABSTRACT

BACKGROUND: Recent CMS billing changes have raised concerns about insurance coverage for deep inferior epigastric perforator (DIEP) flap breast reconstruction. This study compared the costs and utilization of transverse rectus abdominis myocutaneous (TRAM), DIEP, and latissimus dorsi (LD) flaps in breast reconstruction.

METHOD: The study utilized the National Inpatient Sample database to identify female patients who underwent DIEP, TRAM, and LD flap procedures from 2016 to 2019. Key data such as patient demographics, length of stay, complications, and costs (adjusted to 2021 USD) were analyzed, focusing on differences across the flap types.

RESULTS: A total of 17,770 weighted patient encounters were identified, with the median age being 51. The majority underwent DIEP flaps (73.5%), followed by TRAM (14.2%) and LD (12.1%) flaps. The findings revealed that DIEP and TRAM flaps had a similar length of stay (LOS), while LD flaps typically had a shorter LOS. The total hospital charges to costs using cost-to-charge ratio were also comparable between DIEP and TRAM flaps, whereas LD flaps were significantly less expensive. Factors such as income quartile, primary payer of hospitalization, and geographic region significantly influenced flap choice.

CONCLUSION: The study’s results appear to contradict the prevailing notion that TRAM flaps are more cost-effective than DIEP flaps. The total hospital charges to costs using cost-to-charge ratio and hospital stays associated with TRAM and DIEP flaps were found to be similar. These findings suggest that changes in the insurance landscape, which may limit the use of DIEP flaps, could undermine patient autonomy while not necessarily reducing healthcare costs. Such policy shifts could favor less costly options like the LD flap, potentially altering the landscape of microvascular breast reconstruction.

PMID:38716656 | DOI:10.1002/micr.31185

Cancer Control. 2024 Jan-Dec;31:10732748241251712. doi: 10.1177/10732748241251712.

ABSTRACT

INTRODUCTION: Esophageal cancer was the eighth and sixth leading cause of morbidity of all cancers in the world, and the 15th and 12th in Ethiopia, respectively. There is a lack of comprehensive data regarding Ethiopia’s esophageal cancer hotspot, treatment outcome clustering, and other factors.

OBJECTIVE: This scoping review was designed to understand the extent and type of existing evidence regarding spatiotemporal distribution, time to treatment outcome clustering, and determinants of esophageal cancer in Ethiopia up to March 28, 2023.

METHODS: Three-step search strategies were employed for the scoping review from March 15 to 28, 2023. Targeted databases included PubMed/Medline, PubMed Central (PMC), Google Scholar, Hinari, and Cochrane for published studies and different websites for unpublished studies for evidence synthesis. Data were extracted using the Joanna Briggs Institute (JBI) manual format.

RESULTS: Our final analysis comprised 17 (16 quantitative and 1 qualitative) studies. Three studies attempted to depict the country’s temporal distribution, whereas 12 studies showed the spatial distribution of esophageal cancer by proportion. The regional state of Oromia recorded a high percentage of cases. Numerous risk factors linked to the tumor have been identified in 8 investigations. Similarly, 5 studies went into detail regarding the likelihood of survival and the factors that contribute to malignancy, while 2 studies covered the results of disease-related treatments.

CONCLUSIONS: The substantial body of data that underpins this finding supports the fact that esophageal cancer has several risk factors and that its prevalence varies greatly across the country and among regions. Surgery, radiotherapy, or chemotherapy helped the patient live longer. However, no research has investigated which treatment is best for boosting patient survival and survival clustering. Therefore, research with robust models for regional distribution, clustering of time to treatment outcomes, and drivers of esophageal cancer will be needed.

PMID:38716644 | DOI:10.1177/10732748241251712

J Dermatol. 2024 May 8. doi: 10.1111/1346-8138.17253. Online ahead of print.

ABSTRACT

Small plaque psoriasis is the typical form of chronic plaque psoriasis affecting adults in South Korea. The effectiveness of calcipotriol/betamethasone dipropionate (Cal/BD) aerosol foam for large and small psoriasis plaques has not previously been examined. We performed a post hoc analysis of a recent, 4-week observational study of Cal/BD aerosol foam use in routine clinical practice in South Korea. Investigator Global Assessment response ([IGA] 0/1 at week 4), Patient Global Assessment response ([PaGA] 0/1 at week 4), change in Psoriasis Area and Severity Index (PASI), changes in psoriasis symptom scores, change in the Dermatology Life Quality Index (DLQI), and the proportion of patients achieving DLQI ≤5 were analyzed for patients with small (≤5 cm; n = 131) or large (>5 cm; n = 35) baseline plaque size. IGA response rates were similar for patients with small and large plaques (59.5% and 51.4% respectively). Similarly, there was no significant difference between the small and large groups in mean change in PASI (-2.20 vs -3.34), the proportions of patients with DLQI ≤5 (62.3% vs 54.3%) or PaGA 0/1 (29.2% vs 40.0%). Mean improvements in DLQI (-4.04 vs -6.20) and in psoriasis symptoms including itching (-1.50 vs -2.83), sleep loss (-0.67 vs -1.89), dryness (-1.57 vs -2.97), scaling (-1.21 vs -3.57), and redness (-1.17 vs -3.11) were greater in patients with large plaques than those with small plaques. Itching and DLQI differences were not statistically significant after adjustment for baseline characteristics. Stratification by body surface area affected eliminated statistically significant differences between the groups for most outcomes. In conclusion, this analysis suggests that Cal/BD aerosol foam is an effective, well-accepted treatment for adult patients with the small plaques typical of chronic plaque psoriasis in South Korea, as well as for those with large plaques.

PMID:38716641 | DOI:10.1111/1346-8138.17253

Cancer Med. 2024 May;13(9):e7085. doi: 10.1002/cam4.7085.

ABSTRACT

AIMS: To investigate the effect of Self-designed Metabolic Equivalent Exercises (SMEE) on cancer-related fatigue in patients with gastric cancer.

METHODS: 130 patients with gastric cancer admitted to Department of Oncology of a tertiary hospital in Shanghai were enrolled and assessed for eligibility. After excluding 1 patient who declined to participate, 129 eligible patients were randomly assigned into SMEE (n = 65) and control (n = 64) groups. The Revised Piper Fatigue Scale (RPFS) and EORTC QLQ-C30 Quality of Life Scale were used to measure cancer-caused fatigue and quality of life, respectively, in both groups at the first admission and after 3 months.

RESULTS: After excluding patients who did not receive allocated intervention due to medical (n = 3) and personal (n = 2) reasons, those who were lost to follow-up (n = 3), and those who had discontinued intervention (n = 2), 119 patients (64 in the SMEE group and 55 in the control group) were included for analysis. There were no statistically significant differences in the RPFS or QLQ-C30 score between the two groups at baseline. After 3 months, the total RPFS score of the SMEE group was significantly lower than that of the control group (2.86 ± 1.75 vs. 4.65 ± 1.29, p = 0.009), with significant improvements in affective meaning (0.83 ± 0.92 vs. 1.13 ± 0.77, p = 0.044) and sensory (0.70 ± 0.71 vs. 1.00 ± 0.54, p < 0.001) subscales; in the SMEE group, QLQ-C30 scores in somatic (2.00 ± 0.27 vs. 1.31 ± 0.26, p < 0.001), emotional (2.67 ± 0.58 vs. 2.07 ± 0.48, p < 0.001), and social (3.23 ± 0.58 vs. 1.64 ± 0.51, p < 0.001) functioning were significantly higher than those in the control group, with significant improvements in fatigue (p < 0.001), nausea/vomiting (p = 0.014), shortness of breath (p < 0.001), constipation (p < 0.001), and diarrhea (p = 0.001) dimensions.

CONCLUSION: The self-programmed metabolic equivalent manipulation as an exercise intervention could effectively reduce the degree of cancer-caused fatigue and improve quality of life in patients with gastric cancer.

PMID:38716637 | DOI:10.1002/cam4.7085