Category: Statistics

J Clin Monit Comput. 2021 Feb 27. doi: 10.1007/s10877-021-00677-1. Online ahead of print.

ABSTRACT

Strain echocardiography enables the automatic quantification of the global longitudinal strain (GLS), which is a direct measure of ventricular shortening during systole. In the current context of overwhelmed ICUs and clinician shortage, GLS has the advantage to be quick and easy to measure by non-experts. However, little is known regarding its value to assess bi-ventricular systolic function in critically ill COVID-19 patients. Therefore, we designed a study to compare right and left ventricular GLS with classic echo-Doppler indices of systolic function, namely the ejection fraction for the left ventricle (LVEF) and the fractional area change (FAC), the tricuspid annular plane systolic excursion (TAPSE), and the tissue Doppler velocity of the basal free lateral wall (S’) for the right ventricle. Eighty transthoracic echocardiographic evaluations done in 30 ICU patients with COVID-19 were analyzed. We observed a fair relationship (r = 0.73, p < 0.01) between LVEF and left ventricular GLS. The GLS cut-off value of – 22% identified a LVEF < 50% with a sensitivity of 63% and a specificity of 80%. All patients with a GLS > – 17% had a LVEF < 50%. Although statistically significant, relationships between FAC (r = 0.41, p < 0.01), TAPSE (r = 0.26, p < 0.05) and right ventricular GLS were weak. S’ was not correlated with right ventricular GLS. In conclusion, left ventricular GLS was useful to assess left ventricular systolic function. However, right ventricular GLS was poorly correlated with FAC, TAPSE and S’. Further studies are needed to clarify what is the best method to assess right ventricular systolic function in ICU patients with COVID-19.

PMID:33638061 | DOI:10.1007/s10877-021-00677-1

Pharmacoecon Open. 2021 Feb 26. doi: 10.1007/s41669-021-00260-z. Online ahead of print.

ABSTRACT

Novel cancer therapies are associated with survival patterns that differ from established therapies, which may include survival curves that plateau after a certain follow-up time point. A fraction of the patient population is then considered statistically cured and subject to the same mortality experience as the cancer-free general population. Mixture cure models have been developed to account for this characteristic. As compared to standard survival analysis, mixture cure models can often lead to profoundly different estimates of long-term survival, required for health economic evaluations. This tutorial is designed as a practical introduction to mixture cure models. Step-by-step instructions are provided for the entire implementation workflow, i.e., from gathering and combining data from different sources to fitting models using maximum likelihood estimation and model results interpretation. Two mixture cure models were developed to illustrate (1) an “uninformed” approach where the cure fraction is estimated from trial data and (2) an “informed” approach where the cure fraction is obtained from an external source (e.g., real-world data) used as an input to the model. These models were implemented in the statistical software R, with the freely available code on GitHub. The cure fraction can be estimated as an output from (“uninformed” approach) or used as an input to (“informed” approach) a mixture cure model. Mixture cure models suggest presumed estimates of long-term survival proportions, especially in instances where some fraction of patients is expected to be statistically cured. While this type of model may initially seem complex, it is straightforward to use and interpret. Mixture cure models have the potential to improve the accuracy of survival estimates for treatments associated with statistical cure, and the present tutorial outlines the interpretation and implementation of mixture cure models in R. This type of model will likely become more widely used in health economic analyses as novel cancer therapies enter the market.

PMID:33638063 | DOI:10.1007/s41669-021-00260-z

Environ Sci Pollut Res Int. 2021 Feb 26. doi: 10.1007/s11356-021-12735-x. Online ahead of print.

ABSTRACT

Northern Italy was the most affected by CoViD-19 compared to other Italian areas and comprises zones where air pollutants concentration was higher than in the rest of Italy. The aim of the research is to determine if particulate matter (PM) has been the primary cause of the high CoViD-19 spread rapidity in some areas of Northern Italy. Data of PM for all the 41 studied cities were collected from the local environmental protection agencies. To compare air quality data with epidemiological data, a statistical analysis was conducted identifying the correlation matrices of Pearson and Spearman, considering also the possible incubation period of the disease. Moreover, a model for the evaluation of the epidemic risk, already proposed in literature, was used to evaluate a possible influence of PM on CoViD-19 spread rapidity. The results exclude that PM alone was the primary cause of the high CoVid-19 spread rapidity in some areas of Northern Italy. Further developments are necessary for a better comprehension of the influence of atmospheric pollution parameters on the rapidity of spread of the virus SARS-CoV-2, since a synergistic action with other factors (such as meteorological, socio-economic and cultural factors) could not be excluded by the present study.

PMID:33638072 | DOI:10.1007/s11356-021-12735-x

Ann Biomed Eng. 2021 Feb 26. doi: 10.1007/s10439-021-02747-6. Online ahead of print.

ABSTRACT

Although critical for understanding and simulating pelvic floor muscle function and pathophysiology, the fascicle arrangements of the coccygeus and levator ani remain mostly undetermined. We performed close-range photogrammetry on cadaveric pelvic floor muscles to robustly quantify surface fascicle orientations. The pelvic floor muscles of 5 female cadavers were exposed through anatomic dissections, removed en bloc, and photographed from every required angle. Overlapping images were mapped onto in silico geometries and muscle fascicles were traced manually. Tangent vectors were calculated along each trace; interpolated to define continuous, 3D vector fields; and projected onto axial and sagittal planes to calculate angles with respect to the pubococcygeal line. Contralateral and ipsilateral pelvic floor muscles were compared within each donor (Kuiper’s tests) and using mean values from all donors (William-Watsons tests). Contralateral muscles and all but one ipsilateral muscle pair differed significantly within each donor (p < 0.001). When mean values were considered collectively, no contralateral or ipsilateral statistical differences were found but all muscles compared differed by more than 10° on average. Close-range photogrammetry and subsequent analyses robustly quantified surface fascicle orientations of the pelvic floor muscles. The continuous, 3D vector fields provide data necessary for improving simulations of the female pelvic floor muscles.

PMID:33638030 | DOI:10.1007/s10439-021-02747-6

Clin Oral Investig. 2021 Feb 27. doi: 10.1007/s00784-021-03811-0. Online ahead of print.

ABSTRACT

OBJECTIVE: The aim of the present study was to evaluate the in vitro biocompatibility of Theracal PT, Theracal LC, and MTA Angelus, considered as bioactive materials used for vital pulp treatment, on human dental pulp stem cells (hDPSCs).

MATERIALS AND METHODS: Human dental pulp stem cells (hDPSCs) were isolated from third molars, and material eluates were prepared (undiluted, 1:2, and 1:4 ratios). The hDPSC cytotoxicity, adhesion, morphology, viability, and cell migration were assessed. The mineralization nodule formation was determined by Alizarin red S staining (ARS). The odonto/osteogenic differentiation potential was assessed by osteo/odontogenic marker expression real-time qPCR. The chemical composition and ion release of the vital pulp materials were determined by energy dispersive X-ray (EDX) and inductively coupled plasma-mass spectrometry (ICP-MS), respectively. Statistical differences were assessed by ANOVA and Tukey’s test (p < 0.05).

RESULTS: The three vital pulp materials showed variable levels of calcium, tungsten, silicon, and zirconium release and in their chemical composition. Cytocompatibility assays revealed higher hDPSC viability and migration rates when treated with Theracal PT than with Theracal LC. The lowest cell adhesion and spreading were observed in all Theracal LC-treated groups, whereas the highest were observed when treated with MTA. Theracal PT and MTA promoted the upregulation of DSPP and RUNX2 gene expression (p < 0.05). After 21 days, both MTA Angelus and Theracal PT-treated cells exhibited a significantly higher mineralized nodule formation than the negative control (p < 0.05).

CONCLUSIONS: This study demonstrates the favorable in vitro cytocompatibility and bioactive properties of the recently introduced Theracal PT and the well-established MTA Angelus on hDPSCs, as opposed to Theracal LC. More studies, including in vivo animal testing are suggested before these new formulations might be used in the clinical setting.

CLINICAL RELEVANCE: Theracal PT is a new material that could be clinically suitable for vital pulp therapy. Further studies considering its biocompatibility and bioactivity are necessary.

PMID:33638052 | DOI:10.1007/s00784-021-03811-0

Eur Heart J Cardiovasc Imaging. 2021 Feb 26:jeab023. doi: 10.1093/ehjci/jeab023. Online ahead of print.

ABSTRACT

AIMS: The concept of proportionate/disproportionate functional mitral regurgitation (FMR) has been limited by the lack of a simple way to assess it and by the paucity of data showing its prognostic superiority. The aim of this study was to evaluate the prognostic value of an individualized method of assessing FMR proportionality.

METHODS AND RESULTS: We retrospectively identified 572 patients with at least mild FMR and reduced left ventricular ejection fraction (<50%) under medical therapy. To determine FMR proportionality status, we used an approach where a simple equation determined the individualized theoretical regurgitant volume (or effective regurgitant orifice area) threshold associated with haemodynamically significant FMR. Then, we compared the measured with the theoretical value to categorize the population into non-severe, proportionate, and disproportionate FMR. The primary endpoint was all-cause mortality. During a median follow-up of 3.8 years (interquartile range: 1.8-6.2), 254 patients died. The unadjusted mortality incidence per 100 persons-year rose as the degree of FMR disproportionality worsened. On multivariable analysis, disproportionate FMR remained independently associated with all-cause mortality [adjusted hazard ratio: 1.785; 95% confidence interval (CI): 1.249-2.550; P = 0.001]. The FMR proportionality concept showed greater discriminative power (C-statistic 0.639; 95% CI: 0.597-0.680) than the American (C-statistic 0.583; 95% CI: 0.546-0.621; P for comparison <0.001) and European guidelines (C-statistic 0.584; 95% CI: 0.547-0.620; P for comparison <0.001). When added to any of the before-mentioned guidelines, FMR proportionality also improved risk stratification by reclassifying patients into lower and higher risk subsets.

CONCLUSION: Disproportionate FMR is independently associated with all-cause mortality and improves the risk stratification of current guidelines.

PMID:33637993 | DOI:10.1093/ehjci/jeab023

Mod Pathol. 2021 Feb 26. doi: 10.1038/s41379-021-00735-8. Online ahead of print.

ABSTRACT

Pleuropulmonary blastoma (PPB) is a primary embryonal malignancy of childhood that is characterized by distinct morphologic types: type Ir (regressed), type I (cystic), type II (cystic and solid), and type III (solid). Prognosis varies by PPB type. Most cases are associated with a germline pathogenic mutation in DICER1; however, there is limited data on the factor(s) at a cellular level that drive progression from type I to type III. In this study, we evaluated the expression of p53 and its prognostic implications. A total of 143 PPB cases were included in the study with the following distribution in PPB types: Ir (14%), I (23%), II (32%), and III (31%). P53 expression by immunohistochemistry (IHC) was recorded as four groups: 0%, 1-25%, 26-75%, and 76-100%. All type I PPBs showed 0-25% p53 expression compared to the higher p53 expression (>25%) in type III PPB (p < 0.0001), to support the argument that p53 has a role in tumor progression. In addition, type Ir with the architectural hallmarks of type I PPB, but lacking the primitive cell population, has negligible p53 expression. High p53 expression (staining observed in >25% of the tumor cells) was significantly associated with age over 1 year (p = 0.0033), neoadjuvant therapy (p = 0.0009), positive resection margin (p = 0.0008) and anaplasia (p < 0.0001). P53 expression was significantly associated with recurrence-free survival (p < 0.0001) and overall survival (p = 0.0350), with higher p53 expression associated with worse prognosis. Comparisons of concordance statistics showed no significant difference in prognostication when using morphologic types compared to p53 expression groups (p = 0.647). TP53 sequence was performed in 16 cases; the most common variant identified was a missense variant (12 cases), and in one case a frameshift truncating variant was noted. Based on these findings, we recommend performing p53 IHC in all newly diagnosed cases of types II and III PPB to further aid in risk stratification.

PMID:33637876 | DOI:10.1038/s41379-021-00735-8

Br Dent J. 2021 Feb;230(4):229-235. doi: 10.1038/s41415-021-2662-3. Epub 2021 Feb 26.

ABSTRACT

Objective To compare the clinical effectiveness and cost benefit of different frequencies of scale and polish (S&P) treatments in combination with different types of oral hygiene advice (OHA).Design Multi-centre, multi-level cluster randomised factorial open trial with blinded outcome evaluation. UK dental practices were cluster randomised to deliver OHA as usual or personalised. In a separate randomisation, patients were allocated to receive S&P 6-monthly, 12-monthly or never.Setting UK primary dental care.Participants Practices providing NHS care and adults who had received regular dental check-ups.Main outcome measures The percent of sites with bleeding on probing, patient confidence in self-care, incremental net benefits (INB) over three years.Results Sixty-three practices and 1,877 adult patients were randomised and 1,327 analysed (clinical outcome). There was no statistically significant or clinically important difference in gingival bleeding between the three S&P groups (for example, six-monthly versus none: difference 0.87% sites, 95% CI: 1.6 to 3.3, p = 0.48) or between personalised or usual OHA groups (difference -2.5% sites, -95%CI: -8.3 to 3.3, p = 0.39), or oral hygiene self-efficacy (cognitive impact) between either group (for example, six-monthly versus none: difference -0.028, 95% CI -0.119 to 0.063, p = 0.543). The general population place a high value on, and are willing to pay for, S&P services. However, from a dental health perspective, none of the interventions were cost-effective.Conclusion Results suggest S&P treatments and delivering brief personalised OHA provide no clinical benefit and are therefore an inefficient approach to improving dental health (38% of sites were bleeding whatever intervention was received). However, the general population value both interventions.

PMID:33637926 | DOI:10.1038/s41415-021-2662-3

Eye (Lond). 2021 Feb 26. doi: 10.1038/s41433-021-01468-3. Online ahead of print.

ABSTRACT

BACKGROUND: It has been suggested that ocular antihypertensives are associated with an increased risk of nasolacrimal duct obstruction. This study aims to assess the effect of topical antihypertensive treatment on surgical outcomes for patients undergoing Dacryocystorhinostomy (DCR) with intubation.

METHODS: Single centre, retrospective analysis of 170 operations carried out on 144 patients between January 2014 and January 2019. Statistical analysis of DCR failure rates comparing patients on topical ocular antihypertensive treatment and those not on any topical ocular antihypertensive treatment was carried out following medical case record analysis.

RESULTS: 6.9% of patients undergoing DCR surgery were on topical antihypertensive treatment. The overall failure rate for all DCR operations during this time period was 11.2%. There was a statistically significant higher rate of primary DCR failure in patients on antihypertensive treatment (p = 0.02), with the endonasal DCRs worse affected (p = 0.01). The most commonly used topical treatments were carbonic anhydrase inhibitors (CAI, 81.8%), followed by beta-blockers (72.7%). All patients who had failure of primary DCR were using topical beta-blockers and CAI at the time of surgery and post-operatively. There was no statistically significant association between failure rates and the use of preserved or unpreserved drops (p = 1.0) CONCLUSIONS: Topical ocular antihypertensive treatment may lead to a higher failure rate for DCR surgery due to the provocation of an inflammatory cicatricial response. Beta-blockers and CAIs appear to have the strongest association. Considering a primary external approach in this group as well as switching the class of topical antihypertensive treatment pre-operatively could perhaps improve DCR outcomes.

PMID:33637965 | DOI:10.1038/s41433-021-01468-3

Physiol Meas. 2021 Feb 26. doi: 10.1088/1361-6579/abea25. Online ahead of print.

ABSTRACT

OBJECTIVE: Heart rate (HR) monitoring provides a convenient and inexpensive way to predict energy expenditure (EE) during physical activity. However, there is a lot of variation among individuals in the EE-HR relationship, which should be taken into account in predictions. The objective is to develop a model that allows the prediction of EE based on HR as accurately as possible and allows an improvement of the prediction using calibration measurements from the target individual.

APPROACH: We propose a nonlinear (logistic) mixed model for EE and HR measurements and an approach to calibrate the model for a new person who does not belong to the data set used to estimate the model. The calibration utilizes the estimated model parameters and calibration measurements of HR and EE from the person in question. We compare the results of the logistic mixed model with a simpler linear mixed model for which the calibration is easier to perform.

MAIN RESULTS: We show that the calibration is beneficial already with only one pair of measurements on HR and EE. That is an important benefit over an individual-level model fitting which requires a larger number of measurements. Moreover, we present an algorithm for calculating the confidence and prediction intervals of the calibrated predictions. The analysis was based on up to eleven pairs of EE and HR measurements from each of 54 individuals of a heterogeneous group of people, who performed a maximal treadmill test.

SIGNIFICANCE: The proposed method allows accurate energy expenditure predictions based on only a few calibration measurements from a new individual without access to the original dataset, thus making the approach viable for example on wearable computers.

PMID:33636716 | DOI:10.1088/1361-6579/abea25