Category: Statistics

Lifetime Data Anal. 2022 Jun 13. doi: 10.1007/s10985-022-09556-6. Online ahead of print.

ABSTRACT

The heterogeneous inverse Gaussian (IG) process is one of the most popular and most considered degradation models for highly reliable products. One difficulty with heterogeneous IG processes is the lack of analytic expressions for the Fisher information matrix (FIM). Thus, it is a challenge to find an optimum test plan using any information-based criteria with decision variables such as the termination time, the number of measurements and sample size. In this article, the FIM of an IG process with random slopes can be derived explicitly in an algebraic expression to reduce uncertainty caused by the numerical approximation. The D- and V-optimum test plans with/without a cost constraint can be obtained by using a profile optimum plan. Sensitivity analysis is studied to elucidate how optimum planning is influenced by the experimental costs and planning values of the model parameters. The theoretical results are illustrated by numerical simulation and case studies. Simulations, technical derivations and auxiliary formulae are available online as supplementary materials.

PMID:35691960 | DOI:10.1007/s10985-022-09556-6

Ann Surg Oncol. 2022 Jun 12. doi: 10.1245/s10434-022-11973-8. Online ahead of print.

ABSTRACT

BACKGROUND: Preoperative carcinoembryonic antigen (CEA) has been reported as a prognostic factor in patients with colorectal liver metastasis (CRLM) after hepatectomy. However, the impact of a preoperative “CEA uptrend” on prognosis after hepatectomy in these patients remains unknown. This study assessed the impact of CEA uptrend on prognosis in patients undergoing hepatectomy for CRLM.

METHODS: Consecutive patients with CRLM who underwent hepatectomy between 2009 and 2018 were retrospectively analyzed. Patients with CRLM for whom CEA was measured both around 1 month before (CEA-1m) and within 3 days (CEA-3d) before hepatectomy were enrolled. A CEA-3d higher than both the upper limit of normal (5 ng/ml) and CEA-1m was defined as a CEA uptrend.

RESULTS: Study participants comprised 212 patients with CRLM. Of these, 88 patients (41.5%) showed a CEA uptrend. CEA uptrend indicated better discriminatory ability (corrected Akaike information criteria, 733.72) and homogeneity (likelihood ratio chi-square value, 18.80) than CEA-3d or CEA-1m. Patients with CEA uptrend showed poorer overall survival than those without CEA uptrend (p < 0.001). After adjusting for known prognostic factors, the prognostic significance of CEA uptrend retained (hazard ratio 2.63, 95% confidence interval 1.63-4.26, p < 0.001). In subgroup analyses, the prognostic significance of CEA uptrend was retained irrespective of the status of RAS mutation or response to preoperative chemotherapy.

CONCLUSIONS: CEA uptrend offers better prediction of survival outcomes than conventional CEA measurements in patients undergoing hepatectomy for CRLM.

PMID:35691953 | DOI:10.1245/s10434-022-11973-8

ChemSusChem. 2022 Jun 12. doi: 10.1002/cssc.202201006. Online ahead of print.

ABSTRACT

The synthesis of acetic acid by formal isomerization of methyl formate (MF) was investigated using molecular catalysts. The base-catalyzed decarbonylation of MF, yielding CO and methanol in-situ , was integrated with their palladium-catalyzed recombination for the synthesis of acetic acid and methyl acetate in a one pot reaction . The complex [Pd(Cl) 2 (dppe)] (dppe = 1,2-bis(diphenylphosphino)-ethane) in combination with NaI as iodide source and NaOMe as base were identified as promising molecular components to enable the overall conversion. Sequential application of the statistical methods DoE (design of experiments) and simplex optimization was used in combination with thermodynamic analysis of the competing reaction pathways for experimental planning and data analysis. Starting from a proof-of-principle with a turnover number (TON) of 11, the catalytic system could thus be elaborated to allow quantitative conversion of MF with a TON of 43,000 whereby a yield of 83% of acetate groups and a yield of 74% for free acetic acid was obtained.

PMID:35691934 | DOI:10.1002/cssc.202201006

Neurologia (Engl Ed). 2022 Jun 9:S2173-5808(22)00067-0. doi: 10.1016/j.nrleng.2021.10.004. Online ahead of print.

ABSTRACT

BACKGROUND: Recent years have seen considerable changes in the prevention and treatment of acute ischaemic stroke in adult patients. However, the low incidence of paediatric stroke makes the development of specific guidelines more challenging. This study aims to clarify the situation of these children in our region in order to establish a regional protocol to improve the care provided to these patients.

METHODS: We performed a regional incidence study of pediatric stroke (≤ 15 years of age) in Aragon, Spain (1308728 population, 15% aged ≤ 15 years) between 2008 and 2019. Data were obtained from hospital discharge records, including deaths, from the regional health service of Aragón, according to ICD codes for cerebrovascular disease. We analysed demographic, clinical, diagnostic/therapeutic, and prognostic variables.

RESULTS: A total of 21 events were recorded: 8 ischaemic (38.1%) and 13 haemorrhagic strokes (61.9%). The mean age (SD) was 9.3 years (1.0). The sample included 12 boys and nine girls. No statistically significant differences were found between ischaemic and haemorrhagic strokes, except in the chief complaint (language and motor impairment in ischaemic stroke and headache in haemorrhagic stroke). None of the patients with ischaemic stroke received reperfusion therapies. Including the 3 patients who died during hospitalisation, eight patients (42.1%) had modified Rankin Scale scores > 2 at 12 months. Motor deficits were the most common sequela (n=9).

CONCLUSION: Though infrequent, paediatric stroke has an important functional impact. In Spain, Madrid was the first region to adapt the existing code stroke care networks for adult patients. In Aragon, this review has enabled us to work closely with the different stakeholders to offer a care plan for acute paediatric ischaemic stroke. Nevertheless, prospective national registries would be valuable to continue improving the care provided to these patients.

PMID:35691906 | DOI:10.1016/j.nrleng.2021.10.004

Acad Radiol. 2022 Jun 9:S1076-6332(22)00313-0. doi: 10.1016/j.acra.2022.05.011. Online ahead of print.

ABSTRACT

RATIONALE AND OBJECTIVES: To assess the effects of a change from free text reporting to structured reporting on resident reports, the proofreading workload and report turnaround times in the neuroradiology daily routine.

MATERIALS AND METHODS: Our neuroradiology section introduced structured reporting templates in July 2019. Reports dictated by residents during dayshifts from January 2019 to March 2020 were retrospectively assessed using quantitative parameters from report comparison. Through automatic analysis of text-string differences between report states (i.e. draft, preliminary and final report), Jaccard similarities and edit distances of reports following read-out sessions as well as after report sign-off were calculated. Furthermore, turnaround times until preliminary and final report availability to clinicians were investigated. Parameters were visualized as trending line graphs and statistically compared between reporting standards.

RESULTS: Three thousand five hundred thirty-eight reports were included into analysis. Mean Jaccard similarity of resident drafts and staff-reviewed final reports increased from 0.53 ± 0.37 to 0.79 ± 0.22 after the introduction of structured reporting (p < .001). Both mean overall edits on draft reports by residents following read-out sessions (0.30 ± 0.45 vs. 0.09 ± 0.29; p < .001) and by staff radiologists during report sign-off (0.17 ± 0.28 vs. 0.12 ± 0.23, p < .001) decreased. With structured reporting, mean turnaround time until preliminary report availability to clinicians decreased by 20.7 minutes (246.9 ± 207.0 vs. 226.2 ± 224.9; p < .001). Similarly, final reports were available 35.0 minutes faster on average (558.05 ± 15.1 vs. 523.0 ± 497.3; p = .002).

CONCLUSION: Structured reporting is beneficial in the neuroradiology daily routine, as resident drafts require fewer edits in the report review process. This reduction in proofreading workload is likely responsible for lower report turnaround times.

PMID:35691879 | DOI:10.1016/j.acra.2022.05.011

Vaccine. 2022 Jun 9:S0264-410X(22)00476-5. doi: 10.1016/j.vaccine.2022.04.048. Online ahead of print.

ABSTRACT

BACKGROUND: Influenza outbreaks in aged care facilities are a major public health concern. In response to the severe 2017 influenza season in Australia, enhanced influenza vaccines were introduced from 2018 onwards for those over 65 and more emphasis was placed on improving vaccination rates among aged care staff. During the COVID-19 pandemic, these efforts were then further escalated to reduce the additional burden that influenza could pose to facilities.

METHODS: An observational epidemiological study was conducted from 2018 to 2020 in nine Sydney (Australia) aged care facilities of the same provider. De-identified vaccination data and physical layout data were collected from participating facility managers from 2018 to 2020. Active surveillance of influenza-like illness was carried out from 2018 to 2020 influenza seasons. Correlation and Poisson regression analyses were carried out to explore the relationship between physical layout variables to occurrence of influenza cases.

RESULTS: Influenza cases were low in 2018 and 2019, and there were no confirmed influenza cases identified in 2020. Vaccination rates increased among staff by 50.5% and residents by 16.8% over the three-year period of surveillance from 2018 to 2020. For each unit increase in total number of beds, common areas, single rooms, all types of rooms (including double occupancy rooms), the influenza cases increased by 1.02 (95% confidence interval:1.018-1.025), 1.04 (95% confidence interval: 1.019-1.073), 1.03 (95% confidence interval: 1.016-1 0.038) and 1.02 (95% confidence interval:1.005-1.026) times which were found to be statistically significant. For each unit increase in the proportion of shared rooms, influenza cases increased by 1.004 (95% confidence interval:1.0001-1.207) which was found to be statistically significant.

CONCLUSIONS: There is a relationship between influenza case counts and aspects of the physical layout such as facility size, and this should be considered in assessing risk of outbreaks in aged care facilities. Increased vaccination rates in staff and COVID-19 prevention and control measures may have eliminated influenza in the studied facilities in 2020.

PMID:35691870 | DOI:10.1016/j.vaccine.2022.04.048

J Cardiothorac Vasc Anesth. 2022 May 13:S1053-0770(22)00337-8. doi: 10.1053/j.jvca.2022.05.012. Online ahead of print.

ABSTRACT

OBJECTIVE: To evaluate the effect of anticoagulation targets and intensity on bleeding events, thrombotic events, and transfusion requirements in patients with acute respiratory distress syndrome (ARDS) receiving venovenous extracorporeal membrane oxygenation (ECMO) and continuous-infusion heparin.

DESIGN: A retrospective cohort study.

SETTING: At a single-center, large academic medical center.

PARTICIPANTS: One hundred thirty-six critically ill patients.

INTERVENTIONS: The following three therapeutic targets were implemented over time and evaluated: (1) no protocol (September 2013-August 2016): no standardized anticoagulation protocol or transfusion thresholds; (2) <50 seconds (September 2016-January 2018): standardized activated partial thromboplastin time (aPTT) goal of <50 seconds, maximum heparin infusion rate of 1,200 units/h, transfusion threshold of hemoglobin (Hgb) <8 g/dL; and (3) 40-to-50 seconds (February 2018-December 2019): aPTT goal of 40-to-50 sec, no maximum heparin infusion rate, transfusion threshold of Hgb <7 g/dL.

MEASUREMENTS AND MAIN RESULTS: Continuous variables were compared using the Kruskal-Wallis test, and categorical variables were compared using Fisher exact tests. The primary endpoint, an incidence of at least 1 bleeding event, was highest in the no-protocol group though not statistically different among groups (39.3% v 26.7% v 34%, p = 0.5). Thrombotic complications were similar. The median units of packed red blood cells transfused were highest in the no-protocol group (3 v 2 v 0.5, p < 0.001).

CONCLUSION: Anticoagulation protocols standardizing aPTT goals to <50 or 40-to-50 seconds may be a reasonable strategy for patients receiving venovenous ECMO for ARDS. More restrictive hemoglobin transfusion thresholds, in combination with lower aPTT targets, may be associated with a reduction in transfusion requirements.

PMID:35691853 | DOI:10.1053/j.jvca.2022.05.012

Can J Urol. 2022 Jun;29(3):11175-11181.

ABSTRACT

INTRODUCTION: Bladder spasm are common complications following cystoscopic urologic procedures. This study aims to determine the incidence and risk factors for bladder spasm after ambulatory cystoscopic urologic procedures.

MATERIALS AND METHODS: Medical records of adult patients who underwent urologic procedures in our ambulatory center from May 1st, 2018 through December 30th, 2020, were reviewed. Bladder spasm was identified from the administration of antispasmodic therapy (e.g. oxybutynin) during anesthesia recovery. Multivariable analyses were performed to assess the association between bladder spasm and clinical factors.

RESULTS: Included were 2,671 patients, of which 917 (34.3%) developed postoperative bladder spasm, yielding an incidence of 343 (95%CI 325-361) per 1,000 procedures. Risk factors associated with bladder spasm were younger adult age (< 60 years), longer (> 45 minutes) and more complex procedures. Compared to cystoscopy the risk of spasm following transurethral resection of the bladder tumor was OR 4.35 (95%CI 3.22, 5.87) and for transurethral resection of the prostate OR 3.25 (95% CI 2.24, 4.71). Spasm prophylaxis with belladonna and opium suppositories (B&O) was used in 1,158 patients and 384 (33.2%) developed spasms. The use of B&O was not associated with reduction of bladder spasm, OR 0.91 (95%CI 0.75, 1.1, p = 0.318). Postoperative outcomes did not differ between patients who did or did not develop spasms.

CONCLUSION: Bladder spasms are common following ambulatory urologic procedures, more so with more extensive procedures. Prophylaxis with B&O was not significantly associated with a lower rate of bladder spasms.

PMID:35691040

Acta Biochim Pol. 2022 Jun 12. doi: 10.18388/abp.2020_5816. Online ahead of print.

ABSTRACT

BACKGROUND: Primary gastrointestinal diffuse large B-cell lymphoma (PGI-DLBCL) lacks specific clinical manifestations and its malignancy renders prognostication and choice of treatment strategy difficult. The aim of this study was to evaluate microRNA (miR)-21 as potential non-invasive biomarkers for prognosis in PGI-DLBCL patients.

METHODS: Serum miR-21 expression in de novo PGI-DLBCL patients, consecutively enrolled for this study, was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Relative expression was calculated using the comparative Ct method. Statistical significance was determined using the Mann-Whitney rank sum and Fisher’s exact test. Survival analysis was conducted using the Kaplan-Meier method.

RESULTS: Compared with healthy controls, serum miR-21 levels were significantly elevated in the PGI-DLBCL patients (n=156). The high expression level of serum miR-21 at diagnosis was associated with worse progression-free survival (PFS) (30 (9-42) vs 42 (12-52) months in high and low miR-21 groups) and overall survival (OS) (35 (15-52) vs 48 (17-61) months in high and low miR-21 groups) and was an independent risk factor for PFS and OS (hazard ratios 4.345 and 3.311, respectively). Furthermore, Bcl-2, Bcl-6 and Ki-67 were independently and positively associated with miR-21 expression.

CONCLUSIONS: Our results suggest that miR-21 is a potential prognostic marker to predict clinical outcomes in PGI-DLBCL patients and a high miR-21 level is associated with poor outcomes.

PMID:35691029 | DOI:10.18388/abp.2020_5816

JNMA J Nepal Med Assoc. 2022 Jun 1;60(250):521-524. doi: 10.31729/jnma.7217.

ABSTRACT

INTRODUCTION: Neural adaptation to physical training allows a person to better coordinate the activation of all relevant muscles producing maximum force. Nerve conduction velocity measures the speed of impulse along the motor neuron and is strongly associated with muscle contraction time. This study aimed to find out the mean motor nerve conduction velocity of the right ulnar nerve among physically trained adult males in a tertiary care centre.

METHODS: This descriptive cross-sectional study was conducted in the Neurophysiology Laboratory of a tertiary care centre from 3rd November, 2019 to 2nd November, 2020. Thirty young adult males who were engaged in the physical training at a training centre for more than 3 months were studied after receiving ethical approval from the Institutional Review Committee (Reference number: 1578/019). Motor nerve conduction parameters of the right ulnar nerve were measured and data were entered in Microsoft Excel. Statistical analysis was done using the Statistical Packages for the Social Sciences version 25.0. Point estimate at 95% Confidence Interval was calculated along with frequency and percentages for binary data, and mean and standard deviation for continuous data.

RESULTS: Among 30 males studied, the mean motor nerve conduction velocity of the ulnar nerve was found to be 61.02±5.86 m/sec (58.92-63.11 at 95% Confidence Interval). The mean distal latency and amplitude of the muscle action potential were 2.33±0.53 ms and 8.08±1.17 mv respectively.

CONCLUSIONS: Our study found that the mean nerve conduction velocity of the ulnar nerve was similar when compared to studies conducted in similar settings.

KEYWORDS: Nepal; nerve conduction; ulnar nerve.

PMID:35690989 | DOI:10.31729/jnma.7217