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Nevin Manimala Statistics

Cerebrovascular Reactivity Mapping Using Resting-State Functional MRI in Patients With Gliomas

J Magn Reson Imaging. 2022 Apr 9. doi: 10.1002/jmri.28194. Online ahead of print.

ABSTRACT

BACKGROUND: Recently, a data-driven regression analysis method was developed to utilize the resting-state (rs) blood oxygenation level-dependent signal for cerebrovascular reactivity (CVR) mapping (rs-CVR), which was previously optimized by comparing with the CO2 inhalation-based method in health subjects and patients with neurovascular diseases.

PURPOSE: To investigate the agreement of rs-CVR and the CVR mapping with breath-hold MRI (bh-CVR) in patients with gliomas.

STUDY TYPE: Retrospective.

POPULATION: Twenty-five patients (12 males, 13 females; mean age ± SD, 48 ± 13 years) with gliomas.

FIELD STRENGTH/SEQUENCE: Dynamic T2*-weighted gradient-echo echo-planar imaging during a breath-hold paradigm and during the rs on a 3-T scanner.

ASSESSMENT: rs-CVR with various frequency ranges and resting-state fluctuation amplitude (RSFA) were assessed. The agreement between each rs-based CVR measurement and bh-CVR was determined by voxel-wise correlation and Dice coefficient in the whole brain, gray matter, and the lesion region of interest (ROI).

STATISTICAL TESTS: Voxel-wise Pearson correlation, Dice coefficient, Fisher Z-transformation, repeated-measure analysis of variance and post hoc test with Bonferroni correction, and nonparametric repeated-measure Friedman test and post hoc test with Bonferroni correction were used. Significance was set at P < 0.05.

RESULTS: Compared with bh-CVR, the highest correlations were found at the frequency bands of 0.04-0.08 Hz and 0.02-0.04 Hz for rs-CVR in both whole brain and the lesion ROI. RSFA had significantly lower correlations than did rs-CVR of 0.02-0.04 Hz and a wider frequency range (0-0.1164 Hz). Significantly higher correlations and Dice coefficient were found in normal tissues than in the lesion ROI for all three methods.

DATA CONCLUSION: The optimal frequency ranges for rs-CVR are determined by comparing with bh-CVR in patients with gliomas. The rs-CVR method outperformed the RSFA. Significantly higher correlation and Dice coefficient between rs- and bh-CVR were found in normal tissue than in the lesion.

LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 2.

PMID:35396789 | DOI:10.1002/jmri.28194

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Nevin Manimala Statistics

Investigation of the Inter- and Intrascanner Reproducibility and Repeatability of Radiomics Features in T1-Weighted Brain MRI

J Magn Reson Imaging. 2022 Apr 9. doi: 10.1002/jmri.28191. Online ahead of print.

ABSTRACT

BACKGROUND: Radiomics is the high throughput analysis of medical images using computer algorithms, which specifically assess textural features. It has increasingly been proposed as a tool for the development of imaging biomarkers. However, an important acknowledged limitation of radiomics is the lack of reproducibility of features produced.

PURPOSE: To assess reproducibility and repeatability of radiomics variables in brain MRI through a multivisit, multicenter study.

STUDY TYPE: Retrospective.

POPULATION: Fourteen individuals visiting three institutions twice, 10 males with the mean age of 36.3 years and age range 25-51.

FIELD STRENGTH: 3D T1W inversion recovery on three 1.5-T General Electric scanners.

ASSESSMENT: Radiomics analysis by a consultant radiologist performed on the T1W images of the whole brain on all visits. All possible radiomics features were generated.

STATISTICAL TEST: Concordance correlation coefficient (CCC) and dynamic range (DR) for all variables were calculated to assess the test-retest repeatability. Intraclass correlation coefficients (ICCs) were calculated to investigate the reproducibility of features across centers.

RESULTS: Of 1596 features generated, 57 from center 1, 15 from center 2, and 22 from center 3 had a CCC > 0.9 and DR > 0.9. Eight variables had CCC > 0.9 and DR > 0.9 in all centers. Forty-one variables had an ICC of >0.9. No variables had CCC > 0.9, DR > 0.9, and ICC > 0.9.

DATA CONCLUSION: Repeatability and reproducibility of variables is a significant limitation of radiomics analysis in 3DT1W brain MRI. Careful selection of radiomic features is required.

LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY STAGE: 2.

PMID:35396777 | DOI:10.1002/jmri.28191

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Nevin Manimala Statistics

Vitamin D Supplementation for Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis

J Gastroenterol Hepatol. 2022 Apr 8. doi: 10.1111/jgh.15852. Online ahead of print.

ABSTRACT

BACKGROUND AND AIM: Irritable bowel syndrome (IBS) is a prevalent and complex gastrointestinal disorder characterized by chronic abdominal pain and altered bowel habits. Observational studies have suggested a relationship between serum Vitamin D levels and IBS symptoms. This systematic review and meta-analysis aimed to investigate the clinical effects of Vitamin D supplementation on IBS symptom severity and quality of life measures.

METHODS: Medline, Embase, Scopus, Web of Science, and The Cochrane Library databases were systematically searched. Data abstraction and quality assessment were conducted by four authors independently and discrepancies were resolved through consensus from the senior author. Continuous data were pooled with standardized mean difference (SMD) using the DerSimonian and Laird’s random-effects model. Sensitivity analysis by risk of bias and potentially ‘predatory’ publication were performed as well RESULTS: A total of 685 patients across eight studies were included in the meta-analysis. Vitamin D supplementation significantly improved IBS Symptom Severity Scale (IBS-SSS) scores, with a SMD of -0.77 (95% CI -1.47 to -0.07, p = 0.04, I2 = 91%). Improvements in IBS-QOL scores were also observed, albeit not statistically significant (SMD 0.54; 95% CI -0.34 to 1.41, p = 0.15, I2 = 87%). However, small sample sizes, a relatively young study population, limited ethnicities and varied Vitamin D dosing strategies across the studies were notable limitations.

CONCLUSIONS: Vitamin D supplementation could be part of our clinical armamentarium when managing IBS patients due to the potential efficacy and good safety profile. Further randomized, controlled trials are required to confirm the therapeutic effects.

PMID:35396764 | DOI:10.1111/jgh.15852

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Nevin Manimala Statistics

How large should the next study be? Predictive power and sample size requirements for replication studies

Stat Med. 2022 Apr 8. doi: 10.1002/sim.9406. Online ahead of print.

ABSTRACT

We use information derived from over 40K trials in the Cochrane Collaboration database of systematic reviews (CDSR) to compute the replication probability, or predictive power of an experiment given its observed (two-sided) P$$ P $$ -value. We find that an exact replication of a marginally significant result with P=.05$$ P=.05 $$ has less than 30% chance of again reaching significance. Moreover, the replication of a result with P=.005$$ P=.005 $$ still has only 50% chance of significance. We also compute the probability that the direction (sign) of the estimated effect is correct, which is closely related to the type S error of Gelman and Tuerlinckx. We find that if an estimated effect has P=.05$$ P=.05 $$ , there is a 93% probability that its sign is correct. If P=.005$$ P=.005 $$ , then that probability is 99%. Finally, we compute the required sample size for a replication study to achieve some specified power conditional on the p$$ p $$ -value of the original study. We find that the replication of a result with P=.05$$ P=.05 $$ requires a sample size more than 16 times larger than the original study to achieve 80% power, while P=.005$$ P=.005 $$ requires at least 3.5 times larger sample size. These findings confirm that failure to replicate the statistical significance of a trial does not necessarily indicate that the original result was a fluke.

PMID:35396714 | DOI:10.1002/sim.9406

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Nevin Manimala Statistics

Prevalence and features of delirium in older patients admitted to rehabilitation facilities: a multicenter study

Aging Clin Exp Res. 2022 Apr 8. doi: 10.1007/s40520-022-02099-8. Online ahead of print.

ABSTRACT

BACKGROUND: Delirium is thought to be common across various settings of care; however, still little research has been conducted in rehabilitation.

AIM: We investigated the prevalence of delirium, its features and motor subtypes in older patients admitted to rehabilitation facilities during the three editions of the “Delirium Day project”.

METHODS: We conducted a cross-sectional study in which 1237 older patients (age ≥ 65 years old) admitted to 50 Italian rehabilitation wards during the three editions of the “Delirium Day project” (2015 to 2017) were included. Delirium was evaluated through the 4AT and its motor subtype with the Delirium Motor Subtype Scale.

RESULTS: Delirium was detected in 226 patients (18%), and the most recurrent motor subtype was mixed (37%), followed by hypoactive (26%), hyperactive (21%) and non-motor one (16%). In a multivariate Poisson regression model with robust variance, factors associated with delirium were: disability in basic (PR 1.48, 95%CI: 1.17-1.9, p value 0.001) and instrumental activities of daily living (PR 1.58, 95%CI: 1.08-2.32, p value 0.018), dementia (PR 2.10, 95%CI: 1.62-2.73, p value < 0.0001), typical antipsychotics (PR 1.47, 95%CI: 1.10-1.95, p value 0.008), antidepressants other than selective serotonin reuptake inhibitors (PR 1.3, 95%CI: 1.02-1.66, p value 0.035), and physical restraints (PR 2.37, 95%CI: 1.68-3.36, p value < 0.0001).

CONCLUSION: This multicenter study reports that 2 out 10 patients admitted to rehabilitations had delirium on the index day. Mixed delirium was the most prevalent subtype. Delirium was associated with unmodifiable (dementia, disability) and modifiable (physical restraints, medications) factors. Identification of these factors should prompt specific interventions aimed to prevent or mitigate delirium.

PMID:35396698 | DOI:10.1007/s40520-022-02099-8

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Nevin Manimala Statistics

Operating temperature prediction and comparison for rooftop PV arrays in coastal climates of India

Environ Sci Pollut Res Int. 2022 Apr 9. doi: 10.1007/s11356-022-20068-6. Online ahead of print.

ABSTRACT

This article predicts the operational temperature of a 1-MWp rooftop photovoltaic (PV) system installed on buildings of GITAM University, Andhra Pradesh, India, using various temperature models. In the process of photovoltaic conversion, the operating temperature plays a key role, where the module efficiency and output power of the PV module are linearly dependent on temperature. Various temperature models are presented in the literature with simplified working formulas to find the module temperature involving environment and PV system parameters. This study adopts four models NOCT (normal operating cell temperature), Fiaman, Scandia and arbitrary mounting model (AMM), to assess the power, module temperature of the photovoltaic plant and identify the best model to suit the present study location. Their precision is evaluated on a seasonal day (winter, summer, monsoon and autumn) from the measured data. It is observed that winter, summer, monsoon and autumn days have hourly average module temperatures of 45.4 °C, 48.1 °C, 48.2 °C and 45.3 °C, respectively. Results show the highest average DC voltage of 231.2 kW on a summer day with an hourly module temperature of 48.1 °C recorded. The slightest error values of 3.71% MBE, 5.8% NRMSE, 1.89% TS and 0.03% WMBE are noted with the arbitrary mounting temperature model. This study is helpful to validate that the AMM model is best suited for PV simulation in coastal regions.

PMID:35396686 | DOI:10.1007/s11356-022-20068-6

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Nevin Manimala Statistics

Allele frequencies and minor contributor match statistic convergence using simulated population replicates

Int J Legal Med. 2022 Apr 9. doi: 10.1007/s00414-022-02822-0. Online ahead of print.

ABSTRACT

Probabilistic genotyping permits a comparison of forensic evidence given hypotheses regarding the origin of observed short tandem repeat alleles in a mixed DNA profile. Using the publicly available R package forensim, it has been proposed that mixtures with non-contributors from low genetic diversity populations are more likely to be mistakenly identified as contributors to a mixture than non-contributors from high genetic diversity populations. We hypothesized that these observations are attributed to the unique distribution of alleles in the reference population and may not generalize to other samplings of the same population. We used forensim to simulate 200 US populations (50 each of self-reported African-American, Asian-American, European-American, and Hispanic descent). We compared likelihood ratios for 2400 mixtures to those derived from published data and identified stark differences. A minimum of ten population replicates were required to reduce observed differences relative to published data. Deviations from Hardy-Weinberg equilibrium and allele frequency distributions suggest that simulated populations should be sufficiently evaluated for expectations of population genetic parameters prior to use in DNA mixture modeling experiments. Overall, our findings support the utility of forensim and further describe its suitability to model population genetic parameters but suggest that a single population replicate (directly ascertained or simulated) may be insufficient to make conclusions about a given DNA mixture.

PMID:35396663 | DOI:10.1007/s00414-022-02822-0

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Nevin Manimala Statistics

Correction to: Lower low‑density lipoprotein cholesterol levels are associated with an increased risk of hematoma expansion and ensuing mortality in acute ICH patients

Neurol Sci. 2022 Apr 9. doi: 10.1007/s10072-022-06064-1. Online ahead of print.

NO ABSTRACT

PMID:35396638 | DOI:10.1007/s10072-022-06064-1

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Nevin Manimala Statistics

Perineal wound healing after abdominoperineal resection for rectal cancer: a retrospective cohort study

Int J Colorectal Dis. 2022 Apr 8. doi: 10.1007/s00384-022-04141-7. Online ahead of print.

ABSTRACT

PURPOSE: Delayed perineal wound healing is a common complication after abdominoperineal resection (APR) in rectal cancer. The primary aim of this study was to evaluate the number of patients with delayed wound healing after APR. Secondary aims were to identify risk factors, and describe treatment.

METHODS: Prospectively collected data from the Swedish Colorectal Cancer Registry (SCRCR) was used for retrospective analysis of APR performed at Skåne University Hospital Malmö between 2013 and 2018. Medical charts were retrospectively reviewed. Delayed healing was defined as non-healed perineal wound 30 days postoperatively. Patients undergoing extralevator APR requiring reconstruction were excluded. Statistical analysis was made using SPSS. Risk factors for impaired wound healing were analyzed using a multivariable model.

RESULTS: A total of 162 patients were included, of which 114 underwent standard APR (sAPR) and 48 patients intersphincteric APR (isAPR). In the total population, 69% (111/162) were male, with median age 71 (26-87). The overall healing rate was 52% (85/162); 44% (50/114) in sAPR vs 73% (35/48) in isAPR (P < 0.001). Risk factors for impaired healing after multivariable analysis were BMI > 30 (OR 7.0; CI 95% 1.8-26.2, P = 0.004), reoperation (OR 7.9; CI 95% 1.6-39.8, P = 0.013), neoadjuvant radiotherapy (OR 5.2; CI 95% 1.02-25.1, P = 0.047) and sAPR (OR 2.598; CI 95% 1.05-6.41, P = 0.038). Eight percent (13/162) required an intervention (Clavien-Dindo ≥ 3).

CONCLUSION: Delayed perineal wound healing is a frequent complication after APR but the majority could be treated conservatively. Several risk factors were identified. Further studies aiming at interventions reducing delayed perineal wound healing after APR are warranted.

PMID:35396618 | DOI:10.1007/s00384-022-04141-7

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Nevin Manimala Statistics

Impact of Gabapentin on PACU Length of Stay and Perioperative Intravenous Opioid Use for ERAS Hysterectomy Patients

J Med Syst. 2022 Apr 8;46(5):26. doi: 10.1007/s10916-022-01815-1.

ABSTRACT

We investigated the impact of preoperative gabapentin on perioperative intravenous opioid requirements and post anesthesia care unit length of stay (PACU LOS) for patients undergoing laparoscopic and vaginal hysterectomies within an Enhanced Recovery After Surgery (ERAS) pathway. A multidisciplinary team retrospectively examined 2,015 patients who underwent laparoscopic or vaginal hysterectomies between October 2016 and January 2020 at a single academic institution. The average PACU LOS was 168 min among patients who did not receive gabapentin vs. 180 min both among patients who received ≤ 300 mg of gabapentin and patients who received > 300 mg of gabapentin. After adjusting for demographics and medical comorbidities, PACU LOS for patients given ≤ 300 mg gabapentin was 6% longer (rate ratio (RR) = 1.06, 95% CI = 1.01-1.11) than for patients who were not given gabapentin, and for patients who received > 300 mg of gabapentin was 7% longer (RR = 1.07, 95%CI = 1.01-1.13) than for those who did not receive gabapentin. Patients who received ≤ 300 mg gabapentin received 9% less perioperative intravenous hydromorphone than patients who did not receive gabapentin (RR = 0.91, 95% CI = 0.86 – 0.97); patients who received > 300 mg of gabapentin received 12% less perioperative intravenous hydromorphone than patients who did not receive gabapentin (RR = 0.88, 95% CI = 0.82 – 0.95). These findings represent an absolute difference of 0.09 mg intravenous hydromorphone. There were no statistically significant differences in total intravenous fentanyl received. Preoperative gabapentin given as part of an ERAS pathway is associated with statistically but not clinically significant increases in PACU LOS and decreases in total perioperative intravenous opioid use.

PMID:35396607 | DOI:10.1007/s10916-022-01815-1