Tag: statistics

Sci Prog. 2021 Jul-Sep;104(3):368504211028371. doi: 10.1177/00368504211028371.

ABSTRACT

Bayesian Nonparametric (BNP) modelling can be used to obtain more detailed information in test equating studies and to increase the accuracy of equating by accounting for covariates. In this study, two covariates are included in the equating under the Bayes nonparametric model, one is continuous, and the other is discrete. Scores equated with this model were obtained for a single group design for a small group in the study. The equated scores obtained with the model were compared with the mean and linear equating methods in the Classical Test Theory. Considering the equated scores obtained from three different methods, it was found that the equated scores obtained with the BNP model produced a distribution closer to the target test. Even the classical methods will give a good result with the smallest error when using a small sample, making equating studies valuable. The inclusion of the covariates in the model in the classical test equating process is based on some assumptions and cannot be achieved especially using small groups. The BNP model will be more beneficial than using frequentist methods, regardless of this limitation. Information about booklets and variables can be obtained from the distributors and equated scores that obtained with the BNP model. In this case, it makes it possible to compare sub-categories. This can be expressed as indicating the presence of differential item functioning (DIF). Therefore, the BNP model can be used actively in test equating studies, and it provides an opportunity to examine the characteristics of the individual participants at the same time. Thus, it allows test equating even in a small sample and offers the opportunity to reach a value closer to the scores in the target test.

PMID:34236901 | DOI:10.1177/00368504211028371

J Refract Surg. 2021 Jul;37(7):466-471. doi: 10.3928/1081597X-20210406-01. Epub 2021 Jul 1.

ABSTRACT

PURPOSE: To assess the incidence and risk factors of Descemet membrane detachment due to laser application in femtosecond laser-assisted cataract surgery (FLACS).

METHODS: In this retrospective case series, all patients who underwent FLACS with the LenSx system (Alcon Laboratories, Inc) were eligible to participate. The medical records were reviewed to collect data regarding potential risk factors related to Descemet membrane detachment, including patients’ demographics, laser parameters, and ocular measurements. The eyes were separated into two groups based on the clinical diagnosis of Descemet membrane detachment as the femto-second laser was performing the corneal incisions.

RESULTS: Five hundred ten eyes (304 patients) were included. Descemet membrane detachment occurred in 20 (3.9%) eyes of 16 (5.3%) patients. Four (1.3%) patients had a detachment in both eyes. In 16 (3.1%) eyes, the Descemet membrane detachment occurred in the secondary incision site. The eyes that had a detachment had a statistically lower mean endothelial cell density (2,193.40 ± 313.37 versus 2,385.08 ± 357.80 cells/ mm²; P = .019), and a statistically higher prevalence of corneal guttata (25.0% versus 8.8%; P = .015). None of the other analyzed variables statistically differed between the groups (P > .05). The risk of having Descemet membrane detachment was statistically higher among eyes with guttata (odds ratio = 3.47; P = .015) and in those with an endothelial cell density of less than 2,000 cells/mm² (odds ratio = 3.26; P = .014).

CONCLUSIONS: The incidence of Descemet membrane detachment due to laser application in FLACS was 3.9%, with the associated risk factors being endothelial cell density of less than 2,000 cells/mm² and corneal guttata. [J Refract Surg. 2021;37(7):466-471.].

PMID:34236908 | DOI:10.3928/1081597X-20210406-01

J Refract Surg. 2021 Jul;37(7):472-476. doi: 10.3928/1081597X-20210401-01. Epub 2021 Jul 1.

ABSTRACT

PURPOSE: To evaluate the refractive outcomes of the new Carlevale foldable sutureless scleral fixation intraocular lens (SSF-IOL) (Soleko in eyes without capsular support.

METHODS: This retrospective, single-center, noncomparative interventional case series included 25 consecutive eyes of 25 consecutive patients with either aphakia or lens/IOL dislocation due to capsular or zonular defects. The Hoffer Q, Holladay 1, and SRK/T formulas, which do not need measurements of the anterior chamber depth to predict the IOL position, were used to calculate the IOL power. Constant optimization was performed to zero out the mean prediction error (PE). The main outcome measures were mean PE ± standard deviation, median absolute error (MedAE), mean absolute error (MAE), and percentage of eyes with a PE within ±0.50 and ±1.00 diopters (D).

RESULTS: Mean axial length was 24.09 ± 2.09 mm (range: 21.85 to 32.17 mm). No statistically significant differences were found among the three formulas for any parameter. The PE was zero due to constant optimization and its standard deviation ranged between 0.89 and 0.95 D. The MedAE ranged between 0.30 and 0.34 D, whereas the MAE ranged between 0.62 and 0.67 D. The percentage of eyes with a PE within ±0.50 D was between 56% and 64% and the percentage of eyes with a PE within ±1.00 D was between 69% and 72%.

CONCLUSIONS: Reasonably good refractive outcomes can be obtained when implanting SSF-IOLs in eyes with no capsular support, although the accuracy is lower than what is reported for normal in-the-bag IOL implantation. [J Refract Surg. 2021;37(7):472-476.].

PMID:34236911 | DOI:10.3928/1081597X-20210401-01

J Proteome Res. 2021 Jul 8. doi: 10.1021/acs.jproteome.1c00483. Online ahead of print.

ABSTRACT

The standard proteomics database search strategy involves searching spectra against a peptide database and estimating the false discovery rate (FDR) of the resulting set of peptide-spectrum matches. One assumption of this protocol is that all the peptides in the database are relevant to the hypothesis being investigated. However, in settings where researchers are interested in a subset of peptides, alternative search and FDR control strategies are needed. Recently, two methods were proposed to address this problem: subset-search and all-sub. We show that both methods fail to control the FDR. For subset-search, this failure is due to the presence of “neighbor” peptides, which are defined as irrelevant peptides with a similar precursor mass and fragmentation spectrum as a relevant peptide. Not considering neighbors compromises the FDR estimate because a spectrum generated by an irrelevant peptide can incorrectly match well to a relevant peptide. Therefore, we have developed a new method, “subset-neighbor search” (SNS), that accounts for neighbor peptides. We show evidence that SNS controls the FDR when neighbors are present and that SNS outperforms group-FDR, the only other method that appears to control the FDR relative to a subset of relevant peptides.

PMID:34236864 | DOI:10.1021/acs.jproteome.1c00483

Am J Sports Med. 2021 Jul 8:3635465211024249. doi: 10.1177/03635465211024249. Online ahead of print.

ABSTRACT

BACKGROUND: Recently developed multivariate sex-specific statistical models can predict anterior cruciate ligament (ACL) injury risk using various knee anatomic factors. However, screening tools able to identify individuals at an increased injury risk are unlikely to be developed based on these models, given that sophisticated and time-consuming methods were used to measure those factors on research-grade resolution magnetic resonance images (MRIs).

PURPOSE: To determine whether simpler methods, amenable to using clinical-grade resolution MRIs, can identify the same knee anatomic factors previously found to contribute to ACL injury risk using sophisticated methods and research-grade resolution images.

STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2.

METHODS: High-resolution 3-dimensional MRIs previously acquired from 87 patients with primary, noncontact, grade III ACL injury and 87 uninjured matched control participants for a series of published studies were downgraded to clinical-grade resolution images. The 4 knee anatomic factors found to contribute to ACL injury risk in women and in men in these published studies-femoral intercondylar notch width at the anterior outlet of the ACL (NW_O), posterior-inferior directed slope of the middle region articular cartilage surface of the tibial plateau’s lateral compartment (L_atT_ibMCS), ACL volume, and tibial plateau’s lateral compartment posterior meniscus to subchondral bone wedge angle (L_atT_ibMBA)-were measured using clinical-grade resolution MRI-based methods. Stepwise multivariate conditional logistic regressions were used to identify the combinations of factors most highly associated with an ACL injury risk in women and men separately.

RESULTS: The multivariate model that best predicted ACL injury risk in the female participants included the L_atT_ibMCS and the NW_O. For the male participants, this model included the ACL volume and the L_atT_ibMBA. These results corroborate the previously published results that reported models with the same knee anatomic factors to best predict injury risk in this group of young women and men.

CONCLUSION: Simpler methods using MRIs downgraded to a clinical-grade resolution can identify the same knee anatomic factors previously found to significantly contribute to ACL injury risk using sophisticated methods and research-grade resolution MRIs.

PMID:34236896 | DOI:10.1177/03635465211024249

Braz J Cardiovasc Surg. 2021 Jul 7. doi: 10.21470/1678-9741-2020-0542. Online ahead of print.

ABSTRACT

INTRODUCTION: In this study, we aimed to investigate the relationship between postoperative mortality, morbidity, hospital stay and development of postoperative complications with the glycosylated hemoglobin (HbA1c) level and low left ventricular ejection fraction (LVEF) in diabetic and non-diabetic patients who underwent elective coronary artery bypass (CABG) surgery.

METHODS: The medical records of patients who underwent CABG at our clinic between January 2015 and December 2019 were retrospectively analyzed. All patients were divided into two groups according to their diabetes mellitus (DM) diagnosis. Diabetic patients were also divided into two groups according to their HbA1c levels. The HbA1c threshold value was 7%. All patients were divided into two groups in terms of LVEF. The LVEF threshold value was 40%.

RESULTS: We analyzed 393 patients, of which 304 (77.4%) were male and 177 (45.04%) patients were diabetic. For lower LVEF and HbA1c values, we found no relationship between postoperative mortality, prolonged intensive care unit (ICU) stay and development of postoperative complications. Deep surgical site infection (DSSI) was found to be more common in diabetic patients who had a higher HbA1c value. Length of hospital stay was longer in diabetic patients with HbA1c levels <7%.

CONCLUSION: No statistically significant relationship was found between LVEF and HbA1c levels and postoperative mortality, prolonged ICU stay and postoperative complications.

PMID:34236819 | DOI:10.21470/1678-9741-2020-0542

Braz J Cardiovasc Surg. 2021 Jul 7. doi: 10.21470/1678-9741-2020-0618. Online ahead of print.

ABSTRACT

INTRODUCTION: Coronary artery ectasia (CAE) is one of the uncommon cardiovascular disorders and its prognosis is still debated.

OBJECTIVE: We aimed to review long-term follow-up data in patients with CAE and to evaluate the prognosis of CAE patients with coronary slow flow phenomenon (CSFP).

METHODS: This study had a prospective design and 143 patients with CAE were included. The angiographic and demographic characteristics were reviewed in detail. The patients were categorized, based on concomitant coronary artery stenosis detected by angiography, as CCAE group (n=87, ≥30% luminal stenosis) and ICAE group (n=56, <30% luminal stenosis) and also categorized by the coronary flow as CSFP group (n=51) and normal flow coronary ectasia – NCEA group (n=92). All patients were re-evaluated at 6-month intervals. Followup data, cardiovascular (CV) mortality, hospitalization and major adverse cardiac events (MACE) were collected. The level of statistical significance was set at 5%.

RESULTS: Patients were followed up for an average of 56.9±7.4 months. During the follow-up, statistically significant differences were found in hospitalization, CV mortality and MACE between the CCAE and ICAE groups (P=0.038, P=0.003, P=0.001, respectively). The CSFP and NCEA groups were also compared. There was a statistical difference with respect to hospitalization between the CFSP and NCEA groups (P=0.001), but no difference was observed in terms of MACE and CV mortality (P=0.793 and P=0.279).

CONCLUSION: CSFP accompanying CAE may be a predictor of hospitalization. Significant atherosclerotic plaques coexisting with CAE may be predictive for MACE.

PMID:34236824 | DOI:10.21470/1678-9741-2020-0618

Cancer Rep (Hoboken). 2021 Jul 8:e1490. doi: 10.1002/cnr2.1490. Online ahead of print.

ABSTRACT

BACKGROUND: There is strong evidence supporting the efficacy of exercise oncology programs to improve physical and psychosocial outcomes during active treatment. However, there is a paucity of evidence on the effect of exercise on healthcare utilization and cost analyzes of exercise oncology programs.

AIMS: Our objective was to assess the effects of a pragmatic exercise oncology program (ENACT) during active chemotherapy treatment on healthcare utilization and associated costs.

METHODS: We conducted post-hoc analyzes on 160 ENACT participants and 75 comparison participants matched on cancer site, stage, age range, and gender. We obtained complete healthcare utilization histories for each patient (specific to emergency department [ED] visits and hospital admissions) coinciding with their participation in ENACT. A sub-analysis was conducted for advanced stage breast, gastrointestinal, and pancreatic cancer patients.

RESULTS: Healthcare costs for patients who participated in the ENACT exercise oncology intervention were numerically lower than healthcare costs for the comparison group, even after accounting for the cost of the intervention. However, the differences were not statistically significant.

CONCLUSION: Our findings suggest that an exercise oncology program during active chemotherapy treatment are at least cost neutral for all cancer patients, including advanced stage cancers. Additional research is warranted to evaluate the potential for exercise oncology programs to reduce healthcare utilization, particularly in advanced cancer patients.

PMID:34236137 | DOI:10.1002/cnr2.1490

Int J Clin Pract. 2021 Jul 8:e14497. doi: 10.1111/ijcp.14497. Online ahead of print.

ABSTRACT

INTRODUCTION: The present study aimed to investigate the contribution of cone-beam computed tomography (CBCT) to the diagnosis of obstructive sleep apnoea syndrome (OSAS).

METHODS: The present study investigate the relationships among body mass index (BMI), upper airway, septum deviation, nasal cavity width, airway, and the hard and soft palate width using CBCT images of 64 patients obtained in Uşak University Faculty of Dentistry. The study included 31 (8 female and 23 male; mean age: 52.52 ± 10.01 years) and 33 patients (12 female and 21 male; mean age: 47.39 ± 10.27 years) with and without OSAS, respectively. Between-group comparisons of non-normally and normally distributed variables were performed using the Mann-Whitney U test and Student’s t-test, respectively. Spearman’s correlation analysis was used to determine the relationship between quantitative data. Statistical significance was evaluated at P < .01 and P < .05.

RESULTS: There were significant differences between groups in the BMI, nasal septum position, hard and soft palate width, maxillary skeletal width, and palatal alveolar angle (P < .01). In addition it was also found that BMI was higher, the nasopharyngeal airway was longer, and the soft palate was longer and wider in males. (P = .001; P < .01).

CONCLUSION: This study concluded that patients with OSAS had marked narrowing of the upper airway, nasal cavity and maxillary width, shortening and enlargement of the soft palate, and marked increase in BMI. However, to gather sufficiently reliable data for routine use in orthodontic analyses, there is a need for greater number of samples to improve the database.

PMID:34236117 | DOI:10.1111/ijcp.14497

J Magn Reson Imaging. 2021 Jul 8. doi: 10.1002/jmri.27824. Online ahead of print.

ABSTRACT

BACKGROUND: The Liver Imaging Reporting and Data System (LI-RADS) is widely accepted as a reliable diagnostic scheme for hepatocellular carcinoma (HCC) in at-risk patients. However, its application is hampered by substantial complexity and suboptimal diagnostic sensitivity.

PURPOSE: To propose data-driven modifications to the LI-RADS version 2018 (v2018) major feature system (rLI-RADS) on gadoxetate disodium (EOB)-enhanced magnetic resonance imaging (MRI) to improve sensitivity and simplicity while maintaining high positive predictive value (PPV) for detecting HCC.

STUDY TYPE: Retrospective.

POPULATION: Two hundred and twenty-four consecutive at-risk patients (training dataset: 169, independent testing dataset: 55) with 742 LR-3 to LR-5 liver observations (HCC: N = 498 [67%]) were analyzed from a prospective observational registry collected between July 2015 and September 2018.

FIELD STRENGTH/SEQUENCE: 3.0 T/T2-weighted fast spin-echo, diffusion-weighted spin-echo based echo-planar and three-dimensional (3D) T1-weighted gradient echo sequences.

ASSESSMENT: All images were evaluated by three independent abdominal radiologists who were blinded to all clinical, pathological, and follow-up information. Composite reference standards of either histopathology or imaging follow-up were used.

STATISTICAL TESTS: In the training dataset, LI-RADS v2018 major features were used to develop rLI-RADS based on their associated PPV for HCC. In an independent testing set, diagnostic performances of LI-RADS v2018 and rLI-RADS were computed using a generalized estimating equation model and compared with McNemar’s test. A P value <0.05 was considered statistically significant.

RESULTS: The median (interquartile range) size of liver observations was 13 mm (7-27 mm). The diagnostic table for rLI-RADS encompassed 9 cells, as opposed to 16 cells for LI-RADS v2018. In the testing set, compared to LI-RADS v2018, rLI-RADS category 5 demonstrated a significantly superior sensitivity (76% vs. 61%) while maintaining comparably high PPV (92.5% vs. 94.1%, P = 0.126).

DATA CONCLUSION: Compared with LI-RADS v2018, rLI-RADS demonstrated improved simplicity and significantly superior diagnostic sensitivity for HCC in at-risk patients.

LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 2.

PMID:34236120 | DOI:10.1002/jmri.27824