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Nevin Manimala Statistics

The Dental Researcher’s Guide to Data Analysis – Part 2

Int J Oral Maxillofac Implants. 2023 Oct 17;38(5):847-854. doi: 10.11607/jomi.10480.

ABSTRACT

It is important for dental researchers to have a general idea of the different types of data that can be collected from a study and the available statistical tools that can be used with such data. By knowing about what is available, researchers will have an informed idea of the types of studies that should be conducted, the data that should be collected, and the proper statistical methods for analyzing collected data. In the first part of this general overview of statistical methods, we walked through the various types of data that traditional statistical techniques, such as t tests and linear regression, can handle. In this second part, we explore more complex types of data that traditional statistical techniques are unable to handle. Specifically, we discuss longitudinal and time-to-event data because both occur frequently in dental studies and require special modeling techniques in order to analyze correctly. Using two different simulated dental datasets, the proper application of techniques such as repeated measures ANOVA, linear mixed modeling, generalized estimating equations, log-rank test, and Cox proportional hazards models are discussed and illustrated in depth.

PMID:37847827 | DOI:10.11607/jomi.10480

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Nevin Manimala Statistics

Preventable deaths involving falls in England and Wales, 2013-22: a systematic case series of coroners’ reports

Age Ageing. 2023 Oct 2;52(10):afad191. doi: 10.1093/ageing/afad191.

ABSTRACT

BACKGROUND: Falls in older people are common, leading to significant harm including death. Coroners have a duty to report cases where action should be taken to prevent future deaths, but dissemination of their findings remains poor.

OBJECTIVE: To identify preventable fall-related deaths, classify coroner concerns and explore organisational responses.

DESIGN: A retrospective systematic case series of coroners’ Prevention of Future Deaths (PFD) reports, from July 2013 (inception) to November 2022.

SETTING: England and Wales.

METHODS: Reproducible data collection methods were used to web-scrape and read PFD reports. Demographic information, coroner concerns and responses from organisations were extracted and descriptive statistics used to synthesise data.

RESULTS: Five hundred and twenty-seven PFDs (12.5% of PFDs) involved a fall that contributed to death. These deaths predominantly affected older people (median 82 years) in the community (72%), with subsequent death in hospital (70.8%). A high proportion of cases experienced fractures (51.6%), major bleeding (35.9%) or head injury (38.7%). Coroners frequently raised concerns regarding falls risks assessments (20.9%), failures in communication (20.3%) and documentation issues (17.5%). Only 56.7% of PFDs received a response from organisations to whom they were addressed. Organisations tended to produce new protocols (58.5%), improve training (44.6%) and commence audits (34.3%) in response to PFDs.

CONCLUSIONS: One in eight preventable deaths in England and Wales involved a fall. Addressing concerns raised by coroners should improve falls prevention and care following falls especially for older adults, but the poor response rate may indicate that lessons are not being learned. Wider dissemination of PFD findings may help reduce preventable fall-related deaths in the future.

PMID:37847796 | DOI:10.1093/ageing/afad191

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Nevin Manimala Statistics

Investigation of Microscopic Structure, Translucency Parameters, and Fracture Toughness of Two Pressable Lithium Disilicate Glass-Ceramic Materials

Int J Prosthodont. 2023 Oct 17;0(0):0. doi: 10.11607/ijp.8720. Online ahead of print.

ABSTRACT

PURPOSE: To investigate the microscopic structure and fracture toughness of two pressable glass-ceramics comprising GC Initial LiSi Press (LiSi) and IPS e.max Press (e.max) with different levels of translucency.

MATERIALS AND METHODS: Four groups of LiSi and e.max with medium opacity and high translucency levels were examined. The crystal morphology of acid-etched specimens was observed under a scanning electron microscope (SEM). Six specimens in each group were fabricated in square shape (12 mm ’12 mm ‘ 1.5 mm) to measure translucency parameters (TP) using a spectrophotometer. Ten bar-shaped specimens each group with dimension of 23 mm ‘ 2 mm ‘ 4 mm were determined the fracture toughness (KIc) by a surface crack in flexure (SCF) using a universal testing machine. One-way ANOVA and Scheffe post-hoc tests were used for statistical analysis.

RESULTS: LiSi showed fine dense crystals 1 – 1.5 µm in size, while e.max showed long rod-shaped crystals 3 – 4 µm in size. The TP values of all specimens were coincided with their translucency levels.There was no statistical difference in the KIc between different translucency for both ceramics (p<0.05). However, the KIc of e.max was significantly higher than that of LiSi at both translucency levels. As a result of larger and longer crystals in e.max, it could provide better crack deviation mechanism to resist the fracture.

CONCLUSION: Within the limitations of this study, the translucency levels of both lithium disilicate ceramics did not affect the fracture toughness of the materials. The fracture toughness of e.max was statistically higher than LiSi.

PMID:37847790 | DOI:10.11607/ijp.8720

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Nevin Manimala Statistics

Influence of different surface finishing protocols on the wear behavior of a lithium disilicate glass-ceramic

Int J Prosthodont. 2023 Oct 17;0(0):0. doi: 10.11607/ijp.8405. Online ahead of print.

ABSTRACT

PURPOSE: This study aims to evaluate the effect of different finishing protocols on the wear behavior of a lithium disilicate glass-ceramic.

MATERIAL AND METHODS: Specimens were produced from lithium disilicate glass-ceramic prefabricated CAD/CAM blocks and divided into three groups, according to the surface treatment (n = 8): control; polishing; glaze. Ceramic specimens were subjected to wear test using a dual-axis chewing simulator. A 49 N load was applied in the axial direction combined with a lateral movement (1 mm path) using a lithium disilicate glass-ceramic spherical piston for a total of 106 cycles. Qualitative analysis of the wear surface was performed using an optical microscope. Quantitative analysis of surface roughness and volume loss was performed using a confocal microscope and a 3D-image editing software, respectively. Surface roughness and volume loss data were analyzed using Friedman’s non-parametric statistical test for repeated measures and the Student-Newman-Keuls test (α = 0.050).

RESULTS: There were statistical differences for surface roughness and volume loss of lithium disilicate glass-ceramic specimens in the different experimental conditions (P˂0.001). Control and polishing groups showed similar surface roughness and volume loss values for all testing times. Glaze group had greater wear volume after 103, 104 and 105 cycles. After 106 cycles, surface roughness and volume loss were similar among groups. For the piston, surface roughness was similar over time and among groups.

CONCLUSIONS: A distinct wear behavior was found for glazed glass-ceramic specimens in comparison to control and polished specimens. The end of the simulation, the surface roughness and volume loss was similar for the groups.

PMID:37847788 | DOI:10.11607/ijp.8405

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Nevin Manimala Statistics

Psychological Resilience Factors and Their Association With Weekly Stressor Reactivity During the COVID-19 Outbreak in Europe: Prospective Longitudinal Study

JMIR Ment Health. 2023 Oct 17;10:e46518. doi: 10.2196/46518.

ABSTRACT

BACKGROUND: Cross-sectional relationships between psychosocial resilience factors (RFs) and resilience, operationalized as the outcome of low mental health reactivity to stressor exposure (low “stressor reactivity” [SR]), were reported during the first wave of the COVID-19 pandemic in 2020.

OBJECTIVE: Extending these findings, we here examined prospective relationships and weekly dynamics between the same RFs and SR in a longitudinal sample during the aftermath of the first wave in several European countries.

METHODS: Over 5 weeks of app-based assessments, participants reported weekly stressor exposure, mental health problems, RFs, and demographic data in 1 of 6 different languages. As (partly) preregistered, hypotheses were tested cross-sectionally at baseline (N=558), and longitudinally (n=200), using mixed effects models and mediation analyses.

RESULTS: RFs at baseline, including positive appraisal style (PAS), optimism (OPT), general self-efficacy (GSE), perceived good stress recovery (REC), and perceived social support (PSS), were negatively associated with SR scores, not only cross-sectionally (baseline SR scores; all P<.001) but also prospectively (average SR scores across subsequent weeks; positive appraisal (PA), P=.008; OPT, P<.001; GSE, P=.01; REC, P<.001; and PSS, P=.002). In both associations, PAS mediated the effects of PSS on SR (cross-sectionally: 95% CI -0.064 to -0.013; prospectively: 95% CI -0.074 to -0.0008). In the analyses of weekly RF-SR dynamics, the RFs PA of stressors generally and specifically related to the COVID-19 pandemic, and GSE were negatively associated with SR in a contemporaneous fashion (PA, P<.001; PAC,P=.03; and GSE, P<.001), but not in a lagged fashion (PA, P=.36; PAC, P=.52; and GSE, P=.06).

CONCLUSIONS: We identified psychological RFs that prospectively predict resilience and cofluctuate with weekly SR within individuals. These prospective results endorse that the previously reported RF-SR associations do not exclusively reflect mood congruency or other temporal bias effects. We further confirm the important role of PA in resilience.

PMID:37847551 | DOI:10.2196/46518

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Nevin Manimala Statistics

Cancer and Atrial Fibrillation Comorbidities Among 25 Million Citizens in Shanghai, China: Medical Insurance Database Study

JMIR Public Health Surveill. 2023 Oct 17;9:e40149. doi: 10.2196/40149.

ABSTRACT

BACKGROUND: With population aging, the prevalence of both cancer and atrial fibrillation (AF) have increased. However, there is scarce epidemiological data concerning the comorbid state of cancer and AF in low- and middle-income countries, including China.

OBJECTIVE: We aimed to evaluate the site-, sex-, and age-specific profiles of cancer and AF comorbidities in Chinese populations.

METHODS: Data from the Shanghai Municipal Health Commission database between 2015 and 2020 were screened, covering all medical records of Shanghai residents with medical insurance. Site-specific cancer profiles were evaluated for the population with AF relative to the age- and sex-adjusted population of residents without AF. The sex distribution and peak age of cancer diagnosis were also assessed.

RESULTS: A total of 25,964,447 adult patients were screened. Among them, 22,185 patients presented cancers comorbid with AF (median 77, IQR 67-82 years of age; men: n=13,631, 61.44%), while 839,864 presented cancers without AF (median 67, IQR 57-72 years of age; men: n=419,020, 49.89%), thus yielding a higher cancer prevalence among residents with AF (8.27%) than among those without AF (6.05%; P<.001). In the population with AF, the most prevalent cancer type was lung cancer, followed by colorectal, male genital organ, stomach, breast, liver, bladder, thyroid, leukemia, and esophageal cancers. AF was associated with an average of nearly 1.4-fold (prevalence ratio [PR] 1.37, 95% CI 1.35-1.38) increased prevalence of cancer after adjusting for age and sex. For site-specific analyses, an increased prevalence of cancer in the population with AF was observed in 20 of 21 cancer sites. This increased prevalence was most prominent for nonsolid tumors, including multiple myeloma (PR 2.56, 95% CI 2.28-2.87), leukemia (PR 1.73, 95% CI 1.57-1.90), and non-Hodgkin lymphoma (PR 1.59, 95% CI 1.43-1.77); intrathoracic malignancies, including mediastinum (PR 2.34, 95% CI 1.89-2.90), lung (PR 1.64, 95% CI 1.59-1.69), and esophageal cancers (PR 1.41, 95% CI 1.28-1.56); bone and soft tissue neoplasms (PR 1.56, 95% CI 1.37-1.77); and kidney cancer (PR 1.53, 95% CI 1.36-1.72). Cancer prevalence in the population with AF relative to that in the population without AF was higher in men than in women in 14 of 18 cancer sites, and female predominance was only observed for thyroid cancer. The peak age of index cancer diagnosis was lower in the population with AF (age group: 70-74 years) than in that without AF (age group: 75-79 years), especially for specific cancer types, including thyroid, central nervous system, mediastinum, esophageal, bladder, and biliary cancers.

CONCLUSIONS: Patients with AF are associated with increased prevalence, heightened male predominance, and younger peak age of cancer. Further studies are needed to determine whether early screening of specific cancers is cost-effective and beneficial for patients with AF.

PMID:37847541 | DOI:10.2196/40149

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Nevin Manimala Statistics

First-Year Experience of Managing Urology Patients With Home Uroflowmetry: Descriptive Retrospective Analysis

JMIR Form Res. 2023 Oct 17;7:e51019. doi: 10.2196/51019.

ABSTRACT

BACKGROUND: Lower urinary tract symptoms affect a large number of people of all ages and sexes. The clinical assessment typically involves a bladder diary and uroflowmetry test. Conventional paper-based diaries are affected by low patient compliance, whereas in-clinic uroflowmetry measurement face challenges such as patient stress and inconvenience factors. Home uroflowmetry and automated bladder diaries are believed to overcome these limitations.

OBJECTIVE: In this study, we present our first-year experience of managing urological patients using Minze homeflow, which combines home uroflowmetry and automated bladder diaries. Our objective was 2-fold: first, to provide a description of the reasons for using homeflow and second, to compare the data obtained from homeflow with the data obtained from in-clinic uroflowmetry (hospiflow).

METHODS: A descriptive retrospective analysis was conducted using Minze homeflow between July 2019 and July 2020 at a tertiary university hospital. The device comprises a Bluetooth-connected gravimetric uroflowmeter, a patient smartphone app, and a cloud-based clinician portal. Descriptive statistics, Bland-Altman plots, the McNemar test, and the Wilcoxon signed rank test were used for data analysis.

RESULTS: The device was offered to 166 patients, including 91 pediatric and 75 adult patients. In total, 3214 homeflows and 129 hospiflows were recorded. Homeflow proved valuable for diagnosis, particularly in cases where hospiflow was unreliable or unsuccessful, especially in young children. It confirmed or excluded abnormal hospiflow results and provided comprehensive data with multiple measurements taken at various bladder volumes, urge levels, and times of the day. As a result, we found that approximately one-fourth of the patients with abnormal flow curves in the clinic had normal bell-shaped flow curves at home. Furthermore, homeflow offers the advantage of providing an individual’s plot of maximum flow rate (Q-max) versus voided volume as well as an average or median result. Our findings revealed that a considerable percentage of patients (22/76, 29% for pediatric patients and 24/50, 48% for adult patients) had a Q-max measurement from hospiflow falling outside the range of homeflow measurements. This discrepancy may be attributed to the unnatural nature of the hospiflow test, resulting in nonrepresentative uroflow curves and an underestimation of Q-max, as confirmed by the Bland-Altman plot analysis. The mean difference for Q-max was -3.1 mL/s (with an upper limit of agreement of 13 mL/s and a lower limit of agreement of -19.2 mL/s), which was statistically significant (Wilcoxon signed rank test: V=2019.5; P<.001). Given its enhanced reliability, homeflow serves as a valuable tool not only for diagnosis but also for follow-up, allowing for the evaluation of treatment effectiveness and home monitoring of postoperative and recurrent interventions.

CONCLUSIONS: Our first-year experience with Minze homeflow demonstrated its feasibility and usefulness in the diagnosis and follow-up of various patient categories. Homeflow provided more reliable and comprehensive voiding data compared with hospiflow.

PMID:37847531 | DOI:10.2196/51019

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Nevin Manimala Statistics

BNT162b2 versus mRNA-1273 Third Dose COVID-19 Vaccine in Patients with CKD and Maintenance Dialysis Patients

Clin J Am Soc Nephrol. 2023 Oct 17. doi: 10.2215/CJN.0000000000000328. Online ahead of print.

ABSTRACT

BACKGROUND: There is a lack of randomized controlled trial data regarding differences in immunogenicity of varying COVID-19 mRNA vaccine regimens in chronic kidney disease (CKD) populations.

METHODS: We conducted a randomized controlled trial at three kidney centres in Toronto, Ontario, Canada evaluating the SARS-CoV-2 antibody response following third dose vaccination. Participants (n=273) with CKD not on dialysis or receiving dialysis were randomized 1:1 to third dose 30µg BNT162b2 (Pfizer-BioNTech) or 100µg mRNA-1273 (Moderna). The primary outcome of this study was SARS-CoV-2 IgG binding antibodies to the receptor binding domain (anti-RBD). Spike protein (anti-spike), nucleocapsid protein, and vaccine reactogenicity were also evaluated. Serology was measured prior to third dose, 1 month, 3 months, and 6 months following third dose. A subset of participants (n=100) were randomly selected to assess viral pseudovirus neutralization against wild-type D614G, B.1.617.2 (Delta), and B.1.1.529 (Omicron BA.1).

RESULTS: Among 273 participants randomized, 94% were receiving maintenance dialysis and 59% received BNT162b2 for initial two dose COVID-19 vaccination. Third dose of mRNA-1273 was associated with higher mean anti-RBD levels (1871 BAU/mL; 95% CI 829, 2988) over a 6-month period in comparison to third dose BNT162b2 (1332 BAU/mL; 95% CI 367, 2402) with a difference of 539 BAU/mL (95% CI 139, 910; p=0.009). Neither anti-spike levels nor neutralizing antibodies to wild-type, Delta, Omicron BA.1 pseudoviruses were statistically different. COVID-19 infection occurred in 10% of participants:15 (11%) receiving mRNA-1273 and 11 (8%) receiving BNT162b2. Third dose BNT162b2 was not associated with a significant different risk for COVID-19 in comparison to mRNA-1273 (HR 0.78; 95% CI 0.27, 2.2, p=0.63).

CONCLUSIONS: In patients with CKD third dose COVID-19 mRNA vaccination with mRNA-1273 elicited higher SARS-CoV-2 anti-RBD levels in comparison to BNT162b2 over a 6-month period.

PMID:37847518 | DOI:10.2215/CJN.0000000000000328

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Nevin Manimala Statistics

Selenium and Vitamin E for Prevention of Non-Muscle-Invasive Bladder Cancer Recurrence and Progression: A Randomized Clinical Trial

JAMA Netw Open. 2023 Oct 2;6(10):e2337494. doi: 10.1001/jamanetworkopen.2023.37494.

ABSTRACT

IMPORTANCE: Selenium and vitamin E have been identified as promising agents for the chemoprevention of recurrence and progression of non-muscle-invasive bladder cancer.

OBJECTIVE: To determine whether selenium and/or vitamin E may prevent disease recurrence in patients with newly diagnosed NMIBC.

DESIGN, SETTING, AND PARTICIPANTS: This multicenter, prospective, double-blinded, placebo-controlled, 2 × 2 factorial randomized clinical trial included patients with newly diagnosed NMIBC recruited from 10 secondary or tertiary care hospitals in the UK. A total of 755 patients were screened for inclusion; 484 did not meet the inclusion criteria, and 1 declined to participate. A total of 270 patients were randomly assigned to 4 groups (selenium plus placebo, vitamin E plus placebo, selenium plus vitamin E, and placebo plus placebo) in a double-blind fashion between July 17, 2007, and October 10, 2011. Eligibility included initial diagnosis of NMIBC (stages Ta, T1, or Tis); randomization within 12 months of first transurethral resection was required.

INTERVENTIONS: Oral selenium (200 μg/d of high-selenium yeast) and matched vitamin E placebo, vitamin E (200 IU/d of d-alfa-tocopherol) and matched selenium placebo, selenium and vitamin E, or placebo and placebo.

MAIN OUTCOME AND MEASURES: Recurrence-free interval (RFI) on an intention-to-treat basis (analyses completed on November 28, 2022).

RESULTS: The study randomized 270 patients (mean [SD] age, 68.9 [10.4] years; median [IQR] age, 69 [63-77] years; 202 male [75%]), with 65 receiving selenium and vitamin E placebo, 71 receiving vitamin E and selenium placebo, 69 receiving selenium and vitamin E, and 65 receiving both placebos. Median overall follow-up was 5.5 years (IQR, 5.1-6.1 years); 228 patients (84%) were followed up for more than 5 years. Median treatment duration was 1.5 years (IQR, 0.9-2.5 years). The study was halted because of slow accrual. For selenium (n = 134) vs no selenium (n = 136), there was no difference in RFI (hazard ratio, 0.92; 95% CI, 0.65-1.31; P = .65). For vitamin E (n = 140) vs no vitamin E (n = 130), there was a statistically significant detriment to RFI (hazard ratio, 1.46; 95% CI, 1.02-2.09; P = .04). No significant differences were observed for progression-free interval or overall survival time with either supplement. Results were unchanged after Cox proportional hazards regression modeling to adjust for known prognostic factors. In total, 1957 adverse events were reported; 85 were serious adverse events, and all were considered unrelated to trial treatment.

CONCLUSIONS AND RELEVANCE: In this randomized clinical trial of selenium and vitamin E, selenium supplementation did not reduce the risk of recurrence in patients with NMIBC, but vitamin E supplementation was associated with an increased risk of recurrence. Neither selenium nor vitamin E influenced progression or overall survival. Vitamin E supplementation may be harmful to patients with NMIBC, and elucidation of the underlying biology is required.

TRIAL REGISTRATION: isrctn.org Identifier: ISRCTN13889738.

PMID:37847504 | DOI:10.1001/jamanetworkopen.2023.37494

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Nevin Manimala Statistics

Hemodynamic Reactivity to Mental Stress in Patients With Coronary Artery Disease

JAMA Netw Open. 2023 Oct 2;6(10):e2338060. doi: 10.1001/jamanetworkopen.2023.38060.

ABSTRACT

IMPORTANCE: The clinical significance of hemodynamic reactivity to mental stress in the population with coronary artery disease (CAD) is unclear.

OBJECTIVE: To investigate the association between hemodynamic reactivity to mental stress and the risk of adverse cardiovascular events in patients with stable CAD.

DESIGN, SETTING, AND PARTICIPANTS: This cohort study included individuals with stable CAD from 2 prospective studies from a university-based hospital network: the Mental Stress Ischemia Prognosis Study (MIPS) and the Myocardial Infarction and Mental Stress Study 2 (MIMS2). Participants were enrolled between June 2011 and March 2016 and followed up for a median of 6.0 (IQR, 5.6-6.0) years in MIPS and 4.6 (IQR, 3.8-5.3) years in MIMS2. Data were analyzed from December 1, 2022, to February 15, 2023.

EXPOSURES: The rate-pressure product (RPP) was calculated as the mean systolic blood pressure times the mean heart rate at rest. Rate-pressure product reactivity was calculated as the maximum RPP during a standardized mental stress test minus the RPP at rest.

MAIN OUTCOMES AND MEASURES: The primary outcome was a composite of cardiovascular death or nonfatal myocardial infarction. The secondary end point additionally included hospitalizations for heart failure.

RESULTS: From the total of 938 individuals from the pooled cohort (mean [SD] age, 60.2 [10.1] years; 611 [65.1%] men), 631 participated in MIPS and 307 in MIMS2. A total of 373 individuals (39.8%) were Black, 519 (55.3%) were White, and 46 (4.9%) were of unknown race or ethnicity. The RPP increased by a mean (SD) of 77.1% (23.1%) during mental stress (mean [SD] absolute change, 5651 [2878]). For every SD decrease in RPP reactivity with mental stress, the adjusted hazard ratios for the primary and secondary end points were 1.30 (95% CI, 1.04-1.72) and 1.30 (95% CI, 1.06-1.56), respectively, in MIPS and 1.41 (95% CI, 1.06-1.97) and 1.21 (95% CI, 1.02-1.60), respectively, in MIMS2. In the pooled sample, when RPP reactivity to mental stress was added to a model including traditional clinical risk characteristics, model discrimination for adverse events improved (increase in C statistic of 5% for the primary end point; P = .009).

CONCLUSIONS AND RELEVANCE: In this cohort study of individuals with stable CAD, a blunted cardiovascular reactivity to mental stress was associated with adverse outcomes. Future studies are needed to assess the clinical utility of mental stress reactivity testing in this population.

PMID:37847500 | DOI:10.1001/jamanetworkopen.2023.38060