Firth-Type Penalized Methods of the Modified Poisson and Least-Squares Regression Analyses for Binary Outcomes.

The modified Poisson and least-squares regression analyses for binary outcomes have been widely used as effective multivariable analysis methods to provide risk ratio and risk difference estimates in clinical and epidemiological studies. However, there is no certain evidence that assessed their operating characteristics under small and sparse data settings and no effective methods have been proposed for these regression analyses to address this issue. In this article, we show that the modified Poisson regression provides seriously biased estimates under small and sparse data settings. In addition, the modified least-squares regression provides unbiased estimates under these settings. We further show that the ordinary robust variance estimators for both of the methods have certain biases under situations that involve small or moderate sample sizes. To address these issues, we propose the Firth-type penalized methods for the modified Poisson and least-squares regressions. The adjustment methods lead to a more accurate and stable risk ratio estimator under small and sparse data settings, although the risk difference estimator is not invariant. In addition, to improve the inferences of the effect measures, we provide an improved robust variance estimator for these regression analyses. We conducted extensive simulation studies to assess the performances of the proposed methods under real-world conditions and found that the accuracies of the point and interval estimations were markedly improved by the proposed methods. We illustrate the effectiveness of these methods by applying them to a clinical study of epilepsy.

Artificial intelligence-assisted interventions for perioperative anesthetic management: a systematic review and meta-analysis.

BACKGROUND: Integration of artificial intelligence (AI) into medical practice has increased recently. Numerous AI models have been developed in the field of anesthesiology; however, their use in clinical settings remains limited. This study aimed to identify the gap between AI research and its implementation in anesthesiology via a systematic review of randomized controlled trials with meta-analysis (CRD42022353727). METHODS: We searched the databases of Medical Literature Analysis and Retrieval System Online (MEDLINE), Excerpta Medica Database (Embase), Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL), Institute of Electrical and Electronics Engineers Xplore (IEEE), and Google Scholar and retrieved randomized controlled trials comparing conventional and AI-assisted anesthetic management published between the date of inception of the database and August 31, 2023. RESULTS: Eight randomized controlled trials were included in this systematic review (n = 568 patients), including 286 and 282 patients who underwent anesthetic management with and without AI-assisted interventions, respectively. AI-assisted interventions used in the studies included fuzzy logic control for gas concentrations (one study) and the Hypotension Prediction Index (seven studies; adding only one indicator). Seven studies had small sample sizes (n = 30 to 68, except for the largest), and meta-analysis including the study with the largest sample size (n = 213) showed no difference in a hypotension-related outcome (mean difference of the time-weighted average of the area under the threshold 0.22, 95% confidence interval -0.03 to 0.48, P = 0.215, I2 93.8%). CONCLUSIONS: This systematic review and meta-analysis revealed that randomized controlled trials on AI-assisted interventions in anesthesiology are in their infancy, and approaches that take into account complex clinical practice should be investigated in the future. TRIAL REGISTRATION: This study was registered with the International Prospective Register of Systematic Reviews (PROSPERO ID: CRD42022353727).

Effectiveness of a multicomponent intervention to promote physical activity among Japanese remote workers: a pilot open-label randomized controlled trial.

OBJECTIVES: Remote work (ie, teleworking) may adversely affect physical activity (PA) among workers, but no strategies have been effectively implemented to address this issue. We aimed to test whether a multicomponent intervention program could promote the PA of remote workers. METHODS: This study was an 8-week pilot open-label randomized controlled trial. Fifty-one participants (19 women) aged 23-58 years were recruited via an information technology company in Tokyo, Japan, and randomly assigned to the control (n = 26) or intervention (n = 25) group. The intervention group was provided a multicomponent intervention that comprised individual (lecture, print material, goal setting, feedback, and posters), sociocultural (supportive atmosphere and team building), and organizational (encouraging message from an executive) strategies. The control group only received posters. The primary outcome was an 8-week change in objectively measured moderate-to-vigorous PA (MVPA). The secondary outcomes were changes in light PA, moderate PA, vigorous PA, steps, and sedentary time. We also conducted subdomain analyses divided into working and nonworking days. RESULTS: No significant difference was observed in MVPA changes between the 2 groups. However, the intervention group showed significant improvement in light PA by +14.0 min/d (95% CI, 1.7-26.2). Subdomain analyses also showed no significant differences in MVPA changes between the 2 groups. However, MVPA in the intervention group significantly increased by +9.4 min/d (95% CI, 2.5-16.2) on working days. CONCLUSIONS: The present multicomponent intervention was feasible for remote workers, although some revisions are necessary to enhance the effect size.

Risk of postoperative pneumonia after extubation with the positive pressure versus normal pressure technique: a single-center retrospective observational study.

PURPOSE: A normal pressure extubation technique (no lung inflation before extubation), proposed by the Japanese Society of Anesthesiologists to prevent droplet infection during the coronavirus disease 2019 (COVID-19) pandemic, could theoretically increase postoperative pneumonia incidence compared with a positive pressure extubation technique (lung inflation before extubation). However, the normal pressure extubation technique has not been adequately evaluated. This study compared postoperative pneumonia incidence between positive and normal pressure extubation techniques using a dataset from the University of Tsukuba Hospital. METHODS: In our hospital, the extubation methods changed from positive to normal pressure extubation techniques on March 3, 2020 due to the COVID-19 pandemic. Thus, we compared the risk of postoperative pneumonia between the positive (April 1, 2017 to December 31, 2019) and normal pressure extubation techniques (March 3, 2020 to March 31, 2022) using propensity score analyses. Postoperative pneumonia was defined using the International Classification of Diseases, 10th Edition (ICD-10) codes (J13-J18), and we reviewed the medical records of patients flagged with these ICD-10 codes (preoperative pneumonia and ICD-10 codes for prophylactic antibiotic prescriptions for pneumonia). RESULTS: We identified 20,011 surgeries, including 11,920 in the positive pressure extubation group (mean age 48.2 years, standard deviation [SD] 25.2 years) and 8,091 in the normal pressure extubation group (mean age 47.8 years, SD 25.8 years). The postoperative pneumonia incidences were 0.19% (23/11,920) and 0.17% (14/8,091) in the positive and normal pressure extubation groups, respectively. The propensity score analysis using inverse probability weighting revealed no significant difference in postoperative pneumonia incidence between the two groups (adjusted odds ratio 0.98, 95% confidence interval 0.50 to 1.91, P = 0.94). CONCLUSIONS: These results indicated no increased risk of postoperative pneumonia associated with the normal pressure extubation technique compared with the positive pressure extubation technique. CLINICAL TRIAL NUMBER: Clinical trial number: UMIN000048589 https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000055364.

The Effectiveness of Leukocyte-Poor Platelet-Rich Plasma Injections for Symptomatic Mild to Moderate Osteoarthritis of the Knee With Joint Effusion or Bone Marrow Lesions in a Japanese Population: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial.

BACKGROUND: Intra-articular platelet-rich plasma (PRP) injections have been proposed for the treatment of knee osteoarthritis (OA); however, their effectiveness in Japanese patients remains unclear. PURPOSE: To investigate whether 3 intra-articular injections of leukocyte-poor PRP (LP-PRP) improve symptoms and joint function in symptomatic Japanese patients with mild to moderate knee OA. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: Of 72 patients screened, 30 were included and randomized to receive LP-PRP (n = 15) or saline (placebo; n = 15) injections between March 2019 and February 2023. Patients attended a screening visit and 3 treatment visits at 1 week apart, followed by 3 follow-up visits (at 4, 12, and 24 weeks) after the initial treatment visit. The primary efficacy outcome measure was the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, whereas the secondary efficacy outcome measures were the proportion of patients showing a visual analog scale (VAS) improvement of ≥50%. Magnetic resonance imaging was performed to evaluate joint effusion and bone marrow lesions using the Whole-Organ Magnetic Resonance Imaging Score. Patients were followed for 24 weeks. RESULTS: Patients in the PRP group (mean age, 65.9 years) had a mean hip-knee-ankle angle of 5.1°, with 7 and 8 patients demonstrating Kellgren-Lawrence grade 2 and 3 knee OA, respectively. Patients in the placebo group (mean age, 67.9 years) had a mean hip-knee-ankle angle of 3.8°, with 6 and 9 patients showing Kellgren-Lawrence grade 2 and 3 knee OA, respectively. No significant differences were identified in any baseline factors. The percentage change in Western Ontario and McMaster Universities Osteoarthritis Index scores from baseline to 24 weeks was significantly different (P= .032) between the PRP (median, 75.9%; quantile 1 [Q1], 49.6; quantile 3 [Q3], 94.1]) and placebo (median, 27.7%; Q1, -9.4; Q3, 80.9]) groups. Overall, 73.3% and 28.6% of the PRP group and placebo group, respectively, exhibited an improvement in visual analog scale scores of ≥50%, with a significant improvement observed in the PRP group (P = .027). Changes in bone marrow lesions from baseline to 24 weeks, as assessed on magnetic resonance imaging, significantly differed between groups (P = .017), with no significant differences in other secondary endpoints. CONCLUSION: In Japanese patients with knee OA, 3 intra-articular LP-PRP injections led to clinical improvements at 24-week follow-up and significant functional improvements and pain relief after 24 weeks.

Impact of frailty in patients with non-valvular atrial fibrillation undergoing catheter ablation.

Background: The relationships between frailty and clinical outcomes in elderly Japanese patients with non-valvular atrial fibrillation (NVAF) after catheter ablation (CA) have not been established. We evaluated the frailty rate of patients undergoing CA for NVAF, examined whether CA for NVAF improves frailty, and analyzed the CA outcomes of patients with and without frailty. Methods: Elderly Japanese patients (≥65 years; mean age: 72.8 years) who participated in the real-world ablation therapy with anti-coagulants in management of atrial fibrillation registry and who responded to the frailty screening index survey were included (n = 213). Frailty and AF recurrence were assessed preoperatively and at 3 and 6 months after CA. Results: Twenty-six patients (12.8%) were frail, 109 (53.7%) were pre-frail, and 68 (33.5%) were robust. Cardiovascular (frailty: 0.5%/person-year; pre-frailty: 0.1%/person-year; robust: 0.1%/person-year) and cardiac (frailty: 0.5%/person-year; pre-frailty: 0.1%/person-year; robust: 0.1%/person-year) events, as well as major bleeding (frailty: 0.3%/person-year; pre-frailty: 0.1%/person-year; robust: 0.1%/person-year), were numerically more frequent in the frailty group. No deaths from cardiovascular or stroke/systemic thromboembolic events occurred. A large proportion of patients did not experience 3-month (frailty: 96.2%; pre-frailty: 96.3%; robust: 88.2%) or 6-month (frailty: 88.5%; pre-frailty: 91.7%; robust: 86.8%) AF recurrence after CA. Weight loss, walking speed, and fatigue improved in the frailty and pre-frailty groups after CA. Conclusion: Japanese patients aged ≥65 years with frailty or pre-frailty had improved frailty screening index components, such as weight loss, walking speed and fatigue, after CA. Therefore, elderly patients with frailty or pre-frailty may benefit from CA for NVAF.

A Bayesian method to detect drug-drug interaction using external information for spontaneous reporting system.

Due to the insufficiency of safety assessments of clinical trials for drugs, further assessments are required for post-marketed drugs. In addition to adverse drug reactions (ADRs) induced by one drug, drug-drug interaction (DDI)-induced ADR should also be investigated. The spontaneous reporting system (SRS) is a powerful tool for evaluating the safety of drugs continually. In this study, we propose a novel Bayesian method for detecting potential DDIs in a database collected by the SRS. By applying a power prior, the proposed method can borrow information from similar drugs for a drug assessed DDI to increase sensitivity of detection. The proposed method can also adjust the amount of the information borrowed by tuning the parameters in power prior. In the simulation study, we demonstrate the aforementioned increase in sensitivity. Depending on the scenarios, approximately 20 points of sensitivity of the proposed method increase from an existing method to a maximum. We also indicate the possibility of early detection of potential DDIs by the proposed method through analysis of the database shared by the Food and Drug Administration. In conclusion, the proposed method has a higher sensitivity and a novel criterion to detect potential DDIs early, provided similar drugs have similar observed-expected ratios to the drug under assessment.

Moderately hypofractionated proton beam therapy for localized prostate cancer: 5-year outcomes of a phase II trial.

The usefulness of moderately hypofractionated radiotherapy for localized prostate cancer has been extensively reported, but there are limited studies on proton beam therapy (PBT) using similar hypofractionation schedules. The aim of this prospective phase II study is to confirm the safety of a shortened PBT course using 70 Gy relative biological effectiveness (RBE) in 28 fractions. From May 2013 to June 2015, 102 men with localized prostate cancer were enrolled. Androgen deprivation therapy was administered according to risk classification. Toxicity was assessed using Common Terminology Criteria for Adverse Events version 4.0. Of the 100 patients ultimately evaluated, 15 were classified as low risk, 43 as intermediate risk, and 42 as high risk. The median follow-up time of the surviving patients was 96 months (range: 60-119 months). The 5-year cumulative incidences of grade 2 gastrointestinal/genitourinary adverse events were 1% (95% CI: 0.1-6.9) and 4% (95% CI: 1.5-10.3), respectively; no grade ≥ 3 gastrointestinal/genitourinary adverse events were observed. The current study revealed a low incidence of late adverse events in prostate cancer patients treated with moderately hypofractionated PBT of 70 Gy (RBE) in 28 fractions, indicating the safety of this schedule.

Preoperative albumin-bilirubin score and liver resection percentage determine postoperative liver regeneration after partial hepatectomy.

BACKGROUND: The success of liver resection relies on the ability of the remnant liver to regenerate. Most of the knowledge regarding the pathophysiological basis of liver regeneration comes from rodent studies, and data on humans are scarce. Additionally, there is limited knowledge about the preoperative factors that influence postoperative regeneration. AIM: To quantify postoperative remnant liver volume by the latest volumetric software and investigate perioperative factors that affect posthepatectomy liver regeneration. METHODS: A total of 268 patients who received partial hepatectomy were enrolled. Patients were grouped into right hepatectomy/trisegmentectomy (RH/Tri), left hepatectomy (LH), segmentectomy (Seg), and subsegmentectomy/nonanatomical hepatectomy (Sub/Non) groups. The regeneration index (RI) and late regeneration rate were defined as (postoperative liver volume)/[total functional liver volume (TFLV)] × 100 and (RI at 6-months - RI at 3-months)/RI at 6-months, respectively. The lower 25th percentile of RI and the higher 25th percentile of late regeneration rate in each group were defined as "low regeneration" and "delayed regeneration". "Restoration to the original size" was defined as regeneration of the liver volume by more than 90% of the TFLV at 12 months postsurgery. RESULTS: The numbers of patients in the RH/Tri, LH, Seg, and Sub/Non groups were 41, 53, 99 and 75, respectively. The RI plateaued at 3 months in the LH, Seg, and Sub/Non groups, whereas the RI increased until 12 months in the RH/Tri group. According to our multivariate analysis, the preoperative albumin-bilirubin (ALBI) score was an independent factor for low regeneration at 3 months [odds ratio (OR) 95%CI = 2.80 (1.17-6.69), P = 0.02; per 1.0 up] and 12 months [OR = 2.27 (1.01-5.09), P = 0.04; per 1.0 up]. Multivariate analysis revealed that only liver resection percentage [OR = 1.03 (1.00-1.05), P = 0.04] was associated with delayed regeneration. Furthermore, multivariate analysis demonstrated that the preoperative ALBI score [OR = 2.63 (1.00-1.05), P = 0.02; per 1.0 up] and liver resection percentage [OR = 1.02 (1.00-1.05), P = 0.04; per 1.0 up] were found to be independent risk factors associated with volume restoration failure. CONCLUSION: Liver regeneration posthepatectomy was determined by the resection percentage and preoperative ALBI score. This knowledge helps surgeons decide the timing and type of rehepatectomy for recurrent cases.

Multivariate generalized mixed-effects models for screening multiple adverse drug reactions in spontaneous reporting systems.

Introduction: For assessing drug safety using spontaneous reporting system databases, quantitative measurements, such as proportional reporting rate (PRR) and reporting odds ratio (ROR), are widely employed to assess the relationship between a drug and a suspected adverse drug reaction (ADR). The databases contain numerous ADRs, and the quantitative measurements need to be calculated by performing the analysis multiple times for each ADR. We proposed a novel, simple, and easy-to-implement method to estimate the PRR and ROR of multiple ADRs in a single analysis using a generalized mixed-effects model for signal detection. Methods: The proposed method simultaneously analyzed the association between any drug and numerous ADRs, as well as estimated the PRR and ROR for a specific combination of drugs and suspected ADRs. Furthermore, the proposed method was applied to detect drug-drug interactions associated with the concurrent use of two or more drugs. Results and discussion: In our simulation studies, the false-positive rate and sensitivity of the proposed method were similar to those of the traditional PRR and ROR. The proposed method detected known ADRs when applied to the Food and Drug Administration Adverse Event Reporting System database. As an important advantage, the proposed method allowed the simultaneous evaluation of several ADRs using multiple drugs.

Estimating the minimal clinically important difference of upper extremity outcome measures in chronic stroke patients with moderate to severe impairment: a cross-sectional study.

BACKGROUND: Approximately 70% of chronic stroke patients experience upper extremity (UE) functional impairments, and UE outcome measures are often used as quality-of-life indicators. OBJECTIVE: The purpose of this study was to estimate minimal clinically important difference (MCID) values for UE outcome measures in chronic stroke patients with moderate to severe UE hemiplegia. METHODS: This study was a cross-sectional study, conducted as a secondary analysis of data from the ReoGo-J study, a multicenter, prospective, randomized, parallel-group trial of robot-assisted self-training for UE hemiplegia in chronic stroke. The patients were randomized to 1 of 3 treatment groups. Treatment was provided 3 times a week for 10 weeks, and UE outcome measures were evaluated before and after treatment. The anchor-based method was used to estimate MCID values for UE outcome measures, with Stroke Impact Scale (SIS) subscales as anchors. MCID values were estimated by identifying cutoff values in a receiver operating characteristic (ROC) curve. RESULTS: Between-group comparisons of UE outcome measures, based on the clinically important difference (CID) values of SIS subscales, revealed significant differences in both the Amount of Use (AOU) and Quality of Movement (QOM) components of the Motor Activity Log (MAL)-14. The estimated MCID values were 0.89 for the AOU component and 0.77 for the QOM component. CONCLUSIONS: The estimated MCID values for the MAL-14 not only add information regarding the clinical characteristics of the MAL-14 but also facilitate interpretations of changing scores in chronic stroke patients with moderate to severe UE hemiplegia undergoing rehabilitation therapy. STUDY REGISTRATION: https://www.umin.ac.jp/ctr/index.htm (UMIN000022509; 1 July 2016).

Relationship between changes in pulmonary function and patient-reported outcomes of lung cancer surgery.

PURPOSE: To investigate the relationship between changes in pulmonary function (PF) and patient-reported outcomes (PROs) of lung cancer surgery. METHODS: We recruited 262 patients who underwent lung resection for lung cancer, to evaluate the PROs, using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ)-C30 and the Lung Cancer 13-question supplement (LC13). The patients underwent PF tests and PRO assessments preoperatively (Pre) and 1 year after surgery (Y1). Changes were calculated by subtracting the value at Pre from the value at Y1. We set two cohorts: patients under the ongoing protocol (Cohort 1) and patients who were eligible for lobectomy with clinical stage I lung cancer (Cohort 2). RESULTS: Cohorts 1 and 2 comprised 206 and 149 patients, respectively. In addition to dyspnea, changes in PF were also correlated with scores for global health status, physical and role function scores, fatigue, nausea and vomiting, pain, and financial difficulties. Absolute correlation coefficient values ranged from 0.149 to 0.311. Improvement of emotional and social function scores was independent of PF. Sublobar resection preserved PF more than lobectomy did. Wedge resection mitigated dyspnea in both cohorts. CONCLUSION: The correlation between PF and PROs was found to be weak; therefore, further studies are needed to improve the patient's postoperative experience.

Effect of cardiopulmonary bypass on coagulation factors II, VII and X in a primate model: an exploratory pilot study.

OBJECTIVES: The use of cardiopulmonary bypass (CPB) in cardiac surgery is a major risk factor for postoperative bleeding. We hypothesized that consumptive coagulopathy and haemodilution influence the coagulation factors; therefore, we aimed to estimate the activity profiles of coagulation factors II, VII and X during CPB circulation. METHODS: A 120-min bypass was surgically established in cynomolgus monkeys (n = 7). Activities of coagulation factors II, VII and X were measured at 6 time points during the experiment (baseline, 0, 30, 60, 120 min of bypass and 60 min after bypass). To assess the influence of consumptive coagulopathy, the values were adjusted for haemodilution using the haematocrit values. Data were expressed as mean (standard deviation). RESULTS: Activities of coagulation factors decreased during the experiment. In particular, the activities for II, VII and X were decreased the most by 44.2% (5.0), 61.4% (4.3) and 49.0% (3.7) at 30 min following CPB initiation (P < 0.001, P < 0.001 and P < 0.001, respectively). Following adjustments for haemodilution, change magnitudes lessened but remained significant for factor VII. The adjusted concentration of factor VII was observed to decrease from the baseline to the initiation of bypass circulation. CONCLUSIONS: In conclusion, coagulation factor II, VII and X concentrations decreased during CPB. Following adjustment for haemodilution, a decrease in concentration was observed with factor VII.

Continuous glucose monitoring-derived time in range and CV are associated with altered tissue characteristics of the carotid artery wall in people with type 2 diabetes.

AIMS/HYPOTHESIS: Previous studies have suggested that glucose variability may accelerate atherosclerosis progression in people with type 2 diabetes. Current guidelines recommend assessing glycaemic control using continuous glucose monitoring (CGM), which provides a comprehensive glycaemic profile to supplement HbA1c measurement. However, the association between CGM-derived metrics and atherosclerosis progression is not entirely clear. METHODS: This exploratory study used baseline data and data obtained after 104 weeks from an ongoing prospective, multicentre, observational study. Six hundred study participants with type 2 diabetes and no apparent history of symptomatic cardiovascular disease underwent CGM and ultrasonographic atherosclerosis measurements of the carotid arteries, including the intima-media thickness (IMT) and grey-scale median (GSM), at baseline and 104 weeks. Non-invasive ultrasonic tissue characterisation of the carotid artery wall or plaque using the GSM reflects vascular composition. Multivariate regression models were used to analyse the association between CGM-derived indices, mainly time in range (TIR) and CV, and changes in carotid atherosclerosis index values. RESULTS: Over the 104-week study period, there were modest increases in mean IMT (from 0.759±0.153 to 0.773±0.152 mm, p<0.001) and thickened-lesion GSM (from 43.5±19.5 to 53.9±23.5 units, p<0.001), but no significant changes in common carotid artery maximum-IMT (from 1.109±0.442 to 1.116±0.469 mm, p=0.453) or mean GSM (from 48.7±19.3 to 49.8±20.8 units, p=0.092). In a linear regression model with adjustment for possible atherosclerotic risk factors, including HbA1c, TIR and CV at baseline were significantly associated with the annual change in mean GSM (regression coefficient per 10% increase in TIR 0.52; 95% CI 0.06, 0.98; Hochberg-adjusted p value 0.038; regression coefficient per 1% increase in CV -0.12; 95% CI -0.22, -0.02; Hochberg-adjusted p value 0.038). TIR and CV at baseline were also significantly associated with the annual change in thickened-lesion GSM (regression coefficient per 10% increase in TIR 0.95; 95% CI 0.12, 1.79; Hochberg-adjusted p value 0.038; regression coefficient per 1% increase in CV -0.19; 95% CI -0.36, -0.01; Hochberg-adjusted p value 0.038). Participants who achieved target CGM-derived metrics at baseline, as proposed by an international consensus, showed significant annual changes in mean GSM compared with those who did not (0.94±6.88 vs -0.21±6.19 units/year, p=0.007). CONCLUSIONS/INTERPRETATION: TIR and CV were significantly associated with changes in the tissue characteristics of the carotid artery wall. TRIAL REGISTRATION: University Hospital Medical Information Network Clinical Trials Registry, number UMIN000032325.

Long-term efficacy and safety of early alogliptin initiation in subjects with type 2 diabetes: an extension of the SPEAD-A study.

We previously reported in the study of preventive effects of alogliptin on diabetic atherosclerosis (SPEAD-A) that alogliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, attenuated the progression of carotid atherosclerosis in subjects with type 2 diabetes and no history of cardiovascular disease. This extension study of the SPEAD-A trial investigated whether early alogliptin initiation improved long-term cardiovascular outcomes. The SPEAD-A trial randomized 341 subjects with type 2 diabetes to either alogliptin or conventional treatment to investigate the effects of alogliptin on atherosclerosis. All subjects who completed that trial were eligible for this prospective, observational cohort study. The primary endpoint was the first occurrence of a major cardiovascular event, defined as death due to any cause, acute myocardial infarction, or stroke. During the 520-week follow-up period, composite primary outcome events occurred in only a few subjects in each group [8 (5.4%) in the alogliptin group and 9 in the conventional treatment group (5.9%)]. There were no significant differences in the incidence rate of the primary outcome between the two groups. Post hoc Poisson regression analysis showed no significant difference between the two groups in the incidence rate of composite recurrence events for the same outcomes as the primary endpoint. On the other hand, this incidence rate was significantly lower in subjects who received DPP-4 inhibitors before an initial cardiovascular event than in those who did not (5.8 vs. 13.3 per 1000 person-years, respectively, p = 0.04). Early initiation of alogliptin was not associated with a reduced risk of composite cardiovascular disease, which could be attributed to fewer events and/or the addition of DPP-4 inhibitors during the follow-up period.

Kenward-Roger-type corrections for inference methods of network meta-analysis and meta-regression.

Network meta-analysis has been an essential methodology of systematic reviews for comparative effectiveness research. The restricted maximum likelihood (REML) method is one of the current standard inference methods for multivariate, contrast-based meta-analysis models, but recent studies have revealed the resultant confidence intervals of average treatment effect parameters in random-effects models can seriously underestimate statistical errors; that is, the actual coverage probability of a true parameter cannot retain the nominal level (e.g., 95%). In this article, we provided improved inference methods for the network meta-analysis and meta-regression models using higher-order asymptotic approximations based on the approach of Kenward and Roger (Biometrics 1997;53:983-997). We provided two corrected covariance matrix estimators for the REML estimator and improved approximations for its sample distribution using a t-distribution with adequate degrees of freedom. All of the proposed procedures can be implemented using only simple matrix calculations. In simulation studies under various settings, the REML-based Wald-type confidence intervals seriously underestimated the statistical errors, especially in cases of small numbers of trials meta-analyzed. By contrast, the proposed Kenward-Roger-type inference methods consistently showed accurate coverage properties under all the settings considered in our experiments. We also illustrated the effectiveness of the proposed methods through applications to two real network meta-analysis datasets.

MEF2C/p300-mediated epigenetic remodeling promotes the maturation of induced cardiomyocytes.

Cardiac transcription factors (TFs) directly reprogram fibroblasts into induced cardiomyocytes (iCMs), where MEF2C acts as a pioneer factor with GATA4 and TBX5 (GT). However, the generation of functional and mature iCMs is inefficient, and the molecular mechanisms underlying this process remain largely unknown. Here, we found that the overexpression of transcriptionally activated MEF2C via fusion of the powerful MYOD transactivation domain combined with GT increased the generation of beating iCMs by 30-fold. Activated MEF2C with GT generated iCMs that were transcriptionally, structurally, and functionally more mature than those generated by native MEF2C with GT. Mechanistically, activated MEF2C recruited p300 and multiple cardiogenic TFs to cardiac loci to induce chromatin remodeling. In contrast, p300 inhibition suppressed cardiac gene expression, inhibited iCM maturation, and decreased the beating iCM numbers. Splicing isoforms of MEF2C with similar transcriptional activities did not promote functional iCM generation. Thus, MEF2C/p300-mediated epigenetic remodeling promotes iCM maturation.

A comparison of bias-adjusted generalized estimating equations for sparse binary data in small-sample longitudinal studies.

Using a generalized estimating equation (GEE) can lead to a bias in regression coefficients for a small sample or sparse data. The bias-corrected GEE (BCGEE) and penalized GEE (PGEE) were proposed to resolve the small-sample bias. Moreover, the standard sandwich covariance estimator leads to a bias of standard error for small samples; several modified covariance estimators have been proposed to address this issue. We review the modified GEEs and modified covariance estimators, and evaluate their performance in sparse binary data from small-sample longitudinal studies. The simulation results showed that GEE and BCGEE often failed to achieve convergence, whereas the convergence proportion for PGEE was quite high. The bias for the regression coefficients was generally in the ascending order of PGEE < $$ < $$ BCGEE < $$ < $$ GEE. However, PGEE and BCGEE did not sufficiently remove the bias involving 20-30 subjects with unequal exposure levels with a 5% response rate. The coverage probability (CP) of the confidence interval for BCGEE was relatively poor compared with GEE and PGEE. The CP with the sandwich covariance estimator deteriorated regardless of the GEE methods under the small sample size and low response rate, whereas the CP with the modified covariance estimators-such as Morel's method-was relatively acceptable. PGEE will be the reasonable way for analyzing sparse binary data in small-sample studies. Instead of using the standard sandwich covariance estimator, one should always apply the modified covariance estimators for analyzing these data.

Bias in Odds Ratios From Logistic Regression Methods With Sparse Data Sets.

BACKGROUND: Logistic regression models are widely used to evaluate the association between a binary outcome and a set of covariates. However, when there are few study participants at the outcome and covariate levels, the models lead to bias of the odds ratio (OR) estimated using the maximum likelihood (ML) method. This bias is known as sparse data bias, and the estimated OR can yield impossibly large values because of data sparsity. However, this bias has been ignored in most epidemiological studies. METHODS: We review several methods for reducing sparse data bias in logistic regression. The primary aim is to evaluate the Bayesian methods in comparison with the classical methods, such as the ML, Firth's, and exact methods using a simulation study. We also apply these methods to a real data set. RESULTS: Our simulation results indicate that the bias of the OR from the ML, Firth's, and exact methods is considerable. Furthermore, the Bayesian methods with hyper-É¡ prior modeling of the prior covariance matrix for regression coefficients reduced the bias under the null hypothesis, whereas the Bayesian methods with log F-type priors reduced the bias under the alternative hypothesis. CONCLUSION: The Bayesian methods using log F-type priors and hyper-É¡ prior are superior to the ML, Firth's, and exact methods when fitting logistic models to sparse data sets. The choice of a preferable method depends on the null and alternative hypothesis. Sensitivity analysis is important to understand the robustness of the results in sparse data analysis.