Convalescent Plasma Antibody Levels and the Risk of Death from Covid-19.

BACKGROUND: Convalescent plasma has been widely used to treat coronavirus disease 2019 (Covid-19) under the presumption that such plasma contains potentially therapeutic antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that can be passively transferred to the plasma recipient. Whether convalescent plasma with high antibody levels rather than low antibody levels is associated with a lower risk of death is unknown. METHODS: In a retrospective study based on a U.S. national registry, we determined the anti-SARS-CoV-2 IgG antibody levels in convalescent plasma used to treat hospitalized adults with Covid-19. The primary outcome was death within 30 days after plasma transfusion. Patients who were enrolled through July 4, 2020, and for whom data on anti-SARS-CoV-2 antibody levels in plasma transfusions and on 30-day mortality were available were included in the analysis. RESULTS: Of the 3082 patients included in this analysis, death within 30 days after plasma transfusion occurred in 115 of 515 patients (22.3%) in the high-titer group, 549 of 2006 patients (27.4%) in the medium-titer group, and 166 of 561 patients (29.6%) in the low-titer group. The association of anti-SARS-CoV-2 antibody levels with the risk of death from Covid-19 was moderated by mechanical ventilation status. A lower risk of death within 30 days in the high-titer group than in the low-titer group was observed among patients who had not received mechanical ventilation before transfusion (relative risk, 0.66; 95% confidence interval [CI], 0.48 to 0.91), and no effect on the risk of death was observed among patients who had received mechanical ventilation (relative risk, 1.02; 95% CI, 0.78 to 1.32). CONCLUSIONS: Among patients hospitalized with Covid-19 who were not receiving mechanical ventilation, transfusion of plasma with higher anti-SARS-CoV-2 IgG antibody levels was associated with a lower risk of death than transfusion of plasma with lower antibody levels. (Funded by the Department of Health and Human Services and others; ClinicalTrials.gov number, NCT04338360.).

Food-Specific IgG4 Is Elevated Throughout the Upper Gastrointestinal Tract in Eosinophilic Esophagitis.

BACKGROUND: Food-specific immunoglobulin G4 (FS-IgG4) is associated with eosinophilic esophagitis (EoE); however, it is not clear whether production is limited to the esophagus. AIMS: To assess FS-IgG4 levels in the upper gastrointestinal tract and plasma and compare these with endoscopic disease severity, tissue eosinophil counts, and patient-reported symptoms. METHODS: We examined prospectively banked plasma, throat swabs, and upper gastrointestinal biopsies (esophagus, gastric antrum, and duodenum) from control (n = 15), active EoE (n = 24), and inactive EoE (n = 8) subjects undergoing upper endoscopy. Patient-reported symptoms were assessed using the EoE symptom activity index (EEsAI). Endoscopic findings were evaluated using the EoE endoscopic reference score (EREFS). Peak eosinophils per high-power field (eos/hpf) were assessed from esophageal biopsies. Biopsy homogenates and throat swabs were normalized for protein content and assessed for FS-IgG4 to milk, wheat, and egg. RESULTS: Median FS-IgG4 for milk and wheat was significantly increased in the plasma, throat swabs, esophagus, stomach, and duodenum of active EoE subjects compared to controls. No significant differences for milk- or wheat-IgG4 were observed between active and inactive EoE subjects. Among the gastrointestinal sites sampled, FS-IgG4 levels were highest in the esophagus. Esophageal FS-IgG4 for all foods correlated significantly across all sites sampled (r ≥ 0.59, p < 0.05). Among subjects with EoE, esophageal FS-IgG4 correlated significantly with peak eos/hpf (milk and wheat) and total EREFS (milk). EEsAI scores and esophageal FS-IgG4 levels did not correlate. CONCLUSIONS: Milk and wheat FS-IgG4 levels are elevated in plasma and throughout the upper gastrointestinal tract in EoE subjects and correlate with endoscopic findings and esophageal eosinophilia.

Access to and safety of COVID-19 convalescent plasma in the United States Expanded Access Program: A national registry study.

BACKGROUND: The United States (US) Expanded Access Program (EAP) to coronavirus disease 2019 (COVID-19) convalescent plasma was initiated in response to the rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19. While randomized clinical trials were in various stages of development and enrollment, there was an urgent need for widespread access to potential therapeutic agents. The objective of this study is to report on the demographic, geographical, and chronological characteristics of patients in the EAP, and key safety metrics following transfusion of COVID-19 convalescent plasma. METHODS AND FINDINGS: Mayo Clinic served as the central institutional review board for all participating facilities, and any US physician could participate as a local physician-principal investigator. Eligible patients were hospitalized, were aged 18 years or older, and had-or were at risk of progression to-severe or life-threatening COVID-19; eligible patients were enrolled through the EAP central website. Blood collection facilities rapidly implemented programs to collect convalescent plasma for hospitalized patients with COVID-19. Demographic and clinical characteristics of all enrolled patients in the EAP were summarized. Temporal patterns in access to COVID-19 convalescent plasma were investigated by comparing daily and weekly changes in EAP enrollment in response to changes in infection rate at the state level. Geographical analyses on access to convalescent plasma included assessing EAP enrollment in all national hospital referral regions, as well as assessing enrollment in metropolitan areas and less populated areas that did not have access to COVID-19 clinical trials. From April 3 to August 23, 2020, 105,717 hospitalized patients with severe or life-threatening COVID-19 were enrolled in the EAP. The majority of patients were 60 years of age or older (57.8%), were male (58.4%), and had overweight or obesity (83.8%). There was substantial inclusion of minorities and underserved populations: 46.4% of patients were of a race other than white, and 37.2% of patients were of Hispanic ethnicity. Chronologically and geographically, increases in the number of both enrollments and transfusions in the EAP closely followed confirmed infections across all 50 states. Nearly all national hospital referral regions enrolled and transfused patients in the EAP, including both in metropolitan and in less populated areas. The incidence of serious adverse events was objectively low (<1%), and the overall crude 30-day mortality rate was 25.2% (95% CI, 25.0% to 25.5%). This registry study was limited by the observational and pragmatic study design that did not include a control or comparator group; thus, the data should not be used to infer definitive treatment effects. CONCLUSIONS: These results suggest that the EAP provided widespread access to COVID-19 convalescent plasma in all 50 states, including for underserved racial and ethnic minority populations. The study design of the EAP may serve as a model for future efforts when broad access to a treatment is needed in response to an emerging infectious disease. TRIAL REGISTRATION: ClinicalTrials.gov NCT#: NCT04338360.

Cavitary Coccidioidomycosis: Impact of azole antifungal therapy.

Approximately 5 to 15% of patients with pulmonary coccidioidomycosis subsequently develop pulmonary cavities. These cavities may resolve spontaneously over a number of years; however, some cavities never close, and a small proportion causes complications such as hemorrhage, pneumothorax or empyema. The impact of azole antifungal treatment on coccidioidal cavities has not been studied. Because azoles are a common treatment for symptomatic pulmonary coccidioidomycosis, we aimed to assess the impact of azole therapy on cavity closure. From January 1, 2004, through December 31, 2014, we retrospectively identified 313 patients with cavitary coccidioidomycosis and excluded 42 who had the cavity removed surgically, leaving 271 data sets available for study. Of the 271 patients, 221 (81.5%) received azole therapy during 5-year follow-up; 50 patients did not receive antifungal treatment. Among the 271 patients, cavities closed in 38 (14.0%). Statistical modeling showed that cavities were more likely to close in patients in the treated group than in the nontreated group (hazard ratio, 2.14 [95% CI: 1.45-5.66]). Cavities were less likely to close in active smokers than nonsmokers (11/41 [26.8%] vs 97/182 [53.3%]; P = 0.002) or in persons with than without diabetes (27/74 [36.5%] vs 81/149 [54.4%]; P = 0.01).We did not find an association between cavity size and closure. Our findings provide rationale for further study of treatment protocols in this subset of patients with coccidioidomycosis. LAY SUMMARY: Coccidioidomycosis, known as valley fever, is a fungal infection that infrequently causes cavities to form in the lungs, which potentially results in long-term lung symptoms. We learned that cavities closed more often in persons who received antifungal drugs, but most cavities never closed completely.

Diagnosis of Pediatric Non-Esophageal Eosinophilic Gastrointestinal Disorders by Eosinophil Peroxidase Immunohistochemistry.

BACKGROUND: Diagnosis of non-esophageal eosinophilic gastrointestinal disorders requires quantification of tissue eosinophils. Our objective was to evaluate eosinophil peroxidase (EPX) immunohistochemistry (IHC) as a method for histologic diagnosis of eosinophilic gastritis (EG) and eosinophilic duodenitis (EoD). METHODS: We performed a retrospective analysis of biopsies from pediatric EG/EoD cases and controls. Subjects with EG or EoD had ≥30 eosinophils per high power field (eos/hpf) in ≥5 hpf in the stomach and/or ≥3 hpf in the duodenum, respectively. Controls had no histopathologic diagnosis recorded. Tissue eosinophil counts were assessed by hematoxylin & eosin stains. EPX stains were assessed using a unique histopathologic scoring system. Slides were digitized and EPX+ staining area/mm2 was quantified by image analysis. RESULTS: Twenty-six EG/EoD cases and 40 controls were analyzed. EPX scores and EPX/mm2 levels were markedly elevated in EG/EoD (p ≤ 0.0001). Eosinophil density (eos/mm2) correlated strongly with EPX scores and EPX/mm2 levels in the stomach (r ≥ 0.77) and moderately with EPX scores and EPX/mm2 levels in the duodenum (r ≥ 0.52); (p < 0.0001). EPX quantification identified EG/EoD subjects with high diagnostic accuracy (EPX score: AUC = 1 for EG and EoD; EPX/mm2: AUC = 0.98 (95%CI 0.96-1) for EG, AUC = 0.91 (95%CI 0.81-1) for EoD). CONCLUSION: EPX-based assessment of eosinophilic inflammation may facilitate automated histologic diagnosis.

Dose reduction using digital fluoroscopy versus digital subtraction angiography in endovascular aneurysm repair: A prospective randomized trial.

OBJECTIVE: Endovascular aneurysm repair (EVAR) can result in high radiation dose to patients and operators. This prospective randomized study aimed to assess whether patient radiation dose sustained during EVAR could be decreased by predominantly using digital fluoroscopy (DF) vs the standard technique using digital subtraction angiography (DSA). METHODS: Between February 2011 and June 2017, patients with EVAR of infrarenal abdominal aortic aneurysms were prospectively enrolled and randomly assigned to a standard treatment DSA cohort or a DF cohort in which two or fewer DSA acquisitions were allowed for confirmatory imaging. Primary end points included dose-area product (DAP) and cumulative air kerma. Secondary end points included technical success and conversion to DSA standard treatment (if DF was inadequate for visualization). RESULTS: For all 43 patients enrolled (26 in the DF cohort, 17 in the DSA cohort), technical success was 100%. Of the 26 DF patients, 5 (19%) required conversion to the DSA cohort. In an intention-to-treat analysis, mean DAP was significantly lower in the DF cohort than in the DSA cohort (132 vs 174 Gy·cm2; P = .04). When patients were separated by number of DSA acquisitions (two or fewer vs three or more), mean DAP decreased 41% (109 vs 185 Gy·cm2; P = .005) and cumulative air kerma decreased 40% (578 vs 964 mGy; P = .004). CONCLUSIONS: In most patients (81%), DF or limited DSA was adequate for visualization during EVAR. In both intention-to-treat DF and limited-DSA cohorts, mean DAP was significantly decreased. If image quality allows, a DF-only or limited-DSA approach to EVAR decreases radiation dose.

A pilot exploratory study comparing the King-Devick test (KDT) during and between migraine attacks.

BACKGROUND: The King-Devick test is a timed rapid number naming task that involves complex cerebral functions. The objective of this pilot exploratory study is to determine whether there is a difference in the King-Devick test during a migraine attack compared to the interictal phase. METHODS: We evaluated 29 adult subjects with migraine with aura or migraine without aura. For each participant, we performed King-Devick tests during migraine attacks and interictal phases. Subjects served as their own controls. RESULTS: The King-Devick test was slower during the migraine attack compared to the interictal baseline (median 4.6 sec slower, p < 0.001). The slowing of the King-Devick test during migraine attack was more prominent in those with migraine with aura compared to subjects with migraine without aura (median 7.5 vs. 2.8 sec, p = 0.028). CONCLUSIONS: This exploratory, observational study shows changes in the King-Devick test during migraine compared to the interictal phase. Future studies are required to determine if the King-Devick test may be used as a rapid and simple tool to objectively characterize migraine-associated disability.

Effect of bowel preparation volume in inpatient colonoscopy. Results of a prospective, randomized, comparative pilot study.

BACKGROUND: Inpatient status has been shown to be a predictor of poor bowel preparation for colonoscopy; however, the optimal bowel preparation regimen for hospitalized patients is unknown. Our aim was to compare the efficacy of bowel preparation volume size in hospitalized patients undergoing inpatient colonoscopy. METHODS: This prospective, single blinded (endoscopist), randomized controlled trial was conducted as a pilot study at a tertiary referral medical center. Hospitalized patients undergoing inpatient colonoscopy were assigned randomly to receive a high, medium, or low-volume preparation. Data collection included colon preparation quality, based on the Boston Bowel Preparation Scale, and a questionnaire given to all subjects evaluating the ability to completely finish bowel preparation and adverse effects (unpleasant taste, nausea, and vomiting). RESULTS: Twenty-five colonoscopies were performed in 25 subjects. Patients who received low-volume preparation averaged a higher mean total BBPS (7.4, SD 1.62), in comparison to patients who received high-volume (7.0, SD 1.41) and medium-volume prep (6.9, SD 1.55), P = 0.77. When evaluating taste a higher score meant worse taste. The low-volume group scored unpleasant taste as 0.6 (0.74), while the high-volume group gave unpleasant taste a score of 2.2 (0.97) and the medium-volume group gave a score of 2.1 (1.36), P < 0.01. CONCLUSION: In this pilot study we found that low-volume colon preparation may be preferred in the inpatient setting due its better rate of tolerability and comparable bowel cleanliness when compared to larger volume preparation, although we cannot overreach any definitive conclusion. Further more robust studies are required to confirm these findings. TRIAL REGISTRATION: The Affect of Low-Volume Bowel Preparation for Hospitalized Patients Colonoscopies. TRIAL REGISTRATION: NCT01978509 (terminated). Retrospectively registered on November 07, 2013.

Improving Access to Care Through the Establishment of a Local, Teledermatology Network.

Introduction: Access to dermatologic care is a major issue in the United States, especially within the un- and underinsured populations; technology, including teledermatology, will pay a role in improving access to care. Methods: We performed a prospective study between November 2016 and September 2017. We leveraged a partnership between Mayo Clinic and Mountain Park Health Clinic, a community clinic that primarily serves un- and underinsured populations. We implemented a mobile phone-based store and forward (SAF) teledermatology service, which integrated an external community health clinic to an existing electronic health record (EHR) using standardized data capture forms, real-time support, and simple workflows. Results: Thirty-seven patients were enrolled in the study, 65% female and 35% male with an average age of 47.9 (SD = 15.9). The ethnic breakdown was: 81.1% Hispanic, 13.5% Caucasian, and 5.4% African American. The majority, 62.2%, did not have a high school education, 45.9% were unemployed, and 51.4% were uninsured. 64.9% earned less than $25,000 for annual household income. Teledermatology consultation increased the absolute diagnostic and management concordance by 36.6% (p = 0.01, 95% CI 12.2%-61.0%) and 34.2% (p < 0.01, 95% CI 11%-57%), respectively. Primary care providers had a significant increase in mean confidence in the diagnosis and management of dermatology conditions pre and poststudy (3.60 vs. 3.70 and 3.21 vs. 3.60, respectively; p < 0.01). Ninety-six percent of the primary care providers agreed (52.0%) and strongly agreed (44.0%) that they would send another patient for teleconsultation.Conclusion: We successfully implemented a SAF teledermatology consultative service in a community health clinic outside our EHR. A similar approach can be used by other large health care organizations to provide integrated, high-quality consultation to clinics with rural, un- and underinsured populations.

The prognostic value of inositol polyphosphate 5-phosphatase in cutaneous squamous cell carcinoma.

BACKGROUND: Inositol polyphosphate 5-phosphatase (INPP5A) has been shown to play a role in development and progression of cutaneous squamous cell carcinoma (cSCC). The goal of the current study was to explore the prognostic value of INPP5A expression in cSCC. METHODS: A total of 189 cases of actinic keratosis and SCC in 174 patients were identified; clinical and outcome data were abstracted, histopathology was rereviewed, and immunohistochemical staining and interpretation was performed for INPP5A. RESULTS: The majority of tumors (89.4%) had an INPP5A score of 2 or 3. No patients had complete loss of INPP5A. Tumors with an INPP5A score of 1 were more likely to be intermediate- to high-risk tumors (Brigham and Women's Hospital stage ≥T2a 85.0% vs 23.7% [P < .0001]) characterized by a larger diameter (2.4 cm vs 1.3 cm [P = .0004]), moderate-to-poor differentiation (86.7% vs 17.6% [P < .0001]), and perineural invasion (37.5% vs 5.3%, [P < .0001]). An INPP5A score of 1 was associated with a worse 3-year survival (a rate of 42.3% [hazard ratio, 2.81, P = .0006]) and a local metastasis rate of 48.0% (hazard ratio, 4.71; P < .0001). CONCLUSIONS: Low INPP5A scores are predictive of aggressive tumors and may be a useful adjunct to guide clinical management of cSCC.

Clinical and histopathologic features of paraneoplastic granuloma annulare in association with solid organ malignancies: A case-control study.

BACKGROUND: Granuloma annulare (GA) is a granulomatous skin eruption rarely associated with cancer. We report seven cases of paraneoplastic GA in association with solid organ malignancy. OBJECTIVE: To compare the clinical and histopathological features of paraneoplastic GA to case-matched controls of classic GA. METHODS: Retrospective chart and histopathological review of 7 individuals and 13 age- and sex-matched controls. Paraneoplastic GA was defined as GA occurring within 6 months of the diagnosis of solid organ malignancy and/or persistent GA that resolved with cancer treatment. RESULTS: Most cases of paraneoplastic GA were associated with lung cancer (4/7). The clinical and histopathological features of paraneoplastic and classic GA were similar. Compared to classic GA, paraneoplastic GA cases were more often generalized disease (6/7 vs 6/13), refractory to treatment, and had a perivascular inflammatory cell infiltrate (5/7 vs 2/13). All cases of paraneoplastic GA that underwent definitive treatment of their cancer improved. LIMITATIONS: Single-institution, retrospective review with a small sample size. CONCLUSION: Paraneoplastic GA is rare, similar to classic GA, and refractory to treatment. We advocate for age-appropriate screening in individuals with GA that is nonresponsive to multiple lines of systemic treatment and evaluating patients with concerning signs or symptoms for an underlying neoplasm.

The durability of operational improvements with rotational patient assignment.

INTRODUCTION: Previous work has suggested that Emergency Department rotational patient assignment (a system in which patients are algorithmically assigned to physicians) is associated with immediate (first-year) improvements in operational metrics. We sought to determine if these improvements persisted over a longer follow-up period. METHODS: Single-site, retrospective analysis focused on years 2-4 post-implementation (follow-up) of a rotational patient assignment system. We compared operational data for these years with previously published data from the last year of physician self-assignment and the first year of rotational patient assignment. We report data for patient characteristics, departmental characteristics and facility characteristics, as well as outcomes of length of stay (LOS), arrival to provider time (APT), and rate of patients who left before being seen (LBBS). RESULTS: There were 140,673 patient visits during the five year period; 138,501 (98.7%) were eligible for analysis. LOS, APT, and LBBS during follow-up remained improved vs. physician self-assignment, with improvements similar to those noted in the first year of implementation. Compared with the last year of physician self-assignment, approximate yearly average improvements during follow-up were a decrease in median LOS of 18min (8% improvement), a decrease in median APT of 21min (54% improvement), and a decrease in LBBS of 0.69% (72% improvement). CONCLUSION: In a single facility study, rotational patient assignment was associated with sustained operational improvements several years after implementation. These findings provide further evidence that rotational patient assignment is a viable strategy in front-end process redesign.

Are testers also admitters? Comparing emergency physician resource utilization and admitting practices.

OBJECTIVE: To describe the relationship between emergency department resource utilization and admission rate at the level of the individual physician. METHODS: Retrospective observational study of physician resource utilization and admitting data at two emergency departments. We calculated observed to expected (O/E) ratios for four measures of resource utilization (intravenous medications and fluids, laboratory testing, plain radiographs, and advanced imaging studies) as well as for admission rate. Expected values reflect adjustment for patient- and time-based variables. We compared O/E ratios for each type of resource utilization to the O/E ratio for admission for each provider. We report degree of correlation (slope of the trendline) and strength of correlation (adjusted R2 value) for each association, as well as categorical results after clustering physicians based on the relationship of resource utilization to admission rate. RESULTS: There were statistically significant positive correlations between resource utilization and physician admission rate. Physicians with lower resource utilization rates were more likely to have lower admission rates, and those with higher resource utilization rates were more likely to have higher admission rates. CONCLUSIONS: In a two-facility study, emergency physician resource utilization and admission rate were positively correlated: those who used more ED resources also tended to admit more patients. These results add to a growing understanding of emergency physician variability.

Health Behaviors and Preventive Healthcare Utilization Among African-American Attendees at a Faith-Based Public Health Conference: Healthy Churches 2020.

Unhealthy eating habits and physical inactivity along with lack of access to quality healthcare contribute to the marked health disparities in chronic diseases among African-Americans. Faith-based public health conferences offer a potential opportunity to improve health literacy and change health behaviors through health promotion within this population, thereby reducing health disparities. This study examined the self-reported health behaviors and preventive healthcare utilization patterns of 77 participants at a predominantly African-American faith-based public health conference, Healthy Churches 2020. A self-administered questionnaire was distributed to a sample of attendees to assess their health behaviors (diet and physical activity), preventive healthcare utilization (annual healthcare provider visits), and health-promoting activities at their places of worship. The results indicate that attendees of a faith-based public health conference have adequate preventive healthcare utilization, but suboptimal healthy behaviors. Our findings support the need for ongoing health-promoting activities with an emphasis on diet and physical activity among this population.

Impaired Suppression of Plasma Lipid Extraction and its Partitioning Away from Muscle by Insulin in Humans with Obesity.

Context: Humans with obesity and insulin resistance exhibit lipid accumulation in skeletal muscle, but the underlying biological mechanisms responsible for the accumulation of lipid in the muscle of these individuals remain unknown. Objective: We investigated how plasma insulin modulates the extraction of circulating triglycerides (TGs) and non-esterified fatty acids (NEFAs) from dietary and endogenous sources in the muscle of lean, insulin-sensitive humans (Lean-IS) and contrasted these responses to those in humans with obesity and insulin resistance (Obese-IR). Methods: The studies were performed in a postprandial state associated with steady-state plasma TG concentrations. The arterio-venous blood sampling technique was employed to determine the extraction of circulating lipids across the forearm muscle before and after insulin infusion. We distinguished kinetics of TGs and NEFAs from dietary sources across muscle from those from endogenous sources by incorporating stable isotope-labeled triolein in ingested fat. Results: Plasma insulin rapidly suppressed the extraction of plasma TGs from endogenous, but not dietary, sources in the Lean-IS, but same response was absent in the Obese-IR. Furthermore, in the muscle of Lean-IS, plasma insulin decreased the extraction of circulating NEFAs from both dietary and endogenous sources, but in Obese-IR subjects this response was absent for NEFAs from dietary sources. Conclusions: Partitioning of circulating lipids away from the skeletal muscle when plasma insulin increases, such as during the postprandial period, is impaired in humans with obesity and insulin resistance. Trial Registration: ClinicalTrials.gov ( NCT01860911 ).

Avoiding Blunders When Analyzing Correlated Data, Clustered Data, or Repeated Measures.

Rheumatology research often involves correlated and clustered data. A common error when analyzing these data occurs when instead we treat these data as independent observations. This can lead to incorrect statistical inference. The data used are a subset of the 2017 study from Raheel et al consisting of 633 patients with rheumatoid arthritis (RA) between 1988 and 2007. RA flare and the number of swollen joints served as our binary and continuous outcomes, respectively. Generalized linear models (GLM) were fitted for each, while adjusting for rheumatoid factor (RF) positivity and sex. Additionally, a generalized linear mixed model with a random intercept and a generalized estimating equation were used to model RA flare and the number of swollen joints, respectively, to take additional correlation into account. The GLM's ß coefficients and their 95% confidence intervals (CIs) are then compared to their mixed-effects equivalents. The ß coefficients compared between methodologies are very similar. However, their standard errors increase when correlation is accounted for. As a result, if the additional correlations are not considered, the standard error can be underestimated. This results in an overestimated effect size, narrower CIs, increased type I error, and a smaller P value, thus potentially producing misleading results. It is important to model the additional correlation that occurs in correlated data.

Prediction of permanent pacemaker implantation after transcatheter aortic valve replacement: The role of machine learning.

BACKGROUND: Atrioventricular block requiring permanent pacemaker (PPM) implantation is an important complication of transcatheter aortic valve replacement (TAVR). Application of machine learning could potentially be used to predict pre-procedural risk for PPM. AIM: To apply machine learning to be used to predict pre-procedural risk for PPM. METHODS: A retrospective study of 1200 patients who underwent TAVR (January 2014-December 2017) was performed. 964 patients without prior PPM were included for a 30-d analysis and 657 patients without PPM requirement through 30 d were included for a 1-year analysis. After the exclusion of variables with near-zero variance or ≥ 50% missing data, 167 variables were included in the random forest gradient boosting algorithm (GBM) optimized using 5-fold cross-validations repeated 10 times. The receiver operator curve (ROC) for the GBM model and PPM risk score models were calculated to predict the risk of PPM at 30 d and 1 year. RESULTS: Of 964 patients included in the 30-d analysis without prior PPM, 19.6% required PPM post-TAVR. The mean age of patients was 80.9 ± 8.7 years. 42.1 % were female. Of 657 patients included in the 1-year analysis, the mean age of the patients was 80.7 ± 8.2. Of those, 42.6% of patients were female and 26.7% required PPM at 1-year post-TAVR. The area under ROC to predict 30-d and 1-year risk of PPM for the GBM model (0.66 and 0.72) was superior to that of the PPM risk score (0.55 and 0.54) with a P value < 0.001. CONCLUSION: The GBM model has good discrimination and calibration in identifying patients at high risk of PPM post-TAVR.