Faculty Bibliography

BACKGROUND AND PURPOSE/OBJECTIVE:The National Institutes of Health Stroke Scale (NIHSS) measured at an early time point is an appealing surrogate marker for long-term functional outcome of stroke patients treated with endovascular therapy. However, definitions and analytical methods for an early NIHSS-based outcome measure that optimize power and precision in clinical studies are not well-established. METHODS:In this post-hoc analysis of our prospective observational study that enrolled endovascular therapy-treated patients at 12 comprehensive stroke centers across the US, we compared the ability of 24-hour NIHSS, ΔNIHSS (baseline minus 24-hour NIHSS), and percentage change (NIHSS×100/baseline NIHSS), analyzed as continuous and dichotomous measures, to predict 90-day modified Rankin Scale (mRS) using logistic regression (adjusted for age, baseline NIHSS, glucose, hypertension, Alberta Stroke Program Early CT Score, time to recanalization, recanalization status, and intravenous thrombolysis) and Spearman ρ. RESULTS:<0.001). CONCLUSIONS:Twenty-four-hour NIHSS, adjusted for baseline, was the strongest predictor of both dichotomous and ordinal 90-day mRS outcomes for endovascular therapy-treated patients. A dichotomous 24-hour NIHSS score of ≤7 was the second-best predictor. Although ΔNIHSS, continuous and dichotomized at ≥4, predicted 90-day outcomes, absolute 24-hour NIHSS definitions performed better.

Background/UNASSIGNED:Patients on maintenance hemodialysis are particularly vulnerable to infection and hospitalization from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Due to immunocompromised patients and the clustering that occurs in outpatient dialysis units, the seroprevalence of COVID-19 antibodies in this population is unknown and has significant implications for public health. Also, little is known about their risk factors for hospitalization. Methods/UNASSIGNED:nasopharyngeal, real-time, reverse-transcriptase PCR (RT-PCR); SARS-CoV-2 IgG seropositivity; hospitalization; and mortality. Results/UNASSIGNED:<0.001) compared with those who tested negative. Higher positivity rates were also observed among those who took taxis and ambulettes to and from dialysis, compared with those who used personal transportation. Antibodies were detected in all of the patients with a positive PCR result who underwent serologic testing. Of those that were seropositive, 32% were asymptomatic. The hospitalization rate on the basis of either antibody or PCR positivity was 35%, with a hospital mortality rate of 33%. Aside from COPD, no other variables were more prevalent in patients who were hospitalized. Conclusions/UNASSIGNED:We observed significant differences in rates of COVID-19 infection within three outpatient dialysis units, with universal seroconversion. Among patients with ESKD, rates of asymptomatic infection appear to be high, as do hospitalization and mortality rates.

BACKGROUND AND PURPOSE/OBJECTIVE:There has been an increasing prevalence of Moyamoya disorder (MMD) reported from recent US literature. There is a paucity of data available regarding trends of prevalence and epidemiological factors in the United States. To goal of this study was to test the hypotheses that racial-, sex-specific MMD hospitalizations and epidemiological factors have been increasing in the United States over the last decade. METHODS:In this retrospective observational study, using the National Inpatient Sample (NIS) database from 2005 to 2016, MMD-related hospitalizations in patients aged ≥18 years were identified. Trends of epidemiological factors were analyzed over time using the linear regression model with the significance of differences in trend over time assessed using the Wald test. Sex- and race-specific burden of MMD were calculated using the annual US Census data. Joinpoint regression model was used to evaluate trends of hospitalizations over time. RESULTS:A total of 24,484 adult hospitalizations were identified from January 2005 to September 2015 after excluding <18 years. Among them, approximately ~90% were aged ≤60 years, and 73.5% were females. The most common vascular and non-vascular presentations were ischemic stroke (17.3%) and seizures (21%), respectively. The trend of antithrombotic therapy has increased, while extracranial-intracranial bypass has remained stagnant. The actual average hospitalizations of MMD was 10.4 cases/ million population/year (range 4.1-17.9) and varied significantly by sex (females 14.7 [range 6.2-23.6] and males 5.9 [range 1.8-11.9]) over the 2005 to 2016 study period. The burden of hospitalizations also differed by race (African Americans 40.6 [range 32.8-63.7], Asians 24.8 [15.4-34.8], Non-Hispanic Whites 8.1 [range 6.4-11.5], and Hispanics 8.4 [2.8-12.8]) over the 2010 to 2016 study period. Joinpoint regression analysis showed an increasing overall MMD trend across the study period (+11.7%; P < 0.001), which was higher in males (+14.5% vs. +10.7%; P < 0.001). The Hispanic group had significantly increased hospitalizations over the years (+20.2%; P < 0.001). CONCLUSION/CONCLUSIONS:Although overall more prevalent in females, MMD-related hospitalizations are increasing more rapidly in males. Among the racial subpopulations, African Americans had the highest MMD-related hospitalizations, even higher than Asian Americans. MMD-related hospitalizations have increased quicker in Hispanics than in any other racial group.

Background and Purpose- Although higher blood pressure variability (BPV) is associated with worse functional outcome after stroke, this association is not as well established in large vessel occlusion strokes treated with endovascular treatment (EVT). Methods- In this post hoc analysis of BEST (Blood Pressure after Endovascular Therapy for Ischemic Stroke), a prospective, multicenter cohort study of anterior circulation acute ischemic stroke patients undergoing EVT, we determined the association of BPV with poor outcome or death (90-day modified Rankin Scale, 3-6). We calculated BPV during the first 24 hours after EVT for systolic and diastolic BP using 5 methodologies, then divided BPV into tertiles and compared the highest to lowest tertile using logistic regression. Results- Of the 443 patients included in our analysis, 259 (58.5%) had a poor outcome, and 79 (17.8%) died. All measures of BPV were significantly higher in patients with poor outcome or death, but the difference was more pronounced for systolic than diastolic BPV. In the logistic regression, the highest tertile of systolic BPV consistently predicted poor outcome (odds ratio, 1.8-3.5, all P<0.05). The rate of death within 90 days was 10.1% in the tertile with the lowest systolic BPV versus 25.2% in the tertile with the highest BPV (P<0.001). Conclusions- In EVT-treated stroke patients, higher BPV in the first 24 hours is associated with worse 90-day outcome. This association was more robust for systolic BPV. The mechanism by which BPV may exert a negative influence on neurological outcome remains unknown, but the consistency of this association warrants further investigation and potentially intervention.

Background and Purpose- To identify the specific post-endovascular stroke therapy (EVT) peak systolic blood pressure (SBP) threshold that best discriminates good from bad functional outcomes (a priori hypothesized to be 160 mm Hg), we conducted a prospective, multicenter, cohort study with a prespecified analysis plan. Methods- Consecutive adult patients treated with EVT for an anterior ischemic stroke were enrolled from November 2017 to July 2018 at 12 comprehensive stroke centers accross the United States. All SBP values within 24 hours post-EVT were recorded. Using Youden index, the threshold of peak SBP that best discriminated primary outcome of dichotomized 90-day modified Rankin Scale score (0-2 versus 3-6) was identified. Association of this SBP threshold with the outcomes was quantified using multiple logistic regression. Results- Among 485 enrolled patients (median age, 69 [interquartile range, 57-79] years; 51% females), a peak SBP of 158 mm Hg was associated with the largest difference in the dichotomous modified Rankin Scale score (absolute risk reduction of 19%). Having a peak SBP >158 mm Hg resulted in an increased likelihood of modified Rankin Scale score 3 to 6 (odds ratio, 2.24 [1.52-3.29], P<0.01; adjusted odds ratio, 1.29 [0.81-2.06], P=0.28, after adjustment for prespecified variables). Conclusions- A peak post-EVT SBP of 158 mm Hg was prospectively identified to best discriminate good from bad functional outcome. Those with a peak SBP >158 had an increased likelihood of having a bad outcome in unadjusted, but not in adjusted analysis. The observed effect size was similar to prior studies. This finding should undergo further testing in a future randomized trial of goal-targeted post-EVT antihypertensive treatment.

This review identifies 10 common errors and problems in the statistical analysis, design, interpretation, and reporting of obesity research and discuss how they can be avoided. The 10 topics are: 1) misinterpretation of statistical significance, 2) inappropriate testing against baseline values, 3) excessive and undisclosed multiple testing and "P-value hacking," 4) mishandling of clustering in cluster randomized trials, 5) misconceptions about nonparametric tests, 6) mishandling of missing data, 7) miscalculation of effect sizes, 8) ignoring regression to the mean, 9) ignoring confirmation bias, and 10) insufficient statistical reporting. It is hoped that discussion of these errors can improve the quality of obesity research by helping researchers to implement proper statistical practice and to know when to seek the help of a statistician.