P187 Change in Urgency Status Among Ulcerative Colitis Patients: Understanding the Impact of Treatment Changes from the Corrona Inflammatory Bowel Disease Registry

Background Stooling urgency (also known as urgency to defecate) is one of the most common symptoms among Ulcerative Colitis (UC) patients (pts). Understanding factors associated with changes in urgency status, such as the association between timing of treatment changes and subsequent onset or resolution of urgency symptoms, are essential in addressing unmet pts needs. Our aim was to explore treatment frequency and persistence among UC pts stratified by a change in urgency status from enrollment to the 6-month follow-up (6M) visit. Methods Participants included UC pts in the Corrona Inflammatory Bowel Disease Registry between 5/3/17–9/1/20. Stooling urgency was defined as no urgency or urgency using the categories, none and hurry/immediate, from the Simple Clinical Colitis Activity Index (SCCAI). Urgency status groups were formed by urgency at enrollment and the 6M visit: no persistent urgency (NPU), i.e., no urgency at both visits; change from urgency to no urgency (UN); change from no urgency to urgency (NU); and persistent urgency at both visits (PU). Chi-square tests were conducted to compare treatment use and change between urgency status groups (NPU=reference group). Kaplan Meier curves and log-rank tests were used to assess time to first treatment change between urgency status groups. Results The urgency status groups (n=400) included: 44% NPU (n=175), 21% UN (n=86), 14% NU (n=56), and 21% PU (n=83). A higher proportion of UN (47%, p=0.03) and PU (51%, p=0.01) pts received two or more treatments compared to NPU (33%) pts. Compared to NPU pts, pts in all three groups, UN (52% vs. 27%, p< 0.001), NU (45% vs. 27%, p=0.02), and PU (53% vs. 27%, p< 0.001) were more likely to change treatment between enrollment and the 6M visit. Similarly, a higher proportion of pts on a biologic at enrollment, UN (24% vs. 11%, p=0.01), NU (23% vs. 11%, p=0.03), and PU (35% vs 11%, p< 0.001), changed treatment between enrollment and the 6M visit vs. NPU pts. The time to first treatment change was shorter for all other urgency status groups when compared to NPU pts (log-rank tests, all p<0.02) (Figure 1). Among pts without urgency at enrollment, the time to first treatment change was shorter for NU vs. NPU pts (p=0.01) whereas it was similar for pts with urgency at enrollment, UN vs. PU pts (p=0.93) (Figure 1). Conclusion Among UC pts in a real-world setting, there were significant differences in change of treatment and time to treatment change between pts who experienced urgency either at their enrollment visit, 6M, or both, compared to those without urgency. Urgency at any time point is a symptom of great concern to UC pts and is a sign of inadequate therapy, and often is an indication to switch treatment therapy.

A unified approach to power and sample size determination for log-rank tests under proportional and nonproportional hazards

Log-rank tests have been widely used to compare two survival curves in biomedical research. We describe a unified approach to power and sample size calculation for the unweighted and weighted log-rank tests in superiority, noninferiority and equivalence trials. It is suitable for both time-driven and event-driven trials. A numerical algorithm is suggested. It allows flexible specification of the patient accrual distribution, baseline hazards, and proportional or nonproportional hazards patterns, and enables efficient sample size calculation when there are a range of choices for the patient accrual pattern and trial duration. A confidence interval method is proposed for the trial duration of an event-driven trial. We point out potential issues with several popular sample size formulae. Under proportional hazards, the power of a survival trial is commonly believed to be determined by the number of observed events. The belief is roughly valid for noninferiority and equivalence trials with similar survival and censoring distributions between two groups, and for superiority trials with balanced group sizes. In unbalanced superiority trials, the power depends also on other factors such as data maturity. Surprisingly, the log-rank test usually yields slightly higher power than the Wald test from the Cox model under proportional hazards in simulations. We consider various nonproportional hazards patterns induced by delayed effects, cure fractions, and/or treatment switching. Explicit power formulae are derived for the combination test that takes the maximum of two or more weighted log-rank tests to handle uncertain nonproportional hazards patterns. Numerical examples are presented for illustration.

Internal Risk Factors for Low Back Pain in Pole Vaulters and Decathletes: A Prospective Study

Background: Pole vaulters and decathletes frequently experience several types of injuries to their lower back, often resulting in mechanical low back pain (LBP). However, the risk factors for the occurrence of LBP in these athletes have not been defined. Purpose: To determine the physical factors that relate to LBP occurrence for collegiate pole vaulters and decathletes. Study Design: Cohort study; Level of evidence, 2. Methods: We observed 31 pole vaulters and decathletes for 1 year. At the start of the observation period, isokinetic flexion and extension muscle strength of the knee and hip joints were recorded along with active and passive range of motion (ROM) and muscle tightness. Participants were then divided into 2 groups using the median value of each measurement: those below the median (low group) and those above the median (high group). The log-rank test was used to compare LBP occurrence between the low group and high group for all measurements. Multivariate regression analyses were thereafter applied using the Cox proportional hazards regression. Results: Log-rank tests revealed a statistically significant change in the survival curve for the occurrence of LBP in the participants with chronic LBP ( P = .037), the low group for hip flexion peak torque per body weight on the non-takeoff leg ( P = .047), and the low group for passive hip flexion angle on both legs (takeoff leg: P = .034; non-takeoff leg: P = .023). In addition, log-rank tests revealed a statistically significant change in the survival curve for the occurrence of LBP in the low group for passive hip extension angle on the takeoff leg only for the participants without chronic LBP ( P = .014). Conclusion: It may be necessary to acquire sufficient ROM and hip flexion to prevent LBP occurrence in pole vaulters and decathletes.

Extracorporeal Life Support in Kombination mit IABP : Behandlungsmöglichkeiten und Grenzen einer supportiven Therapie bei kardialem Versagen : Retrospektive Analyse von 118 Patienten

Für Patienten mit lebensbedrohlichen Herzkrankheiten ist die Extracorporeal-Life-Support-Behandlung (ECLS) eine sinnvolle Therapiemöglichkeit. Sie bietet für Patienten im kardiogenen Schock ein Zeitfenster, um eine myokardiale Erholung zu erreichen. Hierbei kann in Abhängigkeit vom Krankheitsbild die zusätzliche Anwendung von IABP die Heilungschancen begünstigen. In der durchgeführten retrospektiven Studie wurden 118 Patienten betrachtet, die in der Klinik für Thorax-, Herz- und thorakale Gefäßchirurgie der Universität Frankfurt am Main im Zeitraum von Dezember 2001 bis Ende 2013 eine ECLS-Therapie erhalten haben. Bei 59 Patienten wurde die ECLS-Unterstützung in Kombination mit IABP durchgeführt. Die beiden Patientenkollektive - mit und ohne IABP- sind hinsichtlich ihrer Risikofaktoren vergleichbar. Ausgehend von der Zielsetzung dieser Arbeit wurde analysiert, ob der gleichzeitige Einsatz der IABP bei ECLS – Therapie von Vor- oder sogar von Nachteil ist. Hierfür wurden für die beiden Therapiegruppen Überlebenszeitanalysen nach Kaplan-Meier durchgeführt. Der statistische Vergleich der Überlebensraten und des Weaningerfolgs erfolgte mit Hilfe des Log-Rank-Tests. Die Auswertung der erhobenen Daten hat ergeben, dass kein signifikanter Unterschied bei der 30-Tages-Überlebensrate und dem Weaningerfolg für die beiden Patientenkollektive mit und ohne zusätzliche IABP-Anwendung vorhanden ist. Risikofaktoren wie ein hohes Lebensalter oder eine bereits vor Einlieferung stattgefundene Intubation verringern außerdem die Überlebenschancen nach ECLS - Therapie. Ein fortgeschrittenes NYHA-Stadium konnte nicht als negativer prädiktiver Faktor identifiziert werden. In der Literatur kommt man bezüglich der Mortalität unter alleiniger ECLS-Therapie oder dem zusätzlichen Einsatz einer IABP zu unterschiedlichen Ergebnissen. Diese besagen teilweise, dass ECLS und IABP einander ergänzende Methoden sind, die sich durchaus synergistisch auf den Behandlungserfolg auswirken können und dass die Mortalität beim zusätzlichen Einsatz einer IABP signifikant niedriger ist. Die Durchführung weiterer prospektiver Studien mit vergleichbaren Patientenkollektiven zur Untersuchung des Outcomes bei den unterschiedlichen Behandlungsmethoden ist jedoch erforderlich, um ein aussagekräftiges Fazit ziehen zu können.