Samo Wakounig

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Chronic thromboembolic pulmonary hypertension (CTEPH) is characterised by nonresolving pulmonary thromboemboli that can be treated by surgical pulmonary endarterectomy (PEA). The authors of the present study sought to confirm known and to identify novel CTEPH risk factors in a controlled retrospective cohort study of prevalent CTEPH cases collected in three(More)
BACKGROUND Renal dysfunction confers a grave prognosis for patients with congestive heart failure (CHF); even small increases in plasma creatinine are associated with excess mortality. Little, however, is known about prognostic indices and outcome in patients with CHF who (sub-)acutely progress to dialysis dependency. DESIGN AND SETTING We evaluated(More)
Often the effect of at least one of the prognostic factors in a Cox regression model changes over time, which violates the proportional hazards assumption of this model. As a consequence, the average hazard ratio for such a prognostic factor is under- or overestimated. While there are several methods to appropriately cope with non-proportional hazards, in(More)
The analysis of correlations within pairs of survival times is of interest to many research topics in medicine, such as the correlation of survival-type endpoints of twins, the correlation of times till failure in paired organs, or the correlation of survival time with a surrogate endpoint. The dependence of such times is assumed monotonic and thus(More)
We extend the Tarone and Ware scheme of weighted log-rank tests to cover the associated weighted Mantel-Haenszel estimators of relative risk. Weighting functions previously employed are critically reviewed. The notion of an average hazard ratio is defined and its connection to the effect size measure P(Y > X) is emphasized. The connection makes estimation(More)
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