Immortal time bias is a problem arising from methodologically wrong analyses of time‐dependent events in survival analyses. We illustrate the problem by analysis of a kidney transplantation study. Following patients from transplantation to death, groups defined by the occurrence or nonoccurrence of graft failure during follow‐up seemingly had equal overall mortality. Such naive analysis assumes that patients were assigned to the two groups at time of transplantation, which actually are a consequence of occurrence of a time‐dependent event later during follow‐up. We introduce landmark analysis as the method of choice to avoid immortal time bias. Landmark analysis splits the follow‐up time at a common, prespecified time point, the so‐called landmark. Groups are then defined by time‐dependent events having occurred before the landmark, and outcome events are only considered if occurring after the landmark. Landmark analysis can be easily implemented with common statistical software. In our kidney transplantation example, landmark analyses with landmarks set at 30 and 60 months clearly identified graft failure as a risk factor for overall mortality. We give further typical examples from transplantation research and discuss strengths and limitations of landmark analysis and other methods to address immortal time bias such as Cox regression with time‐dependent covariables.

X-linked adrenoleukodystrophy (X-ALD) is highly variable, ranging from slowly progressive adrenomyeloneuropathy to severe brain demyelination and inflammation (cerebral ALD, CALD) affecting males with childhood peak onset. Risk models integrating blood-based biomarkers to indicate CALD onset, enabling timely interventions, are lacking. Therefore, we evaluated the prognostic value of blood biomarkers in addition to current neuroimaging predictors for early detection of CALD. We measured blood biomarkers in a retrospective, male CALD risk-assessment cohort consisting of 134 X-ALD patients and 66 controls and in a phenotype-blinded validation set (25 X-ALD boys, 4-13 years) using Simoa®and Luminex® technologies. Among 25 biomarkers indicating axonal damage, astrocye/microglia activation, or immune-cell recruitment, neurofilament light chain (NfL) had the highest prognostic value for early indication of childhood/adolescent CALD. A plasma NfL cut-off level of 8.33 pg/mL, determined in the assessment cohort, correctly discriminated CALD with an accuracy of 96% [95% CI: 80-100] in the validation group. Multivariable logistic regression models revealed that combining NfL with GFAP or cytokines/chemokines (IL-15, IL-12p40, CXCL8, CCL11, CCL22, and IL-4) that were significantly elevated in CALD vs healthy controls had no additional benefit for detecting neuroinflammation. Some cytokines/chemokines were elevated only in childhood/adolescent CALD and already upregulated in asymptomatic X-ALD children (IL-15, IL-12p40, and CCL7). In adults, NfL levels distinguished CALD but were lower than in childhood/adolescent CALD patients with similar (MRI) lesion severity. Blood GFAP did not differentiate CALD from non-inflammatory X-ALD. Biomarker-based risk prediction with a plasma NfL cut-off value of 8.33 pg/mL, determined by ROC analysis, indicates CALD onset with high sensitivity and specificity in childhood X-ALD patients. A specific pro-inflammatory cytokine/chemokine profile in asymptomatic X-ALD boys may indicate a primed, immanent inflammatory state aligning with peak onset of CALD. Age-related differences in biomarker levels in adult vs childhood CALD patients warrants caution in predicting onset and progression of CALD in adults. Further evaluations are needed to assess clinical utility of the NfL cut-off for risk prognosis of CALD onset. Austrian Science Fund, European Leukodystrophy Association.

Although concomitant mitral regurgitation (MR) and tricuspid regurgitation (TR) are frequently present in patients with aortic stenosis (AS), outcome data are scarce and treatment strategies are controversial. The aim of the present study was to assess the presentation and outcome of patients with AS and coexisting MR and TR. Eighty-nine consecutive patients with severe AS and at least moderate MR (72 functional and 17 degenerative) were included and followed. Seventy-five patients were symptomatic at presentation. Sixty of these had severe symptoms (New York Heart Association class ≥3). Nine additional patients had an indication for valve procedures during follow-up. However, 35 patients were managed conservatively. Isolated aortic valve intervention was performed in 29 patients (22 valve replacement and 7 transcatheter aortic valve replacement) and concomitant mitral valve surgery in 20 patients. For the assessment of outcome, overall survival (i.e. time from study entry to death from any cause) was assessed: adjusted survival was significantly higher for patients undergoing any valve procedure as compared with patients managed conservatively (P = 0.032). Surgical treatment of severe concomitant MR was associated with improved survival in an unadjusted population but did not reach statistical significance after propensity adjustment. 14 of 36 patients who had concomittant moderate-to-severe tricuspid regurgitation (TR) underwent surgery of which 7 (50 %) died within 3 months postoperatively. On the other hand, only 1 of 35 (3%) with no or mild TR undergoing surgery died within 3 months post-operatively (P < 0.001). Presence of MR in patients with severe AS characterizes a high-risk population. Timely aortic valve intervention confers a survival benefit and concomitant mitral valve surgery should be considered according to operative risk. The additional presence of significant TR is associated with dismal outcomes, regardless of the treatment strategy.

While clinical consequences of thiamine deficiency in alcohol use disorder (AUD) are severe, evidence-based recommendations on dosage, type of administration and duration of thiamine substitution (TS), and its’ target levels remain sparse. This study aimed to compare the effect of two best practice TS regimens on thiamine blood levels (i.e. thiamine pyrophosphate, TPP) and cognitive function. In 50 patients undergoing in-patient alcohol-withdrawal treatment, TPP levels were determined at baseline and end of weeks 1, 2 and 8 following administration of oral TS (3 × 100 mg/day for 7 days followed by 1 × 100 mg/day thereafter) either with or without preceding intravenous TS (3 × 100 mg/day for 5 days). An extensive psychiatric assessment was conducted at baseline, including an evaluation of AUD severity and depressive symptoms. Additionally, cognitive function and depressive symptoms were repeatedly evaluated. Relevant increases (mean increase by 100.2 nmol/l [CI 76.5–123.8], P < 0.001) in peripheral blood TPP levels were observed in all patients at the end of weeks 1 and 2. Furthermore, no relevant difference between the intravenous and the oral group was found (average difference between increases: 2.3 nmol/l, P = 0.912). Importantly, an association between the ‘extent of the response’ to TS and the performance in a memory task was revealed in secondary analyses. TS was associated with improving cognitive function in patients with AUD, independently of the substitution regime. Thus, in clinical practice, oral TS might be a sufficient but obligatory medication to prevent cognitive decline in AUD in the absence of Wernicke–Korsakoff Syndrome.

Sensing of noxious heat has been reported to be mediated by TRPV1, TRPA1, TRPM3, and ANO1 in mice, and this is redundant so that the loss of one receptor is at least partially compensated for by others. We have established an infusion-based human heat pain model. Heat-induced pain probed with antagonists for the four receptors did not match the redundancy found in mice. In healthy participants, only TRPV1 contributes to the detection of noxious heat; none of the other three receptors are involved. TRPV1 inhibition reduced the pain at all noxious temperatures, which can also be seen as an increase in the temperature that causes a particular level of pain. However, even if the TRPV1-dependent shift in heat detection is about 1°C, at the end of the temperature ramp to 52°C, most heat-induced pain remains unexplained. This difference between species reopens the quest for the molecular safety net for the detection of noxious heat in humans.