Dynamic predicting by landmarking as an alternative for multi-state modeling: an application to acute lymphoid leukemia data

This paper considers the problem of obtaining a dynamic prediction for 5-year failure free survival after bone marrow transplantation in ALL patients using data from the EBMT, the European Group for Blood and Marrow Transplantation. The paper compares the new landmark methodology as developed by the first author and the established multi-state modeling as described in a recent Tutorial in Biostatistics in Statistics in Medicine by the second author and colleagues. As expected the two approaches give similar results. The landmark methodology does not need complex modeling and leads to easy prediction rules. On the other hand, it does not give the insight in the biological processes as obtained for the multi-state model

Stereoscopic three-dimensional visualisation technology in anatomy learning: A meta-analysis

Objectives: The features that contribute to the apparent effectiveness of three-dimensional visualisation technology [3DVT] in teaching anatomy are largely unknown. The aim of this study was to conduct a systematic review and meta-analysis of the role of stereopsis in learning anatomy with 3DVT. Methods: The review was conducted and reported according to PRISMA Standards. Literature search of English articles was performed using EMBASE, MEDLINE, CINAHL EBSCOhost, ERIC EBSCOhost, Cochrane CENTRAL, Web of Science and Google Scholar databases until November 2019. Study selection, data extraction and study appraisal were performed independently by two authors. Articles were assessed for methodological quality using the Medical Education Research Study Quality Instrument and the Cochrane Collaboration's tool for assessing the risk of bias. For quantitative analysis, studies were grouped based on relative between-intervention differences in instructional methods and type of control conditions. Results: A total of 3934 citations were obtained of which 67 underwent a full-text review. Ultimately, 13 randomised controlled trials were included in the meta-analysis. When interactive, stereoscopic 3D models were compared to interactive, monoscopic 3D models within a single level of instructional design, for example isolating stereopsis as the only true manipulated element in the experimental design, an effect size [ES] of 0.53 (95% confidence interval [CI] 0.26-0.80; P <.00001) was found. In comparison with 2D images within multiple levels of instructional design, an effect size of 0.45 (95% CI 0.10-0.81; P <.002) was found. Stereopsis had no effect on learning when utilised with non-interactive 3D images (ES = −0.87, 95% CI −2.09-0.35; P =.16). Conclusion: Stereopsis is an important distinguishing element of 3DVT that has a significant positive effect on acquisition of anatomical knowledge when utilised within an interactive 3D environment. A distinction between stereoscopic and monoscopic 3DVT is essential to make in anatomical education and research

Prediction meets causal inference: the role of treatment in clinical prediction models

In this paper we study approaches for dealing with treatment when developing a clinical prediction model. Analogous to the estimand framework recently proposed by the European Medicines Agency for clinical trials, we propose a ‘predictimand’ framework of different questions that may be of interest when predicting risk in relation to treatment started after baseline. We provide a formal definition of the estimands matching these questions, give examples of settings in which each is useful and discuss appropriate estimators including their assumptions. We illustrate the impact of the predictimand choice in a dataset of patients with end-stage kidney disease. We argue that clearly defining the estimand is equally important in prediction research as in causal inference

Influence of genotyping error in linkage mapping for complex traits – an analytic study

<p>Abstract</p> <p>Background</p> <p>Despite the current trend towards large epidemiological studies of unrelated individuals, linkage studies in families are still thoroughly being utilized as tools for disease gene mapping. The use of the single-nucleotide-polymorphisms (SNP) array technology in genotyping of family data has the potential to provide more informative linkage data. Nevertheless, SNP array data are not immune to genotyping error which, as has been suggested in the past, could dramatically affect the evidence for linkage especially in selective designs such as affected sib pair (ASP) designs. The influence of genotyping error on selective designs for continuous traits has not been assessed yet.</p> <p>Results</p> <p>We use the identity-by-descent (IBD) regression-based paradigm for linkage testing to analytically quantify the effect of simple genotyping error models under specific selection schemes for sibling pairs. We show, for example, that in extremely concordant (EC) designs, genotyping error leads to decreased power whereas it leads to increased type I error in extremely discordant (ED) designs. Perhaps surprisingly, the effect of genotyping error on inference is most severe in designs where selection is least extreme. We suggest a genomic control for genotyping errors via a simple modification of the intercept in the regression for linkage.</p> <p>Conclusion</p> <p>This study extends earlier findings: genotyping error can substantially affect type I error and power in selective designs for continuous traits. Designs involving both EC and ED sib pairs are fairly immune to genotyping error. When those designs are not feasible the simple genomic control strategy that we suggest offers the potential to deliver more robust inference, especially if genotyping is carried out by SNP array technology.</p

The skeletons of free distributive lattices

AbstractThe skeletons of free distributive lattices are studied by methods of formal concept analysis; in particular, a specific closure system of sublattices is elaborated to clarify the structure of the skeletons. Up to five generators, the skeletons are completely described

Illness perceptions and quality of life in patients with non-small-cell lung cancer

__Purpose:__ Examine illness perceptions, functional health and quality of life of lung cancer patients throughout chemotherapy treatment. __Patients and Methods:__ Longitudinal design with baseline measure 12 days after the first chemotherapy and follow-up measure 3 months later, where illness perceptions (BIPQ), functional health, and quality of life (EORTC QLQ-C-30) were measured. A total of 21 patients with non-small-cell lung cancer took part. Non-parametric testing was performed given the pilot nature of the study and the associated relatively small sample size. __Results:__ Small to medium changes in illness perceptions and functional health between the two measurement points were detected, with both becoming more positive. More negative illness perceptions at the beginning of the treatment were associated with less functioning and lower quality of life at both beginning and end of treatment. __Conclusion:__ Addressing illness perceptions seems a clinically relevant approach in improving functioning and quality of life of patients with non-small-cell lung cancer

Seksuele disfunctie en relatieproblemen na prostaatkankerbehandeling: De gewenste zorg vanuit het oogpunt van patiënt en partner

Erectile dysfunction (ED) is one of the most common side effects of prostate cancer (PC) treatment and may lead to changes in a relationship. The aim of this study was to identify sexual and/or relational problems and to investigate what kind of supportive care is preferred by patients and their partners. A cross-sectional survey was performed among men diagnosed with PC enrolled in active surveillance or treated with laparoscopic radical prostatectomy, brachytherapy, intensity-modulated radiotherapy or hormonal therapy. If possible, partners were included as well. Out of 250 patients, 80,5% suffered from moderate to severe erectile complaints. Half of them (53,7%) was treated for ED and a great part was partially (30,7%) up to not satisfied (25,7%). Out of 168 partners, 50,6% found it difficult to cope with changes around sexuality. The majority of men (74,7%) preferred a standard consultation with a urologist-sexologist three months after treatment to discuss sexuality

DNA methylation differences after exposure to prenatal famine are common and timing

Prenatal famine in humans has been associated with various later-life consequences, depending on the gestational timing of the insult and the sex of the exposed individual. Epigenetic mechanisms have been proposed to underlie these associations. Indeed, animal studies and our early human data on the imprinted IGF2 locus indicated a link between prenatal nutritional and DNA methylation. However, it remains unclear how common changes in DNA methylation are and whether they are sex-and timing-specific paralleling the later-life consequences of prenatal famine exposure. To this end, we investigated the methylation of 15 loci implicated in growth and metabolic disease in individuals who were prenatally exposed to a war-time famine in 1944-45. Methylation of INSIGF was lower among individuals who were periconceptionally exposed to the famine (n 5 60) compared with their unexposed same-sex siblings (P 5 2 3 10 25 ), whereas methylation of IL10, LEP, ABCA1, GNASAS and MEG3 was higher (all P &lt; 10 23 ). A significant interaction with sex was observed for INSIGF, LEP and GNASAS. Next, methylation of eight representative loci was compared between 62 individuals exposed late in gestation and their unexposed siblings. Methylation was different for GNASAS (P 5 1.1 3 10 27 ) and, in men, LEP (P 5 0.017). Our data indicate that persistent changes in DNA methylation may be a common consequence of prenatal famine exposure and that these changes depend on the sex of the exposed individual and the gestational timing of the exposure

Frequency and prognosis of associated malignancies in 504 patients with lymphomatoid papulosis

Background: Lymphomatoid papulosis (LyP) can be associated with other haematological malignancies (HM), but reported percentages vary from 20% to over 50%. Objective: To evaluate the frequency and prognostic significance of associated HM and non-HM in LyP patients. Methods: In this multicentre cohort study, the complete Dutch LyP population was included from the Dutch Cutaneous Lymphoma Registry between 1985 and 2018. Clinical and histopathological information was retrieved from every individual patient. Results: After a median follow-up of 120 months (range, 6–585), an associated HM was observed in 78/504 (15.5%) patients. Most common associated HM were mycosis fungoides (MF; n = 31) and anaplastic large-cell lymphoma (ALCL; n = 29), while 19 patients had another HM of B-cell (n = 14) or myeloid origin (n = 5). Even after a 25-year follow-up period, percentages of associated HM did not exceed 20%. Thirty-nine of 465 patients (8.4%) without a prior or concurrent associated HM developed an associated HM during follow-up, after a median of 68 months (range of 3–286 months). Nine of 78 patients died of associated HM, including 6/22 patients developing extracutaneous ALCL, while all patients with associated MF or skin-limited ALCL had an excellent prognosis. Compared with the general population, LyP patients showed an increased risk (relative risk, 2.8; 95% confidence intervals, 2.4–3.3) for non-HM, in particular cutaneous squamous cell carcinoma, melanoma and intestinal/lung/bladder cancer. Conclusions: An associated HM was reported in 15.5% of the LyP patients, particularly MF and ALCL. Although the frequency of associated HM is lower than suggested and the prognosis of most patients with associated HM is excellent, a small subgroup will develop aggressive disease, in particular extracutaneous ALCL. Furthermore, LyP patients have a higher risk of developing other malignancies. Clinicians should be aware of these risks, and LyP patients require close monitoring