The relationship between EQ-5D, HAQ and pain in patients with rheumatoid arthritis: further validation and development of the limited dependent variable, mixture model approach

Objective To provide robust estimates of EQ-5D as a function of the Health Assessment Questionnaire (HAQ) and pain in patients with rheumatoid arthritis. Method Repeated observations of patients diagnosed with RA in a US observational cohort (n=100,398 observations) who provided data on HAQ, pain on a visual analogue scale and the EQ-5D questionnaire. We use a bespoke mixture modelling approach to appropriately reflect the characteristics of the EQ-5D instrument and compare this to results from linear regression. Results The addition of pain alongside HAQ as an explanatory variable substantially improves explanatory power. The preferred model is a four component mixture. Unlike the linear regression it exhibits very good fit to the data, does not suffer from problems of bias or predict values outside the feasible range. Conclusions It is appropriate to model the relationship between HAQ and EQ-5D but only if suitable statistical methods are applied. Linear models underestimate the QALY benefits, and therefore the cost effectiveness, of therapies. The bespoke mixture model approach outlined here overcomes this problem. The addition of pain as an explanatory variable greatly improves the estimates

Phenotypic Divergence of Indigenous and Translocated Arctic Charr (Salvelinus alpinus) Populations in Maine

Selection on traits related to trophic ecology is recognized as an important contributing factor in adaptive divergence and speciation. For several freshwater fish species, including Arctic charr (Salvelinus alpinus), such selection is commonly reflected in relationships between diet, habitat use and phenotypic divergence. Trophic specializations that emerge have been extensively studied among sympatric forms, but much less is known of the extent of this type of divergence in allopatry. Trait differences among these forms are also thought to reflect thousands of years of evolution, making it difficult to examine root causes of such divergence in natural populations. Here, I address the hypotheses that selection on trophic characters is important to incipient stages of divergence and the maintenance of specialized forms in allopatry, using indigenous and recently translocated populations of Arctic charr in Maine. To address this, I compared aspects of body shape, gill raker morphology, growth, and diet among six populations, including one transplant and its ancestral source. This examination revealed the presence of at least three trophic forms among Maine charr, including a benthic specialist not previously identified in this region. Differences observed among these populations were analogous to those typical of trophic forms found elsewhere in sympatry, though perhaps less extensive in scale. Divergence between a translocated population and its source suggest some aspects of specialization are labile in contemporary time. In combination, these results indicate trophic ecology may play an important role in all stages of adaptive divergence, and niche stability may be important in maintaining trophic specializations over longer periods of time. In light of this new information, I also suggest that management plans for this species in Maine should seek to incorporate more information about such specialized forms, and should employ ecosystem based management to preserve forms within the unique contexts of their respective lake systems. Management approaches that fail to preserve lake community structure in situ are likely to result in either extinctions or revisions of specializations

A comparison of direct and indirect methods for the estimation of health utilities from clinical outcomes

Background: Analysts often need to estimate health state utility values as a function of other outcome measures. Utility values like EQ-5D have several unusual characteristics that make standard statistical methods inappropriate. We have developed a bespoke approach based on mixture models to directly estimate EQ-5D. An indirect method, “response mapping”, first estimates the level on each of the five dimensions of the EQ-5D descriptive system and then calculates the expected tariff score. These methods have never previously been compared. Methods: We use a large observational database of patients diagnosed with Rheumatoid Arthritis (n=100,398 observations). Direct estimation of UK EQ-5D scores as a function of Health Assessment Questionnaire (HAQ), pain and age was performed using a limited dependent variable mixture model. Indirect modelling was undertaken using a set of generalized ordered probit models with expected tariff scores calculated mathematically. Linear regression was reported for comparison purposes. Results: The linear model fits poorly, particularly at the extremes of the distribution. Both the bespoke mixture model and the generalized ordered probit approach offer improvements in fit over the entire range of EQ-5D. Mean average error is 10% and 5% lower compared to the linear model respectively. Root mean squared error is 3% and 2% lower. The mixture model demonstrates superior performance to the indirect method across almost the entire range of pain and HAQ. Limitations: There is limited data from patients in the most extreme HAQ health states. Conclusions: Modelling of EQ-5D from clinical measures is best performed directly using the bespoke mixture model. This substantially outperforms the indirect method in this example. Linear models are inappropriate, suffer from systematic bias and generate values outside the feasible range

Plötzliche Todesfälle von Athleten: umfassende Prävention braucht Evidenz [Les morts subites d’athlètes: la prévention complète a besoin d’évidence ; Swiss Registry of Athletic Related Death: Swissregard.ch]

Wenn Sportler vor laufender Kamera bei einem Wettkampf versterben, konfrontieren das die Zuschauer in besonderer Weise mit den Risiken des Sports. Die Todesfälle der Fussballer Marc-Vivien Foé am FIFA Confederations Cup 2003 und Paulo Sérgio Oliveira da Silva «Serginho» in Sao Paulo 2004, oder des kürzlich bei Paris-Roubaix verstorbenen Radrennfahrers Michael Goolaerts haben eine weltweite Welle der Betroffenheit ausgelöst. Für die Sportmedizin resultiert daraus der klare Leistungsauftrag, durch geeignete Vorsorgeuntersuchungen und Massnahmen an Wettkämpfen diese tragischen Ereignisse so gut wie möglich zu verhindern. Darüber hinaus illustriert der aktuelle Fall des Fussballspielers Davide Astori, dass bei Athleten ein schicksalhafter plötzlicher Herztod nicht nur auf dem Fussballfeld, sondern auch im Schlaf auftreten kann. Eine Registrierung von plötzlichen Todesfällen von Athleten kann zu einem besseren Verständnis der Ursachen und damit auch zu einer besseren Prävention beitragen. Quand des athlètes meurent dans une compétition devant la caméra, ils confrontent le public d’une manière particulière aux risques du sport. La mort des footballeurs Marc-Vivien Foé à la Coupe des Confédérations de la FIFA 2003 et de Paulo Sérgio Oliveira da Silva «Serginho» à Sao Paulo en 2004 ou le récent décès du cycliste Michael Goolaerts lors de Paris-Roubaix ont déclenché une consternation dans le monde entier. Pour la médecine du sport, il en résulte un mandat clair de de développer des examens préventifs adaptés et des mesures adéquates lors des compétitions, afin de prévenir au mieux ces événements tragiques. En outre, le cas récent du footballeur Davide Astori illustre que la mort subite par arrêt cardiaque peut survenir chez les athlètes non seulement sur le terrain mais aussi pendant le sommeil. L’enregistrement des morts subites d’athlètes peut aider à une meilleure compréhension des causes et ainsi les prévenir au mieux

Sub-lethal effects of a copper sulfate fungicide on development and reproduction in three coccinellid species.

Copper-based fungicides reliably control various foliar diseases in citrus production, although they are suspected to exacerbate mite problems through various mechanisms. Studies have shown negative effects of various copper formulations on entomopathogenic fungi, nematodes, and parasitoids, but few have sought to measure its impact on the biology of predatory insects. We exposed the larvae of three species of ladybeetle (Coleoptera: Coccinellidae) to field rates of copper sulfate in combination with petroleum oil, a formulation commonly applied in Florida citrus. First instar larvae of Curinus coeruleus Mulsant, Harmonia axyridis Pallas, and Olla v-nigrum Mulsant received a 24 h exposure to residues on Petri dishes, and another 24 h exposure in the third instar. Treated larvae of all three species survived to adulthood at the same rate as control larvae, but larvae of O. v-nigrum experienced a significant increase in developmental time. Female adults of C. coeruleus and H. axyridis receiving copper sulfate exposures as larvae did not differ from control adults in pre-reproductive period, fecundity or fertility over ten days of reproduction. Treated O. v-nigrum females had significantly longer pre-reproductive periods than control females and laid significantly fewer eggs, although egg fertility was equivalent. We conclude that copper-sulfate fungicides are unlikely to disrupt biological control processes in citrus groves that are mediated by these coccinellid beetles

The Kolmogorov-Smirnov test for the CMB

We investigate the statistics of the cosmic microwave background using the Kolmogorov-Smirnov test. We show that, when we correctly de-correlate the data, the partition function of the Kolmogorov stochasticity parameter is compatible with the Kolmogorov distribution and, contrary to previous claims, the CMB data are compatible with Gaussian fluctuations with the correlation function given by standard Lambda-CDM. We then use the Kolmogorov-Smirnov test to derive upper bounds on residual point source power in the CMB, and indicate the promise of this statistics for further datasets, especially Planck, to search for deviations from Gaussianity and for detecting point sources and Galactic foregrounds.Comment: Improved significance of the results (which remain unchanged) by using patches instead of ring segments in the analysis. Added sky maps of the Kolmogorov-parameter for original and de-correlated CMB ma

Etat de stress post-traumatique : quel type de psychothérapie proposer? : Revue cochrane pour le praticien

L'état de stress post-traumatique (ESPT) apparaît dans les mois qui suivent un ou plusieurs événements potentiellement traumatiques (EPT) (par exemple, guerre, violences, accidents, chirurgie invasive). Les symptômes comprennent des souvenirs intrusifs, des cauchemars, un évitement et des émotions négatives (par exemple, honte, culpabilité, perte d'espoir, sentiment d'étrangeté), ainsi qu'une hypervigilance. Sous-diagnostiqué et sous-traité, l'ESPT a un impact négatif sur la qualité de vie et le fonctionnement des patients. Sa prévalence en Suisse est de 0,7 % (plus élevée dans certaines populations, par exemple, 13 % chez les hommes requérants d'asile déboutés). L'approche psychothérapeutique est centrale dans la prise en charge, un traitement médicamenteux pouvant également être utile. Cette revue (systématique) cherche à actualiser les connaissances sur l'efficacité des psychothérapies pour le traitement de l'ESPT

Prévention de l'état de stress post-traumatique : efficacité des interventions pharmacologiques ? : Revue cochrane pour le praticien

Après un ou plusieurs événements potentiellement traumatisants (EPT), tels qu'accidents, mort inattendue d'une personne aimée, chirurgie invasive, guerre, violences physiques et sexuelles par exemple, certaines personnes peuvent développer un état de stress posttraumatique (ESPT). Elles ont l'impression de revivre le traumatisme et présentent des comportements d'évitement, une hyperexcitation ainsi que des émotions négatives. L'ESPT est associé à une réduction de la qualité de vie des patients concernéset a un impact majeur sur leur fonctionnement. Son coût économique est également important. Sa prévalence varie en Europe de 0,6 à 6,7 %. En Suisse, elle est estimée à 0,7 % mais peut atteindre des niveaux beaucoup plus élevés selon les populations ; 13 % des hommes demandeurs d'asile déboutés souffrent d'ESPT par exemple. Des études suggèrent que des changements cérébraux d'hormones de stress peuvent contribuer à l'ESPT. Cette revue systématique cherche à déterminer si la prescription d'une médication active au niveau cérébral est susceptible de prévenir l'apparition d'un ESPT