Marginalization of Regression-Adjusted Treatment Effects in Indirect Comparisons with Limited Patient-Level Data

Population adjustment methods such as matching-adjusted indirect comparison (MAIC) are increasingly used to compare marginal treatment effects when there are cross-trial differences in effect modifiers and limited patient-level data. MAIC is sensitive to poor covariate overlap and cannot extrapolate beyond the observed covariate space. Current outcome regression-based alternatives can extrapolate but target a conditional treatment effect that is incompatible in the indirect comparison. When adjusting for covariates, one must integrate or average the conditional estimate over the population of interest to recover a compatible marginal treatment effect. We propose a marginalization method based on parametric G-computation that can be easily applied where the outcome regression is a generalized linear model or a Cox model. In addition, we introduce a novel general-purpose method based on multiple imputation, which we term multiple imputation marginalization (MIM) and is applicable to a wide range of models. Both methods can accommodate a Bayesian statistical framework, which naturally integrates the analysis into a probabilistic framework. A simulation study provides proof-of-principle for the methods and benchmarks their performance against MAIC and the conventional outcome regression. The marginalized outcome regression approaches achieve more precise and more accurate estimates than MAIC, particularly when covariate overlap is poor, and yield unbiased marginal treatment effect estimates under no failures of assumptions. Furthermore, the marginalized regression-adjusted estimates provide greater precision and accuracy than the conditional estimates produced by the conventional outcome regression, which are systematically biased because the measure of effect is non-collapsible

Plataformas emergentes para monitorear la ocurrencia y amenazas de aves marinas críticamente en peligro: El albatros de Galápagos en Chile y en el Pacífico Sudeste

Long-lived seabird species such as albatrosses and petrels, which are widely distributed at sea a nd have small populations are threatened globally by bycatch in fisheries. Among these, the waved albatross Phoebastria irrorata is scarcely detected in the Exclusive Economic Zones (EEZs) of countries beyond its traditional distribution throughout the Southeast Pacific. In this article, in situ distributional records on the waved albatross obtained from non-systematic (pelagic birdwatching) and systematic (fishery monitoring) records were compiled. Occurrence of sightings was carried out in relation to recording traits as presence/absence of breeding period and El Niño proxies such as the Southern Oscillation Index (SOI), among others. A total of 13 sightings of waved albatrosses was described which 76.9% of sightings were related to non-breeding period (December to April). Records indicated waved albatrosses reached 4,391 km south of the Galapagos Islands (38°S) and 920 km west of the South American coast (79°W). The waved albatross was associated with industrial pelagic longline and demersal trawl fisheries, and although there were no records of bycatch, the observation of individuals feeding on discards and offal suggests a potential risk of mortality for this species. 53.8% of sightings were during positive readings of the Southern Oscillation Index (SOI), representing colder conditions than neutral El Niño Southern Oscillation (ENSO).Las especies de aves marinas longevas, tales como albatros y petreles ampliamente distribuidos en el mar y con poblaciones reducidas, tienen a la captura incidental en pesquerías como una de las principales amenazas para su conservación. Entre estas, el albatros de Galápagos Phoebastria irrorata es escasamente detectado en las Zonas Económicas Exclusivas (ZEE) de países más allá de su distribución tradicional a lo largo del Pacífico Sudeste. En este artículo se recopilan registros distribucionales del albatros de Galápagos in situ y obtenidos desde observaciones no sistemáticas en el mar, tales como actividades de turismo (i.e., observación pelágica de aves) desde la década de 1980s en adelante. A su vez, se incorporan registros desde monitoreos sistemáticos en pesquerías de palangre y arrastre, operando entre el norte y centro-sur de Chile (Pacífico Sudeste). La ocurrencia de avistamientos fue analizada según características ambientales relacionadas a estos, como presencia/ausencia de periodo reproductivo e indicadores de eventos El Niño, tal como valores negativos en el Índice de Oscilación Sur (IOS), entre otros. Se describió un total de 13 avistamientos del albatros de Galápagos y con 76,9% de estos fuera de su periodo reproductivo (diciembre a abril). Los registros evidencian una distribución meridional del albatros de Galápagos hasta el centro-sur de Chile (38°S), alcanzando 4.391 km al sur de Islas Galápagos, así como hasta 920 km al oeste (79°O) desde la costa Sudamericana. El albatros de Galápagos fue registrado en asociación con pesquerías industriales de palangre pelágico y arrastre demersal. No hubo registros de captura incidental, aunque la observación de individuos asociados a barcos de estas pesquerías para alimentarse de descartes y eviscerados sugiere un potencial riesgo de mortalidad para esta especie. El 53,8% de los avistamientos fueron durante lecturas positivas del Índice de Oscilación Sur (IOS), representando condiciones más frías que las neutrales de El Niño Oscilación Sur (ENOS)

Utilización de harina de pimiento morrón (capsicum annuum) en la elaboración de pan artesanal

The use of food wastes to enhance existing products such as breads by their nutritional properties, is a field that has become more popular within the years. Bell peppers (Capsicum annuum) are a rich source of fibre and carotenoids, also the increasing need of these nutrients are vital to reduce and prevent future diseases. Along this article, certain methods are employed in order to obtain the bell pepper flour and a 10 %, 15 % and 20 % substitution of wheat flour for bell pepper flour is made. The products were analysed to obtain their unique characteristics, resulting in the 10 % substitution being the best option for either acceptance and versatility in future markets. It showed a P value of 0.318 in relation to the protein content and a P value of 0.000 in relation to the fibre content.El uso de alimentos de desecho para enriquecer las propiedades de un producto como lo es el pan, mediante sus propiedades nutricionales es un área que ha ganado interés en los últimos años. El pimiento morrón (Capsicum annuum) es una rica fuente de fibra y carotenoides. La necesidad del consumo en los humanos de dichos fitonutrientes ha incrementado debido a sus propiedades preventivas. Diferentes métodos como deshidratación y molienda para la obtención de la harina de pimiento y para una realización de panes con diversos porcentajes de sustitución de harina de trigo común por harina de pimiento son mostrados. Sus características únicas mostraron aquel con un 10 % de sustitución como la mejor opción por su aceptación y versatilidad en futuros mercados. Se obtuvo un P valor de 0.318 con relación al contenido proteico mientras que para fibra se obtuvo un P valor de 0.000

PATOLOGIA TENDINEA, VASCULAR Y TUMORAL DE LA MANO: HALLAZGOS ULTRASONOGRAFICOS

El desarrollo de transductores de alta resolución (10-15 MHz), permite ahora evaluar con certeza, en forma rápida y a bajo costo, lesiones inflamatorias, traumáticas y tumorales de las manos. Esta presentación analiza los hallazgos ultrasonográficos de las patologías más frecuentes de la mano. Esto incluye tenosinovitis, roturas tendíneas, lesiones vasculares y tumorales<br>The development of high resolution transducer (10-15 MHz), allows to evaluate with certainty, rapidly ant low cost, inflammatory, traumatic and tumoral lesions of the hand.This article reviews the sonographic findings of the more common pathologic condition of the hands. These include tenosynovitis, tendinous injuries of the hand, vascular lesions and solid soft tissue tumor

Meta-Analyses of Factors Associated with Leptospirosis in Domestic Dogs

Factors related with leptospirosis in domestic dogs have been reported worldwide. The aims of this study were to identify factors associated with this disease described in different observational studies and to combine the coinciding factors in at least four studies using meta-analyses, to obtain a pooled odds ratio (OR) as measure of infection risk. A literature search was performed in electronic databases, electronic databases of specific journals and search engines to find studies published in English, Spanish and Portuguese available from January 1960 to January 2015. Two hundred and eighteen factors were identified in 31 publications including cross-sectional and case-control studies. Finally, independent meta-analyses were performed with six different variables, which included between 4 and 8 articles. The pooled OR indicated that the variables 'mixed-breed dogs', 'flooding occurrence in the habitat of the dog' and 'working dogs' were risk factors for leptospirosis, while 'being a dog less than 1 year old' was a protective factor however, all these associations were not statistically significant. Otherwise, the variables 'male dog' and 'urban dog' were statistically significant risk factors for infection. This study highlights the need for more formal studies on the epidemiology of canine leptospirosis. Nevertheless, the study revealed that some risk factors for infection coincided in different observational studies. These factors could be considered to raise suspicion about the disease, especially when there is a history of exposure to the bacteria

Risk factors for seropositivity to feline retroviruses among owned domestic cats in Valdivia, southern Chile

We identified risk factors associated with seropositivity to feline leukaemia virus (FeLV) or feline immunodeficiency virus (FIV) and the association between seropositivity to these retroviruses and the presence of clinical signs. Cats under veterinary care had lower risk of FeLV seropositivity and male cats had higher risk of FIV seropositivity. FeLV seropositive animals had higher odds of non-specific clinical signs and reproductive disorders. FIV seropositive cats had higher odds of buccal alterations. These findings are useful to obtain a first approach to identifying felines that need the application of diagnostic tests for retroviral infections

Páramos

Publicado en: Aguilera, Manuel O., Azócar, Aura, González, E. (Eds). Biodiversidad en Venezuela. Ediciones Fundación Polar, Venezuela, pp. [email protected]