Anemia en pacientes de edad avanzada con insuficiencia cardíaca ingresados en un servicio de medicina interna

Introducción: la anemia es una entidad muy prevalente en pacientes con insuficiencia cardíaca (IC) y se asocia a mayor morbimortalidad. Objetivos: analizar las comorbilidades de pacientes hospitalizados de ≥ 65 años con IC. Estudiar el impacto de la anemia sobre esta población y comparar esta comorbilidad respecto a aquéllos que no la presentan en relación a la valoración geriátrica integral (VGI), así como la adecuación del tratamiento farmacológico en la IC. Pacientes y métodos: estudio descriptivo observacional transversal de una cohorte de 150 pacientes ingresados en el Servicio de Medicina Interna del Hospital Vall d’Hebron, entre junio de 2007 y enero de 2010, mediante entrevista clínica y recogida de datos de la historia clínica. Resultados: en la muestra prevalecían las mujeres (62%), los pacientes con hipertensión (84%), los que tenían la FEVI conservada (66,4%) y los pacientes con anemia (61,3%), de los cuales el 60,9% presentaban anemia inflamatoria y el 35,9% anemia ferropénica. Los pacientes con anemia tuvieron peor valor de MNA (p=0,017, con un RR de 2,7), mayor diferencial de Barthel (p=0,021) y peor valor de albuminemia (p=0,001). Asimismo, se observó que 53 pacientes con indicación según las guías clínicas de tratamiento con IECA o ARA II no lo seguían, y hasta 105 pacientes en el caso de los betabloqueantes (BB). Conclusiones: los pacientes con anemia presentaban pero estado nutricional, y mayor empeoramiento del índice de Barthel. Respecto al tratamiento de la IC, destacaba el gran número de pacientes sin tratamiento con IECA, ARA II o BB, que deberían llevarlo según las guías de práctica clínica.

Hardy-Weinberg Equilibrium and the Ternary Plot

The Hardy-Weinberg law, formulated about 100 years ago, states that under certainassumptions, the three genotypes AA, AB and BB at a bi-allelic locus are expected to occur inthe proportions p2, 2pq, and q2 respectively, where p is the allele frequency of A, and q = 1-p.There are many statistical tests being used to check whether empirical marker data obeys theHardy-Weinberg principle. Among these are the classical xi-square test (with or withoutcontinuity correction), the likelihood ratio test, Fisher's Exact test, and exact tests in combinationwith Monte Carlo and Markov Chain algorithms. Tests for Hardy-Weinberg equilibrium (HWE)are numerical in nature, requiring the computation of a test statistic and a p-value.There is however, ample space for the use of graphics in HWE tests, in particular for the ternaryplot. Nowadays, many genetical studies are using genetical markers known as SingleNucleotide Polymorphisms (SNPs). SNP data comes in the form of counts, but from the countsone typically computes genotype frequencies and allele frequencies. These frequencies satisfythe unit-sum constraint, and their analysis therefore falls within the realm of compositional dataanalysis (Aitchison, 1986). SNPs are usually bi-allelic, which implies that the genotypefrequencies can be adequately represented in a ternary plot. Compositions that are in exactHWE describe a parabola in the ternary plot. Compositions for which HWE cannot be rejected ina statistical test are typically “close" to the parabola, whereas compositions that differsignificantly from HWE are “far". By rewriting the statistics used to test for HWE in terms ofheterozygote frequencies, acceptance regions for HWE can be obtained that can be depicted inthe ternary plot. This way, compositions can be tested for HWE purely on the basis of theirposition in the ternary plot (Graffelman & Morales, 2008). This leads to nice graphicalrepresentations where large numbers of SNPs can be tested for HWE in a single graph. Severalexamples of graphical tests for HWE (implemented in R software), will be shown, using SNPdata from different human populations

Differential effects of two virtual reality interventions: distraction versus pain control

There is evidence that virtual reality (VR) pain distraction is effective at improving pain-related outcomes. However, more research is needed to investigate VR environments with other pain-related goals. The main aim of this study was to compare the differential effects of two VR environments on a set of pain-related and cognitive variables during a cold pressor experiment. One of these environments aimed to distract attention away from pain (VRD), whereas the other was designed to enhance pain control (VRC). Participants were 77 psychology students, who were randomly assigned to one of the following three conditions during the cold pressor experiment: (a) VRD, (b) VRC, or (c) Non-VR (control condition). Data were collected regarding both pain-related variables (intensity, tolerance, threshold, time perception, and pain sensitivity range) and cognitive variables (self-efficacy and catastrophizing). Results showed that in comparison with the control condition, the VRC intervention significantly increased pain tolerance, the pain sensitivity range, and the degree of time underestimation. It also increased self-efficacy in tolerating pain and led to a reduction in reported helplessness. The VRD intervention significantly increased the pain threshold and pain tolerance in comparison with the control condition, but it did not affect any of the cognitive variables. Overall, the intervention designed to enhance control seems to have a greater effect on the cognitive variables assessed. Although these results need to be replicated in further studies, the findings suggest that the VRC intervention has considerable potential in terms of increasing self-efficacy and modifying the negative thoughts that commonly accompany pain problems.