RESUMEN
Importance: Medicare Advantage is associated with improved health outcomes, increased care efficiency, and lower out-of-pocket costs compared with fee-for-service (FFS) Medicare. When engaged in 2-sided risk arrangements, physicians are incented to offer high value for patients; however, no studies have explored the quality and efficiency outcomes in 2-sided risk Medicare Advantage models compared with FFS Medicare. Objective: To compare quality and efficiency of care between physicians using a Medicare Advantage 2-sided risk model and FFS Medicare. Design, Setting, and Participants: This retrospective cohort analysis with exact and propensity score-matched design used claims data from January 1, 2018, to December 31, 2019. Participants included beneficiaries enrolled in a Medicare Advantage 2-sided risk model (ie, physicians assumed the financial risk of total costs of care) and those in an FFS Medicare program in a 5% limited data set with part A and B coverage residing in 6 states (Arizona, California, Florida, Nevada, Texas, and Utah). Data were analyzed from February 1 to June 15, 2022. Exposures: Medicare Advantage 2-sided risk model seen in practices that are part of a nationwide health care delivery organization compared with traditional FFS Medicare. Main Outcomes and Measures: Comparative analysis of 8 quality and efficiency metrics in populations enrolled in a 2-sided risk-model Medicare Advantage program and 5% FFS Medicare. Results: In this analytic cohort of 316â¯312 individuals (158â¯156 in each group), 46.11% were men and 53.89% were women; 32.72% were aged 65-69 years, 29.44% were aged 70-74 years, 19.05% were aged 75-79 years, 10.84% were aged 80-85 years, and 7.95% were 85 years or older. The Medicare Advantage model was associated with care of higher quality and efficiency in all 8 metrics compared with the FFS model. This included lower odds of inpatient admission (-18%; odds ratio [OR], 0.82 [95% CI, 0.79-0.84]), inpatient admission through the emergency department (ED) (-6%; OR, 0.94 [95% CI, 0.91-0.97]), ED visits (-11%; OR, 0.89 [95% CI, 0.86-0.91]), avoidable ED visits (-14%; OR, 0.86 [95% CI, 0.82-0.89]), 30-day inpatient readmission (-9%; rate ratio, 0.91 [95% CI, 0.86-0.98]), admission for stroke or myocardial infarction (-10%; OR, 0.90 [95% CI, 0.83-0.98]), and hospitalization for chronic obstructive pulmonary disease or asthma exacerbation (-44%; OR, 0.56 [95% CI, 0.50-0.62]). Conclusions and Relevance: The improvements observed in this study may be partly or fully attributed to the Medicare Advantage model. The Medicare Advantage risk adjustment system appears to be meeting its intended goal by aligning the capitation payments to the health care burden of the individual beneficiary and aggregate population served, thus providing revenue to develop infrastructure that supports improvements in quality and efficiency for the patients enrolled in Medicare Advantage models with 2-sided risk.
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Planes de Aranceles por Servicios , Medicare Part C , Masculino , Anciano , Humanos , Femenino , Estados Unidos , Estudios Retrospectivos , Calidad de la Atención de Salud , HospitalizaciónRESUMEN
The variation in molar tooth size in humans and our closest relatives (hominins) has strongly influenced our view of human evolution. The reduction in overall size and disproportionate decrease in third molar size have been noted for over a century, and have been attributed to reduced selection for large dentitions owing to changes in diet or the acquisition of cooking. The systematic pattern of size variation along the tooth row has been described as a 'morphogenetic gradient' in mammal, and more specifically hominin, teeth since Butler and Dahlberg. However, the underlying controls of tooth size have not been well understood, with hypotheses ranging from morphogenetic fields to the clone theory. In this study we address the following question: are there rules that govern how hominin tooth size evolves? Here we propose that the inhibitory cascade, an activator-inhibitor mechanism that affects relative tooth size in mammals, produces the default pattern of tooth sizes for all lower primary postcanine teeth (deciduous premolars and permanent molars) in hominins. This configuration is also equivalent to a morphogenetic gradient, finally pointing to a mechanism that can generate this gradient. The pattern of tooth size remains constant with absolute size in australopiths (including Ardipithecus, Australopithecus and Paranthropus). However, in species of Homo, including modern humans, there is a tight link between tooth proportions and absolute size such that a single developmental parameter can explain both the relative and absolute sizes of primary postcanine teeth. On the basis of the relationship of inhibitory cascade patterning with size, we can use the size at one tooth position to predict the sizes of the remaining four primary postcanine teeth in the row for hominins. Our study provides a development-based expectation to examine the evolution of the unique proportions of human teeth.
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Evolución Biológica , Hominidae/anatomía & histología , Diente/anatomía & histología , Animales , Femenino , Fósiles , Hominidae/clasificación , Humanos , Masculino , Diente Molar/anatomía & histología , Tamaño de los Órganos , Filogenia , Especificidad de la EspecieRESUMEN
OBJECTIVES: Great ape teeth must remain functional over long lifespans. The molars of the most folivorous apes, the mountain gorillas, must maintain shearing function for 40+ years while the animals consume large quantities of mechanically challenging foods. While other folivorous primates experience dental senescence, which compromises their occlusal surfaces and affects their reproductive success as they age, it is unknown whether dental senescence also occurs in mountain gorillas. In this article, we quantified and evaluated how mountain gorilla molars change throughout their long lifespans. MATERIALS AND METHODS: We collected high-resolution replicas of M(1)s (n = 15), M(2)s (n = 13), and M(3)s (n = 11) from a cross-sectional sample of wild mountain gorilla skeletons from the Virunga Volcanoes, ranging in age from 4 to 43 years. We employed dental topographic analyses to track how aspects of occlusal slope, angularity, relief index, and orientation patch count rotated change with age. In addition, we measured the relative length of shearing crests in two- and three-dimensions. RESULTS: Occlusal topography was found to decrease, while 2D relative shearing crest length increased, and 3D relative crest lengths were maintained with age. DISCUSSION: Our findings indicate that shearing function is maintained throughout the long lifetimes of mountain gorillas. Unlike the dental senescence experienced by other folivorous primates, mountain gorillas do not appear to possess senesced molars despite their long lifetimes, mechanically challenging diets, and decreases in occlusal topography with age.
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Envejecimiento/patología , Gorilla gorilla , Diente Molar/patología , Desgaste de los Dientes/patología , Envejecimiento/fisiología , Animales , Femenino , Gorilla gorilla/anatomía & histología , Gorilla gorilla/fisiología , Masculino , Diente Molar/fisiología , Desgaste de los Dientes/fisiopatologíaRESUMEN
Three fundamental ontogenetic pathways lead to the development of size differences between males and females. Males and females may grow at the same rate for different durations (bimaturism), grow for the same duration at different rates, or grow at a mix of rate and duration differences. While patterns of growth and the development of adult body size are well established for many haplorhines, the extent to which rate and duration differences affect strepsirrhine growth trajectories remains unclear. Here, we present iterative piecewise regression models that describe the ontogeny of adult body mass for males and females of five lorisoid species (i.e., lorises and galagos) from the Duke Lemur Center. We test the hypotheses that, like most haplorhines, sexual size dimorphism (SSD) is a result of bimaturism, and males and females of monomorphic species grow at the same rate for a similar duration. We confirm that the galagos in this sample (Galago moholi and Otolemur garnettii) show significant SSD that is achieved through bimaturism. Unlike monomorphic lemurids, the lorises in this sample show a diversity of ontogenetic patterns. Loris tardigradus does follow a lemur-like trajectory to monomorphism but Nycticebuscoucang and Nycticebus pygmaeus achieve larger adult female body sizes through a mixture of rate and duration differences. We show that contrary to previous assumptions, there are patterns of both similarity and difference in growth trajectories of comparably sized lorises and galagos. Furthermore, when ontogenetic profiles of lorisoid and lemurid growth are compared, it is evident that lorisoids grow faster for a shorter period of time.
Asunto(s)
Tamaño Corporal/fisiología , Galago/fisiología , Lorisidae/fisiología , Caracteres Sexuales , Animales , Antropometría , Femenino , Galago/anatomía & histología , Galago/crecimiento & desarrollo , Lorisidae/anatomía & histología , Lorisidae/crecimiento & desarrollo , Masculino , Análisis de RegresiónRESUMEN
Studies of primate life history variation are constrained by the fact that all large-bodied extant primates are haplorhines. However, large-bodied strepsirrhines recently existed. If we can extract life history information from their skeletons, these species can contribute to our understanding of primate life history variation. This is particularly important in light of new critiques of the classic "fast-slow continuum" as a descriptor of variation in life history profiles across mammals in general. We use established dental histological methods to estimate gestation length and age at weaning for five extinct lemur species. On the basis of these estimates, we reconstruct minimum interbirth intervals and maximum reproductive rates. We utilize principal components analysis to create a multivariate "life history space" that captures the relationships among reproductive parameters and brain and body size in extinct and extant lemurs. Our data show that, whereas large-bodied extinct lemurs can be described as "slow" in some fashion, they also varied greatly in their life history profiles. Those with relatively large brains also weaned their offspring late and had long interbirth intervals. These were not the largest of extinct lemurs. Thus, we distinguish size-related life history variation from variation that linked more strongly to ecological factors. Because all lemur species larger than 10 kg, regardless of life history profile, succumbed to extinction after humans arrived in Madagascar, we argue that large body size increased the probability of extinction independently of reproductive rate. We also provide some evidence that, among lemurs, brain size predicts reproductive rate better than body size.