This study was initiated after finding two chromosomal types of Peromyscus maniculatus north and south of the Red River in Texas and Oklahoma. The problem was to explain the chromosomal variations and their implications to the systematics of the grassland subspecies of P. maniculatus in this region.

Photoperiodism is the ability of plants and animals to utilize day length or night length to mitigate seasonal exigencies. The circadian clock allows organisms to organize daily demands. Both process are set by light, and for more than 80 years a functional relationship has been pursued. Previous experiments have revealed, through phenotypic expression, that the daily circadian clock and seasonal photoperiodic timer have evolved independently, yet molecular evidence is lacking. Herein, we use the mosquito, Wyeomyia smithii, to understand the relationship between the photoperiodic response, diapause, and the daily circadian clock. We measured variation in the formal properties of the core circadian clock over a latitudinal and altitudinal gradient which we compare to the critical photoperiod, a measure of diapause, over the same geographic gradient. We found that there is no correlation with any of the formal properties of the core circadian clock and critical photoperiod, indicating independent evolution.

We live in a constantly changing world, where recent human-induced changes and climate change affect virtually every component of the Earth's surface and systems. Coastal ecosystems are particularly at risk, as one of the most utilised and urbanised of natural systems worldwide, as well as being at risk from sea level rise. This will degrade or even destroy many feeding and breeding sites. Those species colonising new habitats in an attempt to escape rising sea level and climate change related threats, will be competing for space with the growing human population and urbanisation. Although 97 of 346 seabird species (28%) are globally threatened, 57 (17%) have increasing populations, including 17 gulls (Larinae). The Kelp Gull Larus dominicanus is a cosmopolitan species with an increasing population worldwide. Kelp Gulls in southern Africa L. d. vetula are one of 15 seabird species that breed in the region, and one of only five breeding seabirds listed as Least Concern in the region. Three Kelp Gull breeding colonies in Plettenberg Bay, Western Cape, were surveyed to provide an updated count for this area. A combination of direct counts and the trial use of an unmanned aerial vehicle (UAV),were used as methods of counting nests. The direct monitoring of nests allowed for the effect of different microhabitats on the breeding performance of Kelp Gulls to be investigated, which has implications for their ability to adapt to future habitat changes. The importance of anthropogenic food items in the diet of Kelp Gulls breeding in Plettenberg Bay was explored through the use of regurgitated pellets of indigestible matter, and chick regurgitations, and how this is reflected in the time spent in various areas as shown by GPS loggers and point counts in urban areas. Another aspect of the urban adaptation of Kelp Gulls is the incorporation of anthropogenic debris in their nests, which was examined at eight breeding colonies throughout the Western Cape.

Aegialomys é membro da tribo Oryzomyini, e se distribui ao longo dos ambientes abertos, a oeste do Peru e do Equador, incluindo o Arquipélago de Galápagos. Esse gênero, recentemente descrito, é constituído por duas espécies: A. galapagoensis e A. xanthaeolus. Contudo, informações recentes sugerem a existência de uma espécie não descrita na região do Equador. Esse fato, juntamente com questões levantadas na literatura a respeito do status taxonômico de Oryzomys xanthaeolus ica, e algumas reservas sobre Oryzomys baroni, motivou a revisão taxonômica desse grupo. Dentro desse contexto, o presente estudo descreveu os padrões de variação da amostra, buscando caracterizar os táxons, em termos morfológicos e morfométricos, descrever sua variação intra e interespecífica, atribuir nomes válidos a todas as espécies e estabelecer a distribuição geográfica de cada espécie reconhecida, bem como a relação de parentesco. Para tanto, foram estudadas coleções científicas nos Estados Unidos, na Inglaterra e no Peru. As análises morfométricas (estatística uni e multivariada) e morfológicas (frequência dos caracteres) foram conduzidas em indivíduos adultos e de ambos os sexos. Os caracteres morfométricos consistiram em dimensões corpóreas e crânio-dentárias. As normalidades univariadas dos dados foram testadas. Em um primeiro momento, foi apresentado o histórico taxonômico do gênero; em seguida, um catálogo sitematizado com informações sobre os tipos das espécies. A distribuição de Aegialomys no continente está limitada por Esmeraldas (Prov. de Esmeraldas, Equador), ao norte; por Hacienda Checayani, Azangaro (Depto. de Puno, Peru), ao sul e a leste; e pela costa a oeste. O gênero é encontrado em uma ilha próxima ao continente, chamada Isla Puna, e no Arquipélago de Galápagos. As análises morfológicas e morfométricas revelaram que os espécimes examinados são similares em seus caracteres externos, cranianos e dentários, independentemente da sua origem geográfica. Entretanto, morfológicamente constatou-se algumas variações com sentido geográfico para caracteres como a coloração dorsal, a coloração ventral, a posição do lacrimal, o tamanho do palato, a presença de flexo no anterocone do M1, e no anteroconídeo e morfometricamente, observamos um acentuado acréscimo nas dimensões cranianas, no sentido norte-sul da distribuição. Unindo dados morfológicos e morfometricos reconhece-se a existência de três grupos distintos - o norte, o sul e Galápagos, aos quais os nomes A. xanthaeolus, A. baroni e A. galapagoensis, foram designados respectivamente. No padrão geral das amostras, o agrupamento Galápagos se mostra mais similar às amostras do sul. Todavia, uma característica importante é compartilhada entre os indivíduos de Galápagos e os do grupo norte, que é a presença de flexo de anterocone e no anteroconídeo. O limite de distribuição das espécies continentais foi concordante com a zona de transição climática existente no sul do Equador e norte do Peru, onde o clima passa da caracterização úmida para árida, e também com dados relacionados às áreas de endemismo e barreiras para a dispersão de fauna encontrada também para outros grupos de vertebrados. A relação de parentesco entre as espécies foi estabelecida com base em uma filogenia morfológica, revelando que as espécies continentais são mais proximamente relacionadas entre si do que com A. galapagoensis. / Aegialomys is a member of Oryzomyini tribe that occurs through the open habitats, west of the Ecuadorian and Peruvian Andes, including the Galapagos Archipelago. This genus, recently described, consists of two species, A. galapagoensis and A. xanthaeolus. Nevertheless, additional information suggests there is one undescribed species in the Ecuadorian region. This fact, along with questions raised in the literature regarding the taxonomic status of Oryzomys xanthaeolus ica, and some reserves about Oryzomys baroni, has motivated a taxonomic review of this group. Within this context the present study describes the patterns of variation of the available samples, in order to characterize the taxa on morphologic and morphometric aspects; to describe the intra and interspecific variation; to assign the valid and available names to all valid taxa; and to establish the geographic distribution of each recognized species, and the kinship. In order to achieve these goals, I studied specimens housed at several scientific collections in the United States, England and Peru. Morphometric (univariate and multivariate statistical analyses) and morphologic (character-state frequencies) analyses were conducted in adult specimens, employing both sexes. The morphometric characters consisted of body dimensions and skull and molar measurements. Univariate normality was tested. At first, I present the genus taxonomic history and a systematic catalog with information regarding the type material of each nominal taxa. The distribution of Aegialomys in the continent is limited by Esmeraldas (Province of Esmeraldas, Ecuador) to the north; by the Hacienda Checayani, Azangaro (Depto. De Puno, Peru) to the south and west; and by the coast to the west. The genus is also found in a continental island close to the continent, Isla Puna, and inoceanic islands that form the Galapagos Archipelago. The morphometric and morphologic data revealed that the specimens examined are similar in some of their external, cranial and dental characters, independently of its geographical origin; however, I notice some variations related to the geography in characters like the dorsal and ventral color, lacrimal position, palate length, presence of anterocone flexus in M1, and presence of anteroconid flexus in M1. A pronounced addition in cranial dimensions is observed through north-south distribution, which revealed the existence of three distinct clusters: North, South and Galapagos of which the names A. xanthaeolus, A. baroni and A. galapagoensis was designated respectively. The samples of Galapagos exhibit morphometric and morphologically similarity to the South samples; however, an important character is shared among the individuals of Galapagos and North cluster, which is the presence of anterocone and anteroconid flexus. The distribution limits of continental species were consistent with the existing climate transition zone in southern Ecuador and northern Peru, where the climate changes from wet to dry, and also consistent with data related to the areas of endemism and barriers to the faunal dispersion reported for other vertebrate groups. The kinship among the species was established based on a morphological phylogeny, revealing that the continental species are more closely related to each other than with A. galapagoensis.

Geographic access to cancer care is an important dimension of quality of cancer care. Previous studies have shown that the more uncertain medical evidence is, the more geographic variation is observed in the medical care utilization that is attributable to local care health care system capacity and local area patient/physician preferences. Chemotherapy for metastatic breast cancer (MBC) is such a case. Although clinical trials have proven the efficacy of chemotherapy in treating MBC, whether to treat elderly MBC patients with chemotherapy is uncertain because of the underrepresentation of elderly patients in the clinical trials. As age advances, uncertainties increase due to competing causes of death, limited life expectancy, and higher risk of toxicities. As a result, geographic access may matter more in chemotherapy choice for older patients than for younger patients. Literature has shown that older patients are less likely to be treated with chemotherapy. In this study, we examined the effect of access to cancer care on age-related difference in chemotherapy use for elderly MBC patients. Access to cancer care is measured by four variables, including travel time to the nearest oncologist practice, local area per capita number of oncologists among stage IV cancer patients, local area per capita number of hospices among stage IV cancer patients, and local area chemotherapy percentage among stage IV cancer patients. The retrospective cohort study used the 1992-2002 SEER-Medicare database. Chemotherapy use was defined as at least one chemotherapy-related claim within 6 months post diagnosis. To examine the age variant effect of access on chemotherapy choice, the analysis adopted both interaction term approach and subgroup analysis. In interaction term analysis, product term between age and access dummy variables were specified in the multivariate logistic regression model controlling for other covariates; in subgroup analysis, age subgroups were specified consistently with interaction term approach. For each age subgroup, we used multivariate logistic regression to estimate the effect of access to cancer care on immediate chemotherapy use controlling for covariates. Among 4533 elderly patients with MBC, 30.16% used chemotherapy. Chemotherapy rate decreased with age. Interaction term approach did not show significant interaction between age and access in each specification. Both interaction term and subgroup analysis showed that the local area treatment rate was positively associated with immediate chemotherapy use across patient age. In addition, subgroup analysis showed among patients who were 85+ years old, the local area oncologist supply was negatively associated with chemotherapy use. This effect was not observed among younger age groups. Our results suggest that estimating all patients in one equation with dummies and interactions can hide results. By estimating each group separately, subgroup analysis showed that provider access is paramount for age subgroup 85 years or older. Our access measures suggest that access to cancer care affects chemotherapy choice among elderly patients whose clinical evidence is uncertain. This can be attributable to local practice style and physician concern of real benefits of chemotherapy. The local area chemotherapy practice styles affect chemotherapy choice for patients across age except patients aged between 80 to 84 years old; provider access plays an important role for patients 85 years or older. The more certain the evidence with age, the more access may affect chemotherapy choice.

Aegialomys é membro da tribo Oryzomyini, e se distribui ao longo dos ambientes abertos, a oeste do Peru e do Equador, incluindo o Arquipélago de Galápagos. Esse gênero, recentemente descrito, é constituído por duas espécies: A. galapagoensis e A. xanthaeolus. Contudo, informações recentes sugerem a existência de uma espécie não descrita na região do Equador. Esse fato, juntamente com questões levantadas na literatura a respeito do status taxonômico de Oryzomys xanthaeolus ica, e algumas reservas sobre Oryzomys baroni, motivou a revisão taxonômica desse grupo. Dentro desse contexto, o presente estudo descreveu os padrões de variação da amostra, buscando caracterizar os táxons, em termos morfológicos e morfométricos, descrever sua variação intra e interespecífica, atribuir nomes válidos a todas as espécies e estabelecer a distribuição geográfica de cada espécie reconhecida, bem como a relação de parentesco. Para tanto, foram estudadas coleções científicas nos Estados Unidos, na Inglaterra e no Peru. As análises morfométricas (estatística uni e multivariada) e morfológicas (frequência dos caracteres) foram conduzidas em indivíduos adultos e de ambos os sexos. Os caracteres morfométricos consistiram em dimensões corpóreas e crânio-dentárias. As normalidades univariadas dos dados foram testadas. Em um primeiro momento, foi apresentado o histórico taxonômico do gênero; em seguida, um catálogo sitematizado com informações sobre os tipos das espécies. A distribuição de Aegialomys no continente está limitada por Esmeraldas (Prov. de Esmeraldas, Equador), ao norte; por Hacienda Checayani, Azangaro (Depto. de Puno, Peru), ao sul e a leste; e pela costa a oeste. O gênero é encontrado em uma ilha próxima ao continente, chamada Isla Puna, e no Arquipélago de Galápagos. As análises morfológicas e morfométricas revelaram que os espécimes examinados são similares em seus caracteres externos, cranianos e dentários, independentemente da sua origem geográfica. Entretanto, morfológicamente constatou-se algumas variações com sentido geográfico para caracteres como a coloração dorsal, a coloração ventral, a posição do lacrimal, o tamanho do palato, a presença de flexo no anterocone do M1, e no anteroconídeo e morfometricamente, observamos um acentuado acréscimo nas dimensões cranianas, no sentido norte-sul da distribuição. Unindo dados morfológicos e morfometricos reconhece-se a existência de três grupos distintos - o norte, o sul e Galápagos, aos quais os nomes A. xanthaeolus, A. baroni e A. galapagoensis, foram designados respectivamente. No padrão geral das amostras, o agrupamento Galápagos se mostra mais similar às amostras do sul. Todavia, uma característica importante é compartilhada entre os indivíduos de Galápagos e os do grupo norte, que é a presença de flexo de anterocone e no anteroconídeo. O limite de distribuição das espécies continentais foi concordante com a zona de transição climática existente no sul do Equador e norte do Peru, onde o clima passa da caracterização úmida para árida, e também com dados relacionados às áreas de endemismo e barreiras para a dispersão de fauna encontrada também para outros grupos de vertebrados. A relação de parentesco entre as espécies foi estabelecida com base em uma filogenia morfológica, revelando que as espécies continentais são mais proximamente relacionadas entre si do que com A. galapagoensis. / Aegialomys is a member of Oryzomyini tribe that occurs through the open habitats, west of the Ecuadorian and Peruvian Andes, including the Galapagos Archipelago. This genus, recently described, consists of two species, A. galapagoensis and A. xanthaeolus. Nevertheless, additional information suggests there is one undescribed species in the Ecuadorian region. This fact, along with questions raised in the literature regarding the taxonomic status of Oryzomys xanthaeolus ica, and some reserves about Oryzomys baroni, has motivated a taxonomic review of this group. Within this context the present study describes the patterns of variation of the available samples, in order to characterize the taxa on morphologic and morphometric aspects; to describe the intra and interspecific variation; to assign the valid and available names to all valid taxa; and to establish the geographic distribution of each recognized species, and the kinship. In order to achieve these goals, I studied specimens housed at several scientific collections in the United States, England and Peru. Morphometric (univariate and multivariate statistical analyses) and morphologic (character-state frequencies) analyses were conducted in adult specimens, employing both sexes. The morphometric characters consisted of body dimensions and skull and molar measurements. Univariate normality was tested. At first, I present the genus taxonomic history and a systematic catalog with information regarding the type material of each nominal taxa. The distribution of Aegialomys in the continent is limited by Esmeraldas (Province of Esmeraldas, Ecuador) to the north; by the Hacienda Checayani, Azangaro (Depto. De Puno, Peru) to the south and west; and by the coast to the west. The genus is also found in a continental island close to the continent, Isla Puna, and inoceanic islands that form the Galapagos Archipelago. The morphometric and morphologic data revealed that the specimens examined are similar in some of their external, cranial and dental characters, independently of its geographical origin; however, I notice some variations related to the geography in characters like the dorsal and ventral color, lacrimal position, palate length, presence of anterocone flexus in M1, and presence of anteroconid flexus in M1. A pronounced addition in cranial dimensions is observed through north-south distribution, which revealed the existence of three distinct clusters: North, South and Galapagos of which the names A. xanthaeolus, A. baroni and A. galapagoensis was designated respectively. The samples of Galapagos exhibit morphometric and morphologically similarity to the South samples; however, an important character is shared among the individuals of Galapagos and North cluster, which is the presence of anterocone and anteroconid flexus. The distribution limits of continental species were consistent with the existing climate transition zone in southern Ecuador and northern Peru, where the climate changes from wet to dry, and also consistent with data related to the areas of endemism and barriers to the faunal dispersion reported for other vertebrate groups. The kinship among the species was established based on a morphological phylogeny, revealing that the continental species are more closely related to each other than with A. galapagoensis.

Spending trends vary greatly across medical conditions. Nervous system conditions comprising epilepsy has shown an increase in spending growth contrary to a decrease observed in aggregate spending growth of 15 condition categories from 2000 to 2010. Increases in total spending of a medical condition can be explained by an increase in either costs per case or the number of cases or in both elements. Determining the number of epilepsy cases and the cost to treat an individual with epilepsy helps to explain spending trends of the disease. Significant variation in overall Medicare spending across geographic regions unrelated to health outcomes has been well-documented. It is uncertain whether reducing payment rates to high-cost areas would curb spending growth without adversely affecting health care quality for Medicare beneficiaries. Reducing geographic variation is therefore, desirable only if the measured variation represents inefficiencies in the health system. In terms of health care, efficiency is a function of cost of care and quality of care. The identification of factors contributing to inefficiency may guide policy change for its improvement. OBJECTIVES The overall objective of this research was to evaluate the potential for change in prevalence of epilepsy cases, the magnitude of maximum inefficiency and factors contributing to inefficiency for the treatment of epilepsy among Medicare beneficiaries. The first specific aim was to determine whether there has been change in the prevalence of epilepsy among Medicare beneficiaries since 2005. The second aim examined the effects of two value-based programs on the geographic variation of Medicare spending per beneficiary. The third aim sought to identify influential factors driving inefficiency in inpatient care among the beneficiaries with epilepsy by examining cost and quality, accounting for spatial dependence. METHODS Analyses for all specific aims included individual-, county-, and state-level data. Individual-level medical data including beneficiaries’ age, race, sex, zip code, and utilization information five percent random sample were obtained from US Medicare administrative data (2011 to 2013). Epilepsy prevalence information for Medicare beneficiaries (2001 to 2005) was estimated by a previous study. County-level data were obtained from Area Health Resources Files (AHRF) and the American Community Survey. State-level data were obtained from State Physician Workforce Data Book; Dartmouth Atlas of Health Care; Centers for Medicare and Medicaid Services; Tracking Accountability in Government Grants System; US Department of Commerce; National Association of Epilepsy Centers; and US Census Bureau. Epilepsy cases were defined using Medicare claims data with any of the following International Classification of Disease-Version 9-Clinical Modification (ICD 9-CM) diagnostic codes: At least one ICD 9-CM 345.xx (epilepsy), or at least two ICD 9-CM 780.3x (seizure) claims occurring at least 30 days apart. Inpatient inefficiency was defined as a function of cost over quality. Inpatient cost was defined by state-level average adjusted inpatient services spending per hospital stay (AIH). The proxy measure for the quality of inpatient care for beneficiaries with epilepsy was the proportion of hospital stays with an epilepsy or seizure admission diagnosis (PHE). Association analysis was performed using the Spearman correlation coefficient. Generalized linear models with log link and gamma distribution were used for the adjusting and modeling of cost dependent variables. Spatial regression models were used when appropriate to account for spatial dependence. RESULTS The prevalence of epilepsy among older Medicare beneficiaries was estimated to be 22.2 cases per 1,000 persons (2011 to 2013). An increase was observed for all racial groups. However, the subgroup with highest prevalence estimate shifted from the younger age group of 65 to 69 years to the female, 85 years and older. Black beneficiaries persistently had the highest prevalence compared to other racial groups. Analysis for the second specific aim showed that state-level total medical expenditures per beneficiary with epilepsy varied from 11,690 to 29,048 (average 19,890, SD 3,774, US$ 2013), 5.3 times the spending variation for those without epilepsy which ranged from 6,466 to 9,458 (average 7,631, SD 710, US$ 2013). Post-implementation of two value-based programs (hospital readmissions reduction program (HRRP) and the hospital value-based purchasing program (HVBP)), spending variation decreased for both the epilepsy and non-epilepsy cohorts (-14.6% and -9.0% respectively). The primary factor contributing to spending variation was health status for beneficiaries with epilepsy (51.9% of variation) and location of the beneficiary for those without epilepsy (26.1% of variation). Analysis conducted to address the third specific aim showed that different factors influenced inefficiency in inpatient care of beneficiaries with epilepsy among US census regions. For the Northeast region, the number of primary physicians was an inefficiency factor. For the South region, inpatient inefficiency factors included the number of medical residents and fellows, proportion of physicians who were primary care physicians, and retention of physicians who graduated from an institution in the state of practice. Some evidence of defensive medicine was detected in the West region while no specific factors were influential to inpatient inefficiency in the Midwest region. The highest and lowest state-level average adjusted inpatient services spending per hospital stay (AIH) were observed in the District of Columbia (13,376 US$ 2013) and South Dakota (7,901 US$ 2013). Rhode Island (1.06%) had the lowest while Idaho (11.29%) had the highest proportion of hospital stays with an epilepsy admission diagnosis (PHE). Rhode Island also had the lowest inpatient inefficiency index or least inefficient (86) compared to the highest inpatient inefficiency index or most inefficient observed in Idaho (1,417). CONCLUSION The prevalence of epilepsy among Medicare beneficiaries appeared to have increased from previous estimates. Heterogeneity among the 48 contiguous states and District of Columbia with respect to inefficiency in inpatient care was detected. Across-the-board cost reduction policy based on cost alone may not be appropriate for all geographic areas across the US and may even be detrimental to health outcomes in some areas. On both national and regional level, inpatient inefficiency was significantly associated with PHE but not with AIH, indicating that the focus to decreasing inpatient inefficiency for beneficiaries with epilepsy should be based on increasing quality or decreasing PHE. Changes made to decrease PHE (increase in quality) may also increase AIH (increase in cost); therefore, it would be wise to monitor both cost and quality when considering policy change while focusing on quality improvement. Programs such as the HVBP and HRRP that link cost to outcomes appeared to be successful in reducing geographic variation of medical expenditures. Instead of total spending per individual, updated knowledge of the prevalence and cost per case treated for specific chronic medical conditions may better assist resource allocation, budget planning, and health program development.

The U.S. health care system is one of the most expensive health care systems in the world, yet it is not as efficient as it is expected. Studies have shown that the use of expensive imaging procedures, such as CT scans, was significantly increasing for the past few years. However, the increased number of CT scans may not help to improve quality of care. No studies are conducted on investigate geographic variation on CT scan usage rate. This research is the first one to examine CT scan usage rate among counties and to examine variation caused by patient and hospital characteristics. We used the 2007 HCUP-SID database provided data for the research. GIS graph was used to illustrate geographic variation on CT scan usage in New York State. Contingency tables were developed to evaluate to what extent patient and hospital characteristics contribute to the variation. A logistic regression model was built to control the variation caused by patient and hospital characteristics in order to find variation contributed by other potential factors such as availability of CT scanners and radiologists. Significant geographic variation of CT scan usage rate in the county level of New York State was found. Patient demographics, insurance status and medical conditions as well as hospital bed size and teaching status were contributing factors to the variation. After controlling these factors, significant geographic variation was still found. It indicates that other potential reasons would influence the technology use. / Master of Science

No description available.

Fibromyalgia syndrome (FMS) is a chronic pain condition with significant societal and personal burdens of illness. Chronic opioid therapy in the treatment of chronic nonmalignant pain has increased drastically over the past decade. This is a worrisome trend in general, but specifically, given the pathophysiologic characteristics seen in fibromyalgia syndrome patients, the use of this class of medication deserves special scrutiny. Although the theoretical case against this therapy choice is strong, little empirical evidence exists. In order to supplement this literature, retrospective analysis methods are utilized to examine the association of state-, provider-, and patient level characteristics with the prevalence of chronic opioid use in this disease state. Data gathered through this analysis is then used to develop a propensity index for the identification of an appropriate control group for fibromyalgia patients, a task that has proven difficult in the literature to date. Using propensity stratification and matching techniques analysis of the impact of fibromyalgia, chronic opioid use, and the interaction of these two variables are undertaken. Several key findings and updates to the understanding of chronic opioid use and fibromyalgia syndrome are reported. Wide geographic variation in chronic opioid utilization between states is seen. The role of diagnosing provider type in the rate of chronic opioid prescribing is significant and can be aggregated at various levels. Demographic characteristics, comorbid conditions, and concurrent medication use are all important associates of chronic opioid use in fibromyalgia syndrome. Additionally, chronic opioid use in fibromyalgia patients, independent of propensity to receive that therapy choice is a significant correlate with healthcare costs. A diagnosis of fibromyalgia is a statistically significant source of healthcare costs, though the clinical significance of its impact when compared to a closely matched control group is minimized. Despite the minimization of the role of this diagnosis the impact of the interaction of chronic opioid use with fibromyalgia, despite control for myriad regressors, is significant both statistically and clinically.