Hasan Guclu | University of Pittsburgh (original) (raw)
Papers by Hasan Guclu
![Research paper thumbnail of [Evaluation of Non-Pharmaceutical Interventions for Reducing Contact Rate in COVID-19 Pandemic: R0 Estimation and Modeling for Istanbul]](https://attachments.academia-assets.com/101108928/thumbnails/1.jpg)
](Mikrobiyoloji bulteni, 2021
After the declaration of the coronavirus-2019 (COVID-19) pandemic and the detection of the COVID-... more After the declaration of the coronavirus-2019 (COVID-19) pandemic and the detection of the COVID-19 case in Turkey, a series of non-pharmaceutical measures were implemented to reduce the number of contacts at the national level. The aim of this study was to determine the change in the epidemic reproduction rate (R0) with non-pharmaceutical interventions including curfews starting with the first reported case in Istanbul and to evaluate the effectiveness of interventions by estimating the number of cases and deaths using a dynamic compartmental model. While keeping transmission probability (beta) as 3% and incubation period as seven days, we developed five scenarios that represented nonpharmaceutical interventions The first scenario was "if nothing was done" and the last scenario was "curfew". The contact matrix of 16 age-groups created by Prem et al. was used in the study as the contact matrix of "if nothing was done" as scenario 1. For all other scenar...
Journal of Neurosurgery, 2019
OBJECTIVEThe authors sought to develop a set of parameters that reliably predict the clinical suc... more OBJECTIVEThe authors sought to develop a set of parameters that reliably predict the clinical success of endoscopic third ventriculostomy (ETV) when assessed before and after the operation, and to establish a plan for MRI follow-up after this procedure.METHODSThis retrospective study involved 77 patients who had undergone 78 ETV procedures for obstructive hydrocephalus between 2010 and 2015. Constructive interference in steady-state (CISS) MRI evaluations before and after ETV were reviewed, and 4 parameters were measured. Two well-known standard parameters, fronto-occipital horn ratio (FOHR) and third ventricular index (TVI), and 2 newly defined parameters, infundibulochiasmatic (IC) angle and anterior third ventricular height (TVH), were measured in this study. Associations between preoperative measurements of and postoperative changes in the 4 variables and the clinical success of ETV were analyzed.RESULTSOf the 78 ETV procedures, 70 (89.7%) were successful and 8 (10.3%) failed. O...
European Archives of Oto-Rhino-Laryngology, 2019
PurposeThe aim of this study was to evaluate the ossicular chain erosions (OCE) in chronic otitis... more PurposeThe aim of this study was to evaluate the ossicular chain erosions (OCE) in chronic otitis media patients with cholesteatoma (COM-C) or without cholesteatoma (COM).Materials and methodsThe OCE and preoperative hearing levels of a total of 915 patients were evaluated retrospectively. Patients were divided into three groups. Of the 915 patients, 615 (67.2%) had COM, 234 (25.6%) had COM-C, and 66 (7.2%) had chronic otitis media with granulation tissue (COM-G).ResultsOCE was found in 291 (31.8%) of 915 patients. OCE was found in 192 (82%) of 234 patients with COM-C, 21 (31.8%) of 66 patients with COM-G, and 78 (12.7%) of 615 patients with COM.ConclusionThe most commonly seen OCE was incus erosion, followed by stapes and malleus erosions. The results of this study show that there are more OCE in the COM-C group than in the COM-G and COM groups. To our knowledge, this study has the widest patient population in the literature focused on the OCE relation with COM, COM-C, and COM-G and its effect on the preoperative hearing level.
Statistical properties of the simulated time horizon in conservative parallel discrete-event simu... more Statistical properties of the simulated time horizon in conservative parallel discrete-event simulations
Computational Complexity and Statistical Physics
In most cases, it is impossible to describe and understand complex system dynamics via analytical... more In most cases, it is impossible to describe and understand complex system dynamics via analytical methods. The density of problems that are rigorously solvable with analytic tools is vanishingly small in the set of all problems, and often the only way one can reliably obtain a system-level understanding of such problems is through direct simulation. This chapter broadens the discussion on the relationship between complexity and statistical physics by exploring how the computational scalability of parallelized simulation can be analyzed using a physical model of surface growth. Specifically, the systems considered here are made up of a large number of interacting individual elements with a finite number of attributes, or local state variables, each assuming a countable number (typically finite) of values. The dynamics of the local state variables are discrete events occurring in continuous time. Between two consecutive updates, the local variables stay unchanged. Another important as...
Bangladesh Journal of Medical Science, 2018
The aim of this study to develop a new scale to evaluate pain threshold, sensory effects of pain ... more The aim of this study to develop a new scale to evaluate pain threshold, sensory effects of pain and pain severity in patients with Fibromyalgia Syndrome (FMS). Material and Methods: This is a cross-sectional survey study and a questionnaire was administered to 52 voluntary patients diagnosed with FMS. In the proposed scale, thereare six questions about severe and less severe pain experience,two questions about the pain severity and sensory effect of FMS. In statistical analysis we used reliability analysis, factor analysis for construct validity, and other statistical tests to compare differences. Results: Exploratory factor analysis showed construct validity of the scale, and detected three factors. The internal consistency of the items of the scale was statistically significant. The agreement between the scores was good. Based on the answers, the patients were divided into two groups as low and high pain thresholds. There was no significant difference between these two groups in terms of severity of pain and sensory change due to fibromyalgia. In addition, the severity of pain in patients is lower than headache and at the level of stomachache and toothache. Discussion and Conclusion: The proposed scale allows the assessment of pain severity to be more detailed and paying attention to visually, it allows determining the pain threshold. It is suggested to compare the pain threshold determined by this scale with the pain threshold determined by different methods.
Physica D: Nonlinear Phenomena, 2001
We study the formation and evolution of chaotic breathers (CBs) on the Fermi-Pasta-Ulam oscillato... more We study the formation and evolution of chaotic breathers (CBs) on the Fermi-Pasta-Ulam oscillator chain with quartic nonlinearity (FPU-β system). Starting with most of the energy in a single high-frequency mode, the mode is found to breakup on a fast time scale into a number of spatially localized structures (CBs) which, on a slower time scale, coalesce into a single CB. On a usually longer time scale, depending strongly on the energy, the CB gives up its energy to lower frequency modes, approaching energy equipartition among modes. We analyze the behavior, theoretically, using an envelope approximation to the discrete chain of oscillators. For fixed boundaries, periodic nonlinear solutions are found. The numerical structures formed after the fast breakup are found to approximate the underlying equilibrium. These structures are shown, theoretically, to undergo slow translational motions, and an estimated time for them to coalesce into a single chaotic breather are found to agree with the numerically determined scaling τ B ∝ E −1. A previously developed theory of the decay of the CB amplitude to approach equipartition is modified to explicitly consider the interaction of the breather with background modes. The scaling to equipartition of T eq ∝ E −2 agrees with the numerical scaling and gives the correct order of magnitude of T eq .
Additional file 1. This file includes all supplemental data/tables referenced in the manuscript.
We consider massively parallel discrete event simulations where the communication topology among ... more We consider massively parallel discrete event simulations where the communication topology among the processing elements is a complex graph. In the case of regular topologies we review recent results on virtual time horizon management. First we analyze the computational scalability of the conservative massively parallel update scheme for discrete event simulations by using the analogy with a well-known surface growth model, then we show that a simple modification of the regular PE communication topology to a small-world topology will also ensure measurement scalability. This leads to a fully scalable parallel simulation for systems with asynchronous dynamics and short-range interactions. Finally, we present numerical results for the evolution of the virtual time horizon on scale-free Barabási-Albert networks serving as communication topology among the processing elements.
arXiv: Statistical Mechanics, 2003
We consider massively parallel discrete event simulations where the communication topology among ... more We consider massively parallel discrete event simulations where the communication topology among the processing elements is a complex graph. In the case of regular topologies we review recent results on virtual time horizon management. First we analyze the computational scalability of the conservative massively parallel update scheme for discrete event simulations by using the analogy with a well-known surface growth model, then we show that a simple modification of the regular PE communication topology to a small-world topology will also ensure measurement scalability. This leads to a fully scalable parallel simulation for systems with asynchronous dynamics and short-range interactions. Finally, we present numerical results for the evolution of the virtual time horizon on scale-free Barabasi-Albert networks serving as communication topology among the processing elements.
In this book we study synchronization phenomena in natural and artificial coupled multi-component... more In this book we study synchronization phenomena in natural and artificial coupled multi-component systems, applicable to the scalability of parallel discrete-event simulation for systems with asynchronous dynamics. We also study the role of various complex communication topologies as synchronization networks. We analyze the properties of the virtual time horizon or synchronization landscape (corresponding to the progress of the processing elements) of these networks by using the framework of non- equilibrium surface growth. When the communication topology mimics that of the short-range interacting underlying system, the virtual time horizon exhibits Kardar-Parisi-Zhang kinetic roughening. Although the virtual times, on average, progress at a nonzero rate, their statistical spread diverges with the number of processing elements, hindering efficient data collection. We show that when the synchronization topology is extended to include quenched random communication links between the pr...
Abstract We study the statistics and the scaling of the extreme fluctuations in small-world-coupl... more Abstract We study the statistics and the scaling of the extreme fluctuations in small-world-coupled interacting systems with relaxational dynamics (H. Guclu and G. Korniss, cond-mat/0311575 (2003).). After introducing random links to a one-dimensional lattice, the average size of the fluctuations becomes finite (synchronized state) and the typical size of the extreme fluctuations diverges only logarithmically in the large system-size limit. This weak logarithmic divergence ensures synchronization in a practical sense in small-world- ...
In this work, we study the target detection and tracking problem in mobile sensor networks, where... more In this work, we study the target detection and tracking problem in mobile sensor networks, where the performance metrics of interest are probability of detection and tracking coverage, when the target can be stationary or mobi le and its duration is finite. We propose a physical coverage-ba sed mobility model, where the mobile sensor nodes move such that the overlap between the covered areas by different mobile nodes i small. It is shown that for stationary target scenario the proposed mobility model can achieve a desired detection probabilitywith a significantly lower number of mobile nodes especially when the detection requirements are highly stringent. Similarly, when the target is mobile the coverage-based mobility model prod uces a consistently higher detection probability compared to ot her models under investigation.
BMC Health Services Research
Background: In the United States, there is well-documented regional variation in prescription dru... more Background: In the United States, there is well-documented regional variation in prescription drug spending. However, the specific role of physician adoption of brand name drugs on the variation in patient-level prescription drug spending is still being investigated across a multitude of drug classes. Our study aims to add to the literature by determining the association between physician adoption of a first-in-class anti-diabetic (AD) drug, sitagliptin, and AD drug spending in the Medicare and Medicaid populations in Pennsylvania. Methods: We obtained physician-level data from QuintilesIMS Xponent™ database for Pennsylvania and constructed county-level measures of time to adoption and share of physicians adopting sitagliptin in its first year post-introduction. We additionally measured total AD drug spending for all Medicare fee-for-service and Part D enrollees (N = 125,264) and all Medicaid (N = 50,836) enrollees with type II diabetes in Pennsylvania for 2011. Finite mixture model regression, adjusting for patient socio-demographic/clinical characteristics, was used to examine the association between physician adoption of sitagliptin and AD drug spending. Results: Physician adoption of sitagliptin varied from 44 to 99% across the state's 67 counties.
Bangladesh Journal of Medical Science
Objective: Quick diagnosis of COVID-19 has been an important factor to manage the ongoing pandemi... more Objective: Quick diagnosis of COVID-19 has been an important factor to manage the ongoing pandemic at hospitals and other health facilities.We aimed to investigate the effects of PCR test on hemogram parameters in COVID-19 patients. Materials and Methods: We collected hemogram data of 120 nasopharyngeal and oropharyngeal combo swab PCR positive and 119 PCR negative patients admitted to our hospital’s COVID-19 clinics with COVID-19 symptoms between 1 April 2020 and 24 June2020. Results: Age, MPV and NLR were found to be higher; hemoglobin, neutrophil, lymphocytes, basophil, platelet, PCT, WBC levels were lower in PCR positive cases.The highest sensitivity, 75 % is found on WBC count with cut off 7.15. Conclusion: Lower leukocyte count than 7.15, lower neutrophil count than 4.91, greater NLR than 2.95, lower platelet than 221.5 may give an idea about the diagnosis of SARS-CoV-2 infection. Bangladesh Journal of Medical Science Vol.20(5) 2021 p.118-124
Comparisons of the utility and accuracy of methods for measuring social interactions relevant to ... more Comparisons of the utility and accuracy of methods for measuring social interactions relevant to disease transmission are rare. To increase the evidence base supporting specific methods to measure social interaction, we compared data from self-reported contact surveys and wearable proximity sensors from a cohort of schoolchildren in the Pittsburgh metropolitan area. Although the number and type of contacts recorded by each participant differed between the two methods, we found good correspondence between the two methods in aggregate measures of age-specific interactions. Fewer, but longer, contacts were reported in surveys, relative to the generally short proximal interactions captured by wearable sensors. When adjusted for expectations of proportionate mixing, though, the two methods produced highly similar, assortative age-mixing matrices. These aggregate mixing matrices, when used in simulation, resulted in similar estimates of risk of infection by age. While proximity sensors an...
Annals of Medical Research
PloS one, 2018
Although physicians learn about new medical technologies from their peers, the magnitude and sour... more Although physicians learn about new medical technologies from their peers, the magnitude and source of peer influence is unknown. We estimate the effect of peer adoption of three first-in-class medications (dabigatran, sitigliptin, and aliskiren) on physicians' own adoption of those medications. We included 11,958 physicians in Pennsylvania prescribing anticoagulant, antidiabetic, and antihypertensive medications. We constructed 4 types of peer networks based on shared Medicare and Medicaid patients, medical group affiliation, hospital affiliation, and medical school/residency training. Instrumental variables analysis was used to estimate the causal effect of peer adoption (fraction of peers in each network adopting the new drug) on physician adoption (prescribing at least the median number prescriptions within 15 months of the new drug's introduction). We illustrate how physician network position can inform targeting of interventions to physicians by computing a social mult...
Healthcare (Amsterdam, Netherlands), Jan 21, 2017
Little is known about physicians' approaches to adopting new cardiovascular drugs and how ado... more Little is known about physicians' approaches to adopting new cardiovascular drugs and how adoption varies between drugs of differing novelty. Using data on dispensed prescriptions from IMS Health's Xponent™ database, we created a cohort of all primary care physicians (PCPs) and cardiologists in Pennsylvania who regularly prescribed anticoagulants, antihypertensives and statins from 2007 to 2011. We examined prescribing of three new cardiovascular drugs of differing novelty: dabigatran, aliskiren and pitavastatin. Outcomes were rapid adoption of each new drug, defined by early and sustained monthly prescribing detected by group-based trajectory models, by physicians within the first 15 months of marketplace introduction. 5953 physicians regularly prescribed each drug class. The majority of physicians (63.8%) adopted zero new drugs in the first 15 months, 35.0% rapidly adopted one or two, and 1.2% rapidly adopted all three. Physicians were more likely to rapidly adopt the most...
Mikrobiyoloji bulteni, 2021
After the declaration of the coronavirus-2019 (COVID-19) pandemic and the detection of the COVID-... more After the declaration of the coronavirus-2019 (COVID-19) pandemic and the detection of the COVID-19 case in Turkey, a series of non-pharmaceutical measures were implemented to reduce the number of contacts at the national level. The aim of this study was to determine the change in the epidemic reproduction rate (R0) with non-pharmaceutical interventions including curfews starting with the first reported case in Istanbul and to evaluate the effectiveness of interventions by estimating the number of cases and deaths using a dynamic compartmental model. While keeping transmission probability (beta) as 3% and incubation period as seven days, we developed five scenarios that represented nonpharmaceutical interventions The first scenario was "if nothing was done" and the last scenario was "curfew". The contact matrix of 16 age-groups created by Prem et al. was used in the study as the contact matrix of "if nothing was done" as scenario 1. For all other scenar...
Journal of Neurosurgery, 2019
OBJECTIVEThe authors sought to develop a set of parameters that reliably predict the clinical suc... more OBJECTIVEThe authors sought to develop a set of parameters that reliably predict the clinical success of endoscopic third ventriculostomy (ETV) when assessed before and after the operation, and to establish a plan for MRI follow-up after this procedure.METHODSThis retrospective study involved 77 patients who had undergone 78 ETV procedures for obstructive hydrocephalus between 2010 and 2015. Constructive interference in steady-state (CISS) MRI evaluations before and after ETV were reviewed, and 4 parameters were measured. Two well-known standard parameters, fronto-occipital horn ratio (FOHR) and third ventricular index (TVI), and 2 newly defined parameters, infundibulochiasmatic (IC) angle and anterior third ventricular height (TVH), were measured in this study. Associations between preoperative measurements of and postoperative changes in the 4 variables and the clinical success of ETV were analyzed.RESULTSOf the 78 ETV procedures, 70 (89.7%) were successful and 8 (10.3%) failed. O...
European Archives of Oto-Rhino-Laryngology, 2019
PurposeThe aim of this study was to evaluate the ossicular chain erosions (OCE) in chronic otitis... more PurposeThe aim of this study was to evaluate the ossicular chain erosions (OCE) in chronic otitis media patients with cholesteatoma (COM-C) or without cholesteatoma (COM).Materials and methodsThe OCE and preoperative hearing levels of a total of 915 patients were evaluated retrospectively. Patients were divided into three groups. Of the 915 patients, 615 (67.2%) had COM, 234 (25.6%) had COM-C, and 66 (7.2%) had chronic otitis media with granulation tissue (COM-G).ResultsOCE was found in 291 (31.8%) of 915 patients. OCE was found in 192 (82%) of 234 patients with COM-C, 21 (31.8%) of 66 patients with COM-G, and 78 (12.7%) of 615 patients with COM.ConclusionThe most commonly seen OCE was incus erosion, followed by stapes and malleus erosions. The results of this study show that there are more OCE in the COM-C group than in the COM-G and COM groups. To our knowledge, this study has the widest patient population in the literature focused on the OCE relation with COM, COM-C, and COM-G and its effect on the preoperative hearing level.
Statistical properties of the simulated time horizon in conservative parallel discrete-event simu... more Statistical properties of the simulated time horizon in conservative parallel discrete-event simulations
Computational Complexity and Statistical Physics
In most cases, it is impossible to describe and understand complex system dynamics via analytical... more In most cases, it is impossible to describe and understand complex system dynamics via analytical methods. The density of problems that are rigorously solvable with analytic tools is vanishingly small in the set of all problems, and often the only way one can reliably obtain a system-level understanding of such problems is through direct simulation. This chapter broadens the discussion on the relationship between complexity and statistical physics by exploring how the computational scalability of parallelized simulation can be analyzed using a physical model of surface growth. Specifically, the systems considered here are made up of a large number of interacting individual elements with a finite number of attributes, or local state variables, each assuming a countable number (typically finite) of values. The dynamics of the local state variables are discrete events occurring in continuous time. Between two consecutive updates, the local variables stay unchanged. Another important as...
Bangladesh Journal of Medical Science, 2018
The aim of this study to develop a new scale to evaluate pain threshold, sensory effects of pain ... more The aim of this study to develop a new scale to evaluate pain threshold, sensory effects of pain and pain severity in patients with Fibromyalgia Syndrome (FMS). Material and Methods: This is a cross-sectional survey study and a questionnaire was administered to 52 voluntary patients diagnosed with FMS. In the proposed scale, thereare six questions about severe and less severe pain experience,two questions about the pain severity and sensory effect of FMS. In statistical analysis we used reliability analysis, factor analysis for construct validity, and other statistical tests to compare differences. Results: Exploratory factor analysis showed construct validity of the scale, and detected three factors. The internal consistency of the items of the scale was statistically significant. The agreement between the scores was good. Based on the answers, the patients were divided into two groups as low and high pain thresholds. There was no significant difference between these two groups in terms of severity of pain and sensory change due to fibromyalgia. In addition, the severity of pain in patients is lower than headache and at the level of stomachache and toothache. Discussion and Conclusion: The proposed scale allows the assessment of pain severity to be more detailed and paying attention to visually, it allows determining the pain threshold. It is suggested to compare the pain threshold determined by this scale with the pain threshold determined by different methods.
Physica D: Nonlinear Phenomena, 2001
We study the formation and evolution of chaotic breathers (CBs) on the Fermi-Pasta-Ulam oscillato... more We study the formation and evolution of chaotic breathers (CBs) on the Fermi-Pasta-Ulam oscillator chain with quartic nonlinearity (FPU-β system). Starting with most of the energy in a single high-frequency mode, the mode is found to breakup on a fast time scale into a number of spatially localized structures (CBs) which, on a slower time scale, coalesce into a single CB. On a usually longer time scale, depending strongly on the energy, the CB gives up its energy to lower frequency modes, approaching energy equipartition among modes. We analyze the behavior, theoretically, using an envelope approximation to the discrete chain of oscillators. For fixed boundaries, periodic nonlinear solutions are found. The numerical structures formed after the fast breakup are found to approximate the underlying equilibrium. These structures are shown, theoretically, to undergo slow translational motions, and an estimated time for them to coalesce into a single chaotic breather are found to agree with the numerically determined scaling τ B ∝ E −1. A previously developed theory of the decay of the CB amplitude to approach equipartition is modified to explicitly consider the interaction of the breather with background modes. The scaling to equipartition of T eq ∝ E −2 agrees with the numerical scaling and gives the correct order of magnitude of T eq .
Additional file 1. This file includes all supplemental data/tables referenced in the manuscript.
We consider massively parallel discrete event simulations where the communication topology among ... more We consider massively parallel discrete event simulations where the communication topology among the processing elements is a complex graph. In the case of regular topologies we review recent results on virtual time horizon management. First we analyze the computational scalability of the conservative massively parallel update scheme for discrete event simulations by using the analogy with a well-known surface growth model, then we show that a simple modification of the regular PE communication topology to a small-world topology will also ensure measurement scalability. This leads to a fully scalable parallel simulation for systems with asynchronous dynamics and short-range interactions. Finally, we present numerical results for the evolution of the virtual time horizon on scale-free Barabási-Albert networks serving as communication topology among the processing elements.
arXiv: Statistical Mechanics, 2003
We consider massively parallel discrete event simulations where the communication topology among ... more We consider massively parallel discrete event simulations where the communication topology among the processing elements is a complex graph. In the case of regular topologies we review recent results on virtual time horizon management. First we analyze the computational scalability of the conservative massively parallel update scheme for discrete event simulations by using the analogy with a well-known surface growth model, then we show that a simple modification of the regular PE communication topology to a small-world topology will also ensure measurement scalability. This leads to a fully scalable parallel simulation for systems with asynchronous dynamics and short-range interactions. Finally, we present numerical results for the evolution of the virtual time horizon on scale-free Barabasi-Albert networks serving as communication topology among the processing elements.
In this book we study synchronization phenomena in natural and artificial coupled multi-component... more In this book we study synchronization phenomena in natural and artificial coupled multi-component systems, applicable to the scalability of parallel discrete-event simulation for systems with asynchronous dynamics. We also study the role of various complex communication topologies as synchronization networks. We analyze the properties of the virtual time horizon or synchronization landscape (corresponding to the progress of the processing elements) of these networks by using the framework of non- equilibrium surface growth. When the communication topology mimics that of the short-range interacting underlying system, the virtual time horizon exhibits Kardar-Parisi-Zhang kinetic roughening. Although the virtual times, on average, progress at a nonzero rate, their statistical spread diverges with the number of processing elements, hindering efficient data collection. We show that when the synchronization topology is extended to include quenched random communication links between the pr...
Abstract We study the statistics and the scaling of the extreme fluctuations in small-world-coupl... more Abstract We study the statistics and the scaling of the extreme fluctuations in small-world-coupled interacting systems with relaxational dynamics (H. Guclu and G. Korniss, cond-mat/0311575 (2003).). After introducing random links to a one-dimensional lattice, the average size of the fluctuations becomes finite (synchronized state) and the typical size of the extreme fluctuations diverges only logarithmically in the large system-size limit. This weak logarithmic divergence ensures synchronization in a practical sense in small-world- ...
In this work, we study the target detection and tracking problem in mobile sensor networks, where... more In this work, we study the target detection and tracking problem in mobile sensor networks, where the performance metrics of interest are probability of detection and tracking coverage, when the target can be stationary or mobi le and its duration is finite. We propose a physical coverage-ba sed mobility model, where the mobile sensor nodes move such that the overlap between the covered areas by different mobile nodes i small. It is shown that for stationary target scenario the proposed mobility model can achieve a desired detection probabilitywith a significantly lower number of mobile nodes especially when the detection requirements are highly stringent. Similarly, when the target is mobile the coverage-based mobility model prod uces a consistently higher detection probability compared to ot her models under investigation.
BMC Health Services Research
Background: In the United States, there is well-documented regional variation in prescription dru... more Background: In the United States, there is well-documented regional variation in prescription drug spending. However, the specific role of physician adoption of brand name drugs on the variation in patient-level prescription drug spending is still being investigated across a multitude of drug classes. Our study aims to add to the literature by determining the association between physician adoption of a first-in-class anti-diabetic (AD) drug, sitagliptin, and AD drug spending in the Medicare and Medicaid populations in Pennsylvania. Methods: We obtained physician-level data from QuintilesIMS Xponent™ database for Pennsylvania and constructed county-level measures of time to adoption and share of physicians adopting sitagliptin in its first year post-introduction. We additionally measured total AD drug spending for all Medicare fee-for-service and Part D enrollees (N = 125,264) and all Medicaid (N = 50,836) enrollees with type II diabetes in Pennsylvania for 2011. Finite mixture model regression, adjusting for patient socio-demographic/clinical characteristics, was used to examine the association between physician adoption of sitagliptin and AD drug spending. Results: Physician adoption of sitagliptin varied from 44 to 99% across the state's 67 counties.
Bangladesh Journal of Medical Science
Objective: Quick diagnosis of COVID-19 has been an important factor to manage the ongoing pandemi... more Objective: Quick diagnosis of COVID-19 has been an important factor to manage the ongoing pandemic at hospitals and other health facilities.We aimed to investigate the effects of PCR test on hemogram parameters in COVID-19 patients. Materials and Methods: We collected hemogram data of 120 nasopharyngeal and oropharyngeal combo swab PCR positive and 119 PCR negative patients admitted to our hospital’s COVID-19 clinics with COVID-19 symptoms between 1 April 2020 and 24 June2020. Results: Age, MPV and NLR were found to be higher; hemoglobin, neutrophil, lymphocytes, basophil, platelet, PCT, WBC levels were lower in PCR positive cases.The highest sensitivity, 75 % is found on WBC count with cut off 7.15. Conclusion: Lower leukocyte count than 7.15, lower neutrophil count than 4.91, greater NLR than 2.95, lower platelet than 221.5 may give an idea about the diagnosis of SARS-CoV-2 infection. Bangladesh Journal of Medical Science Vol.20(5) 2021 p.118-124
Comparisons of the utility and accuracy of methods for measuring social interactions relevant to ... more Comparisons of the utility and accuracy of methods for measuring social interactions relevant to disease transmission are rare. To increase the evidence base supporting specific methods to measure social interaction, we compared data from self-reported contact surveys and wearable proximity sensors from a cohort of schoolchildren in the Pittsburgh metropolitan area. Although the number and type of contacts recorded by each participant differed between the two methods, we found good correspondence between the two methods in aggregate measures of age-specific interactions. Fewer, but longer, contacts were reported in surveys, relative to the generally short proximal interactions captured by wearable sensors. When adjusted for expectations of proportionate mixing, though, the two methods produced highly similar, assortative age-mixing matrices. These aggregate mixing matrices, when used in simulation, resulted in similar estimates of risk of infection by age. While proximity sensors an...
Annals of Medical Research
PloS one, 2018
Although physicians learn about new medical technologies from their peers, the magnitude and sour... more Although physicians learn about new medical technologies from their peers, the magnitude and source of peer influence is unknown. We estimate the effect of peer adoption of three first-in-class medications (dabigatran, sitigliptin, and aliskiren) on physicians' own adoption of those medications. We included 11,958 physicians in Pennsylvania prescribing anticoagulant, antidiabetic, and antihypertensive medications. We constructed 4 types of peer networks based on shared Medicare and Medicaid patients, medical group affiliation, hospital affiliation, and medical school/residency training. Instrumental variables analysis was used to estimate the causal effect of peer adoption (fraction of peers in each network adopting the new drug) on physician adoption (prescribing at least the median number prescriptions within 15 months of the new drug's introduction). We illustrate how physician network position can inform targeting of interventions to physicians by computing a social mult...
Healthcare (Amsterdam, Netherlands), Jan 21, 2017
Little is known about physicians' approaches to adopting new cardiovascular drugs and how ado... more Little is known about physicians' approaches to adopting new cardiovascular drugs and how adoption varies between drugs of differing novelty. Using data on dispensed prescriptions from IMS Health's Xponent™ database, we created a cohort of all primary care physicians (PCPs) and cardiologists in Pennsylvania who regularly prescribed anticoagulants, antihypertensives and statins from 2007 to 2011. We examined prescribing of three new cardiovascular drugs of differing novelty: dabigatran, aliskiren and pitavastatin. Outcomes were rapid adoption of each new drug, defined by early and sustained monthly prescribing detected by group-based trajectory models, by physicians within the first 15 months of marketplace introduction. 5953 physicians regularly prescribed each drug class. The majority of physicians (63.8%) adopted zero new drugs in the first 15 months, 35.0% rapidly adopted one or two, and 1.2% rapidly adopted all three. Physicians were more likely to rapidly adopt the most...