254 research outputs found
Introduction to the special issue: Recap of ninth International Conference on Health Policy Statistics
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Factors associated with geographic variation in cost per episode of care for three medical conditions
Objective: To identify associations between market factors, especially relative reimbursement rates, and the probability of surgery and cost per episode for three medical conditions (cataract, benign prostatic neoplasm, and knee degeneration) with multiple treatment options. Methods: We use 2004–2006 Medicare claims data for elderly beneficiaries from sixty nationally representative communities to estimate multivariate models for the probability of surgery and cost per episode of care as a function local market factors, including Medicare physician reimbursement for surgical versus non-surgical treatment and the availability of primary care and specialty physicians. We used Symmetry’s Episode Treatment Groups (ETG) software to group claims into episodes for the three conditions (n = 540,874 episodes). Results: Higher Medicare reimbursement for surgical episodes and greater availability of the relevant specialists are significantly associated with more surgery and higher cost per episode for all three conditions, while greater availability of primary care physicians is significantly associated with less frequent surgery and lower cost per episode. Conclusion: Relative Medicare reimbursement rates for surgical vs. non-surgical treatments and the availability of both primary care physicians and relevant specialists are associated with the likelihood of surgery and cost per episode
Analyzing Clustered Data: Why and How to Account for Multiple Observations Nested within a Study Participant?
A conventional study design among medical and biological experimentalists involves col- lecting multiple measurements from a study subject. For example, experiments utilizing mouse models in neuroscience often involve collecting multiple neuron measurements per mouse to increase the number of observations without requiring a large number of mice. This leads to a form of statistical dependence referred to as clustering. Inappropriate analy- ses of clustered data have resulted in several recent critiques of neuroscience research that suggest the bar for statistical analyses within the field is set too low. We compare naĂŻve ana- lytical approaches to marginal, fixed-effect, and mixed-effect models and provide guidelines for when each of these models is most appropriate based on study design. We demonstrate the influence of clustering on a between-mouse treatment effect, a within-mouse treatment effect, and an interaction effect between the two. Our analyses demonstrate that these sta- tistical approaches can give substantially different results, primarily when the analyses include a between-mouse treatment effect. In a novel analysis from a neuroscience per- spective, we also refine the mixed-effect approach through the inclusion of an aggregate mouse-level counterpart to a within-mouse (neuron level) treatment as an additional predic- tor by adapting an advanced modeling technique that has been used in social science research and show that this yields more informative results. Based on these findings, we emphasize the importance of appropriate analyses of clustered data, and we aim for this work to serve as a resource for when one is deciding which approach will work best for a given study
Modeling peer effect modification by network strength: The diffusion of implantable cardioverter defibrillators in the US hospital network
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154422/1/sim8466.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/154422/2/sim8466_am.pd
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Changes in the food environment over time: examining 40 years of data in the Framingham Heart Study
Background: Research has explored associations between diet, body weight, and the food environment; however, few studies have examined historical trends in food environments. Methods: In the Framingham Heart Study Offspring (N = 3321) and Omni (N = 447) cohorts, we created food environment metrics in four Massachusetts towns utilizing geocoded residential, workplace, and food establishment addresses from 1971 to 2008. We created multilevel models adjusted for age, sex, education, and census tract poverty to examine trends in home, workplace, and commuting food environments. Results: Proximity to and density of supermarkets, fast-food, full service restaurants, convenience stores, and bakeries increased over time for residential, workplace, and commuting environments; exposure to grocery stores decreased. The greatest increase in access was for supermarkets, with residential distance to the closest supermarket 1406 m closer (95% CI 1303 m, 1508 m) by 2005–2008 than in 1971–1975. Although poorer census tracts had higher access to fast-food restaurants consistently across follow-up, this disparity dissipated over time, due to larger increases in proximity to fast-food in wealthier neighborhoods. Conclusions: Access to most food establishment types increased over time, with similar trends across home, workplace, and commuter environments. Electronic supplementary material The online version of this article (doi:10.1186/s12966-017-0537-4) contains supplementary material, which is available to authorized users
The diving behaviour of mammal-eating killer whales (Orcinus orca): variations with ecological not physiological factors
Mammal-eating killer whales (Orcinus orca (L., 1758)) are a rare example of social predators that hunt together in groups of sexually dimorphic adults and juveniles with diverse physiological diving capacities. Day–night ecological differences should also affect diving as their prey show diel variation in activity and mammal-eating killer whales do not rely on echolocation for prey detection. Our objective was to explore the extent to which physiological aerobic capacities versus ecological factors shape the diving behaviour of this breath-hold diver. We used suction-cup-attached depth recorders (Dtags) to record 7608 dives of 11 animals in southeast Alaska. Analysis of dive sequences revealed a strong bout structure in both dive depth and duration. Day–night comparisons revealed reduced rates of deep dives, longer shallow dives, and shallower long-duration dives at night. In contrast, dive variables did not differ by age–sex class. Estimates of the aerobic dive limit (cADL) suggest that juveniles exceeded their cADL during as much as 15% of long dives, whereas adult males and females never exceeded their cADL. Mammal-eating killer whales in this area appear to employ a strategy of physiological compromise, with smaller group members diving nearer their physiological limits and large-bodied males scaling down their physiological performance
Antitumor activity and safety of the PARP inhibitor rucaparib in patients with high grade ovarian carcinoma and a germline or somatic BRCA1 or BRCA2 mutation: integrated analysis of data from Study 10 and ARIEL2
Objective:
An integrated analysis was undertaken to characterize the antitumor activity and safety profile of the oral poly(ADP-ribose) polymerase inhibitor rucaparib in patients with relapsed high-grade ovarian carcinoma (HGOC).
Methods:
Eligible patients from Study 10 (NCT01482715) and ARIEL2 (NCT01891344) who received a starting dose of oral rucaparib 600 mg twice daily (BID) with or without food were included in these analyses. The integrated efficacy population included patients with HGOC and a deleterious germline or somatic BRCA1 or BRCA2 (BRCA1/2) mutation who received at least two prior chemotherapies and were sensitive, resistant, or refractory to platinum-based chemotherapy. The primary endpoint was investigator-assessed confirmed objective response rate (ORR). Secondary endpoints included duration of response (DOR) and progression-free survival (PFS). The integrated safety population included patients with HGOC who received at least one dose of rucaparib 600 mg BID, irrespective of BRCA1/2 mutation status and prior treatments.
Results:
In the efficacy population (n = 106), ORR was 53.8% (95% confidence interval [CI], 43.8–63.5); 8.5% and 45.3% of patients achieved complete and partial responses, respectively. Median DOR was 9.2 months (95% CI, 6.6–11.6). In the safety population (n = 377), the most frequent treatment-emergent adverse events (AEs) were nausea, asthenia/fatigue, vomiting, and anemia/hemoglobin decreased. The most common grade ≥ 3 treatment-emergent AE was anemia/hemoglobin decreased. Treatment-emergent AEs led to treatment interruption, dose reduction, and treatment discontinuation in 58.6%, 45.9%, and 9.8% of patients, respectively. No treatment-related deaths occurred.
Conclusions:
Rucaparib has antitumor activity in advanced BRCA1/2-mutated HGOC and a manageable safety profile
Cardiology providers’ recommendations for treatments and use of patient decision aids for multivessel coronary artery disease
Background: Rates of recommending percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) vary across clinicians. Whether clinicians agree on preferred treatment options for multivessel coronary artery disease patients has not been well studied. Methods and results: We distributed a survey to 104 clinicians from the Northern New England Cardiovascular Study Group through email and at a regional meeting with 88 (84.6%) responses. The survey described three clinical vignettes of multivessel coronary artery disease patients. For each patient vignette participants selected appropriate treatment options and whether they would use a patient decision aid. The likelihood of choosing PCI only or PCI/CABG over CABG only was modeled using a multinomial regression. Across all vignettes, participants selected CABG only as an appropriate treatment option 24.2% of the time, PCI only 25.4% of the time, and both CABG or PCI as appropriate treatment options 50.4% of the time. Surgeons were less likely to choose PCI over CABG (RR 0.14, 95% CI 0.03, 0.59) or both treatments over CABG only (RR 0.10, 95% CI 0.03, 0.34) relative to cardiologists. Overall, 65% of participants responded they would use a patient decision aid with each vignette. Conclusions: There is a lack of consensus on the appropriate treatment options across cardiologists and surgeons for patients with multivessel coronary artery disease. Treatment choice is influenced by both patient characteristics and clinician specialty
Egocentric Social Network Structure, Health, and Pro-Social Behaviors in a National Panel Study of Americans
Using a population-based, panel survey, we study how egocentric social networks change over time, and the relationship between egocentric network properties and health and pro-social behaviors. We find that the number of prosocial activities is strongly positively associated with having more friends, or an increase in degree, with approximately 0.04 more prosocial behaviors expected for every friend added. Moreover, having more friends is associated with an improvement in health, while being healthy and prosocial is associated with closer relationships. Specifically, a unit increase in health is associated with an expected 0.45 percentage-point increase in average closeness, while adding a prosocial activity is associated with a 0.46 percentage-point increase in the closeness of one’s relationships. Furthermore, a tradeoff between degree and closeness of social contacts was observed. As the number of close social contacts increases by one, the estimated average closeness of each individual contact decreases by approximately three percentage-points. The increased awareness of the importance of spillover effects in health and health care makes the ascertainment of egocentric social networks a valuable complement to investigations of the relationship between socioeconomic factors and health
Medicare Part D Plan Generosity and Medication Use Among Dual-eligible Nursing Home Residents
In 2006, dual-eligible nursing home residents were randomly assigned to a Medicare Part D prescription drug plan (PDP). Subsequently, residents not enrolled in qualified plans at the start of the next year were re-randomized. PDPs vary in generosity through differences in medication coverage and utilization management. Therefore, residents’ assigned plans may be relatively more or less generous for their particular drugs. The impact of generosity on residents’ medication use and health outcomes is unknown
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