Browsing by Author "Abbott, David H"

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Open Access
Characteristics of primary care office visits to nurse practitioners, physician assistants and physicians in United States Veterans Health Administration facilities, 2005 to 2010: a retrospective cross-sectional analysis.
(Hum Resour Health, 2012-11-13) Morgan, Perri A; Abbott, David H; McNeil, Rebecca B; Fisher, Deborah A
UNLABELLED: BACKGROUND: Primary care, an essential determinant of health system equity, efficiency, and effectiveness, is threatened by inadequate supply and distribution of the provider workforce. The Veterans Health Administration (VHA) has been a frontrunner in the use of nurse practitioners (NPs) and physician assistants (PAs). Evaluation of the roles and impact of NPs and PAs in the VHA is critical to ensuring optimal care for veterans and may inform best practices for use of PAs and NPs in other settings around the world. The purpose of this study was to characterize the use of NPs and PAs in VHA primary care and to examine whether their patients and patient care activities were, on average, less medically complex than those of physicians. METHODS: This is a retrospective cross-sectional analysis of administrative data from VHA primary care encounters between 2005 and 2010. Patient and patient encounter characteristics were compared across provider types (PA, NP, and physician). RESULTS: NPs and PAs attend about 30% of all VHA primary care encounters. NPs, PAs, and physicians fill similar roles in VHA primary care, but patients of PAs and NPs are slightly less complex than those of physicians, and PAs attend a higher proportion of visits for the purpose of determining eligibility for benefits. CONCLUSIONS: This study demonstrates that a highly successful nationwide primary care system relies on NPs and PAs to provide over one quarter of primary care visits, and that these visits are similar to those of physicians with regard to patient and encounter characteristics. These findings can inform health workforce solutions to physician shortages in the USA and around the world. Future research should compare the quality and costs associated with various combinations of providers and allocations of patient care work, and should elucidate the approaches that maximize quality and efficiency.
Open Access
Comorbidity, age, race and stage at diagnosis in colorectal cancer: a retrospective, parallel analysis of two health systems.
(BMC Cancer, 2008-11-25) Zafar, S Yousuf; Abernethy, Amy P; Abbott, David H; Grambow, Steven C; Marcello, Jennifer E; Herndon, James E; Rowe, Krista L; Kolimaga, Jane T; Zullig, Leah L; Patwardhan, Meenal B; Provenzale, Dawn T
BACKGROUND: Stage at diagnosis plays a significant role in colorectal cancer (CRC) survival. Understanding which factors contribute to a more advanced stage at diagnosis is vital to improving overall survival. Comorbidity, race, and age are known to impact receipt of cancer therapy and survival, but the relationship of these factors to stage at diagnosis of CRC is less clear. The objective of this study is to investigate how comorbidity, race and age influence stage of CRC diagnosis. METHODS: Two distinct healthcare populations in the United States (US) were retrospectively studied. Using the Cancer Care Outcomes Research and Surveillance Consortium database, we identified CRC patients treated at 15 Veterans Administration (VA) hospitals from 2003-2007. We assessed metastatic CRC patients treated from 2003-2006 at 10 non-VA, fee-for-service (FFS) practices. Stage at diagnosis was dichotomized (non-metastatic, metastatic). Race was dichotomized (white, non-white). Charlson comorbidity index and age at diagnosis were calculated. Associations between stage, comorbidity, race, and age were determined by logistic regression. RESULTS: 342 VA and 340 FFS patients were included. Populations differed by the proportion of patients with metastatic CRC at diagnosis (VA 27% and FFS 77%) reflecting differences in eligibility criteria for inclusion. VA patients were mean (standard deviation; SD) age 67 (11), Charlson index 2.0 (1.0), and were 63% white. FFS patients were mean age 61 (13), Charlson index 1.6 (1.0), and were 73% white. In the VA cohort, higher comorbidity was associated with earlier stage at diagnosis after adjusting for age and race (odds ratio (OR) 0.76, 95% confidence interval (CI) 0.58-1.00; p = 0.045); no such significant relationship was identified in the FFS cohort (OR 1.09, 95% CI 0.82-1.44; p = 0.57). In both cohorts, no association was found between stage at diagnosis and either age or race. CONCLUSION: Higher comorbidity may lead to earlier stage of CRC diagnosis. Multiple factors, perhaps including increased interactions with the healthcare system due to comorbidity, might contribute to this finding. Such increased interactions are seen among patients within a healthcare system like the VA system in the US versus sporadic interactions which may be seen with FFS healthcare.
Open Access
Sequence diversity analyses of an improved rhesus macaque genome enhance its biomedical utility.
(Science (New York, N.Y.), 2020-12) Warren, Wesley C; Harris, R Alan; Haukness, Marina; Fiddes, Ian T; Murali, Shwetha C; Fernandes, Jason; Fernandes, Jason; Dishuck, Philip C; Storer, Jessica M; Raveendran, Muthuswamy; Hillier, LaDeana W; Porubsky, David; Mao, Yafei; Gordon, David; Vollger, Mitchell R; Lewis, Alexandra P; Munson, Katherine M; DeVogelaere, Elizabeth; Armstrong, Joel; Diekhans, Mark; Walker, Jerilyn A; Tomlinson, Chad; Graves-Lindsay, Tina A; Kremitzki, Milinn; Salama, Sofie R; Audano, Peter A; Escalona, Merly; Maurer, Nicholas W; Antonacci, Francesca; Mercuri, Ludovica; Maggiolini, Flavia AM; Catacchio, Claudia Rita; Underwood, Jason G; O'Connor, David H; Sanders, Ashley D; Korbel, Jan O; Ferguson, Betsy; Kubisch, H Michael; Picker, Louis; Kalin, Ned H; Rosene, Douglas; Levine, Jon; Abbott, David H; Gray, Stanton B; Sanchez, Mar M; Kovacs-Balint, Zsofia A; Kemnitz, Joseph W; Thomasy, Sara M; Roberts, Jeffrey A; Kinnally, Erin L; Capitanio, John P; Skene, JH Pate; Platt, Michael; Cole, Shelley A; Green, Richard E; Ventura, Mario; Wiseman, Roger W; Paten, Benedict; Batzer, Mark A; Rogers, Jeffrey; Eichler, Evan E
The rhesus macaque (Macaca mulatta) is the most widely studied nonhuman primate (NHP) in biomedical research. We present an updated reference genome assembly (Mmul_10, contig N50 = 46 Mbp) that increases the sequence contiguity 120-fold and annotate it using 6.5 million full-length transcripts, thus improving our understanding of gene content, isoform diversity, and repeat organization. With the improved assembly of segmental duplications, we discovered new lineage-specific genes and expanded gene families that are potentially informative in studies of evolution and disease susceptibility. Whole-genome sequencing (WGS) data from 853 rhesus macaques identified 85.7 million single-nucleotide variants (SNVs) and 10.5 million indel variants, including potentially damaging variants in genes associated with human autism and developmental delay, providing a framework for developing noninvasive NHP models of human disease.