Letters

inform clinical decision making, public health policy, and qual- tice clinicians in physician specialty practices.5 In this study, ity measure development to enhance patient safety. we characterize levels of and changes in advanced practice clinician employment across different physician practices in Andrew J. Karter, PhD the United States in 2008 and 2016, with a particular focus Howard H. Moffet, MPH on specialty practices. Jennifer Y. Liu, MPH Kasia J. Lipska, MD, MPH Methods | We used the 2008 and 2016 SK&A outpatient pro- vider files for our analyses. The SK&A is a proprietary data Author Affiliations: Division of Research, Kaiser Permanente, Oakland, set that includes information on 90% of physician practices California (Karter, Moffet, Liu); Section of , Department of in the United States. We first categorized specialty practices , Yale School of Medicine, New Haven, Connecticut (Lipska). as single medical or single surgical specialty practices Corresponding Author: Andrew J. Karter, PhD, Division of Research, Kaiser Permanente, 2000 Broadway, Oakland, CA 94612 ([email protected]). (Table), examining multispecialty practices separately. We Accepted for Publication: February 16, 2018. also conducted analysis on the 3 largest categories of pri- Published Online: April 16, 2018. doi:10.1001/jamainternmed.2018.1014 mary care practices: family medicine, internal medicine, and Author Contributions: Dr Karter had full access to all of the data in the study pediatrics. We performed supplementary analyses for the and takes responsibility for the integrity of the data and the accuracy of the data top 10 specialties by practice counts across all years. For analysis. each practice type, we calculated the proportion of practices Concept and design: Karter, Moffet, Lipska. with an advanced practice clinician (overall and by NPs and Acquisition, analysis, or interpretation of data: All authors. Drafting of the manuscript: Karter. PAs) and the percent change between 2008 and 2016. Using Critical revision of the manuscript for important intellectual content: All authors. STATA statistical software (version 15, STATA Corp) we cre- Statistical analysis: Karter, Liu. ated choropleth maps to show variation in the state-level Obtained funding: Karter. proportion of practices that employed advanced practice cli- Administrative, technical, or material support: Moffet. Supervision: Karter. nicians in 2016. Conflict of Interest Disclosures: Dr Karter and Mr Moffet received unrelated funding from AstraZeneca. Mr Moffet and Ms Liu also received unrelated Results | In 2016, approximately 28% of all specialty practices funding from Regeneron. Dr Lipska receives support from the National Institute employed advanced practice clinicians. Multispecialty prac- on Aging and the American Federation of Aging Research through the Paul Beeson Career Development Award (K23 AG048359) and the Yale Claude D. tices were most likely (49%) and surgical specialties least likely Pepper Older Americans Independence Center (P30 AG021342). Dr Karter is (21%) to employ advanced practice clinicians. Among the top also supported by the NIDDK Centers for Diabetes Translational Research 10 specialties, advanced practice clinicians were employed in (P30 DK092924). at least a quarter of practices in the following specialties: car- Funding/Support: This project was supported by the National Institute of diology, obstetrics-gynecology, dermatology, gastroenterol- Health (R01 DK103721, R01 DK065664). ogy, and orthopedic surgery. Specialty practices were more Role of the Funder/Sponsor: The National Institute of Health had no role in the design and conduct of the study; collection, management, analysis, and likely to employ NPs than PAs, with the exception of surgical interpretation of the data; preparation, review, or approval of the manuscript; practices, which relied more on PAs. Overall, from 2008 to and decision to submit the manuscript for publication. 2016, there was a 22% increase in specialty practices employ- 1. Seaquist ER, Anderson J, Childs B, et al. Hypoglycemia and diabetes: a report ing advanced practice clinicians. As a point of comparison, of a workgroup of the American Diabetes Association and the Endocrine there has been a 24% increase in advanced practice clinician Society. Diabetes Care. 2013;36(5):1384-1395. use among primary care practices, such that 35% of these prac- 2. Geller AI, Shehab N, Lovegrove MC, et al. National estimates of insulin-related hypoglycemia and errors leading to emergency department tices have at least 1 advanced practice clinician by 2016. Em- visits and hospitalizations. JAMA Intern Med. 2014;174(5):678-686. ployment of NPs in specialty practices grew faster compared 3. Number of Emergency Department Visits (in Thousands) with Hypoglycemia to PAs (33% vs 20% increase). as First-Listed Diagnosis and Diabetes as Secondary Diagnosis, Adults Aged 18 In the Figure we show that specialty practice advanced Years or Older, United States, 2006–2009. 2014; https://www.cdc.gov practice clinician employment was greatest in the Mountain /diabetes/statistics/hypoglycemia/methods.htm. Accessed November 9, 2013. West and West North Central regions (eg, North Dakota, South 4. Moffet HH, Adler N, Schillinger D, et al. Cohort Profile: The Diabetes Study of Northern California (DISTANCE)—objectives and design of a survey follow-up Dakota, Minnesota, and Iowa) during 2016—analogous to pri- study of social health disparities in a managed care population. Int J Epidemiol. mary care. We also note that restricting our analyses to a bal- 2009;38(1):38-47. anced panel of practices from 2008 to 2016 did not meaning- 5. Ginde AA, Blanc PG, Lieberman RM, Camargo CA Jr. Validation of ICD-9-CM fully change the data patterns we observed. coding algorithm for improved identification of hypoglycemia visits. BMC Endocr Disord. 2008;8:4. Conclusions | We found that about 1 in 4 specialty practices employ advanced practice clinicians, compared with 1 in 3 Employment of Advanced Practice Clinicians primary care practices. Because the NP role was historically in Physician Practices developed to focus on primary care and most advanced Nurse practitioners (NPs) and physician assistants (PAs) are practice clinicians are NPs, one would expect that advanced advanced practice clinicians that are increasingly involved in practice clinicians would have a greater presence in primary the delivery of health care services. The role of advanced care practices. The proportion of practices with advanced practice clinicians in primary care has been described practice clinicians grew modestly over the past 8 years and previously.1-4 However, less is known about advanced prac- the growth was similar across specialty and primary care

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Table. Percent of Physician Practices With Advanced Practice Clinicians and the Percent Change From 2008 to 2016

Any Advanced Total Practices, No. Practice Clinician, % Any NP, % Any PA, % Variable 2008 2016 2008 2016 Change 2008 2016 Change 2008 2016 Change Specialty practicesa 132 682 165 655 23.2 28.3 21.7 14.4 19.2 32.6 11.6 14.0 20.3 Medical specialties 87 178 109 125 20.2 23.3 15.7 13.6 16.3 19.9 8.3 9.9 19.3 Surgical specialtiesb 22 881 22 185 17.8 20.6 15.8 5.8 7.7 32.6 13.6 15.3 12.0 Multispecialty 22 623 34 345 40.5 49.0 20.9 26.3 35.5 34.9 22.4 26.1 16.4 Psychiatry 12 909 16 535 14.7 17.4 18.4 13.1 15.9 20.9 2.2 2.7 19.2 Obstetrics/gynecology 12 676 13 148 29.5 29.3 −0.7 25.3 25.3 0.2 6.1 6.5 5.7 Ophthalmology 9939 10 505 0.8 0.7 −10.8 0.3 0.3 3.7 0.6 0.5 −9.1 Cardiology 6142 8483 30.3 31.0 2.4 22.1 24.3 9.6 12.7 12.9 1.8 Orthopedic surgery 6758 7293 28.0 29.1 3.9 4.9 7.0 43.0 25.3 25.4 0.6 General surgery 6213 6400 11.2 13.8 24.0 5.4 7.6 40.1 6.6 7.5 14.6 Neurology 3814 5162 13.8 21.3 54.2 9.5 15.6 64.5 5.4 8.2 52.4 Plastic surgery 6067 4177 6.4 9.8 54.2 2.7 3.8 39.8 3.9 6.4 62.9 Dermatology 5428 6041 27.4 36.3 32.5 8.4 11.5 36.8 21.7 29.5 35.6 Gastroenterology 3873 5496 25.1 28.7 14.2 15.4 19.2 24.7 12.5 14.4 15.1 Primary care practicesc 68 317 69 755 28.4 35.3 24.3 18.8 26.1 38.8 12.5 14.6 16.8 Family practice 30 322 31 936 36.7 44.8 22.1 22.4 31.6 41.0 18.4 21.0 13.9 Internal medicine 22 514 22 424 18.3 23.9 30.8 12.0 17.6 46.2 7.7 9.3 21.3 Pediatrics 12 164 12 939 27.9 34.3 22.8 23.0 29.3 27.3 7.3 9.0 22.4 Abbreviations: NP, nurse practitioner; PA, physician assistant. rheumatology, sleep medicine, sports medicine, urology, vascular and a Specialty practices include medical specialties: addiction medicine, adolescent interventional radiology. medicine, aerospace medicine, /, anesthesiology, b Surgical specialties include bariatrics, colorectal surgery, general surgery, head cardiology, critical care medicine, dermatology, dialysis, emergency medicine, and neck surgery, neurological surgery, orthopedic surgery, plastic surgery, endocrinology, gastroenterology, general preventive medicine, genetic thoracic surgery, transplant surgery, trauma surgery, and vascular surgery. specialist, gynecologic oncology, holistic medicine, infectious disease, c Primary care includes family practice, general practice, geriatric medicine, nephrology, neurology, nuclear medicine, obstetrics/gynecology, occupational internal medicine, internal medicine/pediatrics, and pediatrics. medicine, oncology/hematology, ophthalmology, otolaryngology, pain management, physical medicine/rehab, psychiatry, pulmonology,

Figure. Percent of Physician Practices With Advanced Practice Clinicians by State

A Specialty practices, 2016 B Primary care practices, 2016

>50 % 37.5-50% 25-37.5% 0-25%

practices. Overall growth in advanced practice clinicians clinicians may also be increasingly moving into specialty may be driven by recent increases in graduates from practices as specialist physicians embrace new roles for advanced practice clinician programs, the emergence of advanced practice clinicians.6 These data have important value-based purchasing models that are incentivizing team- limitations. They only include outpatient providers and they based care, and downward price pressure from public and have no information about the specific duties of advanced private payers—making the lower costs of advanced practice practice clinicians in the practice. As the presence of clinician employment more attractive. Advanced practice advanced practice clinicians in the delivery of specialty care

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increases, future research will need to understand their con- lic evidence.3 Policies that require reporting to ClinicalTrials tributions to access, quality, and value. .gov are designed to ameliorate that problem. ClinicalTrials .gov currently has more than 255 000 registered studies, with Grant R. Martsolf, PhD, MPH summary results information for more than 28 000 studies, Hilary Barnes, PhD of which an estimated half lack corresponding publications.2,4,5 Michael R. Richards, MD, PhD To evaluate the influence of this resource on the evidence base, Kristin N. Ray, MD, MS we examined the extent to which sets of trials registered in Heather M. Brom, PhD, RN ClinicalTrials.gov by individual sponsors for the same drug and Matthew D. McHugh, PhD, MPH condition had results available publicly in ClinicalTrials.gov and/or PubMed. Author Affiliations: School of Nursing, University of Pittsburgh, Pittsburgh, Pennsylvania (Martsolf); RAND Corporation, Pittsburgh, Pennsylvania Methods | We identified ClinicalTrials.gov-registered records for (Martsolf); School of Nursing, University of Delaware, Newark, Delaware (Barnes); Department of Health Policy, Vanderbilt University Medical Center, industry-sponsored, phase 2 to 4 trials of drugs or biologics, Nashville, Tennessee (Richards); School of Medicine, University of Pittsburgh, with at least 1 US study location, completed or terminated from Pittsburgh, Pennsylvania (Ray); Center for Healthcare Outcomes and Policy January 1, 2007, through December 31, 2009 (allowing at least Research, School of Nursing, University of Pennsylvania, Philadelphia, Pennsylvania (Brom, McHugh). 7 years from trial completion for results reporting). We manu- Corresponding Author: Grant R. Martsolf, PhD, MPH, School of Nursing, ally grouped trials into a sponsor-drug-condition trial set when University of Pittsburgh, 3500 Victoria St, Ste 315B, Pittsburgh, PA 15213 the listed sponsor, drug, and condition appeared to be iden- ([email protected]). tical; we limited the analysis to a convenience sample of the Accepted for Publication: March 3, 2018. first 96 sponsor-drug-condition trial sets identified. On July Published Online: April 30, 2018. doi:10.1001/jamainternmed.2018.1515 25, 2017, we assessed the availability of results in PubMed- Author Contributions: Dr Martsolf had full access to all of the data in the study cited publications and/or results posted in ClinicalTrials.gov and takes responsibility for the integrity of the data and the accuracy of the data based on methods used in prior research.4 We also evaluated analysis. whether the drug was approved by the US Food and Drug Ad- Study concept and design: Martsolf, Barnes, Richards, McHugh. Acquisition, analysis, or interpretation of data: Barnes, Richards, Ray, Brom, ministration (FDA) for any use. McHugh. Drafting of the manuscript: Martsolf, Barnes, McHugh. Results | Our sample consisted of 329 trials studying 86 drugs Critical revision of the manuscript for important intellectual content: All authors. Statistical analysis: Martsolf, Barnes, Richards, Brom. and representing 96 unique sponsor-drug-condition trial sets Obtained funding: Barnes. (eg, Amgen-sponsored trials of alendronate for osteoporo- Study supervision: Martsolf, McHugh. sis). The median number of trials per set was 3 (range, 2-11). Conflict of Interest Disclosures: None reported. The median proportion of trials in each set with results pub- 1. DesRoches CM, Clarke S, Perloff J, O’Reilly-Jacob M, Buerhaus P. The quality licly available (in PubMed and/or ClinicalTrials.gov) was 100% of primary care provided by nurse practitioners to vulnerable Medicare (interquartile range, 62.5%-100%). Most trials used parallel as- beneficiaries. Nurs Outlook. 2017;65(6):679-688. signment, double-blinding, randomization, and multiple sites 2. Graves JA, Mishra P, Dittus RS, Parikh R, Perloff J, Buerhaus PI. Role of geography and nurse practitioner scope-of-practice in efforts to expand and had more than 100 participants enrolled (Table 1). As of primary care system capacity: health reform and the primary care workforce. July 25, 2017, results were publicly available for 255 of 329 trials Med Care. 2016;54(1):81-89. (77.5%): 79 (24.0%) from ClinicalTrials.gov only, 63 (19.1%) 3. Perloff J, DesRoches CM, Buerhaus P. Comparing the cost of care provided to from PubMed only, and 113 (34.3%) from both sources. Over- Medicare beneficiaries assigned to primary care nurse practitioners and all, 58 (60.4%) of 96 sponsor-drug-condition trial sets had re- physicians. Health Serv Res. 2016;51(4):1407-1423. sults available for all trials, and 13 (13.5%) had no results avail- 4. Barnes H, Maier CB, Altares Sarik D, Germack HD, Aiken LH, McHugh MD. Effects of regulation and payment policies on nurse practitioners’ clinical able from either source (Table 2). There were 15 (15.6%) trial practices. Med Care Res Rev. 2017;74(4):431-451. sets with results from ClinicalTrials.gov only (10 sets with re- 5. Ray KN, Martsolf GR, Mehrotra A, Barnett ML. Trends in visits to specialist sults posted for all trials and 5 sets with results posted for some physicians involving nurse practitioners and physician assistants, 2001 to 2013. trials) (Table 2). JAMA Intern Med. 2017;177(8):1213-1216. Of 214 trials studying 55 FDA-approved drugs, 184 (86.0%) 6. Brush JE Jr, Handberg EM, Biga C, et al. 2015 ACC Health policy statement on had results available, including 64 (29.9%) in ClinicalTrials cardiovascular team-based care and the role of advanced practice providers. J Am Coll Cardiol. 2015;65(19):2118-2136. .gov only. Of 115 trials studying 31 unapproved drugs, 70 (60.9%) had results publicly available, including 15 (13.0%) with results in ClinicalTrials.gov only. Results Reporting for Trials With the Same Sponsor, Drug, and Condition in ClinicalTrials.gov Discussion | ClinicalTrials.gov was a unique source of results for and Peer-Reviewed Publications nearly one-quarter of sampled drug trials and more than one- Missing or incomplete reporting of clinical trial results and its tenth of sampled sponsor-drug-condition trial sets. How- scientific and ethical consequences are well documented.1,2 ever, results remain unavailable in ClinicalTrials.gov or PubMed One concrete example of this problem occurs when a sponsor 7 or more years after study completion for nearly one-quarter conducts several studies of a particular drug for a particular of sampled drug trials and more than one-tenth of sampled condition but only some (or none) of the studies make their sponsor-drug-condition trial sets. This study is limited by the way into the public domain, leaving a distorted body of pub- convenience sampling approach, omission of unregistered

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