Hot off the press: Diagnostic testing differences between advanced practice providers and physicians.

Abstract

Emergency departments (EDs) increasingly incorporate advanced practice providers (APPs), including physician assistants and nurse practitioners, into their staffing models.1, 2 APPs receive different medical education and training than emergency physicians. Notably, the required length of training in the United States is approximately 2 years for APPs compared with 7 years (4 years of medical education followed by 3–4 years of residency training). Some have postulated that differences in training may increase diagnostic test utilization and hospital admission among APPs. Given the significant burden of diagnostic evaluation on health care costs, discrepancies in testing could have important impacts. This is an observational cohort study that analyzes 3 years of data from approximately 90 EDs, including 663,599 patient visits for chest pain and 946,042 patient visits for abdominal pain.3 The authors used inverse propensity score weights to adjust for measured confounders in the assignment of a visit to an APP or physician. The primary outcomes assessed were laboratory tests, electrocardiograms, imaging studies, and hospital admissions. Observational studies have several limitations, most notably, the existence of both measured and unmeasured confounders. In this study, the authors used propensity scores in an attempt to mitigate the impact of unmeasured confounders. This included clinician-level variables (e.g., time in practice), patient-level variables (e.g., age, sex, insurance, Emergency Severity Index [ESI] level), and visit-level variables (e.g., time of day, day of week). Despite this statistical adjustment, it is possible that other variables that could not be accounted for influenced the diagnostic evaluation or admission rates. Additionally, the two chief complaints evaluated in this study, chest pain and abdominal pain, often have somewhat protocolized evaluations. Often adults with chest pain are evaluated to exclude acute coronary syndromes, pulmonary embolism, or aortic dissection. Diagnostic evaluation including blood work, electrocardiogram, and chest radiographs are often initiated by nursing protocols. Thus, it may not be surprising to find no significant difference between groups. Overall, physicians saw more patients over age 55 (28.1% vs. 17.4% for abdominal pain, 46.2% vs. 29.2% for chest pain) and more patients triaged as an ESI level 2 (7.6% vs. 2.9% for abdominal pain, 47.4% vs. 30.1% for chest pain). After adjustment, the average treatment effect of APP management on the probability of common laboratory, radiology, and hospital admission orders demonstrated little variation from the reference standard (physician). In this study of visits for chest and abdominal pain, APPs did not have higher rates of imaging or hospital admission; however, these results may not be generalized in all practice settings or patient presentations. Justin Hensley, MD FAWM (@EBMgoneWILD): This one is tough. The "chest pain" workup is so standardized in today's US medicolegal climate that you could probably do that study as "doctor" versus "kid with an order sheet that says ‘chest pain’ and ‘not chest pain'". Similarly for abdominal pain. Ryan Radecki, MD MS (@emlitofnote): I’m also not surprised it's hard to find a difference between MD/DOs and APPs when MD/DO practice variation is so profound, in general. Tanker_PA_Dave: Did the authors have the ability to differentiate between practice years for APPs and also for APPs who have gone through post graduate training in EM (fellowships/residencies)? Like all physicians coming out of school PAs and NPs are very green and comparing new PAs and NPs to residency graduate EM physicians is not very equitable. Additionally what is considered supervised in this system, is it case presentations, co-signing charts, full 100% chart reviews or a percentage of charts reviewed? Jesse M. Pines, M.D.: Hi Dave – We did use clinician time in practice in the inversion propensity weights (i.e. it was controlled for in the study), however, we did not have data on additional post-graduate training (i.e., what additional fellowships either physicians or APPs may have done). In terms of supervision, that varied across sites. However, the traditional practice is for physicians to be available for questions rather than staffing every case. In this retrospective observational study evaluating patients with chest pain and abdominal pain in the ED, physicians and APPs had similar practice patterns with regard to diagnostic test ordering and admission rates. The authors have no potential conflicts to disclose. Lauren M. Westafer drafted the manuscript. Christopher Bond and William Milne contributed to its revision.