A Comparison of Rural and Urban Use of Point of Care Ultrasound by Allopathic and Osteopathic Physicians in Oregon

Objective

Point-of-care ultrasound (POCUS) is a versatile diagnostic tool with applications spanning the evaluation of orthopedic issues,¹ ocular imaging,² airway management,³ and spinal trauma,⁴ among others. The E-FAST (Extended Focused Assessment with Sonography in Trauma) is frequently and ubiquitously used in trauma and emergency care and is an example of POCUS.⁵ Beyond clinical use, POCUS has been shown to offer additional benefits such as speed of use, real-time images, cost-effectiveness, lack of ionizing radiation, an increase in patient satisfaction, increased trust in the skills and abilities of the provider, and increased patient-perceived empathy from their provider.^6,7 POCUS may also aid the physician in their diagnostic process by acting as a readily available tool in the clinician’s medical decision-making.⁸ The American Academy of Family Physicians publishing its first POCUS curricular guidelines in 2018,⁹ and POCUS continues to grow its prevalence and integration into medical education curricula.¹⁰

Despite the advantages of POCUS, cost and billing issues remain barriers to the integration of POCUS into residency training programs and professional practice.¹¹ A nationwide survey in the U.S. noted significant regional disparities in POCUS utilization between urban and rural settings, with the urban areas of Southern California and the East Coast emerging as regions of high POCUS use.¹² Rural areas may have specific barriers to the use of POCUS, including smaller budgets, more uninsured patients, and fewer or no emergency departments.¹²

Oregon’s landscape is largely rural, with approximately 86% of the state meeting that definition; 33% of residents live rurally, or more than 10 miles from a population center of 40,000, and 2% live in frontier areas where there are six or less individuals per square mile.¹³ Out of the 26 counties in Oregon, 10 are frontier.¹³ Oregon has not been identified as an area of high POCUS use,¹² but there are high-density urban centers in the state, including Portland, Salem, and Eugene. The use of POCUS in Oregon has not been assessed.

Allopathic (Medical Doctors/MD) and osteopathic (Doctors of Osteopathy/DO) physicians are both able to be licensed in the all 50 states in the U.S., have similar schooling, take similar board exams, compete for the same residencies, and practice in all of the same specialties.¹⁴ A comparative study of allopathic and osteopathic training in POCUS has not been done. Given the gap in knowledge about use of POCUS in Oregon and the use of POCUS among MDs vs. DOs, this study’s research questions were: (1) Are there differences in use or attitudes about POCUS between Oregon DOs and MDs? (2) Does POCUS use differ between urban, suburban, and rural practice areas in Oregon? (3) What other factors influence POCUS use in Oregon?

Survey Methods

A cross-sectional survey-based design was used to address the aims of this study (see Appendix for the survey form). The Western University of Health Science’s Institutional Review Board approved this study (#2238865). All participants gave informed consent for use of their anonymous data.

Sample Size and Power

A contact list was purchased of the 15,067 allopathic and osteopathic physicians licensed by the Oregon Medical Board, as well as a list of members of the Osteopathic Physicians and Surgeons of Oregon. Duplicates and those without email addresses were removed, resulting in a total targeted population of N = 4,593, or 30.5% of licensed physicians in Oregon. Desired sample size to be powered at 80% with alpha level 0.05 and confidence level of 95% was n = 292.

Inclusion/exclusion criteria

Inclusion criteria for participants were that they be a licensed allopathic or osteopathic physician practicing in the state of Oregon, including residents, from any region or specialty. Retired physicians were excluded.

Data Collection

Recruitment

An email was sent from a Western University of Health Sciences account to the contact list, explaining the study and asking for participation in the survey. A link to the survey was included within the survey; the first question informed participants of their rights as a research subject and that their data would be anonymous and reported in aggregate. Reminder emails were sent once per week for three more weeks. After one month the survey was closed.

Survey

Outcome measures were compiled in a Qualtrics survey, a secure online survey platform which is configured for protected health information. The survey took approximately five minutes to complete.

Outcome Measures

1. Information collected including type of schooling (MD/DO), specialty area, years since completion of residency with an option for current residents, practice setting (clinic/ hospital/both/other), urbanity (rural/suburban/urban), if they received formal POCUS curriculum during medical school, and if they were trained on POCUS during clinical rotations in medical school.

2. A Likert scale-based questionnaire was developed based on Johnson et al.'s 2021 study on POCUS training for family medicine residents.⁶ We tested the questionnaire in a focus group of medical students for clarity and completion time. After revisions, the survey contained 14 questions (see Appendix). Questions from Johnson et al.'s survey included experience level; confidence in performing POCUS techniques; confidence in interpreting POCUS images; and beliefs around if POCUS results in health care cost reduction, enhances diagnostic ability, or helps in patient management.⁶ Additional questions beyond Johnson et al.'s survey included asking if POCUS assisted in refining additional tests needed for a patient, or improved patient outcomes. We then added questions based on Peterman et al.'s assessment of rural vs. urban use of POCUS with questions about barriers to use including availability of equipment, affordability of equipment, and compensation for use.¹²

Data Management

Respondents clicked a link in the recruitment email if they wished to participate, which took them to the Qualtrics survey. After the first survey closed, the anonymous data was uploaded to the secure, password-protected Western University of Health Sciences cloud (OneDrive) and compiled in Excel.

Data Analysis

Statistical analysis was done with SPSS version 29.0.2. Data normality was assessed by subgroup size and with histograms. Descriptive statistics were used to obtain frequencies and percentages of participants’ years in practice, specialties, urbanity, and practice setting, as well as means and standard deviations on each Likert scale item. Independent t-tests were used to compare MDs and DOs across the survey questions, and one-way ANOVAs used to compare rural, suburban, and urban physicians, across practice settings, and across specialties. Dunnett’s T3 post-hoc test was used with ANOVAs as a conservative analysis. Linear regression was used to determine if years of practice influenced POCUS use.

Psychometric analysis consisted of assessing the reliability and validity of the outcome measure. Cronbach’s alpha was calculated as a measure of internal consistency.¹⁵ Pearson’s correlation matrix was compared to Pearson critical values to determine validity.

Results

After removal of missing data and retired physicians, n = 193 Oregon physicians participated in the study including n = 38 (19.7%) DOs and n = 155 (80.3%) MDs, a 4.2% response rate. The majority had been practicing for over ten years, were in primary or continuity care, and practiced in an urban area. See [Table 1] for descriptive data.

See [Table 2] for question-by-question responses for all participants.

(Research Question 1) Are there differences in use or attitudes about POCUS between Oregon DOs and MDs?

There were several significant differences found between Oregon MDs and DOs with regards to their location, training with POCUS, and confidence with POCUS. MDs had a small but statistically significant higher mean in years of practice, 4.8 vs. 4.5 years. There was a significant difference in practice area, with more MDs practicing in urban areas than DOs (F(1,191) = 8.42, p = 0.004). DOs reported significantly more training on POCUS during clinical rotations in medical school (t = 2.12, p = 0.04), but MDs reported significantly more confidence with interpretation of POCUS images (t = 2.08, p = 0.04). DOs agreed more than MDs that lack of availability inhibited their use of POCUS (t = 3.20, p = 0.002). No other statistically significant differences were observed.

(Research Question 2) Does POCUS use differ between urban, suburban, and rural practice areas in Oregon?

Experience with POCUS differed by practice area (F(2,176) = 10.87, p < 0.001), with both rural-based (MD = -0.77, p = 0.04), and suburban-based (MD = -1.11, p < 0.001) physicians reporting significantly less experience than urban-based physicians. Frequency of use of POCUS also differed (F(2,175) = 6.98, p = 0.001), with urban physicians using it much more frequently than rural (MD = 0.86, p = 0.03) or suburban physicians (MD = 0.86, p = 0.003). A difference of opinion existed on if POCUS improves patient outcomes (F(2,172) = 6.84, p = 0.001), with urban-based physicians agreeing more that it does compared to rural-based (MD = 0.89, p = 0.02); if POCUS improves diagnostic ability (F(2,162) = 6.29, p = 0.002), with urban-based physicians agreeing more that it does compared to rural-based (MD = 0.88, p = 0.01); if POCUS availability inhibits use (F(2,165) = 4.15, p = 0.02), with suburban-based physicians agreeing more than it does compared to urban-based (MD = 0.58, p = 0.03); if confidence inhibits use (F(2,159) = 4.79, p = 0.01), with suburban-based physicians agreeing more that it does compared to urban-based (MD = 0.85, p = 0.005); and if compensation influences use (F(2,163) = 3.17, p = 0.05), with suburban-based physicians agreeing more that it does compared to urban-based (MD = 0.56, p = 0.02). There were no significant differences for any other measure.

(Research Question 3) What other factors influence POCUS use in Oregon?

We assessed if an inpatient vs. outpatient practice influences POCUS use. Experience significantly differed between physicians who saw primarily inpatients vs. primarily outpatients (F(2,162) = 6.42, p = 0.002), with outpatient physicians reporting significantly less experience than inpatient physicians (MD = -0.94, p = 0.003). Frequency of POCUS use differed between inpatient and outpatient physicians (F(2,161) = 17.97, p < 0.001) with inpatient physicians using POCUS significantly more (MD = 1.18, p < 0.001). Lastly, physicians’ rating of the ability of their workplace to afford equipment differed between inpatient and outpatient physicians (F(2,153) = 5.08, p = 0.008) with inpatient physicians reporting equipment cost as less of a barrier than outpatient physicians (MD = 1.13, p = 0.02).

Several factors differed by specialty as well. For the analysis we divided physician specialties into primary/continuity care (family medicine, internal medicine, OB/GYN, psychiatry, pediatrics), procedural/acute care (surgery, surgical specialty, anesthesia, emergency medicine, radiology, critical care, ophthalmology) or specialized/interdisciplinary (cardiology, osteopathic manipulative medicine (OMM), physical medicine and rehabilitation (PM&R), pain management, palliative care, genetics/endocrine, infectious disease). Differences including frequency of use (F(2,172) = 4.80, p = 0.009), with primary/continuity care physicians using POCUS significantly less than procedural/acute care physicians (MD = -0.73, p = 0.01); confidence with interpretation (F(2,121) = 4.29, p = 0.02), with procedural/acute care physicians more confident in interpretation than primary/continuity care physicians, (MD = 0.73, p = 0.01); belief that availability inhibits use (F(2,162) = 6.00, p = 0.003), with primary/continuity care physicians endorsing this more than procedural/acute care physicians (MD = 0.62, p = 0.03); and if cost of equipment inhibits use (F(2,163) = 5.12, p = 0.007), with primary/continuity care physicians endorsing this more than procedural/acute care physicians (MD = 0.60, p = 0.008). We also assessed if years of practice influenced POCUS use, and found this not to be the case.

Discussion

This study assessed if the use of POCUS varied by degree type (MD vs. DO), practice area (urban vs. suburban vs. rural), practice setting (inpatient vs outpatient), specialty (primary/continuity vs. procedural/acute vs. specialized/interdisciplinary), or time in practice. Close to 80% of respondents were MDs, 60% were in primary/continuity care, most had been in practice for more than a decade, and 69% were practicing in an urban area. Physicians in urban, inpatient, and procedural/acute settings endorsed more experience with, frequency of use, and confidence with POCUS interpretation compared to physicians in rural, outpatient, and primary/continuity care settings.

Differences between MDs and DOs, which included less years in practice and more rural practice among DOs, may explain the higher confidence of interpretation among MDs. Emergency/trauma centers are typically urban, meaning urban physicians may manage complex and emergent cases more regularly, necessitating the use of POCUS more often.^5,16 Urban hospital systems also typically have better funding than rural hospitals or clinics,¹⁷ increasing barriers to use among rural physicians even if POCUS equipment was needed.

A ripple effect may result, where rural-based physicians, who are more likely to be DOs, have less access to and less need of POCUS, therefore gaining or retaining less confidence with use. Oregon DOs reported significantly more training on POCUS during clinical rotations, which otherwise might result in higher confidence with its use, but after an average of more than a decade in practice, training received during medical school rotations and not practiced since is unlikely to be retained. The results may also reflect the type of POCUS training, which was not queried; for example, the E-FAST exam may be taught more regularly to medical students, but musculoskeletal imaging with POCUS may not be. A 2020 survey of US medical schools reported that 57% of the 154 schools who responded had POCUS in their curriculum, but with high variability in when POCUS was taught, what was taught, and how it was assessed (i.e., didactically vs. a skills exam).¹⁸ For the physicians in this study, who on average graduated more than 10 years ago, POCUS training was even more inconsistent, making it likely that current medical students and residents have had more training on POCUS than some of their attendings.

Limitations of this study include a small sample size, low response rate, and small number of DOs, making the data potentially less accurate. This study only assessed Oregon physicians, so results may be significantly different across different states. Response bias may exist as all questions were subjective; it’s possible that some participants did not wish to admit a low level of confidence, which may have inflated scores.

Future research on the use of POCUS would benefit from including rural vs. urban practices and utility, the frequency of use of different exams such as the E-FAST vs. musculoskeletal assessment, and how POCUS is changing the efficiency and effectiveness of healthcare delivery among different settings. As residents join the physician workforce, POCUS provides an opportunity to assess how newer medical skills either filter up or not to older, more experienced physicians, and/or the state of continuing medical education for POCUS.

In summary, POCUS can provide efficient, safe, and accurate imaging for emergent and chronic cases alike when properly utilized. Rural physicians, who are more likely to be DOs, report more barriers to use of POCUS including less experience, less frequent use, lower confidence with interpretation of images, and lower affordability. While rural physicians may have less utility for POCUS with fewer emergency cases, barriers to use in rural areas including cost may inhibit POCUS use that could improve care.