A, Frequency of procedures by year billed by advanced practice professionals (eg, nurse practitioners and physician assistants). B, Frequency of procedures by year billed by dermatologists.
eTable 1. Number and Percentage of Procedures Billed by Advanced Practice Professionals (APP) and Dermatologists From 2012 to 2015
eTable 2. Number of Advanced Practice Professionals (APP) and Dermatologists (Dm) Billing for Procedures and Mean Number of Procedures (Pr) per Clinician From 2012 to 2015
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Zhang M, Zippin J, Kaffenberger B. Trends and Scope of Dermatology Procedures Billed by Advanced Practice Professionals From 2012 Through 2015. JAMA Dermatol. 2018;154(9):1040–1044. doi:10.1001/jamadermatol.2018.1768
What is the scope of dermatologic procedures performed by advanced practice professionals, and how has it changed over time?
In this longitudinal study using Medicare data, for most types of dermatologic procedures, the total number and percentage performed by advanced practice professionals increased significantly each year from 2012 through 2015.
The number and scope of dermatology procedures billed by advanced practice professionals are increasing over time, which prompts further study of outcomes and optimal training.
Advanced practice professionals (APPs) such as nurse practitioners and physician assistants independently perform a large number and variety of dermatologic procedures, but little is known about how the number and scope of these procedures have changed over time.
To examine the trends in scope and volume of dermatology procedures billed by APPs over time.
Design, Setting, and Participants
A longitudinal study was conducted using the Medicare Provider Utilization and Payment Data: Physician and Other Supplier Public Use File from 2012 through 2015. The data encompass nearly all outpatient procedures paid by Medicare Part B in the United States and include the type of clinician under which procedures were billed.
Main Outcomes and Measures
For each type of dermatology procedure, the total number performed by APPs and the total number performed by dermatologists each year.
The total number (and percentage) of all dermatologic procedures performed by APPs increased from 2.69 million of 30.7 million (8.8%) in 2012 to 4.54 million of 33.9 million (13.4%) in 2015. The most common procedures performed by APPs in 2015 were destructions of benign neoplasms (3.6 million), biopsies (788 834), and destructions of malignant neoplasms (48 982). The numbers of patch tests, removals of benign and malignant neoplasms, intermediate and complex repairs, flaps, and surgical pathologic specimen examinations by APPs also increased each year from 2012 through 2015.
Conclusions and Relevance
The number and scope of dermatologic procedures performed by APPs appear to be increasing over time. These procedures can be difficult and invasive. This study suggests that further studies are needed to determine what association these procedures have with patient outcomes and the potential need for more formal training.
Midlevel or advanced practiced professionals (APPs) such as nurse practitioners (NPs) and physician assistants (PAs) are often employed in specialty offices to extend access to care. Coldiron and Ratnarathorn1 demonstrated that APPs also independently bill for a large number of procedures—nearly 5 million in the 2012 Medicare population, 55% of which were dermatologic. In this study, we examine how the scope and number of dermatologic procedures performed by APPs have continued to evolve from 2012 through 2015 in the Medicare population.
A longitudinal study was performed using the Medicare Provider Utilization and Payment Data: Physician and Other Supplier Public Use File from 2012 through 2015.2 This data set contains approximately 100% of outpatient procedures paid by Medicare Part B, excluding only procedures received by fewer than 10 beneficiaries from a clinician, to protect patient confidentiality. Data entries are aggregated by Current Procedural Terminology codes and the National Provider Identifier and include the credentials of the clinician billing for the procedure. The total number of Medicare Part B enrollees each year is also included in the data. The study was exempt from review by the Summa Health System Institutional Review Board because all data are public and deidentified.
Medicare reimburses NPs and PAs at 85% of the physician’s rate.3,4 Under certain circumstances, a nonphysician health care professional can bill for services performed under physician supervision at the full rate of reimbursement, but these services must be billed under the physician. We assume that most procedures billed under APPs were performed by the APP under no supervising physician because otherwise they could be billed under the physician for higher reimbursement.
Data processing and statistical analysis were performed using MATLAB, version R2017a (MathWorks). Dermatologic procedures of interest—including biopsies, removals, destructions, repairs, local skin flaps, full-thickness grafts, and patch testing—were extracted from the data set and analyzed (the full list of procedures and Current Procedural Terminology codes can be found in eTable 1 in the Supplement). Codes for surgical pathologic specimens including skin were also analyzed but not counted toward the frequency of all-category dermatologic procedures because these codes also include many tissue types other than skin. For each procedure, total frequencies and the frequencies and percentages billed by APPs (NP, PA, or clinical nurse specialist) and dermatologists were calculated for each year. Plots of frequencies vs time were more linear after log transformation, so linear regression was used to model the log-transformed number of procedures billed by APPs and dermatologists over time and to calculate the yearly percentage change. Rates of change in the frequency of procedures performed by APPs and dermatologists were compared using a 2-tailed z test5 on the difference between regression coefficients (β) using SEs of the regressions:
Total numbers of APPs and dermatologists billing for procedures each year were calculated by counting unique National Provider Identifiers that billed for a procedure on at least 10 beneficiaries. The number of clinicians billing for each procedure was used to calculate the mean number of procedures per clinician type each year.
Procedure numbers by clinician type each year are shown in the Figure and the Table. Full results with subcategories of procedures can be found in eTable 1 of the Supplement. The total frequencies of all examined dermatologic procedures (excluding pathology) billed by APPs increased from 2.69 million of 30.7 million (8.8%) in 2012 to 4.54 million of 33.9 million (13.4%) in 2015. The procedures most commonly billed by APPs in 2015 were destructions of benign neoplasms (3.6 million; mostly premalignant lesions), biopsies (788 834; including shaves), and destructions of malignant neoplasms (48 982).
Each year, the number of procedures billed by APPs increased significantly, and at a significantly higher rate than procedures billed by dermatologists, for skin biopsies (18.7% per year; 95% CI, 16.0%-21.4%), shaves (11.3%; 95% CI, 9.3%-13.3%), removals of benign neoplasms (16.5%; 95% CI, 3.8%-30.8%), removals of malignant neoplasms (11.8%; 95% CI, 3.3%-21.1%), destructions of benign neoplasms (19.2%; 95% CI, 17.9%-20.6%), destructions of malignant neoplasms (18.5%; 95% CI, 10.4%-27.3%), intermediate repairs (13.3%; 95% CI, 10.4%-16.3%), complex repairs (19.9%; 95% CI, 11.4%-29.2%), local skin flaps (10.6%; 95% CI, 4.6%-17.0%), patch testing (27.9%; 95% CI, 3.1%-58.7%), and surgical pathologic examinations (18.0%; 95% CI, 1.6%-36.9%). Simple repairs and full-thickness skin grafts were the only procedures examined with no significant increase in APP numbers. The numbers of dermatologist procedures each year were more stable. The largest increase among procedures billed by dermatologists was in complex repairs (7.1% per year; 95% CI, 5.4%-8.9%). All other procedures saw no significant change greater than 3.4% per year. Full statistics with confidence intervals for APPs and dermatologists yearly change are summarized in the Table.
The total number of unique APPs billing for any dermatologic procedure (excluding pathologic examination) each year from 2012 to 2015 was 3234 in 2012, 3509 in 2013, 3861 in 2014, and 4308 in 2015, for a 33.2% increase from 2012 to 2015. The total number of unique dermatologists billing for a procedure from 2012 to 2015 was 10 183 in 2012, 10 423 in 2013, 10 604 in 2014, and 10 800 in 2015, for a 6.1% increase from 2012 to 2015. The numbers of APPs and dermatologists billing for specific procedures each year and the mean number of procedures billed by each clinician are presented in eTable 2 in the Supplement. The number of APPs increased each year, at a rate similar to the overall increase for any procedure, for all procedures except simple repairs, local flaps, full-thickness grafts, and surgical pathologic examinations. The mean number of procedures billed per APP was mostly stable, with skin biopsies (195 per APP in 2012 to 216 per APP in 2015), destructions of benign neoplasms (844 per APP in 2012 to 1001 per APP in 2015), and surgical pathologic examinations (121 per APP in 2012 to 206 per APP in 2015) being the only procedures with consistent increases each year. The mean number of procedures per clinician was higher for dermatologists than APPs for every procedure except full-thickness grafts (40-41 per dermatologist per year vs 46-53 per APP per year).
The total number of Medicare Part B enrollees each year from 2012 to 2015 was 33 259 978 in 2012, 33 540 864 in 2013, 33 645 448 in 2014, and 33 682 283 in 2015, for a 1.3% increase from 2012 to 2015. From 2012 to 2015, the number of procedures billed by APPs (excluding pathologic examinations) per Medicare enrollee each year increased from 0.081 to 0.135 (66.7%). During the same time, the number of procedures billed by dermatologists per Medicare enrollee each year increased from 0.774 to 0.807 (4.3%).
The total frequency of examined dermatologic procedures billed by APPs increased from 2.69 million in 2012 to 4.54 million in 2015. The numbers of procedures billed by APPs increased each year—and increased at a significantly higher rate than that of dermatologists—for every category of procedure except simple repairs and skin grafts. Simple repairs did not show strong trends for any type of clinician, and we hypothesize that the complexity and time-consuming nature of skin grafts makes them difficult for APPs to perform.
An increase in the number of APPs appears to be the biggest driving force for increased procedures because the mean number of procedures performed by each APP who billed for those procedures is stable for most procedures. This increase in the number of APPs billing for procedures is consistent with a more general trend of an increasing number of APPs being employed in dermatology practices.6
The trend of an increasing number of procedures performed by APPs, most of which are likely unsupervised, has potential implications for patient safety and outcomes. Advanced practice professionals billed Medicare for nearly 800 000 biopsies in 2015, a 68% increase from 2012. Skin biopsies are more than just procedures; there is a knowledge-based and experience-based component to providing the differential diagnosis: the decision to biopsy; location, depth, and extent of excision; and risk assessment for complications.7 Nault et al8 showed that the number of biopsies needed for a positive diagnosis of skin cancer (all types and melanoma) was twice as high for APPs than for dermatologists owing to biopsies of more benign lesions. In addition to cost, unnecessary biopsies may increase scarring, patient anxiety, and risk of complications such as infection, injury to an artery or nerve, and poor wound healing.
Destruction of benign lesions (mostly premalignant) was the most common procedure performed by APPs, totaling 3.6 million in 2015, an increase of 70.1% from 2.11 million procedures in 2012. Destruction of malignant lesions was also common, with 49 000 performed by APPs in 2015, a 66.1% increase from 29 500 procedures in 2012. This category included destruction of lesions larger than 2 cm on the trunk or larger than 1 cm on the face (10 837 in 2015; 6663 in 2012), which are considered high risk for recurrence or metastases by National Comprehensive Cancer Network guidelines.9,10 Destruction of high-risk lesions requires experience and care because the rates of treatment failure are higher compared with excision or Mohs surgery. Adequate clinical experience and training are needed to diagnose lesions and then to determine which lesions are appropriate for destruction. This problem exists even in dermatology residency programs. For example, recurrence rates of basal cell carcinoma after electrodessication and curettage in a resident clinic decreased by 9% after dedicated efforts to improve supervision and training.11 Such supervision and training are much less formal for APPs, who are able to perform procedures without a specific length of supervision or training or certification in those procedures.
Complex repairs were the second fastest-growing procedure billed by APPs, increasing 76.5% from 8300 procedures in 2012 to 14 700 procedures in 2015. Local flaps and full-thickness grafts billed by APPs were less frequent, at 2860 flaps and 877 grafts billed in 2015, with the number of flaps increasing each year. The numbers of these advanced procedures—including those on the face—being performed by APPs was unexpected. Many board-certified dermatologists are not credentialed to perform local flaps and full-thickness grafts in their hospital privileges, despite formal training and required case logs being a part of residency. In contrast, NPs and PAs do not receive any formal training in advanced cutaneous surgery, which may place patients at increased risk of injury.
Patch testing by APPs saw the largest relative increase, with 32 200 billed in 2015, more than double the amount in 2012 (14 400), with the proportion billed by dermatologists decreasing substantially. This finding was surprising given the cognitive component of this test, requiring knowledge of occupational exposures and manufacturing, skin disease and pattern recognition, determination of relevance, evaluation of new literature, and often multiple concomitant diagnoses.12 However, APPs may be billing solely for the test application, with a dermatologist interpreting the results on a separate day. The data set does not link patch application to the follow-up visit, so we cannot determine who did the interpreting.
Billing by APPs for gross and microscopic examinations of surgical pathologic specimens increased 72.3% from 13 022 in 2012 to 22 440 in 2015. Unlike most procedures, the number of APPs billing for pathologic examinations remained stable, and the increase is from more procedures billed per APP each year. This increase was surprising because training for surgical pathologic examinations is highly specialized, with many pathologists training in fellowships after residency. Lack of proper training is particularly dangerous because clinicians often rely on pathologic diagnoses to inform their ultimate decision making. Unfortunately, the Current Procedural Terminology codes for pathologic examinations include different types of tissue, so we have no means of knowing whether the increase in billing by APPs for pathologic examinations is in dermatology or other specialties such as gastroenterology, gynecology, and urology.
There is a tradeoff between expertise and availability of care. The mean wait time for a new patient to be seen at a dermatology office—including those with APPs—was more than 1 month, with 22% of patients waiting more than 2 months in 2007.13 It may be reasonable for a patient to risk a higher chance of an unnecessary biopsy if it means receiving a diagnosis and starting treatment several months sooner, saving anxiety and risk of disease progression. Aside from the study on biopsies by Nault et al,8 there are few outcomes data on other procedures performed by APPs. To truly weigh the benefits and risks of APPs performing procedures, more research is needed that compares outcomes and safety between specialists, nonspecialists, and APPs.
Increasing numbers of APPs may reflect an increasing demand for dermatology services, but recent changes in business practices may also play a role. The number of Medicare Part B enrollees increased by only 1.3% during the 4-year study period, while the number of procedures per Medicare enrollee billed by APPs increased by 67%. This discrepancy in growth raises the question of how many of these extra procedures are actually necessary or appropriate. In recent years, there has been an increasing number of dermatology practices acquired by private equity firms.14 These firms often employ a higher ratio of APPs to dermatologists to lower costs and maximize profits. Although this practice may lower costs for the firms, the increasing rate of procedures performed may increase costs for patients, insurance companies, and the health care system. It will be interesting to observe how the role of APPs in dermatology continues to evolve in the midst of these changes.
With ongoing increases in the numbers of APPs performing even more complex dermatologic procedures, there is need for uniformity in training and credentialing requirements. The core competencies defined for NPs do not mention a dermatology curriculum or surgical training.15 The scope of practice for APPs is defined by state laws, which are generally very broad and nonrestrictive. For example, laws in New York and Ohio allow NPs and PAs to perform any services within the scope of the supervising physician’s practice.16-18 Given the large and growing amount of procedures being performed by APPs, it would be beneficial if training and qualification guidelines for APPs, such as a minimum number of supervised procedures documented and the education and testing of APPs on the skin diseases necessitating procedures, were better defined.
The limitations of this study include its being restricted to the Medicare population, most of whom are older than 65 years. With an aging population and members of the baby boomer generation qualifying for Medicare in recent years, it is possible that the increase in the numbers of procedures billed by APPs reflects the growth of the elderly population and is less pronounced in the younger population. However, the increase in the numbers of procedures billed by dermatologists in the same population is markedly slower, so there is likely a component specific to APPs. Procedures used for skin cancers may also be overrepresented, given their increased prevalence in the elderly population. However, the total number for every procedure is undoubtedly higher for the entire US population than those presented. Another limitation is the assumption that the person under whom the procedure is billed is the one who performed it. It is possible that some procedures billed under an APP were directly supervised by a physician and, conversely, that some procedures billed to dermatologists may have been performed by an APP. However, the reimbursement by Medicare is lower for procedures performed by APPs than it is for procedures performed by dermatologists, so we expect that supervised procedures would most often be billed under the physician. It is likely that the number of procedures performed by APPs is underestimated because APPs can also bill under a physician’s name for higher reimbursement under “incident to” services.
The number and scope of dermatologic procedures billed independently by APPs—including advanced procedures such as destruction of malignant lesions, complex repairs, and skin flaps—continue to increase over time and at a much higher rate than procedures billed by dermatologists. The number of dermatologic procedures billed by APPs per Medicare enrollee is increasing at 19% per year. Further studies are needed to determine what association these procedures have with patient outcomes and the potential need for more uniform oversight, training, and credentialing requirements for APPs.
Accepted for Publication: April 30, 2018.
Corresponding Author: Myron Zhang, MD, Department of Internal Medicine, Summa Akron City Hospital, 55 Arch St, Ste 1B, Akron, OH 44304 (email@example.com).
Published Online: July 11, 2018. doi:10.1001/jamadermatol.2018.1768
Author Contributions: Dr Zhang had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Concept and design: Kaffenberger.
Acquisition, analysis, or interpretation of data: All authors.
Drafting of the manuscript: Zhang.
Critical revision of the manuscript for important intellectual content: Zippin, Kaffenberger.
Statistical analysis: Zhang.
Conflict of Interest Disclosures: None reported.