BRIEF ARTICLE Five Years Later: Continuing Disparity in the Geographic Density and Distribution of U.S. Dermatologists

Despite expansion of the dermatologic workforce, a discrepancy remains in the geographical distribution of dermatologists across the United States (US). From a 2014 American Academy of Dermatology (AAD) survey, dermatologists in rural areas were more likely to report an undersupply of dermatologists, while dermatologists in urban areas were more likely to


METHODS
Like the previous studies, de-identified data for AAD members were retrieved from the most current AAD membership database, the 2021 AAD membership database for this analysis.Demographic information included the member's category, state, and zip code.Fellows were included as practicing dermatologists.US territories were excluded from this analysis.US population data was obtained from the American Community Survey.Information associated with 5-digit zip codes were consolidated to their corresponding larger 3-digit zip codes.Compound annual growth rates (CAGR) were calculated to assess annual percentage growth.And descriptive statistics and unpaired two-sample t-tests were used.Institutional review board approval was not necessary as no human subjects were used for this study.
The 10 highest and lowest dermatologist density locations from the current analysis and the 2016 analysis are listed (Figure 1 and Figure 2).This listing is based on locations that have at least 1 dermatologist.The average density for the 10 densest locations was 24.6 dermatologists per 100,000, an increase from 23.3 in 2016 (1.1% CAGR), but a decrease from 25 in 2009 (-0.13%CAGR).And 83.5% of the dermatologists in the top 10 areas practice in the northeast.Specifically, 93% can be found in either Manhattan or Boston.Currently, 36.5% of dermatologists practice in the 100 densest areas, a downtrend from 38.6% in 2016 (-1.11%CAGR) and 40% in 2009 (-0.76%CAGR).Conversely, only 1.6% of dermatologists practice in the 100 least dense areas as compared to 1.8% in 2016 (-2.33%CAGR).

Our
analysis reveals an enduring maldistribution of dermatologists between urban and rural areas (Figure 3).Almost 20% of populated zip codes did not have a single dermatologist.Like in 2009, the 10 densest zip codes had an average density 7 times the national average.Also, 9 of the 10 densest zip codes in 2016 remained among the top 10 in 2021.None of the least dense areas in 2016 improved to more than 1 dermatologist per 100,000.Some suggest that 4 dermatologists per 100,000 people is the ratio needed to sufficiently care for a population. 3Consistent with 2016, over 70% of areas do not meet that target density and nearly 60% have less than 3 per 100,000.In the past 5 years, only 5 more zip codes reached this threshold.These results may indicate that initiatives aimed at redistribution of dermatologists have not made a major difference.Addressing underserved areas remains paramount as dermatologist density is associated with patient outcomes, particularly in melanoma and Merkel cell carcinoma. 4,5Multiple solutions have been considered.One of the strongest barriers in rural physician retention is lack of geographical connection, partly due to the limited residency positions available.Partnerships between residency programs and rural hospitals may expand residency spots, while also supporting underserved areas. 6Advanced practice practitioners may alleviate rural areas, however, they tend to favor urban areas as well. 7And teledermatology has proven to be effective in rural communities, with reimbursement constraints as the greatest barrier. 8Other strategies to consider include financial incentives, increasing physician spouse job opportunities, and recruiting students of rural backgrounds.

DISCUSSION
This study is limited by the AAD membership database, as AAD membership distribution may not represent the true distribution of all US dermatologists.However, this analysis may still add to the overall discussion and provide insight into the subject, since we used a consistent methodology as previous studies and present trends over a 5-and 12year span.Another limitation is our analysis assumes each area requires similar a dermatologist density (4 dermatologists per

Figure 1 .
Figure 1.Comparison of the 10 most dermatologist-dense areas, for locations with at least 1 dermatologist, in the United States in 2021 vs 2016.

Figure 2 .
Figure 2. Comparison of the 10 least dermatologist-dense areas, for locations with at least 1 dermatologist, in the United States in 2021 vs 2016.

Figure 3 .
Figure 3. US Dermatologist Density by 3-Digit Zip Code.The number of dermatologists practicing per 100,000 people in each 3-digit zip code is indicated by the colors on the map.Zip codes without any dermatologists are included in white.