Trends in the Access and Cost of Photodynamic Therapy Among Medicare Beneficiaries in the United States, 2012-2017

Abstract

This cross-sectional study evaluates the geographical variation in the availability of photodynamic therapy for the Medicare population in the United States and characterizes the temporal trends of photodynamic therapy cost and use from 2012 to 2017.

Photodynamic therapy (PDT) is used in dermatology as “field therapy” for diffuse premalignant actinic keratoses and as treatment for superficial nonmelanoma skin cancers (NMSCs).¹ Photodynamic therapy may be a useful strategy in response to the increasing incidence of NMSCs, especially for the Medicare population, in which treatment of NMSCs is a major expenditure.^2,3 There are, however, challenges associated with the use of PDT, including the need for incubation time with the photosensitizer. This challenge may be most relevant in rural areas where patients may live far from the nearest dermatologist. Work studying other specialized dermatologic treatments suggests that patients in rural areas have limited access to certain treatments.^4,5 Nevertheless, the temporal and geographical trends in the use and cost of PDT have not been characterized, to our knowledge. This cross-sectional study evaluates the geographical variation in the availability of PDT for the Medicare population in the United States and characterizes the temporal trends of PDT cost and use from 2012 to 2017.

Methods

The data originated from detailed data files from the Medicare Provider Utilization and Payment Data: Physician and Other Supplier Public Use Files for calendar years 2012 to 2017. These files include claims submitted to the Medicare Part B program. Claims were included if they were submitted by a dermatologist for PDT services. This study was deemed not human participants research by the Yale University School of Medicine Institutional Review Board.

Counties were assigned a Rural-Urban Continuum Code as defined by the Urban-Rural Classification Scheme for Counties.⁶ Claims and counties from US territories were excluded from this analysis. Data analysis was performed from November 11, 2019, to April 28, 2020, using STATA, version 13 (StataCorp LP).

Results

The year-over-year trends of the number of dermatologists providing PDT and the total number of dermatologists for both metropolitan and nonmetropolitan counties are outlined in Table 1. The increased number of dermatologists offering PDT has led to a rise in the density of such physicians from 0.540 per 100 000 individuals in 2012 to 0.725 per 100 000 individuals in 2017 within metropolitan regions and from 0.270 per 100 000 individuals in 2012 to 0.344 per 100 000 individuals in 2017 within nonmetropolitan regions. Although PDT services were offered in 41.6% of metropolitan counties (483 of 1162) in 2017, they were available in only 5.4% of nonmetropolitan counties (105 of 1957) in 2017.

Table 1. Distribution of Dermatologists Providing PDT Services Across Metropolitan and Nonmetropolitan Counties.

Year	Metropolitan counties (RUCC 1-3) (n = 1162)					Nonmetropolitan counties (RUCC 4-9) (n = 1957)
	Dermatologists				Counties with a PDT provider, No. (%)	Dermatologists				Counties with a PDT provide, No. (%)
	No. (%) offering PDT	Density, No. offering PDT/100 000 individuals	Total No.	Density, No./100 000 individuals		No. (%) offering PDT	Density, No. offering PDT/100 000 individuals	Total No.	Density, No./100 000 individuals
2012	1416 (14.6)	0.540	9696	3.696	429 (36.9)	124 (20.4)	0.270	607	1.320	98 (5.0)
2013	1587 (16.0)	0.605	9914	3.779	457 (39.3)	134 (22.0)	0.291	609	1.324	102 (5.2)
2014	1667 (16.5)	0.635	10 128	3.861	459 (39.5)	148 (23.7)	0.322	625	1.359	105 (5.4)
2015	1774 (17.3)	0.676	10 283	3.920	475 (40.9)	166 (26.7)	0.361	622	1.352	109 (5.6)
2016	1862 (17.8)	0.710	10 454	3.985	477 (41.1)	160 (25.9)	0.348	617	1.342	108 (5.5)
2017	1903 (17.8)	0.725	10 676	4.070	483 (41.6)	158 (25.7)	0.344	616	1.339	105 (5.4)

Abbreviations: PDT, photodynamic therapy; RUCC, Rural-Urban Continuum Code.

Between 2012 and 2017, overall Medicare reimbursements for PDT services in metropolitan regions increased by $1 601 015 (average annual growth rate [AAGR], 4.0%), with 19 219 (AAGR, 4.7%) additional claims; overall Medicare reimbursements for PDT services in nonmetropolitan regions increased by $122 076 (AAGR, 3.2%), with 1625 (AAGR, 3.9%) additional claims (Table 2). As of 2017, metropolitan counties accounted for 90.9% of Medicare reimbursements for PDT claims ($9 260 322 of $10 184 822).

Table 2. Trends in Medicare Costs Associated With PDT Across Metropolitan and Nonmetropolitan Counties.

Year	Metropolitan (RUCC 1-3)					Nonmetropolitan (RUCC 4-9)
	Reimbursement total, $	Submitted total, $	Mean claim amount, $	Mean claim reimbursement, $	Total No. of claims	Reimbursement total, $	Submitted total, $	Mean claim amount, $	Mean claim reimbursement, $	Total No. of claims
2012	7 659 307	17 300 000	228.79	101.43	75 514	802 424	2 092 962	242.27	92.88	8639
2013	8 628 905	19 300 000	233.88	104.56	82 528	796 517	2 021 095	246.32	97.08	8205
2014	8 317 276	20 800 000	240.52	96.38	86 300	763 691	2 055 167	239.81	89.11	8570
2015	8 938 254	22 700 000	250.08	98.31	90 918	806 829	2 237 437	251.26	90.60	8905
2016	9 409 551	24 500 000	255.08	97.96	96 056	955 625	2 449 310	240.58	89.83	10 638
2017	9 260 322	24 600 000	259.46	97.75	94 733	924 500	2 556 987	249.12	90.07	10 264

Abbreviations: PDT, photodynamic therapy; RUCC, Rural-Urban Continuum Code.

Discussion

In this study, we present data characterizing the trends in use, accessibility, and cost of PDT among the US Medicare population. Despite the consistent growth in the number of dermatologists offering PDT, the density of dermatologists providing PDT in nonmetropolitan counties is less than half of that in metropolitan counties in the most recent study year; this difference has widened from 2012 to 2017.

With the incidence of NMSCs rising, PDT could be important for prevention and treatment of some NMSCs while maintaining low costs.² Strategies leading to more dermatologists offering PDT, such as recent increases to reimbursements, may, therefore, ultimately lower Medicare expenditures on skin cancer treatment, especially in nonmetropolitan areas, where our study suggests that PDT access is particularly lacking.

This study has several limitations. Our use of Medicare claims data precludes evaluation of PDT use for patients with commercial insurance. Likewise, while PDT is generally performed in outpatient settings, exclusion of institutional providers (such as hospitals) in the data set may limit our ability to capture all PDT services.

Conclusions

We found that the use of PDT increased in both metropolitan and nonmetropolitan regions from 2012 to 2017 but that there remains notably less access to PDT in nonmetropolitan regions in comparison with metropolitan regions in the United States.