Industry Payments to Nephrologists in the United States

Background Industry payments to physicians raise concerns about conflicts of interest that have the potential to impact patient care. In this study, we explored nonresearch and nonownership payments from industry to nephrologists to identify trends in compensation. Methodology Using data from the Centers for Medicare and Medicaid Services (CMS), we explored financial relationships between industry and US nephrologists from 2014 to 2018. We analyzed payment characteristics including payment categories, payment distribution among physicians, regional trends, and biomedical manufacturers. Results In this retrospective study, a total of $75,174,999 was paid to nephrologists in the United States during the study period (i.e., 2014-2018). The number of board-certified nephrologists receiving payment from the industry increased from 11,642 in 2014 to 13,297 in 2018. Among board-certified nephrologists, 56% to 63% received industry payments during the study period. The total payments to nephrologists increased from $13,113,512 in 2014 to $16,467,945 in 2017, with consulting fees (24%) and compensation for services other than consulting (35%) being the highest-paid categories. The top 10% of physician beneficiaries collected 90% of the total industry payments. Conclusions A small proportion of US nephrologists consistently received the majority of industry payments, the value of which grew over the study period.


Introduction
Physicians often collaborate with organizations in the healthcare industry. Approximately 94% of physicians in the United States report some relationship with the industry which ranges from receiving food to being paid for various services [1]. Even though such collaborations can encourage research and patient care, they introduce potential conflicts of interest. For example, receiving industry-sponsored meals has been associated with increased prescription of brand-name medications [2,3]. Industry-sponsored research, compared to nonindustry-sponsored research, shows that these practices have more favorable results and less evidence of harm [4].
Due to concerns about the potential detrimental effects of physician-industry financial relationships, the Centers for Medicare and Medicaid Services (CMS) Open Payments Program (OPP) was initiated by the Physician Payments Sunshine Act of 2009 [5]. CMS OPP mandates public reporting of industry payments made to physicians, teaching hospitals, group purchasing organizations, and medical product manufacturers [6]. Such information about eligible payments has been available through the CMS OPP website since August 2013. Physician-industry financial relationships have been reported in several clinical specialties [7,8], and this study reports the trends and details of such payments in the field of nephrology.

Data sources
Data on industry payments to nephrologists reported from January 1, 2014, through December 31, 2018, were extracted from the CMS OPP database, and a retrospective analysis was performed. Only general payments were analyzed, and research and partnership payments were excluded. The general payments were divided into nine subcategories ( Table 1). The database record for each payment carries a unique physician profile identification, recipient state, sponsor, and related product. Each payment to each physician has a separate entry, even if the physician received multiple payments.

Consulting fee
Payments made to physicians for advice and expertise on a particular medical product or treatment, typically provided under a written agreement and in response to a particular business need.

Data analysis
To obtain the total amount paid to each nephrologist, individual payments to each unique physician profile identification were added. From these calculations, 10% of the nephrologists who received the highest amount of industry payments each year were identified. For each year, the sum of all payments received by the top 10% of nephrologists was calculated as a proportion of the total amount of industry payments.
Using the total number of nephrologists in the United States as a denominator, we calculated the proportion of nephrologists who received industry payments. The mean, median, minimum, maximum, and 90th percentile were calculated for these payments. To explore the distribution of payments among US nephrologists, we calculated the Gini index (a statistical measure of dispersion) for physicians who received any payment each year. The Gini index ranges from 0 (all physicians received an equal number of payments) to 1 (one physician received all the payments).

Results
Results of this retrospective study revealed that the industry paid a total of $75,174,999 to US nephrologists during the study period 2014-2018 (    Veltassa, Acthar, and Auryxia were the drugs most commonly associated with payments to nephrologists in 2018 ( Table 5). These drugs consistently ranked high among the drugs associated with payments from 2016 to 2018. Soliris was one of the top drugs associated with the highest payments to nephrologists in 2016, but payments associated with Soliris decreased in 2017 and 2018.

Discussion
The present study used the CMS OPP database to explore the financial relationships between industry and US nephrologists over a five-year period. Results revealed that total payments increased from 2014 to 2017, which was followed by a downturn in 2018. Although the exact reason for this trend is unclear, it could be related to changes in the industry's activities due to OPP and the Sunshine Act. However, it is unclear whether underreporting occurred.
Additionally, even though the number of board-certified nephrologists increased during the study period and annual payments to nephrologists increased tremendously, the proportion of nephrologists receiving payments remained relatively stable throughout the study period. Similar to results reported for other subspecialties, such as cardiology and vascular neurology [9,10], we report substantial inequality among nephrologists receiving industry payments. Overall, 90% of the total payments were received by only 10% of the nephrologists. This pattern of skewed payments may be related to industries targeting physicians who are perceived as leaders in the field with the ability to influence the practice patterns of other physicians [11,12]. It is encouraging that most nephrologists did not receive significant payments, so they are not particularly prone to the potential biases introduced by financial relationships with the industry.
Compensation for services, consulting fees, and travel and lodging consistently remained the top payment categories throughout the study period. Categories varied widely among different specialties, with royalties and licensing accounting for the highest-paid category among surgical specialties [13,14]. Consistent with reports from other medical subspecialties, our results showed that payments were the largest for engagements related to noneducational activities [15]. In nephrology, medications remain important categories for industrial payments, which differs from the field of vascular neurology in which payments shifted from pharmacological utilities to medical devices [9].
A few limitations of our study must be noted. Our retrospective analysis is based on information obtained from the CMS OPP database, which could have ambiguities and incomplete records. Potential inaccuracies may result from the retrospective nature of the study and its reliance on self-reported data. Additionally, nephrologists who are not board-certified were excluded. We did not explore research and ownership payments by the industry and their compensation trends. Finally, we could not report the most recent trends (i.e., 2020-2021) because we were limited by data collected through 2018.

Conclusions
We report that the industry paid the greatest amount of money to a small percentage of nephrologists, which was consistent throughout the study period. Controversy continues to surround financial relationships between industry and physicians, as well as the potential influence of these relationships on research and patient care. Further studies are warranted to help overcome the limitations of the present study and to increase our understanding of financial conflicts of interest and the subsequent impact on patient care.

Additional Information Disclosures
Human subjects: All authors have confirmed that this study did not involve human participants or tissue. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue.

Conflicts of interest:
In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.