Geographic variation of parathyroidectomy in patients receiving hemodialysis: a retrospective cohort analysis
Wetmore et al. BMC Surgery
Geographic variation of parathyroidectomy in patients receiving hemodialysis: a retrospective cohort analysis
James B. Wetmore 0 1 2
Jiannong Liu 1
Paul J. Dluzniewski 5
Areef Ishani 1 2 4
Geoffrey A. Block 3
Allan J. Collins 1 2
0 Division of Nephrology, Hennepin County Medical Center , Minneapolis, MN , USA
1 Chronic Disease Research Group, Minneapolis Medical Research Foundation , 914 South 8th Street, Suite S4.100, Minneapolis, MN 55404 , USA
2 Department of Medicine, University of Minnesota , Minneapolis, MN , USA
3 Denver Nephrology Clinical Research Division , Denver, CO , USA
4 Section of Renal Diseases and Hypertension, Minneapolis Veterans Administration Health Care System , Minneapolis, MN , USA
5 Center for Observational Research, Amgen Inc , Thousand Oaks, CA , USA
Background: Secondary hyperparathyroidism (SHPT) is associated with adverse outcomes in patients receiving maintenance dialysis. Parathyroidectomy is a treatment for SHPT; whether parathyroidectomy utilization varies geographically in the US is unknown. Methods: A retrospective cohort analysis was undertaken to identify all patients aged 18 years or older who were receiving in-center hemodialysis between 2007 and 2009, were covered by Medicare Parts A and B, and had been receiving hemodialysis for at least 1 year. Parathyroidectomy was identified from inpatient claims using relevant International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes. Patient characteristics and End-Stage Renal Disease Network (a proxy for geography) were ascertained. Adjusted odds ratios for parathyroidectomy were estimated from a logistic model. Results: A total of 286,569 patients satisfied inclusion criteria, of whom 4435 (1.5%) underwent PTX. After adjustment for a variety of patient characteristics, there was a 2-fold difference in adjusted odds of parathyroidectomy between the most- and least-frequently performing regions. Adjusted odds ratios were more than 20% higher than average in four networks, and more than 20% lower in four networks. Conclusions: Parathyroidectomy use varies substantially by geography in the US; the factors responsible should be further investigated.
End-stage renal disease; Dialysis; Mineral metabolism; Parathyroidectomy; Secondary hyperparathyroidism
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Background
Secondary hyperparathyroidism (SHPT) is associated
with adverse outcomes in patients receiving
maintenance dialysis [1, 2]. Anecdotally, physicians appear to
have widely variable criteria regarding which patients
they choose to refer for parathyroidectomy, at least in
the US. Perhaps reflecting uncertainty over its role,
rates of parathyroidectomy have changed substantially
over time in recent decades [3]. While guidelines
recommend parathyroidectomy in patients with severe
SHPT [4], how it might be used most optimally is
uncertain. Parathyroidectomy has been shown to be
associated with improved outcomes in some studies
[5, 6]; however, it has also been shown to be
associated with mortality, protracted hypocalcemia, and
over-suppression of parathyroid hormone (PTH) [7],
and its results with regard to mineral metabolic
control are often suboptimal [8]. Thus, understanding the
differences between hemodialysis patients who do and
do not undergo parathyroidectomy may be important.
However, the effect of geographic variation, which is
associated with a variety of outcomes and care
differences in the dialysis population [9, 10] has not been
examined in the context of parathyroidectomy. We
therefore conducted a retrospective cohort study to
examine whether parathyroidectomy use varies
geographically in the United States.
Methods
Using the United States Renal Data System end-stage
renal disease database, we identified patients aged 18
years or older who were receiving in-center
hemodialysis between 2007 and 2009, were covered by
Medicare Part A (inpatient, outpatient, skilled nursing
facility, hospice, or home health agency) and Part B
(physician/supplier) as primary payer, and had been
receiving hemodialysis for at least 1 year.
Parathyroidectomy was identified from inpatient claims using
International Classification of Diseases, Ninth Revision,
Clinical Modification procedure codes 06.81 (complete
parathyroidectomy), 06.89 (partial parathyroidectomy and
parathyroidectomy not otherwise specified), and 06.95
(parathyroid tissue reimplantation).
Patient characteristics, derived from the end-stage
renal disease database Medical Evidence Report and
Medicare claims, were assessed on the
parathyroidectomy date and on January 1 for non-parathyroidectomy
patients. Characteristics included age, sex, race, body
mass index, cause of renal disease, dialysis duration, and
common comorbid conditions, as have been used
previously [11]. Our proxy for geography was US End-Stage
Renal Disease Network (n = 18, Table 1), geographically
based regions designed to facilitate care and monitor
Table 1 End-stage renal disease netwo (...truncated)