Sood A. et al., 2021: Use of ultra-low dose computed tomography versus abdominal plain film for assessment of stone-free rates after shock-wave lithotripsy: implications on emergency room visits, surgical procedures, and cost-effectiveness.

Thursday, 30 September 2021

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Sood A, Wong P, Borchert A, Budzyn J, Keeley J, Heilbronn C, Eilender B, Littleton R, Leavitt DA.
VCORE-Vattikuti Urology Institute Center for Outcomes Research, Analytics and Evaluation, Henry Ford Hospital, 2799 W. Grand Boulevard, Detroit, MI, 48202, USA.
Vattikuti Urology Institute, Henry Ford Hospital, Detroit, MI, USA.
Vattikuti Urology Institute, Henry Ford Hospital, Detroit, MI, USA.
VCORE-Vattikuti Urology Institute Center for Outcomes Research, Analytics and Evaluation, Henry Ford Hospital, 2799 W. Grand Boulevard, Detroit, MI, 48202, USA.
Department of Urology, Indiana University School of Medicine, Indianapolis, IN, USA.
Department of Urology, Icahn School of Medicine At Mount Sinai, New York, NY, USA.

Abstract

The aims of this investigation were: (1) to compare residual stone-fragment (RSF) detection rates of ultra-low dose computed tomography (ULD-CT) and abdominal plain film (KUB) in urolithiasis patients undergoing shock-wave lithotripsy (SWL), and (2) to evaluate the downstream sequelae of utilizing these two disparate imaging pathways of differing diagnostic fidelity. A retrospective chart-review of patients undergoing SWL at two high-volume surgical centers was undertaken (2013-2016). RSF diagnostic rates of ULD-CT and KUB were assessed, and the impact of imaging modality used on subsequent emergency room (ER) visits, unplanned procedures, and cost-effectiveness was investigated. Adjusted analyses examined association between imaging modality used and outcomes, and Markov decision-tree analysis was performed to identify a cost advantageous scenario for ULD-CT over KUB. Of 417 patients studied, 57 (13.7%) underwent ULD-CT while the remaining 360 underwent KUB. The RSF rates were 36.8% and 22.8% in the ULD-CT and KUB groups, respectively (p = 0.019). A 5.6% and 18% of the patients deemed stone-free on ULD-CT and KUB, respectively, returned to the ER (p = 0.040). Similarly, 2.8% and 15.1% needed an unplanned surgery (p = 0.027). These findings were confirmed on multivariable analyses, Odds ratios CT-ULD versus KUB: 0.19 and 0.10, respectively, p < 0.05. With regards to cost-effectiveness, at low ULD-CT charges, the ULD-CT follow-up pathway was economically more favorable, but with increasing ULD-CT charges, the KUB follow-up pathway superseded. ULD-CT seems to provide a more 'true' estimate of stone-free status, and in consequence mitigates unwanted emergency and operating room visits by reducing untimely stent removals and false patient reassurances. Further, at low ULD-CT costs, it may also be economically more favourable.
Urolithiasis. 2021 May 16. doi: 10.1007/s00240-021-01273-3. Online ahead of print. PMID: 33993338.

Comments 1

Peter Alken on Thursday, 30 September 2021 10:30

The expected impact of this publication is to stimulate stakeholders to change from KUB to ULD-CT in post ESWL imaging. Precision and low radiation would favour ULD-CT: According to a reference “the average effective dose for ultra-low-dose CT was 0.57 mSv, which is less than the reported average effective dose of a KUB (0.7 mSv) and is 92% lower than the standard low-dose CT of the abdomen and pelvis“ (1).
A limit seems to be money. In the same reference the Medicare reimbursements were reported as: “the global service fee is $195.96 for unenhanced abdominopelvic CT (CPT 74176), $152.64 for unenhanced abdominal CT (CPT 74150), $116.28 for renal US (CPT 76770), and $27.72 for a single view KUB (CPT 74018)” (1). That was in May 2018; there was obviously no official reimbursement for ULD-CT.

In the present publication “the imaging type ordered was based on surgeons’ discretion, however, the main factor ultimately governing the kind of imaging the patient underwent was insurance authorization, as an ULD-CT was requested in 196 patients, but it was approved in only 57 patients.”
When it comes to finances, there is frequently a confusion in the medical literature: Costs, fees, charges and reimbursement represent different entities and are different amounts of money (2): In the present paper “for cost-effectiveness analysis, charge estimates were obtained via online search of publicly available government repositories, … The charges were estimated at: 1. ULD-CT, median 1191$ (range $38–$2000), 2. KUB, median 161$ (range $74–$208), 3. Median charges of a typical emergency room visit with imaging and labs: 1265$ + 1191$ + 55$ = 2511$, 4. Medicare reimbursement for the year 2018 for ureteroscopy: 3483$, and 5. Medicare reimbursement for the year 2018 for ureteral stent placement: 2541$.”
These figures may serve the purpose to calculate simple Markov decision-tree analysis models but are difficult to understand.
The Markov model showed less overall costs for imaging plus unplanned ER visits and additional procedures only at a low-charge for ULD-CT of 382 $ and 74 $ KUB charges. With 1.191 $ for ULD-CT, KUB is economically more efficient.

In the present study 49 patients with insufficient follow-up were excluded just as
21, which got a secondary treatment before the imaging was done 4-6 weeks after the first ESWL. There are no details on these patients. In an intention to treat analysis this could have influenced the results. The study is interesting but needs to be confirmed.

Peter Alken

In the present publication “the imaging type ordered was based on surgeons’ discretion, however, the main factor ultimately governing the kind of imaging the patient underwent was insurance authorization, as an ULD-CT was requested in 196 patients, but it was approved in only 57 patients.”
When it comes to finances, there is frequently a confusion in the medical literature: Costs, fees, charges and reimbursement represent different entities and are different amounts of money (2): In the present paper “for cost-effectiveness analysis, charge estimates were obtained via online search of publicly available government repositories, … The charges were estimated at: 1. ULD-CT, median 1191$ (range $38–$2000), 2. KUB, median 161$ (range $74–$208), 3. Median charges of a typical emergency room visit with imaging and labs: 1265$ + 1191$ + 55$ = 2511$, 4. Medicare reimbursement for the year 2018 for ureteroscopy: 3483$, and 5. Medicare reimbursement for the year 2018 for ureteral stent placement: 2541$.”  
These figures may serve the purpose to calculate simple Markov decision-tree analysis models but are difficult to understand.
The  Markov model showed less overall costs for imaging plus unplanned ER visits and additional procedures only at a low-charge for ULD-CT of 382 $ and 74 $ KUB charges. With 1.191 $ for ULD-CT, KUB is economically more efficient.

In the present study 49 patients with insufficient follow-up were excluded just as
21, which got a secondary treatment before the imaging was done 4-6 weeks after the first ESWL. There are no details on these patients. In an intention to treat analysis this could have influenced the results. The study is interesting but needs to be confirmed.

Peter Alken

The expected impact of this publication is to stimulate stakeholders to change from KUB to ULD-CT in post ESWL imaging. Precision and low radiation would favour ULD-CT: According to a reference “the average effective dose for ultra-low-dose CT was 0.57 mSv, which is less than the reported average effective dose of a KUB (0.7 mSv) and is 92% lower than the standard low-dose CT of the abdomen and pelvis“ (1). A limit seems to be money. In the same reference the Medicare reimbursements were reported as: “the global service fee is $195.96 for unenhanced abdominopelvic CT (CPT 74176), $152.64 for unenhanced abdominal CT (CPT 74150), $116.28 for renal US (CPT 76770), and $27.72 for a single view KUB (CPT 74018)” (1). That was in May 2018; there was obviously no official reimbursement for ULD-CT. In the present publication “the imaging type ordered was based on surgeons’ discretion, however, the main factor ultimately governing the kind of imaging the patient underwent was insurance authorization, as an ULD-CT was requested in 196 patients, but it was approved in only 57 patients.” When it comes to finances, there is frequently a confusion in the medical literature: Costs, fees, charges and reimbursement represent different entities and are different amounts of money (2): In the present paper “for cost-effectiveness analysis, charge estimates were obtained via online search of publicly available government repositories, … The charges were estimated at: 1. ULD-CT, median 1191$ (range $38–$2000), 2. KUB, median 161$ (range $74–$208), 3. Median charges of a typical emergency room visit with imaging and labs: 1265$ + 1191$ + 55$ = 2511$, 4. Medicare reimbursement for the year 2018 for ureteroscopy: 3483$, and 5. Medicare reimbursement for the year 2018 for ureteral stent placement: 2541$.” These figures may serve the purpose to calculate simple Markov decision-tree analysis models but are difficult to understand. The Markov model showed less overall costs for imaging plus unplanned ER visits and additional procedures only at a low-charge for ULD-CT of 382 $ and 74 $ KUB charges. With 1.191 $ for ULD-CT, KUB is economically more efficient. In the present study 49 patients with insufficient follow-up were excluded just as 21, which got a secondary treatment before the imaging was done 4-6 weeks after the first ESWL. There are no details on these patients. In an intention to treat analysis this could have influenced the results. The study is interesting but needs to be confirmed. Peter Alken

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