Ultrasound Is Cost-Effective in Diagnosing CTS—Sometimes

Jennie McKee

It is cost-effective for specialists to use ultrasound to confirm a clinical diagnosis of carpal tunnel syndrome (CTS); however, ultrasound may not be cost-effective when used as a first-line diagnostic tool by general practitioners, according to research presented by John R. Fowler, MD, and his colleagues in Poster P229, “Ultrasound as a First Line Test in the Diagnosis of Carpal Tunnel Syndrome: A Cost-Effectiveness Analysis,” currently on display in Academy Hall B.

“Current recommendations by the AAOS are to obtain a confirmatory test in patients for whom carpal tunnel surgery is being considered, but the recommendations do not specify a preferred test,” said Dr. Fowler.

The investigators noted that using ultrasound to diagnose CTS has been reported to have many benefits, including causing less patient discomfort and requiring less time to perform, while still having comparable sensitivity and specificity when compared to electrodiagnostic testing (EDX).

Thus, the researchers sought to determine whether ultrasound is a more cost-effective first-line diagnostic test than using EDX alone.

Conducting the study
Investigators used a fictional population of 38,000 patients and assigned each patient a probability for having true-positive, false-positive, true-negative, and true-positive ultrasound and EDX tests over an expected range of both sensitivity and specificity values, using a Monte Carlo simulation model.

“Two physician scenarios were chosen: specialist and general practitioner,” explained Dr. Fowler. “It was assumed that a specialist would have a higher prevalence of patients referred for confirmatory testing than the general practitioner.”

The researchers tested the following three scenarios for each physician type:

Ultrasound alone
EDX alone
Ultrasound followed by EDX for confirmation

Analyzing costs
Dr. Fowler reported that, in the general practitioner scenario, EDX alone was the most cost-effective tool for diagnosing CTS, with an average charge of $400.30 per patient. Costs were higher (average charge, $476.30 per patient) for the general practitioner who used ultrasound alone.

“The difference in charges between the use of EDX alone and ultrasound alone was $76 per patient in favor of EDX,” noted Dr. Fowler.

The most cost-effective strategy in the specialist scenario was the use of ultrasound alone as a diagnostic test for CTS, with an average charge of $367.80 per patient. In addition, specialists who used EDX alone—the most commonly used method in most practices—resulted in an average patient charge of $428.30.

In the specialist scenario, noted Dr. Fowler, “the difference in charge between the use of EDX alone and ultrasound alone was $60.50 per patient in favor of ultrasound” while “the average charge for the use of ultrasound as a first-line diagnostic test followed by EDX for confirmation of a negative ultrasound test was $369.50 per patient, nearly identical to use of ultrasound alone.”

Drawing conclusions
According the Dr. Fowler, the study results indicate that the use of ultrasound as a first-line diagnostic tool for confirming a clinical diagnosis of CTS is “a cost-effective strategy in the hands of a specialist.”

“Although first-line ultrasound demonstrated improved false-negative rates over the use of EDX alone in the general practitioner model, it resulted in a significant increase in charges over the use of EDX alone,” he said.

He concluded that “ultrasound is a cost-effective option for confirmation of a clinical diagnosis of carpal tunnel syndrome in the specialist’s office.”

Dr. Fowler’s coauthors on “Ultrasound as a First Line Test in the Diagnosis of Carpal Tunnel Syndrome: A Cost-Effectiveness Analysis” are Mitchell Maltenfort, PhD; and Asif M. Ilyas, MD.

Disclosure information: Drs. Fowler and Maltenfort—no conflicts. Dr. Ilyas—Medartis; Integra Life Sciences; Jaypee Medical Publishers; Elsevier (Ortho Clinics).

2013 Annual Meeting News
Tuesday through Friday, February 19 – 23, 2013.
http://www.aaos.org/news/acadnews/2013/AAOS14_3_22.asp