Clinical Outcomes of Electrodiagnostic Testing Conducted in Primary Care

The Journal of the American Board of Family Medicine

Mark M. Shepherd¹ 

[1] From the Intermountain Medical Group, Salt Lake City, UT

关键词: Nerve Conduction;    Clinical Outcomes;    NC-stat;    Primary Care;   

DOI  :  10.3122/jabfm.2010.05.100071

学科分类：过敏症与临床免疫学

来源: The American Board of Family Medicine

【 摘 要 】

Background: Focal and generalized neuropathies, such as carpal tunnel syndrome and diabetic peripheral neuropathy, have high prevalence among the US population. Primary care physicians are increasingly using computerized electrodiagnostic (EDX) testing to evaluate these patients. The impact of this diagnostic modality on physician diagnostic reasoning and patient management has not been directly studied.

Methods: Consecutive computerized EDX tests conducted in a primary care clinic were prospectively evaluated using a diagnostic before-and-after study design. The pretest diagnosis and patient management plan were noted before EDX testing. Five clinical outcomes were assessed after the test: (1) test abnormality, (2) confirmation of pretest diagnosis, (3) change in pretest diagnosis, (4) expansion of pretest diagnosis, and (5) change to patient management plan.

Results: One hundred computerized EDX tests were performed among 85 patients. A total of 88 tests were abnormal. The pretest diagnosis was confirmed in 59 tests. The pretest diagnosis was changed by 14 tests and it was expanded by 18 tests. The computerized EDX tests triggered a change in clinical management in 30 cases, with referral to orthopedic surgery and metabolic workup for polyneuropathy as the most common changes.

Conclusions: Computerized EDX testing was clinically valuable in patients with moderate to high pretest probability of common neuropathies such as carpal tunnel syndrome and diabetic polyneuropathy. In approximately one third of cases, the test led to a change in clinical management.

• Nerve Conduction
• Clinical Outcomes
• NC-stat
• Primary Care

Focal and generalized neuropathies have become increasingly common during the past several decades. A study of carpal tunnel syndrome¹ among the general population reported a 14.4% prevalence of symptoms in the median nerve distribution and a 2.7% prevalence of electrodiagnostically confirmed disease. In a population-based study of diabetes,² 22% of participants had moderate to severe peripheral neuropathy. Another large study recently showed that peripheral sensory neuropathies are common, with a prevalence of 31% among primary care patients aged 65 years or older.³ Because of the high prevalence of focal and generalized neuropathies, family and internal medicine physicians may now be encountering neuropathies at higher rates and earlier in their natural history.

Although a neurological examination is central to the workup of patients with suspected neuropathies, it may not have adequate diagnostic accuracy.^4–6 Therefore, objective confirmation of a neuropathy and grading of severity may benefit patient management.⁷ Nerve conduction studies (NCSs) provide the most objective and reliable diagnostic assessment of neuropathies.^8,9 As such, expanded access to NCSs has the potential to improve clinical outcomes.⁷ However, constraints on the availability of NCSs have probably limited its usage,^7,10 particularly within primary care and early in the episode of care. In response, technological advances in computerized electrodiagnostic (EDX) instrumentation and methods have been introduced during the past 10 years. These innovations include nerve-specific electrode arrays, computer-aided data acquisition, and decision support.¹¹ Because this technology standardizes and automates NCSs up to the point of diagnostic interpretation (which is performed by the physician), data quality is essentially independent of clinical setting. This property has led to use of computerized EDX instrumentation in multicenter drug registration trials¹² and large-scale epidemiologic studies.^13,14 Further, because of inherent consistency, the accuracy of the results as assessed in controlled clinical studies should translate to clinical practice. Diagnostic accuracy, with traditional EDX instrumentation or neuroimaging (for radiculopathy) as reference standards, has been reported for carpal tunnel syndrome,^15–17 upper-extremity nerve function in symptomatic patients,^18–20 diabetic peripheral neuropathy,^21,22 lumbosacral radiculopathy,^23–26 and lower-extremity nerve function in symptomatic patients.²⁷

Computerized EDX studies are now commonly provided by primary care physicians. Several large observational studies have evaluated the use of NCSs within primary care.^28,29 These studies showed that patient selection was appropriate and that computerized EDX testing results had the potential to alter pretest diagnoses. However, these studies did not specifically evaluate the clinical impact of testing.³⁰ The objective of this study was to measure changes in physician diagnostic reasoning and patient management resulting from computerized EDX testing in primary care.

【 授权许可】

Unknown   

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