Using a Patient-reported Questionnaire to Assist in Diagnosing Neuropathic Pain Conditions

Neuropathic pain can be difficult to diagnose and treat, especially for primary care physicians who have little pain medicine training but who are often called upon to manage patients who present with neuropathic pain. Thus there is a need for tools that can aid clinicians in accurately assessing the symptoms of neuropathic pain.

At the 2014 annual clinical meeting of the American Academy of Pain Management, in Phoenix, AZ, Alesia Sadosky, PhD, MPH, MBA, and colleagues presented results from their study that evaluated the accuracy and reliability of the patient-reported painDETECT questionnaire for identifying patients with neuropathic pain (NeP).

According to the study abstract, the painDETECT questionnaire “has been assessed psychometrically and is used for identifying patients with neuropathic pain.” The current study was designed to assess “scoring, internal consistency reliability, and item-level discrimination of painDETECT for identifying NeP across a range of conditions.”

painDETECT is a 9-item instrument (seven pain symptom items, one pain course pattern item, and one pain irradiation item) with a total score that ranges from -1 to 38. Scores ≥ 19 “indicate NeP is likely with a > 90% probability.” The 7-item version consists only of the pain symptoms and has a score range of 0 to 35.

To evaluate the consistency of painDETECT scoring for a variety of neuropathic pain conditions, the authors administered the questionnaire to 112 patients with confirmed diagnoses of painful diabetic peripheral neuropathy (pDPN;), 103 patients with human immunodeficiency virus-related peripheral NeP (HIV), 100 patients with post-trauma/post-surgical NeP (PTPS), 103 with spinal cord injury-related NeP (SCI), 106 with NeP in chronic low back pain (CLBP), and 100 with small fiber neuropathy (SFN) identified during routine office visits to US community-based physicians.

The data were analyzed to obtain 9- and 7-item painDETECT scores adjusted for a variety of factors (age, gender, race, ethnicity, time since NeP diagnosis, and number of comorbidities). For each NeP condition, “internal consistency reliability was assessed with Cronbach’s alpha and item-level discrimination was assessed using corrected item-to-total correlations.”

The authors reported the following adjusted mean 9-item scores:

• HIV: 23.8
• pDPN: 23.8
• CLBP: 22.3
• SFNS: 24.3
• PTPS: 21.2
• SCI: 21.0

In the study abstract, they wrote that “Cronbach’s alpha gave internal consistency reliability of 0.76 across all conditions and gave the following estimates for individual conditions: 0.82 (HIV), 0.78 (pDPN), 0.76 (CLBP), 0.74 (SFNS), 0.78 (PTPS), and 0.63 (SCI).”

Mean scores and Cronbach’s alphas for the 7-item version were generally similar to those for the 9-item version for all conditions.

These results showed that painDETECT scores “were similar for all 6 NeP conditions and were within the range indicating high probability of NeP,” with both versions of the questionnaire generally showing “evidence of internal consistency reliability and item-level discrimination.” The authors concluded that these results “suggest that painDETECT is a useful screening measure for identifying NeP across a range of conditions.”