Does the painDETECT questionnaire identify impaired conditioned pain modulation in people with musculoskeletal pain? - a diagnostic accuracy study.

Background: People with neuropathic-like symptoms had more unfavourable pain features than people with nociceptive. Moreover, deficient conditioned pain modulation is common in people with neuropathic-like symptoms. PainDETECT questionnaire have been used to assess the central sensitisation sign and symptoms. However, whether the painDETECT questionnaire can identify the conditioned pain modulation's impairment is still unknown. Therefore, the current study aimed to evaluate the diagnostic accuracy of the painDETECT questionnaire in detecting the impairment of conditioned pain modulation in people with musculoskeletal pain.

Methods: We conducted a diagnostic accuracy comparing the painDETECT questionnaire (index method) with the cold pressor test, the psychophysical test used to assess the conditioned pain modulation (reference standard). We determined diagnostic accuracy by calculating sensitivity, specificity, predictive values, and likely hood ratios.

Results: We retrospectively enrolled 308 people with musculoskeletal pain in outpatient departments. Most participants were female (n 20 = 220, 71.4%) and had a mean age of 52.2 (± 15.0) years. One hundred seventy-three (56.1%) participants were classified as nociceptive pain, 69 (22.4%) as unclear, and 66 (21.4%) as neuropathic-like symptoms. According to the cold pressor test, 60 (19.4%) participants presented impairment of conditioned pain modulation. The cutoff point of 12 of the painDETECT questionnaire showed values of diagnostic accuracy below 70% compared to the cold pressor test, except for a negative predictive value [76.9 95% Confidence Interval (CI) 71.7 to 81.5]. The cutoff point 19 showed high specificity (78.6%, 95% CI 73.0 to 83.5), high negative predictive value (80.5%, 95% CI 78.1 to 82.7), and accuracy of 67.5% compared to the cold pressor test.

Conclusion: The painDETECT questionnaire seems valuable for ruling out people with musculoskeletal pain and impairment of conditioned pain modulation.