The aim of this study was to culturally adapt into Spanish and validate the painDETECT questionnaire, a brief self-administered instrument designed to screen the presence of a neuropathic pain component in usual clinical practice.
The original English painDETECT questionnaire was culturally adapted into Spanish (Spain) by 2 independent translators under supervision of an expert panel. The LANNS, and a pain visual analog scale were administered along with the painDETECT questionnaire to a sample of 252 patients with neuropathic, nociceptive, or mixed pain for at least 3 months. Patients were classified by experienced specialists under normal conditions of clinical practice. A retest measure after 24 to 48 hours was also carried out. Reliability, construct validity, convergent validity, criterion, and discriminant validity were assessed.
An effective sample of 221 patients with chronic pain was recruited, 32% diagnosed of neuropathic origin, 32% of nociceptive, and remaining 36% presented mixed pain. The average age was 57.8 years (SD=14.2) and 59% were women. Cronbach alpha attained a value of 0.86, and the intraclass correlation coefficient with the retest was 0.93. The factor structure was coherent with the one informed for the original instrument. Pearson correlation with the LANSS scale was 0.88. Area under the receiver operating characteristic curve was 0.88 when comparing neuropathic and nociceptive groups. Using the suggested cutoff value for pain presence of 19 points or higher, the following discriminant values are obtained: sensitivity=75%, specificity=84%, Youden Index=0.595, positive predictive value=92%, and negative predictive value=60%. The absence cutoff value of 12 points or bellow raised the following values: sensitivity=93%, specificity=68%, Youden Index=0.61, positive predictive value=87%, and negative predictive value=80%. When mixed pain patients are included in the group with a neuropathic component, discriminant values are slightly reduced, as expected.
The culturally adapted version of the painDETECT presents good psychometric properties and shows to be a valid patient-reported outcome for measuring the presence of a neuropathic component in patients with chronic pain.