Reliability of the English version of the painDETECT questionnaire

Abstract

Background: The painDETECT questionnaire (PD-Q) has been used widely for the identification of neuropathic pain (NeP); however, the reliability of the English version of the PD-Q has never been investigated.

Objective: This study aimed to determine the reliability of the PD-Q pre- (T0) and immediately post- (T1) clinical consultation and at one-week follow-up (T2).

Methods: We recruited 157 patients attending a Neurosurgery Spinal Clinic and Pain Management Department. Minor changes to PD-Q instructions were made to facilitate patient understanding; however, no changes to individual items or scoring were made. Intraclass correlation coefficients (ICCs) were used to assess the reliability of PD-Q total scores between T0–T1 and T0–T2; weighted kappa (κ) was used to assess the agreement of PD-Q classifications (unlikely NeP, ambiguous, likely NeP) between all time-points. To ensure stability of clinical pain, patients scoring ≤2 or ≥6 on the Patient Global Impression Scale (PGIC) at T2 were excluded from the T0–T2 analysis.

Results: Accounting for missing data and exclusions (change in PGIC score), data for 136 individuals (mean [SD] age: 56.8 [15.2]; 54% male) was available, of whom n = 129 were included in the T0–T1 and n = 69 in the T0–T2 comparisons. There was almost perfect agreement between the PD-Q total scores at T0–T1 time-points (ICC 0.911; 95% CI: 0.882–0.941) and substantial agreement at T0–T2 (ICC 0.792; 95% CI: 0.703–0.880). PD-Q classifications demonstrated substantial agreement for T0–T1 (weighted κ: 0.771; 95% CI: 0.683–0.858) and for T0–T2 (weighted κ: 0.691; 95% CI: 0.553–0.830). Missing data was accounted in 13% of our cohort and over 42% of our patients drew multiple pain areas on the PD-Q body chart.

Conclusion: The English version of the PD-Q is reliable as a screening tool for NeP. The validity of the questionnaire is still in question and has to be investigated in future studies.

Keywords:

• Clinical assessment
• neuropathic pain
• reliability
• screening tool

Transparency

Declaration of funding

Internal funding by the Department of Physiotherapy, Sir Charles Gairdner Hospital, Perth, Western Australia and the School of Physiotherapy and Exercise Science, Faculty of Health Sciences, Curtin University, Perth, Western Australia. The following authors contributed equally to the work: T.B., M.C., M.K., A.M.M., E.C.N.

Declaration of financial/other relationships

B.T. has disclosed that she has a Clinician Research Fellowship from the Department of Health Western Australia and Raine Medical Research Foundation and a nationally competitive research grant from Arthritis Australia; the research grants are not related to the work reported in this article. H.S. has disclosed that she has received research grants from state governments (Western Australia) and nationally competitive research grants from Arthritis Australia and the Physiotherapy Research Foundation; the research grants are not related to the work reported in the manuscript. T.B., M.C., M.K., A.M.M., E.C.N., and C.B. have disclosed that they have no significant relationships with or financial interests in any commercial companies related to this study or article.

CMRO peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Acknowledgments

We would like to thank the staff of the Sir Charles Gairdner Hospital Department of Pain Management and Neurosurgery Spinal Clinic, specifically Heide Murphy and Jan Mountford, for their assistance with organization of clinics and patient recruitment, and Michelle Trevenen at the Department of Research, Sir Charles Gairdner Hospital for statistical support. We would also like to thank Dr. Kathy Briffa at Curtin University School of Physiotherapy and Exercise Science for her assistance and guidance throughout our study.

Previous presentations: Some of the results of this study were presented as a poster titled: “painDETECT for screening neuropathic pain: the English version is reliable” at the International Federation of Orthopaedic Manipulative Physical Therapists (IFOMPT) conference, Glasgow, 4–8 July 2016; and as a poster titled: “Reliability of the English version of the painDETECT questionnaire and its pain descriptors” at the Deutscher Schmerzkongress, Mannheim, 19–22 October 2016.