Validation and usefulness of the Danish version of the Pain Medication Questionnaire in opioid-treated chronic pain patients.

Abstract

Addiction is a feared complication of long-term opioid therapy for chronic pain patients. A screening tool to assess the potential risk of addiction may be helpful. The Pain Medication Questionnaire (PMQ) was translated into Danish by a 'forward' and 'backward' translation procedure. Patients with chronic non-cancer pain and cancer pain treated at a tertiary pain center were screened for addiction using Portenoy's criteria and invited to answer the Danish version of the PMQ. Two hundred nine patients participated in the study. PMQ was able to discriminate between addicted and non-addicted patients. Patients with high PMQ scores indicating a risk of addiction drank more alcohol, smoked more tobacco, used higher doses of morphine, had a higher anxiety and depression score, and had poorer mental health. Using a cut-off score of 22, the PMQ had a sensitivity of 82%, but the specificity at this cut-point was 56%, indicating a risk of false positive cases. Convergent and discriminant validity were confirmed by correlation with opioid doses, alcohol and tobacco use, anxiety and depression scores, and inverse correlation with mental health and social role. Test-retest showed a very strong correlation. Cronbach's alpha for internal consistency was 0.61. Ten components were found to have eigenvalues above 1.0, confirming the multidimensional structure of the questionnaire. The PMQ may assist physicians in addiction risk assessment and stratification when treating chronic pain patients with opioids. PMQ is not a diagnostic tool and should only be used as an indicator for possible addiction problems.