Reliability and Validity of the Thai Short-Form McGill Pain Questionnaire-2 (SF-MPQ-2)

Abstract

Background: By adding 7 neuropathic pain descriptors, the Short-form McGill Pain Questionnaire-2 (SF-MPQ-2) enables clinicians to assess not only nociceptive pain but also neuropathic pain and presents an improvement over the first version (SF-MPQ). Unfortunately, no Thai language version of this new tool was available, we therefore undertook to create and validate one. Materials and methods: The translation included the following steps: 1) forward translation: English to Thai, 2) backward translation: Thai to English, 3) testing on patients 4) proof-reading and finalization. Adults suffering from cancer or non-cancer chronic pain completed Thai SF-MPQ and Thai SF-MPQ-2 during 2 separate visits 30 hours apart. Reliability was evaluated by assessing internal consistency and test-retest reliability. Three types of validity were investigated, including concurrent, construct and convergent validity. Results: A total of 220 Thai patients (127F: 93 M), aged 53 ± 14 year-old, participated in this study. Cancer pain was the most common cause of pain (n=52, 24%), followed by spine related pain (n=48, 22%) and neuropathic pain (n=48, 22%). The reliability for each questionnaire item was high (Cronbach’s alpha coefficient 0.771-0.993, ICC 0.985-0.996, Spearman’s correlation coefficient r>0.4 p<0.001). In addition, fit indices values of each pain aspect were good. Most descriptors had an acceptable factor loading value, except gnawing and itching (factor loading value; gnawing=0.47, itching=0.49). However, all descriptor had a significant t-value and R2 value. Conclusion: The Thai-MPQ-2 had high reliability as well as concurrent, construct and convergent validity. It is a reliable and comprehensive tool for pain assessment in Thai patients.