Validity and reliability of the Malay version of the Structured Migraine Interview (SMI) Questionnaire.

Background: The Structured Migraine Interview (SMI) is a valid and reliable instrument for migraine diagnosis. However, a Malay version of the SMI is not available to be applied to the local Malaysian population. This study was designed to access the validity and reliability of a new Malay version of the SMI questionnaire.
Methods: Patients with headache attending the Neurology Clinic, Hospital Universiti Sains Malaysia, Kelantan, Malaysia, were screened against the inclusion/exclusion criteria before recruitment. A standard translation procedure was used to translate and adapt the questionnaire into the Malay language. The translated version was tested for face, content and construct validities. Subsequently, validity and reliability studies were conducted (1(st) compilation), followed by retesting seven days later (2(nd) compilation).
Results: A total of 157 patients between 15 and 60 years of age were enrolled in this study. The kappa value was 0.70 (p < 0.001) with high sensitivity (0.97) and specificity (0.63). The misclassification rate was 0.15, with a positive predictive value of 0.82 and a negative predictive value of 0.92. The positive likelihood ratio was 2.62, while the negative likelihood ratio was 0.05. The Cronbach's alpha was 0.93 (1(st) compilation) and 0.90 (2(nd) compilation), respectively. The Spearman's correlation coefficient ranged from 0.86 (Question 4) to 0.95 (Question 1). The overall concordance for item 1 was very high (97%), followed by item 4 (83%), item 2 (71%) and finally item 3 (64%).
Conclusion: The Malay version of the SMI questionnaire is comparable to the English version in terms of validity and reliability. It was highly reliable with good internal consistency and can be used for the diagnosis of migraine in clinical settings in Malaysia.