Psychometric properties of a Spanish version of the McGill Pain Questionnaire in several Spanish-speaking countries

Versions of the McGill Pain Questionnaire are available in a several languages and are used in clinical studies and sociocultural or ethnic comparisons of pain issues. However, there is a lack of studies that compare the validity and reliability of the instrument in the countries where it is used. The current study investigates the psychometric properties of a Spanish version of the McGill Pain Questionnaire in five Spanish-speaking countries.

The authors conducted a multicenter and transnational study with one investigator in each center. Patients were evaluated once with a Spanish version of the McGill Pain Questionnaire, a visual analog scale, and a verbal rating scale.

The study was performed in pain clinics and acute pain units of four Latin American countries (Argentina, Costa Rica, Mexico, and Panama) and Spain.

The study included 205 patients (84 with acute pain, 121 with chronic pain) from Latin America. Their data were compared with those of 282 Spanish patients.

The McGill Pain Questionnaire, visual analog scale, and verbal rating scale were administered once to all patients. The McGill Pain Questionnaire was administered again to patients from Latin America countries to ascertain descriptor comprehension.

Demographic data, McGill Pain Questionnaire parameters, and visual analog scale and a verbal rating scale scores were obtained from patients with chronic and acute pain. Psychometric properties of the Spanish version of the McGill Pain Questionnaire were established for each country by calculating the ordinal consistency by means of rank-scale correlation (Spearman test), intercategory correlation, and interparameter correlation (Pearson test). Concurrent validity was also calculated by comparing scores from the visual analog scale (Pearson test) and verbal rating scale (Spearman test) with questionnaire parameters (qualitative-to-quantitative comparisons).

The Spanish version of the McGill Pain Questionnaire maintained a high internal validity when tested in different countries. Ordinal consistency, intercategory, interparameter, and qualitative-to-quantitative parameter correlations were similar in all countries. Few descriptors were considered to be inappropriate or difficult to understand.

The psychometric properties of the Spanish version of the McGill Pain Questionnaire assessed in different Latin-American countries suggest that the questionnaire may be used to evaluate Spanish-speaking patients. The validity of this test should be extended with reliability studies to further establish its usefulness in the evaluation of pain.