Impact of rheumatoid arthritis on sexuality: adaptation and validation of the Qualisex questionnaire for use in Spain.

Patients with rheumatoid arthritis (RA) have a significantly increased risk of sexual dysfunction. However, it is not properly included in commonly used questionnaires to assess health-related quality of life in RA. Qualisex is a questionnaire developed in France to assess the impact of RA on patients´ sexual function. Our aim was to adapt and validate this questionnaire for use with Spanish RA patients. Two independent translations and a backward translation were obtained. The final version was tested in a pilot study with 10 RA patients to detect any aspects that could hinder interpretation. The validity and reliability of the linguistically validated questionnaire were studied in a multicenter cross-sectional study, with a longitudinal component for reliability estimation. 125 RA patients were included. The response process, discrimination, internal consistency, internal structure, convergent validity (correlation with MGH-SFQ questionnaire, DAS-28, physician global assessment, patient global health assessment, RAID, HAQ, HADS and SF-12©) and reliability were analyzed. The inclusion of two extra items was proposed in the pilot study. The validity analysis detected responses for item 10 that were not coherent with responses for the rest of items. The Cronbach alpha coefficient was 0.971. The highest correlation (0.665) was obtained with MGH-SFQ (questionnaire measuring sexual functioning), followed by RAID (0.516). The intra-class correlation was 0.880 (95% CI 0.815; 0.923), higher than 0.85, which indicates excellent reliability. All parameters used to assess this questionnaire show highly acceptable values. Qualisex allows for a global score of RA patients' sexual functioning and can be self-administered.