Development and Validation of RLS Diagnostic Questionnaire for Indian Population

Abstract

Restless legs syndrome is a common condition affecting nearly 2% Indian population. Certain questionnaires for screening or diagnostic purpose have been developed in the West, and they were translated to Hindi. However, those questionnaires have been found to have limitations in Indian context considering the cultural effect on vocabulary for the description of symptoms. Based on the IRLSSG criteria, a 12-item questionnaire was developed. Most of the items had dichotomous responses. This questionnaire was tested in subjects having RLS. Control group consisted of subjects suffering from clinically significant anxiety, myalgia of legs, arthralgia in legs, burning feet syndrome, nocturnal leg cramps and somatic symptoms disorder persistent pain type; conditions that could mimic RLS. Face validity and content validity were examined. Internal consistency of the questionnaire was assessed. Diagnostic outcome from the new questionnaire was assessed against clinical diagnosis, which is considered as gold standard at present. This study included 49 cases of RLS and 44 subjects in control group. Female preponderance was noted in both groups (69.4% in RLS group and 63.6% in control group; P = 0.55). Mean age of subjects in both groups was comparable (38.1 ± 2.3 years in RLS and 40.1 ± 2.5 years in control group; P = 0.10). New diagnostic questionnaire had sensitivity of 73.4% (95% CI = 58.9–85.0) and specificity of 88.6% (95% CI = 75.4–96.2). Positive predictive value was 87.8% (95% CI = 75.6–94.3%) and negative predictive value was 75% (95% CI = 65–82.8) with the diagnostic accuracy of 80.6% (95% CI = 71.1–88.1). New questionnaire correlated well with clinical diagnosis (r = 0.62; P < 0.001). This questionnaire is a short and reliable method for diagnosis of RLS in Indian population.