Cross-cultural adaptation of the Richards-Campbell Sleep Questionnaire for intensive care unit inpatients in Brazil: internal consistency, test-retest reliability, and measurement error

Abstract Study objectives To perform the cross-cultural adaptation of the Richards-Campbell sleep questionnaire (RCSQ) to Portuguese-Brazil and to eval its internal consistency, test-retest reliability, and measurement error in intensive care unit (ICU) inpatients. Methods The study enrolled 113 inpatients at medical/surgical ICU in Curitiba, Brazil. The RCSQ was first translated to Portuguese-Brazil according to the principles of good practice for the translation and cultural adaptation process for patient-reported outcomes and then applied in 30 inpatients. The final version (RCSQ-PT-Br) was applied to measure content validity (83 inpatients, 47 men [56.6%], 60.4 ± 14.2 years), and test-retest reliability and measurement error (a subset of 53 inpatients). Internal consistency of the RCSQ-PT-Br was estimated using Cronbach's a; test-retest reliability (2 independent rates) was assessed using the single measurement, absolute agreement, two-way random effects model (ICC2,1). Results Group-average RCSQ-PT-Br total score was 46.9 ± 26.7 (range 3.4–98.8). The RCSQ-PT-Br total score showed good content internal consistency (Cronbach's α = 0.850 95%CI = [0.789–0.897]) and excellent test-retest reliability (ICC2,1 = 0.840 95% CI = [0.739–0.904]). Measurement error was low (standard error of mean = 11 mm, mean difference = 30 mm). Conclusions The RCSQ-PT-Br is a valid and reliable instrument to evaluate the sleep of patients hospitalized in the ICU in Brazil.