Assessment of Health Literacy and validation of single-item literacy screener (SILS) in a sample of Italian people

Background. Health literacy (HL) is a complex concept with multiple components; it involves the ability to effectively use and interpret texts, documents, and numbers. The aims of our study were: to measure HL levels among a sample of adult Italian patients; to develop and validate the Italian version of the single-item literacy screener (SILS); to assess the diagnostic accuracy of the SILS as an indicator of limited reading ability regarding health documents, compared to the newest vital sign (NVS). Methods. The subjects were enrolled in emergency departments, primary care settings, and specialist departments. The Italian versions of the NVS and of the SILS were administered to the patients, as well as a questionnaire aimed in collected socio-demographic information. Results. Overall, 174 patients completed the interview (compliance: 87%). Considering the NVS, 24.1% of the subjects presented high likelihood of limited HL, 13.2% a possibility of limited HL, and 62.6% adequate HL. SILS has shown a good concurrent validity compared to NVS (Spearman’s rho r= −0.679; p < 0.001). The diagnostic accuracy of the SILS was high. The best performance parameters in assessing the diagnostic accuracy of SILS are found to be for threshold value of 2 in in identifying subjects with high likelihood of limited HL at the NVS (sensitivity: 83.3%; specificity: 82.6%; accuracy: 82.8%; positive predicted value: 60.3%; negative predicted value: 94%; Cohen's kappa: 0.6). Conclusion. The Italian version of SILS-as an indicator of limited reading and understanding ability regarding health information-is a good tool to measure HL in comparison to more complex measurement instruments of functional HL, like NVS