Effects of health literacy interventions on health-related outcomes in socioeconomically disadvantaged adults living in the community: a systematic review

OBJECTIVES: The objectives of this review were: i) to identify and synthesize the best available evidence on the effectiveness on health-related outcomes of health literacy interventions for enabling socioeconomically disadvantaged people living in the community to access, understand, appraise and apply health information; and ii) to identify components of health literacy interventions associated with improved health-related outcomes. INTRODUCTION: Health literacy is defined as a person's competence in accessing, understanding, appraising and applying health information in order to make sound health decisions. A high level of health literacy is positively related to better health outcomes. However, nearly half of the American and European populations have low health literacy levels. Socioeconomically disadvantaged groups in particular present with the weakest health literacy levels, suggesting that differences in health literacy levels contribute to health disparities. Therefore, there is a need to understand the conditions under which health literacy interventions aiming at improving health-related outcomes among socioeconomically disadvantaged people can be implemented. INCLUSION CRITERIA: This review considered studies on socioeconomically disadvantaged adults living in the community identified using the socially stratifying PROGRESS factors (Place of residence, Race/ethnicity, Occupation, Gender, Religion, Education, Socioeconomic status, Social capital).This review considered studies evaluating the following interventions: i) targeting health literacy based on either a clinical and/or a public health approach, ii) delivered at the individual, interpersonal, community or societal level, iii) delivered by any healthcare/social work professional, and iv) using a single or multicomponent strategy. The comparator was no treatment, standard care or a variation of the intervention. All randomized and non-randomized controlled trials as well as quasi-experimental designs were included. Outcomes considered were: i) health-related quality of life and health-related outcomes, ii) health behavior outcomes, and iii) outcomes related to the access and use of healthcare services. METHODS: A three-step strategy was conducted for primary research published up to May 2018 across seven databases without any language restriction. A search for gray literature was also conducted. Titles and abstracts were screened for assessment against the inclusion criteria. Studies that