AssessmentCross-cultural adaptation and validation of the health literacy assessment tool METER in the Portuguese adult population
Introduction
Individual health literacy is the degree to which individuals have the capacity to obtain, process, and understand basic health information and services needed to make appropriate health decisions [1]. Inadequate health literacy is more prevalent among the elderly, those with lower levels of educational attainment [2] and with chronic disease [3]. It is associated with poorer self-management skills, less successful navigation of the healthcare system, higher morbidity and mortality [3], [4], [5], [6].
The European Health Literacy Survey 2011 [7], conducted in eight European countries (Austria, Bulgaria, Germany, Greece, Ireland, the Netherlands, Poland, and Spain) found that only between 36.7% (in Spain) to 76.3% of the population (in the Netherlands) had adequate health literacy, as assessed by the Newest Vital Sign [8]. In Portugal, although health literacy has started to appear in the national political agenda [9], there are no published studies on the prevalence of adequate health literacy.
Health literacy is commonly measured using instruments based on word recognition or pronunciation: Medical Term Recognition Test (METER) [10], Rapid Estimate of Adult Literacy in Medicine (REALM) [11], Short Assessment of Health Literacy for Spanish-speaking Adults (SAHLSA) [12], Medical Terminology Achievement Reading Test (MART) [13]; or reading comprehension and numeracy: Newest Vital Sign (NVS) [8], Test of Functional Health Literacy in Adults (TOFHLA) [14]. Most instruments were initially developed in English or Spanish and are being adapted worldwide [15], [16], [17], [18], [19]. Word pronunciation-based instruments perform well in English but have failed adaptation to languages with very high letter to sound correspondence (such as Spanish, Portuguese and Korean) because they are unable to discriminate between health literacy and ability to read [12], [16], [20]. METER is based on word/non-word recognition and is open-use, very brief, and self-administered, which means it can be added to a form or questionnaire without increasing participant burden considerably. We aimed to culturally adapt and validate METER in the Portuguese population, and to define cut-off values for adequate health literacy.
Section snippets
Original instrument
METER is an English language open use instrument based on REALM, consisting of a list of 40 medical words and 30 made-up non-words that intuitively sound like real medical terms. It is self-administered and it takes on average two minutes to complete. The participants are requested to mark only the words they are sure to be actual words. The score is calculated as the sum of all the correct words marked. The original METER performance cut-off points defined by the authors were 0–20 for low,
Results
Demographic characteristics of the sample by validation group are summarized in Table 1. Women made up the majority of respondents in all validation groups (56.6%), except for the group of researchers in areas unrelated to health (12.0%). Less educated people were older.
Discussion
We culturally adapted a health literacy instrument that is brief and simple, and showed it was valid and reliable. This instrument can be used to assess health literacy levels and to sort between adequate and inadequate health literacy. We propose that words and non-words should be treated as different sub-scales with separate scoring.
Exploratory factor analysis revealed two dimensions of the instrument, one for words and another for non-words, implying that some individuals scored high in one
Acknowledgments
We thank Teresa Oliveira, Gabriel Coutinho, Joe Pereira and Paul Charles for the translation and back-translation of the instrument. We are also grateful to each of the participants and to the institutions Faculdade de Engenharia da Universidade do Porto, Instituto de Saúde Pública da Universidade do Porto and Unidade de Saúde Familiar Monte Murado, for enabling participant recruitment.
This work was supported by Fundação para a Ciência e a Tecnologia (HMSP-IISE/SAU-ICT/0004/2009).
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