Validity and Reliability of the Greek Version of the Literacy Assessment for Diabetes Scale

1. INTRODUCTION

Health Literacy (HL) encompasses the cognitive and social skills that determine an individual’s motivation and ability to access, understand and use information in ways that promote and maintain good health. At the same time, HL is a means of developing both individuals and society as a whole, as it improves citizens' access to health-related information and their ability to use it [1].

The World Health Organization (WHO) has defined HL since 1998. HL is a concept that represents the cognitive and social skills determining an individual’s ability and motivation to access, understand, and use health-related information to promote and maintain good health. Achieving this goal requires knowledge, personal skills, and confidence, which are crucial factors in improving both individual and community health by influencing behaviors and living conditions [2, 3].

According to modern perceptions of health, people actively participate in controlling their health by making the right decisions. Good decisions require skills in understanding and utilizing health promotion information. These skills have been characterized as HL [4]. Its important contribution as a determinant of health is widely recognized, which is why HL has been increasingly prioritized in public health policy formulation by national healthcare systems over the past decades [5]. Despite its importance and critical role, studies focusing on HL remain limited. Although several assessment tools exist, there is a general consensus that HL lacks a single, comprehensive tool for its measurement [6]. In the management of chronic conditions, such as diabetes mellitus (DM), practical skills are often more directly linked to individuals' self-care needs [7], while low HL can act as a significant barrier to effective self-management [8].

According to the data by the WHO, diabetes mellitus (DM) is among the 10 leading causes of death worldwide, responsible for 1.5 million deaths [2, 9]. The assessment scales of HL in DM care are constantly expanding and improving. Core scales have been constructed and are used in the context of HL assessment and the development of educational interventions for people with DM. These scales assess the ability to read, pronounce, and understand words related to DM, as well as the ability to perform basic numerical calculations. Several scales incorporate one or more of these skills related to DM self-management and are available in English and other languages [10]. For community nurses, HL assessment scales are useful tools in effective communication with people with DM and their self-care. Reading fluency does not necessarily presuppose the ability to understand the meaning of words and concepts. However, the cognitive processes required to understand spoken and written instructions are directly related to an individual's verbal and numerical ability [3].

The HL scale, known as the Diabetes Literacy Assessment Scale (LAD), is designed to measure the verbal ability of individuals with DM in reading words of graded difficulty. These words are related to terms and concepts commonly encountered in daily life and specifically relevant to DM care [11]. The LAD is a reliable and valid tool for assessing HL in adults with DM. In addition to its original English version, it has recently been translated and culturally adapted into Arabic [12]. However, the LAD scale has not yet been translated, culturally adapted, or validated in the Greek language. Therefore, the purpose of this study was to translate, culturally adapt, and evaluate the validity and reliability of the LAD in a Greek population with DM.

2. MATERIALS & METHODS

3. RESULTS

3.2. The Validation of LAD

The Greek version of LAD was assessed in terms of its validity and reliability.

3.2.1. Descriptives of the Scale

The mean score for the “Pronunciation” subscale was 54.28 ± 4.34, for “Knowledge”, it was 56.76 ± 3.75, and for the “Comprehension” subscale, it was 48.92 ± 7.05 (Table 2). All participants achieved scores within the highest reading level category (41–60). Partial knowledge of the assessed words was evident in nearly all participants, as reflected by the high average score in the Knowledge subscale (56.76), approaching the maximum possible score of 60. In comparison, the Pronunciation subscale showed a slightly lower mean score (54.28), while the Comprehension subscale displayed a more noticeably reduced performance (48.92).

In terms of adaptive percentage performance in verbal assessment (Fig. 1), the “Knowledge” subscale was rated at 94.6%, “Pronunciation” at 90.5%, and “Comprehension” at 81.5%.

Table 1.

Age (years)	Mean±SD	67±23.10
-	-	N	%
Gender	Men	29	58
	Women	21	42
Marital Status	Married	31	62
	Unwed/ widowed/divorced	19	38
Accomodation	Alone	16	32
	Family	34	68
Εducation	Primary	24	48
	Secondary	17	34
	Τertiary	9	18
Εmployment	Εmployed	8	16
	Unemployed/retired	42	84
Counselling	Physician	25	50
	Physician/internet/mass communication/social environment	13	26
	Physician/Nurse	12	24
Comorbidities	None	14	28
	Cardiovascular diseases	10	20
	Retinopathy	9	18
	Νeuropathy	5	10
	Cancer	3	6
	Αutoimmune disorder	2	4
	Other	7	14

Table 2.

LAD	Mean± SD	Min	Max
Comprehension	48.92±7.06	34	60
Pronunciation	54.28±4.34	42	60
Knowledge	56.76±3.75	38	60

Abbreviation: *SD:standard deviation.

Table 3.

LAD	Age Group (years)	Mean±SD	P*
Knowledge	≤67	55.67±2.73	0.047
	>67	57.77±4.31	-
Pronunciation	≤67	52.17±3.89	0.001
	>67	56.23±3.85	-
Comprehension	≤67	45.58±6.18	0.001
	>67	52.00±6.48	-
Knowledge	Employment	-	-
	Εmployed	59.50±1.07	0.023
	Unemployed/retired	56.24±3.86
Pronunciation	Εmployed	58.63±2.20	0.001
	Unemployed/retired	53.45±4.16
Comprehension	Εmployed	56.38±5.88	0.001
	Unemployed/retired	47.50±6.38

Note: * Independent-samples t-test.

Table 4.

-	Primary (N=24)	Secondary (N=17)	Tertiary (N=9)	-	-
-	Mean±SD	Mean±SD	Mean±SD	F*	P
Knowledge	54.67±4.31	58.06±1.60	59.89±0.33	11.118	<0.001
Pronunciation	51.17±3.82	56.06±2.11	59.22±1.20	28.473	<0.001
Comprehension	43.58±5.14	51.41±3.43	58.44±2.24	45.122	<0.001

Note: *One-way ANOVA.

3.2.2. Reliability

The reliability of the LAD scale was tested for the characteristics of stability and internal consistency.

3.2.3. Internal Consistency

To assess the internal consistency of the LAD, Cronbach's alpha coefficient was calculated. The values were 0.87 for the “Pronunciation” subscale, 0.86 for “Knowledge,” and 0.92 for “Comprehension,” indicating a high level of internal consistency across all subscales.

3.2.4. Test-Retest Method

From the total of 50 patients, 10 of them completed the questionnaire for a second time (retest) after a ten-day period. The results of repeatability (test–retest) were r = 0.721 and p= 0.019, showing the consistency between the two occasions.

4. DISCUSSION

This study aimed to evaluate the validity and reliability of the Greek version of the LAD scale by applying it for the first time in a Greek population. The objective was to establish the scale as a practical tool for nurses and other healthcare professionals managing adults with diabetes mellitus (DM) in community settings. The Greek version demonstrated excellent internal consistency and test-retest reliability, suggesting strong potential for its future application in this population. However, the types of validity that could be assessed were limited, primarily due to the lack of a validated, comparable questionnaire in Greece and the consistently high scores observed across most items in the study.

Participants with DM demonstrated a notably high level of accuracy in pronouncing words and terminology related to DM commonly encountered in daily disease management. Despite the generally low educational level of the sample, most participants achieved high scores in both the knowledge and pronunciation components across all three word lists, which were organized in increasing order of difficulty. This performance may be attributed to the fact that the scale was translated into the participants’ native language, facilitating greater familiarity and comprehension.

This study represents an additional effort to translate and culturally adapt an HL assessment tool from English. In the context of DM care, accurate and quantitative assessment of HL is essential, as it directly supports effective self-management of the disease. A representative example of an HL assessment tool is the European Health Literacy Survey Questionnaire (HLS-EU-Q) [13], which has been translated into more than ten languages. However, many commonly used HL tools tend to assess only specific domains, primarily reading and writing skills, while often overlooking other critical competencies, such as verbal communication, navigating the healthcare system, and informed decision-making. Moreover, the approach to translation and cultural adaptation varies depending on linguistic, cultural, and methodological factors, as well as the nature of the tool being adapted [14].

The structure of health literacy assessment tools, their mode of administration, and the time required for completion are key factors that affect their applicability and effectiveness in both clinical and research settings [15]. Although the LAD scale is considered a valuable assessment tool, having been evaluated against instruments such as the Wide Range Achievement Test (WRAT) and the Rapid Estimate of Adult Literacy in Medicine (REALM), it has appeared in only a limited number of studies, and typically in combination with other assessment scales [2, 10, 16]. In contrast, other tools like the DNT-15 (Latino) have been more widely adapted, with the Spanish version developed specifically to address the assessment needs of Hispanic populations in the United States [17].

Translations of the LAD scale remain limited in the Western world, with the first known translation and cultural adaptation conducted in Arabic in 2020. In the Arabic version, minor modifications were made to a few words, which were rephrased or rearranged to improve clarity [12], though no subscales were added. The process of translating and adapting the scale into Arabic presented notable challenges due to significant cultural differences in language, customs, and dietary practices between the Western and Arab contexts. Consequently, specific terms had to be replaced to ensure both cultural relevance and semantic equivalence. Further revisions have been suggested to enhance cultural adaptation and maintain the intended conceptual meaning within the Arab cultural framework [12].

On the contrary, in the present study, the translation and rendering of the meaning of the words in Greek encountered no significant difficulties. The application of the LAD scale in the Arabic version took several minutes to complete, and no changes to the scale title or the included instructions were required. However, demographic data were obtained separately, as the LAD scale was administered concurrently with other scales. In the Arabic version of the LAD scale, the order of the words in the three lists was rearranged from their original sequence in the English version. However, such modifications were not necessary in the Greek adaptation, where the original word order was preserved.

The use of the LAD scale contributes significantly to the design and implementation of educational interventions in populations with DM to improve their self-care. In the research by Omar et al. (2020), an educational intervention was carried out in people with DM, through WhatsApp, in order to investigate the effect of the intervention on glycated hemoglobin (HbA1c) values. The LAD scale was also used in the research to assess the possible association of HL and numerical calculation ability related to DM and intervention results. The results showed no correlation between LAD scale scores and HbA1c values at baseline, three months, or six months post-intervention. However, the WhatsApp-based intervention proved effective for all participants, including those with low HL scores. This outcome may be attributed to the use of simple, easily understandable language and supportive visual aids, such as videos and images, designed to be accessible to all individuals with DM, regardless of their HL level [18].

The limitations of the study included its small sample, which limited the analyses, and the limited number of translations of the scale into languages. The scale was originally created in English [11] and was recently translated and culturally adapted in Arabic [12]. Additionally, there was a lack of sufficient international studies using the LAD, making it difficult to compare the analysis results.

The present study is unique in that it assesses the reliability and validity of a scale that has not been previously systematically used or tested. Additionally, the Greek version of the LAD includes two additional subscales, “knowledge” and “comprehension”, which are considered important for Greek adults with DM who are treated in the community. This Greek validation applies to adults with DM who speak the Greek language. Nevertheless, the scale requires further psychometric validation in other populations, settings, and countries. Validation of the LAD scale should be conducted with a larger and more diverse sample, ensuring greater gender and geographic representation, and ideally recruiting participants from multiple sites across Greece to enhance the generalizability and cultural applicability of the findings.

CONCLUSION

The Greek version of the LAD scale is an easy-to-use and reliable tool that can aid in assessing health literacy (HL) among Greek adults with diabetes mellitus (DM). By correctly utilizing the Greek LAD scale, nurses and healthcare professionals can help adults with diabetes better understand essential dietary and medical instructions related to their condition. This, in turn, enables the provision of person-centered care tailored to each individual’s level of health literacy and comprehension. In community and primary care settings, community nurses can employ the LAD scale to design and plan targeted educational interventions aimed at promoting more effective self-management of the disease. However, it is recommended that the scale’s validity parameters be reexamined in larger, more diverse samples and settings in future research.

AUTHORS’ CONTRIBUTIONS

The conceptualization of the study was carried out by Maria Milaka and Anna Kavga. Data curation was performed by Maria Milaka, Agoritsa Koulouri, and Alexandra Nikitopoulou. Formal analysis was conducted by Eugenia Vlachou. The investigation was led by Maria Milaka. Resources were provided by Maria Milaka, Agoritsa Koulouri, and Alexandra Nikitopoulou. Supervision was overseen by Anna Kavga. Visualization was done by Maria Milaka, Eugenia Vlachou, and Ioanna Tsatsou. The original draft of the manuscript was written by Maria Milaka, Ioannis Kalemikerakis, and Ioanna Tsatsou. Writing, review, and editing were performed by Maria Milaka, Ioannis Kalemikerakis, Ioanna Tsatsou, and Anna Kavga.

REFERENCES