Assessment
Validation of the short-form Health Literacy Scale in patients with stroke

https://doi.org/10.1016/j.pec.2015.02.021Get rights and content

Highlights

  • This is the first evidence of the SHEAL's psychometric properties in stroke patients.

  • The internal consistency reliability of the SHEAL was adequate.

  • The convergent and discriminative validities of the SHEAL were sound.

  • The SHEAL was a reliable and valid health literacy measure for use in stroke patients.

  • The SHEAL can be too easy for some patients with high levels of health literacy.

Abstract

Objective

We aimed to validate a Mandarin version of the short-form Health Literacy Scale (SHEAL) in patients with stroke.

Methods

Each patient with stroke was interviewed with the SHEAL. The Public Stroke Knowledge Quiz (PSKQ) was administered as a criterion for examining the convergent validity of the SHEAL. The discriminative validity of the SHEAL was determined with age and education level as independent grouping variables.

Results

A total of 87 patients with stroke volunteered to participate in this prospective study. The SHEAL demonstrated sufficient internal consistency reliability (alpha = 0.82) and high correlation with the PSKQ (r = 0.62). The SHEAL scores between different age groups and education level groups were significantly different. The SHEAL, however, showed a notable ceiling effect (24.1% of the participants), indicating that the SHEAL cannot differentiate level of health literacy between individuals with high health literacy.

Conclusion

The internal consistency reliability, convergent validity, and discriminative validity of the SHEAL were adequate. However, the internal consistency reliability and ceiling effect of the SHEAL need to be improved.

Practice implications

The SHEAL has shown its potential for assessing the health literacy of patients with stroke for research purposes. For clinical usage, however, the SHEAL should be used with caution.

Introduction

Stroke is a chronic disease and has become the leading cause of death and serious, long-term disability globally [1]. More than 7.1‰ of the world population are affected by stroke annually [1]. To manage chronic diseases and long-term disabilities requires the active participation of the patients [2], [3], [4], [5], and this can only occur when patients have adequate health literacy [6], [7], [8], [9]. Health literacy is defined as the degree to which individuals have the capacity to obtain, process, and understand basic health information and services needed to make appropriate health decisions [10]. Health literacy is an essential aspect of self-management and shared decision-making to improve health outcomes in patients with stroke. Numerous studies have highlighted the importance of an adequate level of health literacy to the disease management process [11], [12], [13], [14] and noted that inadequate health literacy is a potentially modifiable determinant of poor health outcomes in people with chronic disease [15], [16], [17], [18]. Thus, it is important to assess the health literacy of stroke survivors early on in order to identify patients at risk of low literacy. Such information is useful for clinicians to ameliorate patients’ health literacy and help them manage their health.

Measures of health literacy with sound psychometric properties are a prerequisite to successfully understanding, monitoring, and managing patients’ health literacy. To date, more than a dozen validated measures of health literacy have been developed [19], [20], [21]. Although these measures have been used in several adult or patient populations, their usefulness and applicability for patients with stroke remain unknown. To the best of our knowledge, no measures assessing health literacy have been validated in patients with stroke, which not only hampers clinicians in assessing and understanding the health literacy required for stroke management, but also hinders researchers investigating the concepts of stroke-specific health literacy skills. Thus, there is a need to validate existing health literacy measures in patients with stroke, in order to provide clinicians and researchers empirical evidence for assessing and managing health literacy in stroke populations.

The short-form Health Literacy Scale (SHEAL) was designed to assess the general population's comprehension and numeracy skills needed to promote health, seek health care, and manage self-care [22]. The SHEAL contains 11 items simplified from the Health Literacy Scale [22], [23]. The SHEAL is brief and quick to administer (around 5 min), so it could be an efficient measure for assessing health literacy in busy clinical settings [22]. The SHEAL also shows satisfactory psychometric properties (including internal consistency reliability, factorial validity, convergent validity and discriminative validity) in the general public [22]. Hence, the SHEAL is a potential measure for assessing health literacy in patients with stroke.

However, the SHEAL has not been validated in patients with stroke. The psychometric properties of a measure are sample dependent [24], [25], and all relevant psychometric properties must be examined comprehensively in patient samples to ensure quality of assessment [24]. Consequently, despite the fact that the SHEAL has been validated in the general population, the psychometric findings from the previous study cannot be directly applied to patients with stroke. The psychometric properties of the SHEAL have to be validated in patients with stroke to provide empirical evidence to support its use in these patients.

The purpose of this study was to examine the psychometric properties (including internal consistency reliability, convergent validity, and discriminative validity) of the SHEAL in patients with stroke. We hypothesized that the SHEAL would have good internal consistency reliability, as well as sufficient convergent validity and good discriminative validity.

Section snippets

Participants

This study was conducted between July 1 2013, and October 31 2013. Although there are no commonly accepted methods for calculating the required sample size in a psychometric study, a sample size of at least 50–100 subjects is generally recommended [26]. Subjects were recruited from the rehabilitation departments of two teaching hospitals in northern Taiwan. Patients were invited to participate in the study if they met the following criteria: (1) diagnosis (International Classification of

Demographics of the participants

A total of 87 (54% male) patients with stroke joined this study. The average age of the participants was 57 years. The majority of the participants were outpatients with chronic stroke (≥6 months post stroke) and diagnosed as ischemic stroke (63.2% and 59.8%, respectively). The average duration after stroke of the participants was 21 months. Most of the participants had 10–16 years of formal schooling (senior high to college) and lived in urbanized cities. Other demographic characteristics of

Discussion

This study, to the authors’ knowledge, is the first to investigate the psychometric validity of the SHEAL in patients with stroke. Owing to the lack of health literacy measures validated in stroke survivors, no health literacy measures with robust psychometric evidence can be used in a stroke population. The findings of this study can provide psychometric evidence of the SHEAL for both clinicians and researchers to assess health literacy in patients with stroke.

Conflicts of interest

The authors have no conflicts of interest relevant to this article.

Informed consent and patient details

I confirm all patient/personal identifiers have been removed or disguised so the patient/person(s) described are not identifiable and cannot be identified through the details of the story.

Acknowledgements

This study was supported by research grants from the Taipei Medical University (TMU101-AE1-B21), Chi Mei Medical Center (103CM-TMU-12), E-Da Hospital (EDAHT103019), Ministry of Science and Technology (102-2314-B-038-007-MY3) and National Health Research Institutes (NHRI-EX102-10207PI).

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    These authors contributed equally to this paper.

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