This study investigated levels of HL in terms of social support for health, engaging with healthcare providers, and understanding health information among PLWHIV in Denmark. Overall, the study found that PLWHIV had high levels of HL despite differences in their demographic characteristics. However, we found that patients living alone or who were not in employment reported lower levels of HL compared to those living with a partner or who were in employment. Patients also reported a high degree of involvement in interactions with the healthcare professionals at the outpatient clinic.

Studies show that poor HL is a social barrier to accessing healthcare services and obtaining suitable medical treatment among patients living with HIV and is influenced by low socioeconomic status [24, 25]. The review by Palumbo [25] found that levels of HL among PLWHIV influence their life situation and health status. Especially persons from inadequately served ethnic minority groups, people with refugee backgrounds, substance abuse, mental illness or homelessness. In this study, we found that PLWHIV from other countries reported lower scores on HLQ4 and HLQ9 compared to their counterparts with a Danish background; however, the differences were small and not statistically significant. In our study, participants living with a partner had higher HLQ9 scores (understanding written information) compared to participants living alone. Associations between living alone and low HL have been identified in a Danish study population living with cancer [26]. This raises an issue, which has been discussed in the literature, acknowledging that the links between HL and health outcomes are not direct or linear. Rather, they are “mediated” by factors that are themselves indivisible from each individual’s social environment. Studies shows that the HL abilities, skills, and practices of other people in the same social environment influence an individual’s HL. This means that HL is a “distributed resource” within the individual’s social network, which is the situation for people living with a chronic disease such as HIV. Edwards et al. [27] argue that while individuals’ HL may vary within a group, they can overcome personal insufficiencies in their HL skills by merging their efforts. In this way, distributed HL becomes a resource that can mediate the negative consequences of low HL. Our study also showed a statistically significant difference in scores for HLQ4, HLQ6, and HLQ9 between those who were in employment and those who were not. This finding is supported by a Danish study that revealed those who were not working and who were receiving economic public support were more likely to demonstrate inadequate HL competencies compared to those who were active in the labor market, when age and socioeconomic factors were taken into account [28]. Another Danish study, involving patients with liver cirrhosis, also found low levels of HL among patients with low levels of education and those living alone [29]. Based on the literature, factors that influence an individual’s level of HL may include: (1) demographic, social, and cultural circumstances (e.g., socioeconomic status, employment, income, social support, culture, and language), and (2) individual characteristics (e.g., age, gender, cultural background, physical abilities, social skills, cognitive skills, earlier experience with illness, and experience of the healthcare system) [7, 30]. One study investigated the impact of HL levels on healthcare utilization in a Danish context in relation to various chronic diseases. It revealed that patients with cardiovascular disease, chronic obstructive pulmonary disease, diabetes, and mental disorders reported lower levels of HL in terms of having more difficulties than the general population in understanding health information and engaging with healthcare professionals [26]. For PLWHIV with access to ART, HIV has become a chronic condition requiring a lifetime dedication to cope with their disease. As such, patients living with HIV have ongoing interactions with the healthcare system and professionals throughout the course of their life. Longer experience of navigating the healthcare system may result in the development of better HL skills. This is a potential reason why our findings indicate that a high proportion of PLWHIV do not find navigating the healthcare system particularly complex, whatever their gender, age, and level of education. This is supported by Dawson-Rose et al. [31], who found that HL is strongly influenced by the relationships PLWHIV develop with their healthcare providers. HL is a complex phenomenon involving access to and use of health information to inform and empower health decisions and behaviors. HL consists of several competencies which are not merely functional competencies and include interactive and critical skills. HL is dynamic, responding to various contextual, individual, and situational factors [7]. The view of HL as a process that is actively influenced by the relationships individuals develop with their healthcare professionals, and by changes during their lives, is supported by Brinkley-Rubenstein et al. [32]. They maintain that HL should be conceptualized and operationalized as a process rather than a static situation where knowledge is given from healthcare professional to the patient. They argue that important relational factors necessary for the development of HL include trust, acknowledging the patient’s multiple social identities, and understanding the range of needs that the patient might have. Individuals’ requirements for health competencies depend on the complexity of their condition and the healthcare they are offered. Their individual and social resources may change during the course of their life. Therefore, participants’ HLQ responses may have been influenced by the complexity of their health needs and the contextual challenges of their disease. This highlights the need for ongoing research, including the development of modified tools to measure HL that are relevant to cope with HIV-related conditions. To improve the quality of future studies, Fernandez-Guiterrez et al. [33] suggest using an HL framework that includes both the functional, interactive, and critical dimensions. Studies have reported that levels of HL influence on knowledge of HIV [34, 35] and are determinants of adherence to HIV treatment [36, 37], and that low levels of HL are associated negatively on patients’ understanding of health information [35]. Our study found high levels of HL and adherence to ART. Other studies report inconsistent findings on the association between HL and medication adherence among people living with HIV [5, 35, 36, 38], which might be due to the many definitions of HL and therefore the diverse scales used to measure it. Based on an understanding of HL as a complex phenomenon which goes beyond the functional [36] and a meta-analysis of the literature, D’Eath et al. [39] observed that the HL intervention literature has remained focused on functional literacy. Due to a lack of agreement on both the definition and measurement of HL, it has contributed to a lack of consensus on the HL, which leads to difficulties in comparing results across studies. In this study, we measured average HLQ scores for the subscales HLQ4, HLQ6, and HLQ9. Overall scores were high for all participants. However, HLQ 9 (understanding written information) scores were lower than those of the Danish background population [20]. Among the 481 participants in the study by Maindal et al. [20], the mean value for HLQ9 was 3.99 compared to 2.9 in our study. This might be explained by the differences in the two cohorts’ national origins: in the 2016 study, 92.9% were Danish; in our study, 72% were Danish and 28% from other countries. In our study, the participants experienced high levels of involvement in their consultation, e.g., they had talked about their issues and concerns, about their experiences with their disease, and how best to manage their condition. Having an ongoing and trusting patient-provider relationship is one of the most important contributors to the health of PLWHIV [31]. Building the necessary trust is an iterative and mutual process that occurs over time [31]. Further involvement in decision-making might also positively affect medication adherence behaviors and survival [40].

Our study had some limitations. Firstly, it was a cross-sectional study and could not preclude any causal conclusion. Secondly, the survey had a modest response rate of 55%, and the absence of information about non-responders affects our knowledge about potential challenges for this population, e.g., patients’ low literacy or issues around engaging with care might lead to selection bias. We know from findings in other Danish studies in patients with epilepsy and rheumatoid arthritis that non-responders and patients without access to a digital postbox had a lower sociodemographic status [41, 42]. Considering that, non-responders in our study might have lower HL, so our results potentially represent an overestimate of HL levels. The ability and motivation to complete a health survey represent an HL competency in themselves; thus, the most vulnerable groups may not have participated in the study. Thirdly, the questionnaire was only available in Danish, limiting participation in the study to patients literate in the language. An equitable and inclusive approach are of major importance in health survey research [43]. To increase an inclusive approach in our study, we should have considered different modes of questionnaire administration and language versions Finally, the study was only conducted in one hospital department. However, to the best of our knowledge, this is the first study addressing HL levels among PLWHIV in a Danish context. A strength of the study is that it was based on three of the nine dimensions of the HLQ and used a validated and culturally adapted questionnaire. The three subscales were selected because they cover two distinct and central dimensions of HL, providing valuable insights into the HL challenges facing individuals with chronic disease. However, the selection of only three scales might result in underrepresentation of the complexities involved in HL.