Exploring the Association Between Health Literacy and Depression Prevalence Through Personal Health Record Associated With Health Insurance Claims Data

OBJECTIVES: Productivity loss due to depression, including absenteeism and presenteeism, was estimated at approximately 0.92 trillion yen in Japan in 2005. With depression becoming more common in Japan, it's likely that these losses have grown even larger. Concurrently, there is growing recognition of the importance of health literacy (HL) in effectively managing and improving health outcomes by enabling individuals to make informed health decisions. In this context, this study aims to determine the relationship between health literacy and prevalence of depression. The analysis results are expected to help reduce the risk of depression and associated productivity loss.

METHODS: This study utilized a confidential health insurance claims database provided by DeSC Healthcare. Individuals diagnosed with depression in 2022 were identified through at least one confirmed diagnosis of ICD-10 codes "F32" or "F33". Health literacy was measured through the primary component analysis of responses to the Communicative and Critical Health Literacy Scale, developed by Ishikawa et al. Participants were categorized into three health literacy levels: low (33.3%), medium (42.9%), and high (23.8%). The prevalence of depression across these health literacy levels was calculated and compared after demographic adjustment.

RESULTS: The sample consisted of 27,909 insureds with heath literacy data, with an average age of 49.8 years, of whom 66.3% were male. The overall prevalence of depression was identified at 4.4%. After demographic adjustments, the prevalence rates of depression were found to be 5.0% (95%CI [4.1%, 4.6%]) for the low HL group, 4.2% (95%CI [3.8%, 4.5%]) for the medium HL group, and 3.9% (95%CI [3.5%, 4.4%]) for the high HL group, respectively.

CONCLUSIONS: The findings indicate that individuals with higher health literacy levels are less likely to experience depression. Enhancing health literacy may be an effective strategy to reduce depression prevalence and its productivity loss.