Introduction
Atopic dermatitis (AD) is the most common inflammatory skin disease with an increasing prevalence worldwide and a heavy burden on patients' quality of life and healthcare resources. In addition to recurrent eczema, AD is associated with a variety of comorbidities such as metabolic, cardiovascular, and psychiatric diseases. Recent studies have shown that patients with AD have lower bone mineral density (BMD) compared to the general population. This study investigated the risk of osteoporosis and fracture in AD patients, and whether systemic therapy affects this risk, to explore the fracture risk of AD patients after adjusting for bone mineral density and other factors.
Study design
This study retrospectively analyzed men aged 45 years and older and postmenopausal women aged 45 years and older who underwent bone density testing at a hospital in Taiwan from July 2010 to February 2023. Bone mineral density in participants' femoral neck, total hip, and lumbar vertebrae (L1–L4) was measured separately, and new fractures and fracture sites were determined based on medical records and radiological images (excluding cancer-related pathologic fractures). Participants were divided into AD group and control group according to whether they had AD or not.
Findings:
A total of 50 AD patients and 308 controls were followed up. The median age was 70 years in the AD group and 60 years in the control group. The AD group had higher rates of oral corticosteroid exposure, anti-osteoporotic therapy, fracture history, rheumatoid arthritis, diabetes, chronic kidney disease, cardiovascular disease, and chronic lung disease compared with the control group. After propensity score matching (PSM) was performed on participants, 50 participants in each of the AD and control groups were included in the analysis. The study found no difference in bone mineral density and FRAX fracture risk scores across all sites over 10 years between the two groups. A total of 13 fractures occurred in the two groups (Table 1), of which 69% were vertebral fractures.
Table 1 Baseline characteristics of AD patients and control groups
Note: *Propensity score matching was performed by adjusting for unbalanced covariates, including age, corticosteroid use, fracture history, chronic kidney disease, cardiovascular disease, and chronic lung disease. Compared with AD patients, the P<0.05. AD, atopic dermatitis, FRAX, fracture risk assessment tool, IQR, interquartile range, Na, missing value.
Table 2: Multivariate Cox regression analysis of new fractures in patients with atopic dermatitis and control groups
Note: *P<0.05;FRAX, fracture risk assessment tool.
This study also evaluated the effect of systemic therapy on fracture risk in AD patients. The results showed that patients had similar bone mineral density, FRAX risk scores, and fracture rates regardless of whether they were treated or not. In this study, the FRAX score was calculated based on bone mineral density and other clinically important factors, and after a median follow-up of 1.7 years, it was found that there was an increased risk of vertebral fracture in elderly AD patients. In older patients with AD, both insomnia and the use of sleeping pills may increase the risk of falls and thus fractures, and increasing age is one of the major risk factors for osteoporotic fractures. In this study, older AD patients were included and had a median FRAX risk of major fracture at baseline of 13%. The results suggest that older AD patients have fracture susceptibility and also have a higher risk of osteoporotic fractures.
Research Discussion
This study suggests that older AD patients have a higher short-term risk of new-onset vertebral fractures compared with controls. Patients with AD often have chronic inflammation, which may interfere with bone homeostasis, leading to decreased bone mass and an increased risk of osteoporosis. While some studies have found that AD is associated with lower bone mineral density scores in the total femur and lumbar spine, this study did not find that bone mineral density was lower in older AD patients at all sites when comparing AD patients with a control group selected by the PSM method. By analysing UK primary care databases, the investigators found that patients with AD were at higher risk of osteoporotic fractures and were not associated with the use of oral corticosteroids.
In patients with rheumatoid arthritis and psoriasis, biologic therapy has been shown to stabilize bone mineral density and reduce the occurrence of osteoporotic fractures in patients with rheumatoid arthritis to some extent. Although bone mineral density data are lacking in patients with AD, the use of disease-modifying antirheumatic drugs (DMARDs) has been shown to reduce the risk of new fractures in patients. The results of this study showed that AD patients who received systemic therapy had similar bone mineral density and fracture rates compared to those who received topical therapy alone. Of these AD patients who received systemic therapy, the only patients who developed a fracture were those who received oral corticosteroids but did not take DMARDs at the same time.
Although some progress has been made in this study, there are still some limitations. First, as this is a retrospective cohort study, there may be some omissions in the medical records that may leave some of the data incomplete. Second, there may be a selection bias because AD patients who are susceptible to osteoporosis and fractures are more likely to undergo bone density testing. Third, retrospective assessment of medication adherence and skin severity in AD patients is difficult. Fourth, only drugs that have been used for at least 3 months were included in this study, which may have led to some cases not being included in the study. Therefore, due to the above limitations, this study may not be able to fully detect the difference in the incidence of new fractures between AD patients and controls.
Taken together, this retrospective cohort study showed that patients with AD had similar bone mineral density compared with controls, but had a higher short-term risk of vertebral fractures, and the risk did not differ with or without systemic therapy. Older patients with AD who are susceptible to fractures should be considered to reduce the risk of new fractures.
bibliography
Hsiao, YY, Chen, YH, Chen, YW, et al. The Fracture Risk of Elderly Patients With Atopic Dermatitis. DERMATITIS. 2024; doi: 10.1089/derm.2023.0174
Yimaitong is a professional online doctor platform, and the mission of the platform is to "sense the pulse of the world's medicine and help China's clinical decision-making". Yimaitong has a series of products such as "Clinical Guidelines", "Medication Reference", "Medical Literature King", "Yizhiyuan", "eYantong" and "ePulse", which fully meet the needs of medical workers in clinical decision-making, obtaining new knowledge and improving scientific research efficiency.