Study Highlights Comorbidities Before, After Bullous Pemphigoid Diagnosis

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Individuals with bullous pemphigoid prior to diagnosis have greater odds of psoriasis, pressure ulcers, intracerebral hemorrhage, acute renal failure, scabies, drug eruption, and neuropsychiatric disorders, according to recent findings.¹

In this same analysis, investigators found that patients had greater odds of pneumonia, chronic renal disease, sepsis, and cardiac arrest after diagnosis. These data on patients with bullous pemphigoid were authored by a team led by Bo Ri Kim, from the department of dermatology at Seoul National University Bundang Hospital.

Kim and colleagues noted that prior research, including epidemiological studies, had pointed to associations between bullous pemphigoid and other types of comorbid conditions.¹

“Recognition of these associations before and after [bullous pemphigoid] diagnosis can provide insights into comorbidities that may trigger [bullous pemphigoid] development and those that affect patient outcomes,” Kim et al. wrote. “The aim of the study was to comprehensively identify BP-associated comorbidities and their patterns of associations before and after [bullous pemphigoid] diagnosis.”¹

Background and Design

Approximately 97% of Korean citizens are covered by a universal, single-payer national healthcare system. This system documents a comprehensive set of healthcare information, including data related to medications, treatments, procedures, and diagnoses for around 50 million people.

The investigators employed a matched case–control design and accessed population-based data drawn from the Korean Health Insurance Review and Assessment Service (HIRA), spanning October 2010 - December 2021. Consistent longitudinal data was provided through a standardized patient identifier system across hospitals in the HIRA database.

In 2006, the Korean National Health Insurance Service (NHI) had launched a rare intractable diseases (RID) registration program that included bullous pemphigoid as 1 of the conditions. The team’s diagnostic process adheres to RID criteria established by the NHI and the team’s research underwent institutional review prior to their submission to the NHI, ensuring the data's reliability and validity.

Overall, the investigators sought to identify and evaluate the comorbidities that were linked to bullous pemphigoid, in addition to assessing their patterns. It included 5,066 subjects with cases of bullous pemphigoid and 10,132 matched controls in the time period between 2011 - 2021. Their comprehensive assessment was conducted on 546 diagnostic codes with the aim of looking into related comorbidities 5 years before and after participants’ diagnoses.

Notable Findings

The investigative team noted that 89.4% of those with bullous pemphigoid were over the age of 60, adding that 54.2% were reported to be female. Prior to subjects’ diagnoses, they were more likely to have conditions such as psoriasis, intracerebral hemorrhage, pressure ulcers, neuropsychiatric disorders, scabies, drug reactions, and acute renal failure. After their diagnoses, the patients had increased likelihood of sepsis, pneumonia, chronic kidney disease, and cardiac arrest.

The research team also highlighted notable relationships between neuropsychiatric disorders prior to diagnoses, including dementia, Alzheimer’s disease, hemiplegia, cerebral infarction, and the sequelae of cerebrovascular disease. Additionally, the investigators reported that there had been a strong bidirectional link between Alzheimer’s dementia and pneumonia after diagnoses had been made.

“Further research on the direct and indirect etiologic associations between these comorbidities and [bullous pemphigoid] will help elucidate the pathomechanisms and improve [bullous pemphigoid] treatment,” they wrote.¹

References

1. ^{Kim BR, Lee KH, Paik K, Kim M, Bae JM, Choi CW, et al. Comorbid diseases in bullous pemphigoid: A population-based case–control study. J Dermatol. 2024; 00: 1–12. https://doi.org/10.1111/1346-8138.17577.}
2. ^{Martin E, Mauer I, Malzahn U, Heuschmann PU, Goebeler M, Benoit S. Comorbid diseases among bullous pemphigoid patients in Germany: new insights from a case-control study. J Dtsch Dermatol Ges. 2022; 20: 798–805.}