Associations between bullous pemphigoid and comorbidities: A Swedish nationwide cohort study of 5,738 patients

AI Summary

BP strongly associated with increased overall comorbidity risk (HR 2.20) and elevated pre-diagnosis comorbidity (POR 2.72).
BP associated with neurodegenerative, psychiatric, autoimmune and metabolic disorders, including dementia, Parkinson's, schizophrenia, diabetes, psoriasis, systemic sclerosis.
Comorbidity hazard highest in first year after BP diagnosis (HR 2.88) and remains elevated beyond one year (HR 1.57).

AI Summary

BACKGROUND: Bullous pemphigoid (BP) has been linked to neurological and psychiatric disorders, but no nationwide population-based study has comprehensively examined the association of various comorbidities in BP patients in Sweden.

Pre-diagnosis association included dementia, Parkinson's disease, epilepsy, amyotrophic lateral sclerosis, multiple sclerosis, schizophrenia, unipolar/bipolar disorders, suicide, diabetes, stroke, systemic lupus erythematosus, systemic sclerosis, psoriasis, lichen planus, alopecia areata, and vitiligo.

Post-diagnosis associations remained elevated for dementia, Parkinson's disease, epilepsy, schizophrenia, unipolar/bipolar, diabetes, psoriasis, lichen planus and autoimmune diseases such as systemic sclerosis and Sjögren's syndrome.

Basic summary

J Multimorb Comorb. 2026 May 23;16:26335565261455676. doi: 10.1177/26335565261455676. eCollection 2026 Jan-Dec.

ABSTRACT

OBJECTIVES: To investigate the associations between BP and various comorbidities, comparing these conditions before and after BP diagnosis with a matched control group.

METHODS: A nationwide cohort study was conducted in Sweden from 2005 to 2016, including 5,738 BP cases and 17,167 age, sex and county of residence matched controls. Multivariable Cox proportional hazard regression models were used to calculate hazard ratios (HR). Univariable logistic regression assessed pre-diagnosis comorbidities, generating prevalence odds ratios (POR) with 95% confidence intervals (CI).

RESULTS: BP was associated with a significantly higher overall HR for comorbidity (HR: 2.20, 95% CI: 2.08-2.33). Before BP diagnosis, the overall comorbidity was significantly increased POR 2.72 (95% CI: 2.56-2.90). Pre-diagnosis association included dementia, Parkinson’s disease, epilepsy, amyotrophic lateral sclerosis, multiple sclerosis, schizophrenia, unipolar/bipolar disorders, suicide, diabetes, stroke, systemic lupus erythematosus, systemic sclerosis, psoriasis, lichen planus, alopecia areata, and vitiligo. After diagnosis, the overall hazard ratio (HR) for comorbidities was highest within the first year (HR 2.88, 95% CI: 2.68-3.10) and remained elevated beyond one year (HR 1.57, 95% CI: 1.44-1.71). Post-diagnosis associations remained elevated for dementia, Parkinson’s disease, epilepsy, schizophrenia, unipolar/bipolar, diabetes, psoriasis, lichen planus and autoimmune diseases such as systemic sclerosis and Sjögren’s syndrome.

CONCLUSION: BP is strongly associated with neurodegenerative, psychiatric, autoimmune, and metabolic comorbidities before and after diagnosis, highlighting their clinical significance as predisposing and prognostic factors in BP patients.

PMID:42186604 | PMC:PMC13198647 | DOI:10.1177/26335565261455676

Document this CPD