Comorbidity profile in dementia with Lewy bodies versus Alzheimer’s disease: a linkage study between the Swedish Dementia Registry and the Swedish National Patient Registry

INTRODUCTION: Compared to Alzheimer’s disease (AD), dementia with Lewy bodies (DLB) is usually associated with a more complex clinical picture and higher burden of care. Yet, few investigations have been performed on comorbidities and risk factors of DLB. Therefore, we aimed to compare clinical risk factors and comorbidity profile in DLB and AD patients using two nationwide registries. METHODS: This is a linkage study between the Swedish dementia registry (SveDem) and the Swedish National Patient Registry conducted on 634 subjects with DLB and 9161 individuals with AD registered during the years 2007–2012. Comorbidity profile has been coded according to the International Classification of Diseases version 10 (ICD 10) in addition to the date of each event. The main chapters of the ICD-10, the Charlson score of comorbidities and a selected number of neuropsychiatric diseases were compared between the DLB and AD groups. Comorbidity was registered before and after the dementia diagnosis. RESULTS: “Mental and behavioral disorders”, “diseases of the nervous system”, “diseases of the eye and adnexa”, diseases of the “circulatory”, “respiratory”, and “genitourinary” systems, “diseases of the skin and subcutaneous tissue” and “diseases of the musculoskeletal system and connective tissue” occurred more frequently in the DLB group after multivariate adjustment. Depression [adjusted OR = 2.12 (95%CI 1.49 to 3.03)] and migraine [adjusted OR = 3.65 (95%CI 1.48 to 9.0)] were more commonly recorded before the diagnosis of dementia in the DLB group. Following dementia diagnosis, ischemic stroke [adjusted OR = 1.89 (95%CI 1.21 to 2.96)] was more likely to happen among the DLB patients compared to the AD population. CONCLUSIONS: Our study indicated a worse comorbidity profile in DLB patients with higher occurrence of depression, stroke and migraine compared with the AD group. Deeper knowledge about the underlying mechanisms of these associations is needed to explore possible reasons for the different pattern of comorbidity profile in DLB compared to AD and their prognostic significance.