Deep vein thrombosis among patients with mild cognitive decline

The prevalence of deep vein thrombosis (DVT) is high in patients with severe major neurocognitive disorders and motor deficits. However, it is unknown whether patients with mild cognitive decline without major motor deficits have an increased risk for DVT. Recently, Nakanishi et al. proposed the Himi score to evaluate DVT risk in frail elderly individuals. The score accounts for the independence level in daily life among patients with dementia, graded as I/II, III, IV and M, as an assessment item. In the present study, we investigated DVT prevalence among patients with mild cognitive decline. Participants were recruited from the patients who visited our outpatient clinic between August 2022 and February 2023. To be eligible for enrollment, patients were required to be diagnosed with mild cognitive impairment or early-stage major neurocognitive disorder and able to walk independently. Individuals were excluded if they had an active malignancy, had a bed rest time of more than 24 h owing to an external injury within 3 months before the study, received general anesthesia, or had undergone central venous access catheter insertion within 3 months before the study. Overall, written informed consent was obtained from 22 patients. Clinical data, including the Mini-Mental State Examination and Alzheimer’s Disease Assessment Scale-Cognitive scores, were collected. Physical examinations were performed to evaluate the following symptoms in the lower extremities: pain, edema, erythema, varicose veins, and Homan’s sign. We calculated the Wells score and Padua Prediction score, which are well-established for evaluating DVT risk. We also calculated the Himi score. Whole-leg vein ultrasonography was performed to detect DVT in 12 patients with leg symptoms or elevated blood d-dimer levels. DVT was detected in two of the 22 participants (9%). Although the DVT prevalence in the general population is unknown, our pilot study results may reflect increased prevalence of DVT in patients with mild cognitive decline without major motor impairment. Neither patient with DVT had a major risk for DVT according to the Wells and Padua Prediction scores. In contrast, two patients had high Himi scores, suggesting that low activities of daily living owing to cognitive decline are associated with DVT. Our data suggest that the Himi score is useful for detecting potential DVT risks in elderly individuals without apparent motor deficits or other major risk factors.