[Delirium and subsyndromal delirium: prevalence of a disease spectrum]

Introduction: Subsyndromal delirium (SSD) is a developing concept of disease with a spectrum beyond the diagnostic dichotomy of delirium with standard criteria.

Material and methods: To study the prevalence and significance of SSD we have conducted a cross-sectional prospective multicenter study of all patients admitted to three Geriatric Departments in tertiary hospitals. The SSD diagnostic criteria used were based on Marcantoniós criteria, and the DRS-R-98 scale was also used as a continuous variable of the degree of delirium.

Results: We studied 85 patients, 56% women, Barthel 62 (SD: 32), age 87 (SD: 6), CIRS-G 24 (SD: 6.85). Three quarters (75.3%) of patients had at least one CAM positive item, and half of them with at least 13 points in the DRS-R-98 scale. The prevalence of delirium was 53% and 22.3% for SSD. The degree of delirium-DSS was associated with different geriatric syndromes, levels of malnutrition, and degree of functional and cognitive impairment, with a significant linear trend between groups. Patients without delirium have higher levels than those with subsyndromal delirium, and these in turn are higher than those without diagnosed delirium. There is also a tendency in the degree of delirium measured by the DRS-R-98.

Conclusion: Beyond the dichotomous concept of the presence or absence of delirium, this study suggests the probable continuity of cognitive processes and the possibility of more effective and earlier diagnostic and therapeutic measures.