Background: Delirium, an acute decline in attention and cognition, is found to be a common life-threatening clinical syndrome among hospitalized older patients. However, there has been no study to date regarding prevalence and incidence of delirium in Thai older patients.
Objective: The authors aimed to determine prevalence and incidence of delirium in older patients admitted to general medical wards in a university hospital in Thailand.
Material and Method: A prospective observational study was conducted in Siriraj Hospital. All patients aged 70 years or older admitted to general medical wards during study period were included. Delirium assessments were undertaken initially within the first 24 hours of admission and serially every 48 hours until patients developed delirium or were discharged. Delirium was diagnosed by experienced geriatricians based on the DSM-IV criteria. Prevalence was based on delirium identified at the first assessment, whereas incidence was defined based on cases developed during hospitalization.
Results: Two hundred and twenty five patients were enrolled. The prevalence of delirium was 40.4%, while the incidence of delirium was 8.4%. Therefore, the total occurrence rate of delirium was remarkably high (48.9%). Occurrence rate of delirium significantly increased with age (p = 0.003) and illness severity (p < 0.001). Number of impaired activities of daily living was also associated with occurrence rate of delirium in older patients.
Conclusion: In conclusion, the prevalence of delirium among older patients admitted to general medical wards in the present study were alarmingly high. Meanwhile, the incidence of delirium was comparable to other studies. Obviously, it requires serious attention from physicians, nurses and hospital administrators. These findings may reflect the importance of delirium detection for proper management. To lower morbidity and mortality in older patients, effective preventive strategies of delirium should be implemented promptly during hospital admission.

Keywords: Delirium, Older patients, Hospitalized, Prevalence, Incidence