Delirium in Parkinson’s disease patients. A five-year follow-up study Marcos Serrano-Duen ˜as a,b, * , Marı ´a J. Bleda c,d a Abnormal Movement Disorders Unit, Neurological Service, Hospital Carlos Andrade Marı ´n b Facultad de Medicina, Pontificia Universidad Cato ´lica del Ecuador, P.O. Box: 17-03-1694, Quito - Ecuador c National Center of Epidemiology, Carlos III Research Institute, Madrid - Spain d Department of Statistics, Universidad Carlos III de Madrid Received 23 July 2004; revised 10 May 2005; accepted 11 May 2005 Abstract Objective: To assess the significance of delirium in parkinsonian patients in a 5-year follow-up case-control study with three groups of patients: Parkinsonian and Delirium (PDG), Parkinsonian (PG) and Control (CG). Methods: Comparisons of Short Test of Mental Status (STMS) and Unified Parkinson’s Disease Rating Scale-motor section (UPDRS(m)) between groups were performed using analysis of variance with repeated measurements. Comparisons of survival functions and Cox regression models were used to analyse the time until death. Results: STMS and UPDRS(m) mean scores were statistically different between PDG group and the other two groups (p!0.001) and between PDG and PG groups (p!0.001), respectively. Including all groups, PG’s patients (HRZ0.29; 95% C.I.Z0.09–0.93) and CG’s patients (HRZ0.13; 95% C.I.Z0.03–0.60) had less hazard to die than PDG’s patients; patients with a STMS basal score O33 (HRZ0.37; 95% C.I.Z0.13–0.99) had less hazard to die than patients with a score %33. Finally, including PDG and PG groups, patients with basal UPDRS(m) score O17 (HRZ4.88; 95% C.I.Z1.11–21.48) had higher hazard to die than patients with a score %17. Conclusion: For patients with Parkinson’s, delirium is an increased risk factor for developing dementia, to have a more severe motor impairment and to death. q 2005 Elsevier Ltd. All rights reserved. Keywords: Parkinson’s disease; Delirium; Survival analysis; Repeated measurements 1. Introduction Delirium is an acute organic brain syndrome presenting with whole cognitive impairment, attention disorders, reduced level of consciousness, increased or decreased psychomotor activity, and wake-sleep rhythm disorders [1– 5]. The prevalence of delirium is variable due to the difference in population studied and distinct diagnostic criteria used [5], but there is consensus that this increases with aging [6], with rates as high as 60% reported in hospitalised elderly patients [7]. On the other hand, Parkinson’s Disease (PD) mostly affects older people [8], and risk for postoperative delirium varying between 2.8 and 8.1 among patients with PD against controls [9], and occurrence of delirium in 5–25% of Parkinson patients treated with levodopa have been reported [10]. The mesocortical dopaminergic system has been involved in the physiopathology of delirium. This proposal has been supported by the fact that neuroleptics are useful in treating delirium [5], and additionally because dopamin- ergic medications are known to be likely to cause delirium [10], which determines the great complexity in handling delirium in parkinsonian patients, in which neuroleptics aggravate the disease [11]. While delirium has traditionally been considered as temporary and reversible [12], recent evidence has associated it with increased morbidity, mortality and as a risk factor for developing dementia, i.e., it can lead to catastrophic consequences [2,3,6]. This 5-year prospective comparison observational study was conducted to identify behavior in patients with PD developing delirium against a group of patients with PD and a control group. 2. Patients, materials, and methods A consecutive series of 21 patients with PD (recorded on the Abnormal Movements Clinic, Neurology Service, Parkinsonism and Related Disorders 11 (2005) 387–392 www.elsevier.com/locate/parkreldis 1353-8020/$ - see front matter q 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.parkreldis.2005.05.002 * Corresponding author. E-mail address: serranom@pi.pro.ec (M. Serrano-Duen ˜as).