Effect of best practice advisory on the administration of contraindicated medications to hospitalized patients with Parkinson's disease and related disorders.

Objective: To determine the effect of a Best Practice Advisory (BPA) on the ordering and administration of contraindicated dopamine blocking agents (DBA) to hospitalized patients with Parkinson's disease (PD) and related disorders. Background: Patients with PD are more likely to require hospitalization and are at increased risk of complications. Administration of contraindicated DBA contributes to worsened outcomes in this patient population. Electronic medical record (EMR) warnings (also referred to as BPA) have been proposed as a way to prevent the administration of contraindicated medications. Methods: A BPA was launched in January 2020 within the University of Rochester EMR system, which alerts the provider when a contraindicated DBA is ordered in hospitalized patients with PD and related disorders. Patients with PD and related disorders hospitalized at two hospitals affiliated to the University of Rochester during a time period before (t1: 1/1/2019-1/1/2020) and after (t2: 1/8/2020-1/8/2021) the implementation of the BPA were included in this study. Epic SliderDicer was used to collect the data from the University of Rochester EMR. The number of patients who had contraindicated DBA orders and administrations in both time periods, and the number of patients who had the BPA triggered during t2 were obtained. We compared the results before and after the implementation of the BPA. Results: 306 patients with PD and related disorders were hospitalized during t1 and 273 during t2. There was significantly less percentage of patients who had contraindicated DBA orders (41.5% in t1 vs. 17.6% in t2) and patients who had contraindicated DBA administrations (16% in t1 vs. 8.8% in t2) during t2 (p < 0.05 for both comparisons). There was no significant difference between the percentage of patients who had contraindicated DBA orders in t1 and patients with attempted orders (BPA triggered) in t2 (p = 0.27). Conclusion: The results of this study increase the evidence of the potential benefit of EMR warnings for the optimization of inpatient medication management in patients with PD and related disorders. In particular, our results suggest that EMR warnings help reduce the administration of contraindicated medications, which is a known contributing factor for hospital complications in this patient population.

Complications and outcomes of hospitalizations for patients with and without Parkinson disease.

Objective: To examine complications and outcomes of hospitalizations for common indications for hospitalization among patients with Parkinson disease (PD). Methods: We identified and selected the ten most common indications for hospitalization among individuals ≥65 years of age using principal diagnoses from the California State Inpatient Database, 2018-2020. Patients with comorbid PD were identified using secondary diagnosis codes and matched one-to-one to patients without PD based on principal diagnosis (exact matching), age, gender, race and ethnicity, and Elixhauser comorbidity index (coarsened exact matching). We identified potentially preventable complications based on the absence of present on admission indicators among secondary diagnoses. In the matched cohort, we compared inpatient complications, early Do-Not-Resuscitate (DNR) orders (placed within 24 h of admission), use of life-sustaining therapies, new nursing facility requirement on discharge, and death or hospice discharge for patients with and without PD. Results: We identified 35,457 patients with PD among the ten leading indications for hospitalization in older adults who were matched one-to-one to patients without PD (n = 70,914 in total). Comorbid PD was associated with an increased odds of developing aspiration pneumonia (OR 1.17 95% CI 1.02-1.35) and delirium (OR 1.11 95% CI 1.02-1.22) during admission. Patients with PD had greater odds of early DNR orders [placed within 24 h of admission] (OR 1.34 95% CI 1.29-1.39). While there was no difference in the odds of mechanical ventilation (OR 1.04 95% CI 0.98-1.11), patients with PD demonstrated greater odds of tracheostomy (OR 1.41 95% CI 1.12-1.77) and gastrostomy placement (OR 2.00 95% CI 1.82-2.20). PD was associated with greater odds of new nursing facility requirement upon discharge (OR 1.58 95% CI 1.53-1.64). Patients with PD were more likely to die as a result of their hospitalization (OR 1.11 95% CI 1.06-1.16). Conclusion: Patients with PD are at greater risk of developing aspiration pneumonia and delirium as a complication of their hospitalization. While patients with PD more often have early DNR orders, they have greater utilization of life-sustaining therapies and experience worse outcomes of their hospitalization including new nursing facility requirement upon discharge and greater mortality.

Change in the Parkinson Anxiety Scale correlates with change in other clinical measures of anxiety over time.

The Parkinson's disease (PD)-specific Parkinson Anxiety Scale (PAS) is an anxiety rating scale that has been validated in cross-sectional studies. In a study of buspirone for anxiety in PD, it appears that the PAS may be sensitive to change in anxiety demonstrating moderate-to-high correlation with participant-reported and clinician-administered scales.

A trial of buspirone for anxiety in Parkinson's disease: Safety and tolerability.

INTRODUCTION: In Parkinson's disease (PD), anxiety is common, associated with lower health-related quality of life, and undertreated. The primary objective of this study was to determine the tolerability of buspirone for the treatment of anxiety in PD. METHODS: Individuals with PD and clinically significant anxiety were randomized 4:1 to flexible dosage buspirone or placebo for 12 weeks. Treatment was initiated at 7.5 mg twice daily and titrated based on response and tolerability to an optimal dosage (maximum 30 mg twice daily). The primary outcome was the proportion of participants who failed to complete the study on study drug. Secondary outcomes included adverse events, dosage reductions, motor function, dyskinesias, and anxiety. RESULTS: A total of 21 participants enrolled, 4 were randomized to placebo and 17 to buspirone (mean (SD) age 65.5 (9.8), 76.5% male, 88% on concomitant antidepressant or anxiolytic). In the buspirone group, 7 (41%) failed to complete the study on drug, 5 due to intolerability. The median buspirone dosage was 7.5 mg twice daily. No serious adverse events occurred. A total of 9 (53%) buspirone participants experienced adverse events consistent with worsened motor function. In the buspirone group, mean (SD) improvement from baseline to week 12 in Hamilton Anxiety Rating Scale was -3.9 (3.8) and Parkinson Anxiety Scale -7.1 (6.4). CONCLUSION: Tolerability concerns do not support moving immediately forward with a large-scale efficacy trial. However, concomitant anxiolytics may have affected tolerability and a signal of efficacy was seen suggesting that future studies of buspirone monotherapy be considered.

Erratum: Author Correction: Report from a multidisciplinary meeting on anxiety as a non-motor manifestation of Parkinson's disease.

[This corrects the article DOI: 10.1038/s41531-019-0102-8.].

Report from a multidisciplinary meeting on anxiety as a non-motor manifestation of Parkinson's disease.

Anxiety is a severe problem for at least one-third of people living with Parkinson's disease (PD). Anxiety appears to have a greater adverse impact on quality of life than motor impairment. Despite its high prevalence and impact on daily life, anxiety is often undiagnosed and untreated. To better address anxiety in PD, future research must improve knowledge about the mechanism of anxiety in PD and address the lack of empirical evidence from clinical trials. In response to these challenges, the Parkinson's Foundation sponsored an expert meeting on anxiety on June 13th and 14th 2018. This paper summarizes the findings from that meeting informed by a review of the existing literature and discussions among patients, caregivers, and an international, clinician-scientist, expert panel working group. The goal is to provide recommendations to improve our understanding and treatment of anxiety in PD.

Parkinson's disease psychosis: presentation, diagnosis and management.

Parkinson's disease is a neurodegenerative disorder characterized by motor and nonmotor symptoms. Psychosis is a common feature of Parkinson's disease. Parkinson's disease psychosis (PDP) encompasses minor phenomena (illusions, passage hallucinations and presence hallucinations), visual and nonvisual hallucinations and delusions. PDP is associated with reduced function and quality of life. The initial management approach should focus on identification and treatment of any contributory medical factors, reduction or discontinuation of medications with potential to induce or worsen psychosis, nonpharmacological strategies and consideration of acetylcholinesterase inhibitor treatment in the setting of dementia. Pimavanserin, quetiapine and clozapine may all be considered for use in PDP. In this review, we discuss the presentation, diagnosis and management of PDP.

Long-term follow-up of a randomized AAV2-GAD gene therapy trial for Parkinson's disease.

BACKGROUND. We report the 12-month clinical and imaging data on the effects of bilateral delivery of the glutamic acid decarboxylase gene into the subthalamic nuclei (STN) of advanced Parkinson's disease (PD) patients. METHODS. 45 PD patients were enrolled in a 6-month double-blind randomized trial of bilateral AAV2-GAD delivery into the STN compared with sham surgery and were followed for 12 months in open-label fashion. Subjects were assessed with clinical outcome measures and 18F-fluorodeoxyglucose (FDG) PET imaging. RESULTS. Improvements under the blind in Unified Parkinson's Disease Rating Scale (UPDRS) motor scores in the AAV2-GAD group compared with the sham group continued at 12 months [time effect: F(4,138) = 11.55, P < 0.001; group effect: F(1,35) = 5.45, P < 0.03; repeated-measures ANOVA (RMANOVA)]. Daily duration of levodopa-induced dyskinesias significantly declined at 12 months in the AAV2-GAD group (P = 0.03; post-hoc Bonferroni test), while the sham group was unchanged. Analysis of all FDG PET images over 12 months revealed significant metabolic declines (P < 0.001; statistical parametric mapping RMANOVA) in the thalamus, striatum, and prefrontal, anterior cingulate, and orbitofrontal cortices in the AAV2-GAD group compared with the sham group. Across all time points, changes in regional metabolism differed for the two groups in all areas, with significant declines only in the AAV2-GAD group (P < 0.005; post-hoc Bonferroni tests). Furthermore, baseline metabolism in the prefrontal cortex (PFC) correlated with changes in motor UPDRS scores; the higher the baseline PFC metabolism, the better the clinical outcome. CONCLUSION. These findings show that clinical benefits after gene therapy with STN AAV2-GAD in PD patients persist at 12 months. TRIAL REGISTRATION. ClinicalTrials.gov NCT00643890. FUNDING. Neurologix Inc.

Modeling anxiety in Parkinson's disease.

BACKGROUND: The aim of this work was to construct a model for anxiety in PD and compare the relative contributions of PD-specific and -nonspecific general population risk factors for anxiety in this model. METHODS: Structural equation modeling of associations of risk factors with the anxiety outcome using a cross-sectional data set of 342 patients with PD were used. RESULTS: A model with acceptable to good fit was generated that explained 65% of the variance in anxiety scores. A previous history of depression and the severity of the depressive symptoms scored on the Hamilton Depression Rating Scale were the only nonspecific variables with a direct effect on anxiety. The presence of motor fluctuations and disease-related decline in activities of daily living were PD-specific markers of anxiety. Nonspecific risk factors had a greater influence in the model than PD-specific risk factors. Standardized regression coefficients suggested that the Hamilton Depression Rating Scale score was the most important contributor to the variation in anxiety. A post-hoc analysis showed that the effects of the following variables on anxiety levels were fully mediated by depression: sex; family history of depression; previous history of anxiety; cognitive status; difficulties in non-disease-specific activities of daily living; and severity of motor signs. CONCLUSION: In this cross-sectional study, we showed that nonspecific general population risk factors are more important markers for anxiety than PD-specific risk factors. Depression was the most prominent marker. PD-specific markers for anxiety appear to be more situational and related to off periods and disease-specific disturbances of activities of daily living.

Feasibility of Virtual Research Visits in Fox Trial Finder.

BACKGROUND: Fox Trial Finder is an online registry for individuals with and without Parkinson disease (PD) interested in participating in PD research. However, distance or disability could prevent such individuals from participating in traditional, clinic-based research at major centers. OBJECTIVE: Use videoconferencing to connect participants to specialists to: (1) demonstrate feasibility of virtual research visits within this population (2) collect phenotypic data of the participants, (3) validate self-reported diagnosis, and (4) gauge interest in virtual research visits. METHODS: We solicited volunteers throughout the United States through Fox Trial Finder. Interested individuals with PD provided consent, were given web cameras if needed, completed baseline surveys, and downloaded videoconferencing software remotely. Participants had a test connection and assessment appointment which included the Montreal Cognitive Assessment (MoCA), then a virtual research visit with a neurologist who reviewed their history and assessed their PD using a modified Movement Disorders Society Unified Parkinson's Disease Rating Scale. Neurologists assessed PD diagnosis and symptomatology. Physicians and participants were surveyed about their experience. RESULTS: Of 204 individuals who consented, 166 (81% ) individuals from 39 states completed all visits. The mean age was 62 and mean disease duration was 8.0 years. Mean MoCA score was 26.5, and mean modified MDS-UPDRS motor score was 22.8 (out of a possible 124). Neurologists judged PD as the most likely diagnosis in 97% of cases. Overall satisfaction with the visits was 79% (satisfied or very satisfied) among neurologists and 93% among participants. CONCLUSIONS: Through virtual research visits, neurologists engaged, characterized, and validated self-reported diagnosis in individuals with PD over a broad geography. This model may facilitate future research participation.

Anxiety has specific syndromal profiles in Parkinson disease: a data-driven approach.

BACKGROUND: Anxiety symptoms are common in Parkinson disease (PD). Recent evidence suggests that anxiety syndromes as encountered in clinical practice may not correspond to the DSM-IV classification of anxiety disorders. OBJECTIVE: To examine the syndromal pattern of the anxiety spectrum in a large series of patients with PD, as determined with a data-driven approach using latent class analysis (LCA). METHODS: 342 patients with PD were recruited from referrals to movement disorders or psychiatry clinics at six tertiary centers. Participants were assessed with a structured psychiatric interview and specific scales rating the severity of anxiety, depression, cognition and parkinsonism. The main outcome measure was classes of patients with a specific syndromal profile of anxiety symptoms based on LCA. RESULTS: LCA identified four classes that were interpreted as "no anxiety or depression", "episodic anxiety without depression", "persistent anxiety with depression", and "both persistent and episodic anxiety with depression". Symptoms of persistent anxiety were almost invariably associated with symptoms of depression. There were significant differences between classes in terms of history of depression and anxiety, use of psychoactive medication, and on the Mentation and Complications sections of the Unified Parkinson Disease Rating Scale. CONCLUSIONS: Patients with PD show different syndromic profiles of anxiety that do not align with the symptom profiles represented by DSM-IV anxiety disorders and major depression. Accordingly, DSM-IV criteria for anxiety disorders may not be clinically useful in PD. The different classes identified here provide empirically validated phenotypes for future research.

Modeling depression in Parkinson disease: disease-specific and nonspecific risk factors.

OBJECTIVE: To construct a model for depression in Parkinson disease (PD) and to study the relative contribution of PD-specific and nonspecific risk factors to this model. METHODS: Structural equation modeling of direct and indirect associations of risk factors with the latent depression outcome using a cross-sectional dataset of 342 patients with PD. RESULTS: A model with acceptable fit was generated that explained 41% of the variance in depression. In the final model, 3 PD-specific variables (increased disease duration, more severe motor symptoms, the use of levodopa) and 6 nonspecific variables (female sex, history of anxiety and/or depression, family history of depression, worse functioning on activities of daily living, and worse cognitive status) were maintained and significantly associated with depression. Nonspecific risk factors had a 3-times-higher influence in the model than PD-specific risk factors. CONCLUSION: In this cross-sectional study, we showed that nonspecific factors may be more prominent markers of depression than PD-specific factors. Accordingly, research on depression in PD should focus not only on factors associated with or specific for PD, but should also examine a wider scope of factors including general risk factors for depression, not specific for PD.

Rasch analysis of anxiety scales in Parkinson's disease.

OBJECTIVE: Anxiety is a common non-motor symptom in Parkinson's disease (PD). This study analyzed the measurement properties of three frequently used anxiety scales in PD: the Beck Anxiety Inventory (BAI), the Hamilton Anxiety Rating Scale (HARS), and the Hospital Anxiety and Depression Scale-Anxiety subscale (HADS-A). METHOD: The Rasch model was applied to a multicenter international cohort of 342 patients and assessed the following aspects: fit to the Rasch model, unidimensionality, reliability, response category ordering, item local independence, differential item functioning, and scale targeting. RESULTS: In their original form, the BAI, HARS, and HADS-A, did not fit the Rasch model. A good fit to the Rasch model was only found after significant modifications, including rescoring some items and deleting those failing to fit the model. For the BAI and HADS-A, these adjustments resulted in unidimensionality. The HARS was not unidimensional and separate analyses were performed for its psychic and somatic subscales. Whereas the somatic anxiety subscale fit the Rasch model, this was achieved for the psychic anxiety subscale after modifications. CONCLUSION: None of the currently used anxiety scales display satisfactory measurement properties for assessing anxiety in PD. The results suggest the need to develop a new disease-specific scale for measuring anxiety in PD.

Anxiety rating scales in Parkinson's disease: a validation study of the Hamilton anxiety rating scale, the Beck anxiety inventory, and the hospital anxiety and depression scale.

BACKGROUND: Anxiety is a prevalent and disabling condition in Parkinson's disease (PD). The lack of anxiety rating scales validated for this population hampers research into anxiety in PD. The aim of this study is to assess the clinimetric properties of the Hamilton anxiety rating scale (HARS), the Beck anxiety inventory (BAI), and the hospital anxiety and depression scale (HADS) in PD patients. DESIGN: Three hundred forty-two PD patients underwent a standardized assessment including a structured interview for diagnostic and statistical manual diagnoses of anxiety disorders and completion of the HARS, BAI, and HADS. Inter-rater reliability of the HARS was assessed in 60 patients; test-retest reliability of the BAI and HADS in 213 and 217 patients, respectively. RESULTS: Thirty-four percent of patients suffered from an anxiety disorder, whereas an additional 11.4% had clinically significant anxiety symptoms in the absence of a diagnosis of anxiety disorder. Acceptability, score distribution, and known groups validity over different levels of anxiety were adequate. Inter-rater reliability for the HARS and test-retest reliability for the BAI and HADS were good. The HARS, but not the BAI and HADS, had a satisfactory inter-item correlation, convergent validity and factorial structure. For all scales, the positive predictive value was poor, and the negative predictive value was moderate. CONCLUSIONS: Given the adequate known groups validity of all three rating scales, each of these scales is likely to be useful in clinical practice or research for evaluation of symptom severity. Limitations in the construct validity of the anxiety scales in this study raise questions regarding suitability for their use in PD.

AAV2-GAD gene therapy for advanced Parkinson's disease: a double-blind, sham-surgery controlled, randomised trial.

BACKGROUND: Gene transfer of glutamic acid decarboxylase (GAD) and other methods that modulate production of GABA in the subthalamic nucleus improve basal ganglia function in parkinsonism in animal models. We aimed to assess the effect of bilateral delivery of AAV2-GAD in the subthalamic nucleus compared with sham surgery in patients with advanced Parkinson's disease. METHODS: Patients aged 30-75 years who had progressive levodopa-responsive Parkinson's disease and an overnight off-medication unified Parkinson's disease rating scale (UPDRS) motor score of 25 or more were enrolled into this double-blind, phase 2, randomised controlled trial, which took place at seven centres in the USA between Nov 17, 2008, and May 11, 2010. Infusion failure or catheter tip location beyond a predefined target zone led to exclusion of patients before unmasking for the efficacy analysis. The primary outcome measure was the 6-month change from baseline in double-blind assessment of off-medication UPDRS motor scores. This trial is registered with ClinicalTrials.gov, NCT00643890. FINDINGS: Of 66 patients assessed for eligibility, 23 were randomly assigned to sham surgery and 22 to AAV2-GAD infusions; of those, 21 and 16, respectively, were analysed. At the 6-month endpoint, UPDRS score for the AAV2-GAD group decreased by 8·1 points (SD 1·7, 23·1%; p<0·0001) and by 4·7 points in the sham group (1·5, 12·7%; p=0·003). The AAV2-GAD group showed a significantly greater improvement from baseline in UPDRS scores compared with the sham group over the 6-month course of the study (RMANOVA, p=0·04). One serious adverse event occurred within 6 months of surgery; this case of bowel obstruction occurred in the AAV2-GAD group, was not attributed to treatment or the surgical procedure, and fully resolved. Other adverse events were mild or moderate, likely related to surgery and resolved; the most common were headache (seven patients in the AAV2-GAD group vs two in the sham group) and nausea (six vs two). INTERPRETATION: The efficacy and safety of bilateral infusion of AAV2-GAD in the subthalamic nucleus supports its further development for Parkinson's disease and shows the promise for gene therapy for neurological disorders. FUNDING: Neurologix.

Symptomatology and markers of anxiety disorders in Parkinson's disease: a cross-sectional study.

Anxiety is understudied in Parkinson's disease (PD), which is not justified by the prevalence and impact of anxiety disorders on quality of life in PD patients. In this cross-sectional study, 342 patients suffering from idiopathic PD underwent a research-based assessment including DSM IV criteria for anxiety disorders, the Hamilton anxiety rating scale (HARS) and the beck anxiety inventory (BAI). Thirty-four percent (34%) of subjects met the DSM IV criteria for at least one anxiety disorder; 11.8% met criteria for multiple anxiety disorders; and 11.4% had clinically relevant anxiety symptoms without meeting the criteria for any specific anxiety disorder. Score profiles on the HARS and BAI differed significantly between the disorders, but these differences were associated with different scores on a limited number of items, and the respective symptom profiles were not readily interpretable. Female sex, the presence of motor fluctuations, as well as a previous history of an anxiety disorder were markers for anxiety disorders. The use of a mono-amino oxidase (MAO)-B inhibitor was associated with a reduced prevalence of anxiety disorders. Research into anxiety in PD is hampered by the questionable validity of DSM IV defined anxiety disorders in this population. A first focus for research should therefore be the identification of clinically useful anxiety presentations and their validation in PD.

Anxiety rating scales in Parkinson's disease: critique and recommendations.

Anxiety syndromes are common in patients with Parkinson's disease (PD) with up to 30% suffering from panic disorder, and up to 11% from generalized anxiety disorder (GAD). Anxiety is associated with increased subjective motor symptoms, more severe gait problems, dyskinesias, freezing, and on/off fluctuations. Anxiety has a negative impact on health related quality of life and is strongly associated with depressive syndromes. Since a variety of anxiety scales have been used in PD patients, the Movement Disorder Society commissioned a task force to assess the clinimetric properties of these scales in PD. A systematic review was conducted to identify anxiety scales that have either been validated or used in patients with PD. Six anxiety rating scales were identified. These were the Beck anxiety inventory, the hospital anxiety and depression scale, the Zung self-rating anxiety scale and anxiety status inventory, the Spielberger state trait anxiety inventory, and the Hamilton anxiety rating scale. In addition, Item 5 (anxiety) of the neuropsychiatric inventory was included in the review. No scales met the criteria to be "recommended," and all scales were classified as "suggested." Essential clinimetric information is missing for all scales. Because several scales exist and have been used in PD, the task force recommends further studies of these instruments. If these studies show that the clinimetric properties of existing scales are inadequate, development of a new scale to assess anxiety in PD should be considered.

Apathy and anhedonia rating scales in Parkinson's disease: critique and recommendations.

Apathy is a common condition in Parkinson's disease (PD) and is generally defined as a lack of motivation. It is associated with more severe cognitive dysfunction and a decrease in activities of daily living (ADL) performance. Anhedonia, the inability to experience pleasure, can be a symptom of both depressive and apathetic syndromes. The Movement Disorder Society (MDS) commissioned a task force to assess the clinimetric properties of apathy and anhedonia scales in PD patients. A systematic literature review was conducted to identify scales that have either been validated or used in PD patients. Apathy scales identified for review include the Apathy Evaluation Scale (AES), the Apathy Scale (AS), the Apathy Inventory (AI), and the Lille Apathy Rating Scale (LARS). In addition, item 4 (motivation/initiative) of the Unified Parkinson's Disease Rating Scale (UPDRS) and item 7 (apathy) of the Neuropsychiatric Inventory (NPI) were included. Anhedonia scales identified for review were the Snaith-Hamilton Pleasure Scale (SHAPS) and the Chapman scales for physical and social anhedonia. Only the AS is classified as "recommended" to assess apathy in PD. Although item 4 of the UPDRS also meets the criteria to be classified as recommended, it should be considered for screening only because of the obvious limitations of a single item construct. For the assessment of anhedonia, only the SHAPS meets the criteria of "Suggested." Information on the validity of apathy and anhedonia scales is limited because of the lack of consensus on diagnostic criteria for these conditions.

Risk factors for somnolence, edema, and hallucinations in early Parkinson disease.

BACKGROUND: The CALM-PD trial evaluated the development of motor complications in subjects with early Parkinson disease (PD) randomized to initial treatment with either pramipexole or levodopa. A secondary finding of the trial was a higher than anticipated development or worsening of somnolence and edema and development of hallucinations. OBJECTIVES: To investigate risk factors for somnolence, edema, and hallucinations in patients with early PD initiating dopaminergic therapy. METHODS: This was a secondary analysis of data from the CALM-PD trial. Baseline patient characteristics were evaluated for their associations with the development or worsening of somnolence and edema and the development of hallucinations using Cox proportional hazards regression models. RESULTS: Kaplan-Meier estimates of the 4-year incidence of the development or worsening of somnolence and edema and the development of hallucinations were 35%, 45%, and 17%. Initial pramipexole treatment (hazard ratio [HR] 2.22, 95% CI 1.41, 3.50, p < 0.001), male gender (HR 1.79, 95% CI 1.09, 2.93, p = 0.02), and >5 systems with a comorbid illness (HR 1.62, 95% CI 1.04, 2.51, p = 0.03) were associated with somnolence. Initial pramipexole treatment (HR 3.18, 95% CI 1.95, 5.18, p < 0.0001), female gender (HR 1.46, 95% CI 0.94, 2.27, p = 0.09), and comorbid cardiac disease (HR 1.59, 95% CI 1.02, 2.47, p = 0.04) were associated with edema. Age > or =65 (HR 2.06, 95% CI 0.98, 4.32, p = 0.06), Mini-Mental State Examination score >28 (HR 0.42, 95% CI 0.19, 0.91, p = 0.03), and >5 systems with a comorbid illness (HR 3.42, 95% CI 1.59, 7.38, p = 0.002) were associated with hallucinations. CONCLUSIONS: Comorbid illnesses are important and overlooked risk factors for the development of somnolence, edema, and hallucinations. When initiating therapy with pramipexole, patients should be counseled about and monitored for somnolence and edema. Slight decrements in cognitive function and older age are associated with an increased risk of hallucinations.