Use Of Antiparkinsonian Drugs Research Articles

Assessing the Risk of Developing Delirium on Admission to Inpatient Rehabilitation: A Clinical Prediction Model

ObjectivesTo develop a clinical model to predict the risk of an individual patient developing delirium during inpatient rehabilitation, based on patient characteristics and clinical data available on admission. DesignRetrospective observational study based on electronic health record data. Setting and ParticipantsWe studied a previously validated data set of inpatients including incident delirium episodes during rehabilitation. These patients were admitted to ZURZACH Care, Rehaklinik Bad Zurzach, a Swiss inpatient rehabilitation clinic, between January 1, 2015, and December 31, 2018. MethodsWe performed logistic regression analysis using backward and forward selection with alpha = 0.01 to remove any noninformative potential predictor. We subsequentially used the Akaike information criterion (AIC) to select the final model among the resulting “intermediate” models. Discrimination of the final prediction model was evaluated using the C-statistic. ResultsOf the 20 candidate predictor variables, 6 were included in the final prediction model: a linear spline of age with 1 knot at 60 years and a linear spline of the functional independence measure (FIM), a measure of the functional degree of patients independency, with 1 knot at 64 points, diagnosis of disorders of fluid, electrolyte, and acid-base balance (E87), use of other analgesic and antipyretics (N02B), use of anti-parkinson drugs (N04B), and an anticholinergic burden score (ACB) of ≥3 points. Conclusions and ImplicationsOur clinical prediction model could, upon validation, identify patients at risk of incident delirium at admission to inpatient rehabilitation, and thus enable targeted prevention strategies.

Sex differences in factors influencing hospital-acquired pneumonia in schizophrenia patients receiving modified electroconvulsive therapy.

Sex differences may be presented in the clinical features or symptoms of schizophrenia patients but also affect the occurrence of hospital-acquired pneumonia (HAP). Modified electroconvulsive therapy (mECT) is a common treatment method for schizophrenia, used in combination with antipsychotics. This retrospective research explores the sex difference in HAP affecting patients with schizophrenia who have received mECT treatment during hospitalization. We included schizophrenia inpatients treated with mECT and antipsychotics between January 2015 and April 2022. Blood-related and demographic data collected on admission were analyzed. Influencing factors of HAP in male and female groups were assessed separately. A total of 951 schizophrenia patients treated with mECT were enrolled in the study, including 375 males and 576 females, of which 62 patients experienced HAP during hospitalization. The risk period of HAP in these patients was found to be the first day after each mECT treatment and the first three sessions of mECT treatment. Statistically significant differences in the incidence of HAP were identified in male vs. female groups, with an incidence in men about 2.3 times higher than that in women (P < 0.001). Lower total cholesterol (Z = -2.147, P = 0.032) and the use of anti-parkinsonian drugs (χ2 = 17.973, P < 0.001) were found to be independent risk factors of HAP in male patients, while lower lymphocyte count (Z = -2.408, P = 0.016), hypertension (χ2 = 9.096, P = 0.003), and use of sedative-hypnotic drugs (χ2 = 13.636, P < 0.001) were identified in female patients. Influencing factors of HAP in schizophrenia patients treated with mECT have gender differences. The first day after each mECT treatment and the first three sessions of mECT treatment were identified to have the greatest risk for HAP development. Therefore, it would be imperative to monitor clinical management and medications during this period according to these gender differences.

Development of the ADFICE_IT Models for Predicting Falls and Recurrent Falls in Community-Dwelling Older Adults: Pooled Analyses of European Cohorts With Special Attention to Medication.

BackgroundUse of fall prevention strategies requires detection of high-risk patients. Our goal was to develop prediction models for falls and recurrent falls in community-dwelling older adults and to improve upon previous models by using a large, pooled sample and by considering a wide range of candidate predictors, including medications.MethodsHarmonized data from 2 Dutch (LASA, B-PROOF) and 1 German cohort (ActiFE Ulm) of adults aged ≥65 years were used to fit 2 logistic regression models: one for predicting any fall and another for predicting recurrent falls over 1 year. Model generalizability was assessed using internal–external cross-validation.ResultsData of 5 722 participants were included in the analyses, of whom 1 868 (34.7%) endured at least 1 fall and 702 (13.8%) endured a recurrent fall. Positive predictors for any fall were: educational status, depression, verbal fluency, functional limitations, falls history, and use of antiepileptics and drugs for urinary frequency and incontinence; negative predictors were: body mass index (BMI), grip strength, systolic blood pressure, and smoking. Positive predictors for recurrent falls were: educational status, visual impairment, functional limitations, urinary incontinence, falls history, and use of anti-Parkinson drugs, antihistamines, and drugs for urinary frequency and incontinence; BMI was a negative predictor. The average C-statistic value was 0.65 for the model for any fall and 0.70 for the model for recurrent falls.ConclusionCompared with previous models, the model for recurrent falls performed favorably while the model for any fall performed similarly. Validation and optimization of the models in other populations are warranted.

Multiple system atrophy in Hokkaido, Japan: a prospective registry study of natural history and symptom assessment scales followed for 5 years

ObjectivesMultiple system atrophy (MSA) is a refractory neurodegenerative disease, but novel treatments are anticipated. An accurate natural history of MSA is important for clinical trials, but is insufficient. This regional...

Antidopaminergic-Antiparkinsonian Medication Prescribing Cascade in Persons with Alzheimer's Disease.

Persons living with Alzheimer's disease (AD) may be at increased risk for prescribing cascades due to greater multimorbidity, polypharmacy, and the need for more complex care. Our objective was to assess the proportion of the antidopaminergic-antiparkinsonian medication prescribing cascades among persons living with Alzheimer's disease. Two large administrative claims databases in the United States. We identified patients aged ≥50 on January 1, 2017, who were dispensed a drug used to treat Alzheimer's disease for at least 1 day in the 365 days prior to or on cohort entry date and who had medical and pharmacy coverage in the 365 days prior to the cohort entry date. We excluded individuals with a recent institutional stay. We identified incident antidopaminergic (antipsychotic/metoclopramide) use in the 183 days following cohort entry and identified subsequent incident antiparkinsonian drug use within 8 to 365 days. There were 121,538 patients with Alzheimer's disease eligible for inclusion. Approximately 62% were women with a mean age of 79.5 (SD ± 8.6). The mean number of drugs dispensed was 9.2 (SD ± 4.9). There were 36 incident antiparkinsonian users among 4,534 incident antipsychotic/metoclopramide users (0.8%). We determined that the proportion of antidopaminergic-antiparkinsonian medication prescribing cascades, widely considered as high-priority, was low. Our approach can be used to assess the proportion of prescribing cascades in populations considered to be at high risk and to prioritize system-level interventional efforts to improve medication safety in these patients.

Psychotropic drug-prescribing correlates of disorganized speech in Asians with schizophrenia: The REAP-AP study

BackgroundAlthough disorganized speech is seen as one of the nuclear features of schizophrenia, there have been few reports of disorganized speech-associated psychotropic drug-prescribing patterns in large samples of schizophrenia patients. ObjectiveWe aimed to examine the prevalence of disorganized speech and its correlates in terms of psychotropic drug prescribing, using the data from the Research on Asian Psychotropic Patterns for Antipsychotics (REAP-AP) study. MethodA total of 3744 patients with the ICD-10 diagnosis of schizophrenia were enrolled from 71 survey centers in 15 Asian countries/areas. An essential criterion of disorganized speech was that it was “severe enough to impair substantially effective communication” as defined in the DSM-5. A binary logistic model was fitted to identify the psychotropic drug-prescribing correlates of disorganized speech. ResultsAfter adjusting for the potential effects of confounding variables, the binary logistic regression model showed that the presence of disorganized speech was directly associated with adjunctive use of mood stabilizers (P < 0.001) and cumulative diazepam equivalent dose (P < 0.0001), and inversely associated with adjunctive use of anti-Parkinson drugs (P < 0.0001). ConclusionThe association between disorganized speech and adjunctive use of mood stabilizers could perhaps be understood in the context of a relationship with impulsiveness/aggressiveness, or in terms of deconstructing the Kraepelinian dualism.

Efficacy and safety of aripiprazole for the treatment of schizophrenia: an overview of systematic reviews.

To conduct an overview to summarize the efficacy and safety of aripiprazole for the treatment of schizophrenia. A literature search was performed in PubMed, the Cochrane Library, LILACS, and the Centre for Reviews and Dissemination, for articles published until March 31, 2017. We included systematic reviews with meta-analyses of randomized controlled trials assessing the efficacy, and/or the safety of aripiprazole, for patients with schizophrenia. Two authors independently performed the study selection, data extraction, and quality assessment. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach and the Risk of Bias in Systematic Review (ROBIS) tool were used to appraise the quality of evidence and the risk of bias in the reviews, respectively. Fourteen studies fulfilled the inclusion criteria. Aripiprazole showed efficacy similar to that of both typical and atypical antipsychotic drugs (except olanzapine and amisulpride). Aripiprazole caused significantly lower weight gain and alterations in glucose and cholesterol levels, as compared to clozapine, risperidone, and olanzapine. In addition, aripiprazole caused significantly fewer general extrapyramidal side effects, less use of antiparkinsonian drugs, and akathisia, compared with typical antipsychotic drugs and risperidone. The overall quality of evidence in the reviews ranged from "very low" to "moderate," principally because of the risk of bias of original trials, inconsistency, and imprecision in the outcomes. According to the ROBIS tool, there are four reviews with "high" risk of bias and five with "unclear" risk of bias. Aripiprazole exhibited efficacy similar to that of other antipsychotic drugs and a better safety profile than that of typical (i.e., less some extrapyramidal side effects) and atypical (i.e., less metabolic changes) antipsychotic drugs.

Prevalence and correlates of antipsychotic polypharmacy in Hong Kong.

Antipsychotic polypharmacy (APP) remains a common practice despite inconclusive empirical evidence of additional efficacy and potential exacerbation of side effects. Previous studies suggest APP rate is notably high in East Asia. This paper aims to investigate the prevalence and correlates of APP in Hong Kong. This was a cross-sectional study of 728 patients with psychosis. The demographics and clinical information, including age, gender, diagnosis, hospitalization history, and medication were collected. Chi-square tests and logistic regression analyses were used to study correlates of APP. The APP rate for psychosis was 24.2% (n = 728) and that for schizophrenia was 26.0% (n = 611), both considerably lower than our previous local data and that from East Asian regions. The most widely used APP prescription fell within the atypical/atypical combination (i.e., Amisulpride/Clozapine and Paliperidone/Olanzapine), and Olanzapine was the most commonly prescribed antipsychotic. At least 75% of APP patients with psychosis took at least one type of atypical antipsychotics in their medical regimen. Typical/typical polypharmacy was associated with older age and use of antiparkinson drugs. Typical/atypical polypharmacy was associated with the use of antiparkinson drugs and anxiolytics, as well as inpatient status. Atypical/atypical polypharmacy was associated with younger age, inpatient status, and the use of mood stabilizers. Overall, our study highlights a relatively low APP rate in Hong Kong when compared to other countries in East Asia. Age, inpatient status and use of antiparkinson drugs, anxiolytics and mood stabilizers were associated with use of APP.

Prevalence and Correlates of Anti-Parkinson Drug Use in a Nationally Representative Sample.

Although numerous prescription drugs are available to treat Parkinson's disease (PD), little is known about national use in clinical practice and which factors may influence variability in care. The objectives of this study were to describe the prevalence of anti-Parkinson drug use among Medicare beneficiaries with PD and to identify demographic and clinical factors associated with drug use. This retrospective study was based on a random sample of annual 5% Medicare Part A and B claims linked with Medicare Part D drug files from 2007 through 2010. The study sample included fee-for-service Medicare beneficiaries with continuous stand-alone Part D enrollment who had been diagnosed with PD in the given year. First, any PD drug use and drug use by class (levodopa, dopamine agonist, anticholinerigc, monoamine oxidase B inhibitors, catechol-O-methyltransferase inhibitors, and amantadine) were described. Using generalized estimating equation regressions, patient and provider characteristics associated with anti-Parkinson drug use and choice were examined. Over 81% of patients with PD were treated with anti-Parkinson drugs, and this proportion was stable over the 4 years of the study. The majority were treated with levodopa (90%); followed by dopamine agonists (29-31%); then monoamine oxidase B inhibitors, anticholinergics, amantadine, and catechol-O-methyltransferase inhibitors (all between 5% and 11%). Holding all else equal, patients who were not seen by a neurologist (odds ratio, 0.41; 95% confidence interval, 0.38-0.44; P < 0.001) and African-American patients (odds ratio, 0.80; 95% confidence interval, 0.69-0.93; P = 0.003) were significantly less likely to be treated. Among a national sample of Medicare beneficiaries with PD, the majority received anti-Parkinson drugs. However, there was relative under-treatment of African-Americans and patients who were not seen by a neurologist for care.

Lithium Use in Older Adults is Associated with Increased Prescribing of Parkinson Medications

To test the hypothesis of an increased incidence of antiparkinson drug prescribing or Parkinson disease (PD) diagnostic codes after chronic lithium treatment compared with chronic valproic acid or antidepressant treatment among older adults. A retrospective cohort study using healthcare administrative databases in Ontario, Canada included 1,749 lithium users, 1,787 valproic acid users, and 285,154 other antidepressant users ≥ 66 years old having used the drug continuously in monotherapy for at least 1 year. Outcome measures were start of (1) a dopaminergic medication (levodopa or a dopamine agonist), (2) any antiparkinson drug (levodopa, dopamine agonists, anticholinergic medication, amantadine, monoamine oxidase B inhibitors), (3) any antiparkinson drug or a diagnostic code for PD, and (4) any antiparkinson drug in the absence of a diagnostic code for PD. For patients with no previous antipsychotic use, lithium monotherapy was associated with an increased incidence of dopaminergic drug use (adjusted HR: 1.87; 95% CI: 1.06-3.30) and an increased incidence of antiparkinson drug use or a PD diagnosis (adjusted HR: 1. 68; 95% CI: 1.13-2.48) compared with antidepressant monotherapy. Chronic lithium use is associated with an increased incidence of dopaminergic drug use compared with antidepressants, identifying a prescribing cascade related to lithium use in the elderly. Whether this reflects inappropriate treatment of action tremor or treatment of drug-induced parkinsonism should be addressed by a close examination of prescribing practices.

Early-onset vs. Late-onset Parkinson's disease: A Clinical-pathological Study.

Several studies have compared early-onset Parkinson disease (EOPD) and late-onset Parkinson disease (LOPD) but most are not based on autopsy confirmed cases. We compared clinical and pharmacological profiles, time to reach irreversible Hoehn and Yahr (H&Y) Stage 3 and levodopa motor complications in autopsy confirmed EOPD and LOPD cases. At first clinic visit EOPD cases were younger but had longer disease duration and they died at a younger age (all p<0.0001). Anti-Parkinsonian drug use, including levodopa, was significantly delayed in EOPD. Lifetime use of amantadine (p<0.05) and dopamine agonists (p<0.01) were higher in EOPD. While lifetime use of levodopa was similar in the two groups, levodopa was used for a significantly longer period by EOPD (p< 0.0001). EOPD had a higher cumulative incidence of dyskinesias (p<0.01), wearing-off (p<0.01), and on-off (p<0.01). However, the time to dyskinesia onset was similar in the two groups. The threshold to wearing-off was much longer in EOPD (p<0.01). H&Y stage profile at first visit was similar in the two groups. The duration from disease onset to reach irreversible H&Y stage 3 was significantly longer in EOPD. Our observations indicate that progression of PD is slower in EOPD and suggest that the pre-clinical interval in this group is longer. These findings can be used for case selection for drug trials and studies of the pathogenesis of PD.

Trends in inpatient antiparkinson drug use in the USA, 2001-2012.

PurposeAlthough therapeutic options and clinical guidelines for Parkinson’s disease (PD) have changed significantly in the past 15 years, prescribing trends in the USA remain unknown. The purpose of this population-based cohort study was to examine patterns of inpatient antiparkinson drug use between January 2001 and December 2012 in relation to clinical guideline publication, drug introduction/withdrawal, and emerging safety concerns.MethodsA total of 16,785 inpatients receiving pharmacological treatment for PD were identified in the Cerner Health Facts database. Our primary outcome was standardized (age, sex, race, and census region) annual prevalence of antiparkinson drug use. We also examined antiparkinson medication trends and polypharmacy by age and sex.ResultsThe most frequently prescribed antiparkinson drugs between 2001 and 2012 were levodopa (85 %) and dopamine agonists (28 %). Dopamine agonist use began declining in 2007, from 34 to 27 % in 2012. The decline followed publication of the American Academy of Neurology’s practice parameter refuting levodopa toxicity, pergolide withdrawal, and pramipexole label revisions. Despite safety concerns for cognitive impairment and falls, individuals ≥80 years of age demonstrated stable rates of dopamine agonist use from 2001 to 2012. Polypharmacy was most common in younger patients.ConclusionsDopamine agonist use declined from 2007 to 2012, suggesting that increased awareness of safety issues and practice guidelines influenced prescribing. These events appear to have minimally influenced treatment provided to older PD patients. Antiparkinson prescribing trends indicate that safety and best practice information may be communicated effectively.Electronic supplementary materialThe online version of this article (doi:10.1007/s00228-015-1881-4) contains supplementary material, which is available to authorized users.

Antiparkinson drug use in response to practice parameter publication, drug availability, and ‘unofficial’ prescribing forces (P4.149)

Antiparkinson drug use in response to practice parameter publication, drug availability, and ‘unofficial’ prescribing forces (P4.149)

Evaluating rehabilitation interventions in Parkinson's disease with functional MRI: a promising neuroprotective strategy.

Evaluating rehabilitation interventions in Parkinson's disease with functional MRI: a promising neuroprotective strategy.

Prevalencia de las complicaciones del tratamiento antiparkinsoniano: revisión sistemática y estimación de proyecciones

The development of Parkinson's disease (PD) presents different complications deriving from the disease itself, but also from its treatment. The appearance of side effects with the use of antiparkinsonian drugs is common and their management is complicated, which makes it necessary to determine the epidemiological impact of these problems related with antiparkinsonian medication. To estimate the prevalence of the side effects of the treatment for the motor symptoms of PD and the possible long-term impact. A systematic review was performed in the biomedical databases since the year 2004; the most relevant studies were selected and the frequencies of the most common side effects were identified. The data thus obtained were projected in order to estimate their impact in the long term. Altogether 218 studies were identified, of which 24 were selected for the review. Data were obtained for 20 types of complications deriving from the antiparkinsonian treatment, including heart problems, oedemas and neuropsychiatric symptoms. The estimations performed indicate that the number of patients with PD and therefore the prevalence of the side effects of antiparkinsonian treatments may well double by the year 2050.

Prevalence and Predictors of Anti-Parkinson Drug Use in a Nationally Representative Sample of Medicare Beneficiaries, 2006-2010 (S17.005)

Prevalence and Predictors of Anti-Parkinson Drug Use in a Nationally Representative Sample of Medicare Beneficiaries, 2006-2010 (S17.005)

Antiparkinson Drug Adherence and Its Association with Health Care Utilization and Economic Outcomes in a Medicare Part D Population

ObjectivesWe examine the associations of adherence to antiparkinson drugs (APDs) with health care utilization and economic outcomes among patients with Parkinson’s disease (PD). MethodsBy using 2006–2007 Medicare administrative data, we examined 7583 beneficiaries with PD who filled two or more APD prescriptions during 19 months (June 1, 2006, to December 31, 2007) in the Part D program. Two adherence measures— duration of therapy (DOT) and medication possession ratio (MPR)—were assessed. Negative binomial and gamma generalized linear models were used to estimate the rate ratios (RRs) of all-cause health care utilization and expenditures, respectively, conditional upon adherence, adjusting for survival risk, sample selection, and health-seeking behavior. ResultsApproximately one-fourth of patients with PD had low adherence (MPR < 0.80, 28.7%) or had a short DOT (≤400 days, 23.9%). Increasing adherence to APD therapy was associated with decreased health care utilization and expenditures. For example, compared with patients with low adherence, those with high adherence (MPR = 0.90–1.00) had significantly lower rates of hospitalization (RR = 0.86), emergency room visits (RR = 0.91), skilled nursing facility episodes (RR = 0.67), home health agency episodes (RR = 0.83), physician visits (RR = 0.93), as well as lower total health care expenditures (−$2242), measured over 19 months. Similarly, lower total expenditure (−$6308) was observed in patients with a long DOT versus those with a short DOT. ConclusionsIn this nationally representative sample, higher adherence to APDs and longer duration of use of APDs were associated with lower all-cause health care utilization and total health care expenditures. Our findings suggest the need for improving medication-taking behaviors among patients with PD to reduce the use of and expenditures for medical resources.

A case of brucellosis displaying Parkinsonian-like tremor

We report a rare case of brucellosis with Parkinsonian-like tremor and simple partial motor seizure. This patient worked as a sheep butcher and the sheep were imported from brucellosis-endemic areas. He presented with classical manifestations of brucellosis; infection was confirmed using the Rose Bengal Plate and Standard Tube Agglutination tests. The patient also suffered from headache, partial seizures, changes of personality and static tremor of both upper limbs. After anti-infection therapy, but without the use of anti-Parkinson drugs, the patient fully recovered and remained free of Parkinsonian-like tremor. Brucellosis can present with atypical symptoms, clinicians should widen their diagnostic view of brucella infection.

Antiparkinson Drug Use and Adherence in Medicare Part D Beneficiaries With Parkinson’s Disease

BackgroundAntiparkinson drugs (APDs) are the mainstay of managing Parkinson’s disease (PD). However, there is paucity of evidence documenting patterns of APD use and examining factors associated with adherence to APDs. ObjectivesOur goal was to provide updated, comprehensive population-based data on APD use and adherence and to examine characteristics associated with adherence behaviors. MethodsWe analyzed data from 7583 beneficiaries with PD who had ≥2 APD prescription fills and were continuously enrolled in Medicare Parts A, B, and D for up to 19 months (from June 1, 2006, through December 31, 2007) or until death in 2007. We assessed 5 patterns of APD use: (1) concurrent use of ≥2 APD classes for ≥30 days; (2) switching of APDs from 1 to another; (3) augmentation of the existing regimen with a new APD; (4) duration of therapy, defined as days of APD treatment; and (5) adherence measured by using the medication possession ratio (MPR). We corrected for sample selection bias inherent in patients’ self-selection into either a Part D plan or a Medicare Advantage Prescription Plan by using Heckman’s 2-stage procedures. ResultsAPD users were pre-dominantly aged ≥65 years (93.6%), female (59.9%), and white (89.3%). Almost one half (43.2%) of APD users concurrently used ≥2 APD classes. One in 4 APD users experienced changes in their APD regimen, with 16.4% switching medications and 21.1% augmenting their current regimen. Three quarters of APD users had therapy lasting ≥436 days (75.3%) and an MPR ≥0.8 (72.7%). Multivariate analyses revealed that patients aged ≥65 years, of non-white race, non–low-income subsidy recipients, late Part D enrollees, cognitively impaired, highly comorbid, and who experienced multiple changes in APD therapy were less likely to adhere to APD therapy. We were able to generalize our findings to all Part D enrollees by correcting for sample selection bias using the Heckman approach. These population-level, generalizable observations provide better understanding of APD use and adherence and assist in the design of interventions for poor adherence. Limitations include cross-sectional study design and constraints in administrative data that preclude measurement of other potential factors related to adherence. ConclusionsA substantial proportion of these Medicare beneficiaries with PD used multiple APDs concurrently, experienced switching and/or augmentation of APDs, and had poor adherence to APDs. Patient characteristics and clinical and drug-related factors were important predictors of APD adherence.

Use of antiparkinson medications among elderly Medicare beneficiaries with Parkinson's disease

Background: Antiparkinson drugs (APDs) are the mainstay in the management of Parkinson's disease (PD). However, the use of APDs has not been investigated in a nationally representative sample. Objectives: This study aimed to describe the prevalence and patterns of APD use and to identify determinants of APD use among elderly Medicare beneficiaries with PD. Methods: Data from the Medicare Current Beneficiary Survey and Medicare claims from 2000 to 2003 were used to identify beneficiaries ≥65 years of age with PD. The APDs included in the study were levodopa, dopamine agonists, monoamine oxidase-B inhibitors, amantadine, anticholinergic agents, and catechol- O-methyltransferase inhibitors. The annual prevalence of APD use was calculated; patterns of APD use were measured by drug class and type of drug regimens (monotherapy or combination therapy). Potential determinants of APD use included sociodemographic characteristics (age, sex, race, education, marital status, and annual income), self-reported health status, residential status (institution or community), prescription drug coverage, disability (functional, physical, and mental), and disease-specific factors (dementia, depression, and other comorbidities). Multivariate logistic regression analyses with generalized estimating equations were used to estimate odds ratios (ORs) of any APD use associated with the determinants. Results: The data revealed 571 beneficiaries with PD (30.1% aged ≥85 years, 55.0% female, 88.3% white), who were observed for a total of 924 person-years. The annual prevalence of APD use was 58.2% (538/924). Levodopa was the most frequently used agent, either as monotherapy or in combination with other APDs (85.5%; 460/538). Multivariate analyses found that patients 65 to 74 years of age (OR = 0.70; 95% CI, 0.49–0.99; P < 0.05) and those ≥85 years of age (OR = 0.57; 95% CI, 0.40–0.81; P < 0.01) were less likely to use APDs than were patients aged 75 to 84 years of age. Patients who had attained a high level of education (more than a high school diploma) were more likely to use APDs than were patients with a low level of education (a high school diploma or less) (OR = 1.51; 95% CI, 1.04–2.19; P < 0.05). In addition, institutionalization (OR = 1.78; 95% CI, 1.17–2.71; P < 0.01), prescription drug coverage (OR = 1.50; 95% CI, 1.15–1.94; P < 0.01), activities of daily living (ADLs) (OR = 1.47; 95% CI, 1.16–1.87; P < 0.01), and depression (OR = 1.25; 95% CI, 1.02–1.53; P < 0.05) were significantly associated with use of APDs. The probability of APD use was lower among those with dementia than among those without dementia (OR = 0.62; 95% CI, 0.48–0.80; P < 0.001). Conclusions: Almost half of the elderly Medicare beneficiaries with PD in this study did not use any APD between 2000 and 2003. Levodopa was the most frequently used APD, either as monotherapy or in combination with other APDs. The identified determinants of APD use (age, education, prescription drug coverage, ADLs, dementia, depression, and residing in an institution) may be helpful in developing interventions for this population.