Mortality Among Parkinson's Disease Patients Treated With Pimavanserin or Atypical Antipsychotics: An Observational Study in Medicare Beneficiaries

OBJECTIVE

Pimavanserin, a serotonin 5-HT₂ antagonist, is indicated for treatment of hallucinations and delusions associated with Parkinson's disease psychosis. In premarketing trials in patients with Parkinson's disease psychosis, 11% of patients died during open-label pimavanserin treatment. Antipsychotics, which are used off-label in Parkinson's disease psychosis, increase mortality in dementia patients. The authors compared mortality with pimavanserin and atypical antipsychotics in a large database.

METHODS

This was a retrospective new-user cohort study of Medicare beneficiaries with Parkinson's disease initiating pimavanserin (N=3,227) or atypical antipsychotics (N=18,442) from April 2016 to March 2019. All-cause mortality hazard ratios and 95% confidence intervals were estimated for pimavanserin compared with atypical antipsychotics, using segmented proportional hazards regression over 1-180 and 181+ days of treatment. Potential confounding was addressed through inverse probability of treatment weighting (IPTW).

RESULTS

Pimavanserin users had a mean age of approximately 78 years, and 45% were female. Before IPTW, some comorbidities were more prevalent in atypical antipsychotic users; after IPTW, comorbidities were well balanced between groups. In the first 180 days of treatment, mortality was approximately 35% lower with pimavanserin than with atypical antipsychotics (hazard ratio=0.65, 95% CI=0.53, 0.79), with approximately one excess death per 30 atypical antipsychotic-treated patients; however, during treatment beyond 180 days, there was no additional mortality advantage with pimavanserin (hazard ratio=1.05, 95% CI=0.82, 1.33). Pimavanserin showed no mortality advantage in nursing home patients.

CONCLUSIONS

Pimavanserin use was associated with lower mortality than atypical antipsychotic use during the first 180 days of treatment, but only in community-dwelling patients, not nursing home residents.

Entacapone and prostate cancer in Parkinson's disease patients: A large Veterans Affairs healthcare system study

BACKGROUND

An increased incidence of prostate cancer was observed in Parkinson's disease (PD) patients treated with entacapone during a pre-approval randomized clinical trial; the relation has not been robustly investigated in the U.S. ambulatory setting.

OBJECTIVE

To investigate whether entacapone is associated with prostate cancer and to assess whether the associations are correlated with advanced disease at the time of cancer diagnosis.

METHODS

Using data from the Department of Veterans Affairs healthcare system, new-user cohorts were created of PD patients treated with add-on entacapone or add-on dopamine agonist/monoamine oxidase B inhibitors between January 2000 and December 2014. Patients were followed on-treatment for occurrence of prostate cancer, identified via linkage to the VA cancer registry.

RESULTS

Mean follow-up time was 3.1 and 4.0 years in the entacapone and control cohort, respectively. There were 17,666 subjects meeting study criteria (mean age, 74 (SD 8.6) years); the entacapone-treated group comprised 5,257 subjects. Twenty-three prostate cancer cases occurred in the entacapone cohort and ninety-seven in the control cohort. The overall incidence of prostate cancer was 1.8 per 1,000 person-years of risk. There was no difference in risk of prostate cancer between the cohorts for increased duration of entacapone intake (adjusted HR: 1.08; 95% confidence interval: 0.46-2.51 for cumulative exposure of ≥2 years). Time since starting drug therapy and cumulative dose (mg) also do not suggest a difference in prostate cancer risk between cohorts.

CONCLUSIONS

Prolonged therapy with entacapone was not associated with increased prostate cancer incidence; however, findings suggest a higher severity of prostate cancer.

Involvement of the central somatosensory system in restless legs syndrome

Objective

To investigate morphologic changes in the somatosensory cortex and the thickness of the corpus callosum subdivisions that provide interhemispheric connections between the 2 somatosensory cortical areas.

Methods

Twenty-eight patients with severe restless legs syndrome (RLS) symptoms and 51 age-matched healthy controls were examined with high-resolution MRI at 3.0 tesla. The vertex-wise analysis in conjunction with a novel cortical surface classification method was performed to assess the cortical thickness across the whole-brain structures. In addition, the thickness of the midbody of the corpus callosum that links postcentral gyri in the 2 hemispheres was measured.

Results

We demonstrated that a morphologic change occurred in the brain somatosensory system in patients with RLS compared to controls. Patients with RLS exhibited a 7.5% decrease in average cortical thickness in the bilateral postcentral gyrus (p < 0.0001). Accordingly, there was a substantial decrease in the corpus callosum posterior midbody (p < 0.008) wherein the callosal fibers are connected to the postcentral gyrus, suggesting altered white matter properties in the somatosensory pathway.

Conclusion

Our results provide in vivo evidence of morphologic changes in the primary somatosensory system, which could be responsible for the sensory functional symptoms of RLS. These results provide a better understanding of the pathophysiology underlying the RLS sensory symptoms and could lead to a potential imaging marker for RLS.

Abstract 2303: Entacapone and prostate cancer in patients with Parkinson’s disease: A large Veterans Health Administration study

Background: An increased risk of prostate cancer was observed in Parkinson’s disease (PD) patients treated with entacapone during a pre-approval randomized clinical trial.

Objective: To investigate a potential association between entacapone use and prostate cancer in an ambulatory setting.

Methods: Using data from the Department of Veterans Affairs (VA) healthcare system, new-user cohorts were created of PD patients treated with add-on entacapone or add-on dopamine agonist/monoamine oxidase B inhibitors between January 2000 and December 2014. Patients were followed on-treatment for occurrence of prostate cancer, identified via VA cancer registry linkage. Cox proportional hazards regression with time-dependent exposure was used to calculate hazard ratios (HR) and 95% confidence intervals (CI). Confounding was controlled by using inverse probability treatment weighting calculated from propensity scores.

Results: Mean follow-up time was 3.1 and 4.0 years in the entacapone and control cohort, respectively. There were 17,666 subjects meeting study criteria (mean age, 74 (SD 8.6) years); the group treated with entacapone comprised 5,257 subjects. Twenty-three prostate cancers occurred in the entacapone cohort and 97 in the control cohort. The overall incidence of prostate cancer was 1.8 per 1000 person-years of risk. There was no difference in risk of prostate cancer between the cohorts for increased duration of entacapone intake (adjusted HR: 1.08; 95% confidence interval: 0.46-2.51 for cumulative exposure of ≥2 years). Time since starting drug therapy and cumulative dose (mg) were also examined.

Conclusion: In this cohort of PD patients, extended duration of entacapone use was not associated with an increased incidence of prostate cancer.

Note: This abstract was not presented at the meeting.

Citation Format: Jacqueline M. Major, Francesca Cunningham, Diane Dong, Kunthel By, Kwan Hur, David C. Shih, Simone P. Pinheiro, Gerald D. Podskalny, David J. Graham. Entacapone and prostate cancer in patients with Parkinson’s disease: A large Veterans Health Administration study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2303. doi:10.1158/1538-7445.AM2017-2303

Chorea caused by lithium intoxication: a case report and literature review

We report a patient who developed an acute, reversible, generalized choreiform disorder from lithium (Li) intoxication. This medication was prescribed for manic-depressive disorder, and serum levels became elevated after the addition of a diuretic for the treatment of hypertension. There were no other apparent causes for the movement disorder, and it was associated with other known features of Li intoxication, including ataxia and encephalopathy. There was a delay between the initial symptoms of Li intoxication and the onset of chorea. The chorea improved as serum Li levels diminished, with some lag time. This represents the eleventh case report of Li-induced chorea, but only the sixth in a patient without concomitant neuroleptic therapy, and the first presented with videotape confirmation. A review of these other cases is included, and possible mechanisms are discussed.

Psychogenic movement disorders: frequency, clinical profile, and characteristics

Of 842 consecutive patients with movement disorders seen over a 71 month period, 28 (3.3%) were diagnosed as having a documented or clinically established psychogenic movement disorder. Tremor was most common (50%) followed by dystonia, myoclonus, and parkinsonism. Clinical descriptions of various types are reviewed. Clinical characteristics common in these patients included distractability (86%), abrupt onset (54%), and selective disabilities (39%). Distractability seems to be most important in tremor and least important in dystonia. Other diagnostic clues included entrainment of tremor to the frequency of repetitive movements of another limb, fatigue of tremor, stimulus sensitivity, and previous history of psychogenic illness. On examination, 71% had other psychogenic features. Over 60% had a clear history of a precipitating event and secondary gain and 50% had a psychiatric diagnosis (usually depression). Twenty five per cent of patients presented with combined psychogenic movement disorder and organic movement disorder; 35% resolved and this subgroup had a shorter duration of disease than those who are unresolved. Psychogenic movement disorder represents an uncommon diagnosis among patients with movement disorders. The ability to make a diagnosis rests on the presence of a multitude of clinical clues and therapeutic action should be taken as early as possible.

Parkinson's disease: drug-induced psychiatric states

Drug-induced psychiatric states occur frequently in PD. In the prelevodopa era, depression and other psychiatric disorders were described in PD, but in untreated patients psychosis was rare. Since the development of levodopa and other pharmacological treatments for PD, however, psychotic symptoms have become much more common (10-50%). In some individuals these problems can be more disabling than the motor features of PD and, as a result, pose a serious threat to the patient's ability to maintain independence. The drug-induced psychoses consist of several distinct psychiatric syndromes that can be divided broadly into those occurring on a background of a clear sensorium and those which are accompanied by confusion and clouding of consciousness. Benign organic hallucinosis is the most common of these syndromes (30%). It usually occurs on a background of a clear sensorium and may not be a particularly troublesome problem if the patient is able to retain insight into the nature of these symptoms. More disabling syndromes usually include delusional thinking that is frequently paranoid, confusion and even frank delirium. Although all these psychotic syndromes can occur in isolation, there is a tendency for mild symptoms to progress to more disabling ones if adequate and timely treatment is not instituted. Abnormal dreaming and sleep disruption often precede these difficulties by weeks to months and may provide an important early clue to their onset. The mechanisms responsible for drug-induced psychotic symptoms in PD are unknown, but dopaminergic (especially mesolimbic) and serotoninergic systems are likely to be involved. The treatment of the drug-induced psychoses in PD should be undertaken in a stepwise manner. A detailed discussion of this approach, including the use of anti-PD medication adjustment, clozapine, and other medications (neuroleptic and nonneuroleptic) and ECT is provided (see Fig. 1). Although drug-induced psychoses are the most important of the drug-induced psychiatric states, mania, anxiety, and hypersexuality may also occur. Depression is also common in PD, but it is unlikely to occur as a side effect of antiparkinsonian medications.

Persistent neuroleptic-induced rigidity and dystonia in AIDS dementia complex: a clinico-pathological case report

Patients with AIDS dementia complex (ADC) appear to have an increased likelihood of developing acute onset parkinsonism and dystonia when treated with dopamine antagonists. It has been hypothesized, based on clinical evidence, that hypersensitivity to these drugs in ADC is probably related to direct invasion of the basal ganglia by the HIV virus and a secondary alteration in dopaminergic mechanisms. We report the first pathological description of a patient with ADC who developed acute onset, generalized rigidity and dystonia after a brief trial of low dose neuroleptic therapy administered for psychotic symptoms. An unusual clinical feature of this case was the persistence of his movement disorder. Pathological examination revealed a generalized encephalitic process with substantial neuronal loss observed primarily in the medial and lateral globus pallidus. Correlation with a current model of basal ganglia pathophysiology and other disorders with pallidal lesions is discussed. Clinical and pathological features of this case confirm the previous contention and indicate that dopamine antagonists should be utilized with extreme caution in patients with ADC.

Clozapine: a 2-year open trial in Parkinson's disease patients with psychosis

We treated 17 patients with Parkinson's disease (PD) complicated by psychosis with the atypical antipsychotic drug, clozapine, for 6 to 24 months (mean, 15 months) in a prospective, open-label trial. At 3-month intervals we evaluated patients, using a simplified brief Psychiatric Rating Scale (PRS), the motor examination portion of the Unified Parkinson's Disease Rating Scale, and the Mini-Mental State Examination (MMSE). Mean PRS score was significantly improved when compared with baseline over 1 year (p < 0.01) and nonsignificantly improved for the second year. We maintained the levodopa dose at levels that were 17 to 68% higher than baseline, and the mean motor examination score improved by 11 to 22% in the first 15 months. Clozapine dosage utilized in the trial ranged from 6.25 mg every other day to 150 mg/d. Adverse effects, including sedation and confusion, were common. These results demonstrate that clozapine therapy can be effective in treating psychosis in PD patients over 1 to 2 years. The decline in efficacy in the second year was most likely related to an increase in daily levodopa dose, progression of dementia (illustrated by a decline in MMSE score), and an inability of PD patients to tolerate higher doses of clozapine.

Report of congenital anaplastic astrocytoma discovered in a newborn

Reports of congenital anaplastic astrocytoma have been rare, representing less than 2% of all brain tumors. We present a case of a congenital anaplastic astrocytoma discovered during the first 24 hours after delivery. A recent literature review found 12 additional cases since 1972. The presenting signs, most common findings on neuroimaging, treatment, and outcome are examined.