Impact of recommendations on the initial therapy of Parkinson's disease: a population-based study in France

Factors affecting the choice of first-line therapy in Parkinson's disease patients in Wales: A population-based study

First line treatment for Parkinson’s disease (PD) is typically either L-dopa or a non-ergot dopamine agonist (DA). However, the options for the treatment of motor symptoms in PD patients have increased in the last thirty years, which have seen several new classes of PD medications introduced onto the market. The purpose of this study is to examine the changes in first line therapy of newly diagnosed Parkinson’s patients between 2000 and 2016 in Wales.

A population-based study evaluated data from the Secure Anonymised Information Linkage (SAIL) Databank of residents in Wales, aged 40 years or older, newly treated with PD medications between 2000 and 2016. The data was compared across three intervals: 2000–2005, 2006–2011 and 2012–2016. Patients were classified by age at diagnosis into young: 40–60 years; mid, 61–80 years; and older >80 years. Logistic regression was undertaken to determine the predictors of PD medication prescribing.

For the whole study period, the profiles of 9142 newly diagnosed PD patients were analysed. L-dopa was the most common first line therapy (80.6%), followed by non-ergot DAs (12.9%) and monoamine oxidase B (MAO-B) inhibitors (7.9%). Odds of L-dopa prescribing were greater in patients >80 years (OR = 20.46 95%CI: 16.25–25.76) and in the period 2012–2016 (OR = 1.98 95% CI: 1.70–2.29). Prescribing of non-ergot DAs significantly declined in 2012–2016 (OR = 0.42 95% CI: 0.35–0.49). Additional factors influencing first line therapy were deprivation, presence of diabetes and prior use of antidepressants. For example, PD patients residing in the least deprived area were less likely to be prescribed L-dopa compared to patients residing in the most deprived area (OR = 0.77 95% CI: 0.65–0.93).

First line therapy in PD in Wales has undergone a significant switch towards L-dopa over the last 16 years. The data indicates reasonable compliance with guidelines on efficacy and safety issues related to Parkinson’s medications.

The characteristics and treatment patterns of patients with Parkinson's disease in the United States and United Kingdom: A retrospective cohort study

Objectives

The objective of the study was to describe treatment patterns in patients newly diagnosed with Parkinson’s disease (PD) in the United States (US) and the United Kingdom (UK).

Methods

This retrospective cohort study used the US IBM MarketScan database (2012–2017) and the UK Clinical Practice Research Datalink (CPRD) (2004–2015) database to describe treatment patterns in incident PD cases. Patients fulfilling the case definition of PD, ≥30 years, with a 2-year baseline period prior to the index date (date of PD diagnosis), and ≥90 days of follow-up were included in the study. Treatment was classified as monotherapy (one PD medication for ≥60 continuous days), polytherapy (at least two PD medications concurrently for ≥60 days), or untreated (no PD medication prescription). Treatment patterns described included type of medication, duration and outcome of treatment.

Results

There were 11,280 patients in IBM MarketScan and 7775 patients in CPRD who fulfilled the study criteria. The proportion of treated patients was 62.4% (US) and 78.6% (UK). The majority of patients were prescribed monotherapy as first-line treatment (US: 85.2%, UK: 68.5%). Levodopa was the most frequently prescribed first-line medication (US: 70.1%, UK: 29.0%). There were 57.9% in the US and 23.8% in the UK who remained on the first monotherapy treatment till the end of the study.

Conclusion

The study has highlighted the current treatment practices in the US and UK, and underscored differences in the two regions impacted by treatment policies and guidelines.

Patterns and Determinants of Prescribing for Parkinson's Disease: A Systematic Literature Review

Since the discovery of levodopa (L-dopa) in 1967, the range of medications available to treat Parkinson's disease has increased significantly and guidance on the use, efficacy, and safety of these medications has evolved. To assess levels of adherence to national prescribing guidelines and awareness of changes in the efficacy and safety data published in the profiles of medications for the treatment of PD, we have reviewed studies on patterns and determinants of prescribing PD medications conducted in the last 50 years (since the discovery of L-dopa). A systematic literature review was conducted using EMBASE (1967 to March, 2018), Ovid MEDLINE(R) ALL (1967 to March 16, 2018), PsycINFO (1967 to the 2nd week of March, 2018), and PubMed to identify all studies measuring prescribing patterns of PD medication between 1967 and 2017. Study design, source of data, country, year of study, number of patients and/or prescriptions, unit of analysis, prescribing determinants, and percentage utilisation of PD medications were extracted where possible. 44 studies examining prescribing patterns and/or prescribing determinants across 17 countries were identified. Unsurprisingly, L-dopa was the most commonly prescribed medication in all studies, accounting for 46.50% to 100% of all prescriptions for PD. In several studies, the prescribing rate of ergot-derived dopamine agonists (DAs) decreased over time in concordance with guidance. In contrast, the prescribing rates of non-ergot DAs increased over the last ten years in most of the included studies. In examining prescribing factors, two major categories were exemplified, patients' factors and prescribers' factors, with patients' age being the most common factor that affected the prescription in most studies. In conclusion, L-dopa is now the most commonly prescribed medication for cases of PD but there is large variation in the prescribing rates of catechol-O-methyltransferase (COMT) inhibitors, monoamine oxidase B (MAO-B) inhibitors, amantadine, and anticholinergics between countries. New studies examining the effects of recent clinical trials and measuring the prescribing rates of newly approved medications are warranted.

Smoking and Parkinson disease: Evidence for gene-by-smoking interactions

OBJECTIVE

To investigate whether cigarette smoking interacts with genes involved in individual susceptibility to xenobiotics for the risk of Parkinson disease (PD).

METHODS

Two French population-based case-control studies (513 patients, 1,147 controls) were included as a discovery sample to examine gene-smoking interactions based on 3,179 single nucleotide polymorphisms (SNPs) in 289 genes involved in individual susceptibility to xenobiotics. SNP-by-cigarette smoking interactions were tested in the discovery sample through an empirical Bayes (EB) approach. Nine SNPs were selected for replication in a population-based case-control study from California (410 patients, 845 controls) with standard logistic regression and the EB approach. For SNPs that replicated, we performed pooled analyses including the discovery and replication datasets and computed pooled odds ratios and confidence intervals (CIs) using random-effects meta-analysis.

RESULTS

Nine SNPs interacted with smoking in the discovery dataset and were selected for replication. Interactions of smoking with rs4240705 in the RXRA gene and rs1900586 in the SLC17A6 gene were replicated. In pooled analyses (logistic regression), the interactions between smoking and rs4240705-G and rs1900586-G were 1.66 (95% CI 1.28-2.14, p = 1.1 × 10^-4, p for heterogeneity = 0.366) and 1.61 (95% CI 1.17-2.21, p = 0.003, p for heterogeneity = 0.616), respectively. For both SNPs, while smoking was significantly less frequent in patients than controls in AA homozygotes, this inverse association disappeared in G allele carriers.

CONCLUSIONS

We identified and replicated suggestive gene-by-smoking interactions in PD. The inverse association of smoking with PD was less pronounced in carriers of minor alleles of both RXRA-rs4240705 and SLC17A6-rs1900586. These findings may help identify biological pathways involved in the inverse association between smoking and PD.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Parkinson disease male-to-female ratios increase with age: French nationwide study and meta-analysis

BACKGROUND

Parkinson's disease (PD) is 1.5 times more frequent in men than women. Whether age modifies this ratio is unclear. We examined whether male-to-female (M-F) ratios change with age through a French nationwide prevalence/incidence study (2010) and a meta-analysis of incidence studies.

METHODS

We used French national drug claims databases to identify PD cases using a validated algorithm. We computed M-F prevalence/incidence ratios overall and by age using Poisson regression. Ratios were regressed on age to estimate their annual change. We identified all PD incidence studies with age/sex-specific data, and performed a meta-analysis of M-F ratios.

RESULTS

On the basis of 149 672 prevalent (50% women) and 25 438 incident (49% women) cases, age-standardised rates were higher in men (prevalence=2.865/1000; incidence=0.490/1000 person-years) than women (prevalence=1.934/1000; incidence=0.328/1000 person-years). The overall M-F ratio was 1.48 for prevalence and 1.49 for incidence. Prevalence and incidence M-F ratios increased by 0.05 and 0.14, respectively, per 10 years of age. Incidence was similar in men and women under 50 years (M-F ratio <1.2, p>0.20), and over 1.6 (p<0.001) times higher in men than women above 80 years (p trend <0.001). A meta-analysis of 22 incidence studies (14 126 cases, 46% women) confirmed that M- F ratios increased with age (0.26 per 10 years, p trend=0.005).

CONCLUSIONS

Age-increasing M-F ratios suggest that PD aetiology changes with age. Sex-related risk/protective factors may play a different role across the continuum of age at onset. This finding may inform aetiological PD research.

Choice of dopaminergic therapy among early, mild Parkinson disease subjects in North America

The choice of dopaminergic therapy in early Parkinson disease (PD) is an important clinical decision, yet factors influencing this decision have not been extensively studied. We sought to investigate the factors that may be associated with the choice of dopaminergic therapy at the NINDS Exploratory Trials in PD (NET-PD) Long-Term Study-1 (LS1). NET-PD LS1 was a clinical trial of creatine versus placebo in participants with early, mild PD on stable doses of dopaminergic therapy. Baseline data from 1616 out of the 1741 participants were evaluated using univariable and multivariable logistic or generalized logit regression analyses for available factors associated with the choice of dopaminergic therapy. The dopaminergic therapy choice was determined as: (i) therapy that subjects recalled taking 180days before the study; (ii) therapy at baseline; and (iii) the longest duration of therapy reported by participants. Younger age, higher education level, longer length of time since PD diagnosis and use of an adjunctive, non-dopaminergic or monoamine oxidase inhibitor medication were associated with more frequent use of dopamine agonist compared to levodopa or combination therapy.

The impact of extended release dopamine agonists on prescribing patterns for therapy of early Parkinson's disease: an observational study

Background

Dopamine agonists (DA) are the first-choice drug for treatment of the early stage of Parkinson’s disease (PD) in subjects younger than 70 years. Recently, a number of third generation DA have been marketed, including transdermal patch of rotigotine and extended release oral formulation of ropinirole and pramipexole.

We investigated the impact of third generation DA on management of the early stage of PD in an outpatient service for Movement Disorders in Italy.

Methods

Two 12-month observation periods were selected (January - December, 2007, and January - December, 2011) as representative for prescription of immediate and extended release formulations of DA respectively. Within each period, PD patients were divided into subgroups according to age (<65 years; 65–75 years; >75 years) or functional requirement (high; moderate; low). For each period, the number of subjects receiving monotherapy with DA, monotherapy with levodopa (LD), or combined DA/LD therapy and the relative doses were calculated. The severity of parkinsonian motor symptoms was calculated by means of the Unified Parkinson’s Disease Rating Scale part III (UPDRS-III) score. The frequency and severity of side-effects leading to discontinuation or reduction of DA drugs at each time point were also calculated.

Results

We found a significant reduction of daily LD dose (both as mono- and combined therapy) between the second and the first observation period. There was also a significant increase of monotherapy with DA and corresponding reduction of monotherapy with LD in patients aged 65–75 years, as well as in PD patients with moderate functional requirements. A significant reduction of frequency of side-effects was measured with extended release DA as compared to immediate release formulations. There were no significant differences of the UPDRS-III scores between the 2 observation periods in any subgroup.

Conclusions

Our results suggest that extended release DA might optimize therapeutic management of the early stages of PD even in patients older than 70 years of age.

Association between Parkinson's disease and the HLA-DRB1 locus

Two genome-wide association studies (GWASs) recently highlighted the HLA-DRA and HLA-DRB5 genes as associated with Parkinson disease (PD). However, because HLA-DRA displays a low level of polymorphisms and HLA-DRB5 is only present in approximately 20% of the population, these findings are difficult to interpret. Our aims were: (1) to replicate and investigate in greater detail the association between PD and the HLA-DR region; (2) to identify PD-associated HLA alleles; and (3) to perform a meta-analysis of our top finding. As part of 2 French population-based case-control studies of PD including highly ethnically homogeneous participants, we investigated the association between PD and 51 Single-nucleotide polymorphisms (SNPs) in the HLA-DR region. HLA-DRB1 alleles were imputed using the HLA(*) IMP software. HLA typing was performed in a subsample of the participants. We performed a meta-analysis of our top finding based on 4 GWAS data sets. Among 499 cases and 1123 controls, after correction for multiple testing, we found an association with rs660895 (OR/minor allele, 0.70; 95% CI, 0.57-0.87) within the HLA-DRB1 gene, which encodes the most polymorphic HLA-DR chain (DRβ). A meta-analysis (7996 cases, 36455 controls) confirmed this association (OR, 0.86; 95% CI, 0.82-0.91; P < .0001). SNP-based imputation of HLA alleles showed an inverse association between PD and the HLA-DRB1(*) 04 allele. We replicated an association between PD and the HLA-DR region and provided further insight into the loci and alleles involved. The highly polymorphic HLA-DRB1 locus contains rs660895, which represents a more legitimate candidate than previous ones. Our finding is in agreement with the hypothesis of an immune component in PD pathophysiology.