A B S T R AC T :This study was undertaken to perform a systematic review and meta-analysis of studies of mortality in Parkinson's disease (PD) and to investigate which factors were associated with mortality. We conducted comprehensive searches of studies reporting a ratio of mortality in PD versus controls, descriptive survival measures, or factors predicting survival; assessed study quality; and extracted relevant data. Descriptive analysis, meta-analysis, and meta-regression were performed as appropriate. Eighty-eight studies were included in the review with variable study methods and quality. Almost all studies reported increased mortality in PD (vs. controls), with mortality ratios ranging from 0.9 to 3.8, with major between-study heterogeneity. Inception cohorts were more consistent with a pooled mortality ratio of approximately 1.5. Inception cohorts, measurements at longer follow-up duration, and older study recruitment year were associated with lower mortality ratios, but these findings were not robust in sensitivity analyses. Within studies, mortality ratios increased over time. No robust evidence was found that mortality has decreased after the introduction of levodopa (L-dopa). On average, PD survival reduced by approximately 5% every year of follow-up, although there was significant heterogeneity. In post-mortem studies, mean duration until death ranged from 6.9 to 14.3 years. Increasing age and presence of dementia were most commonly associated with increased mortality. Parkinson's disease is associated with increased mortality, but major heterogeneity is seen in estimates of mortality, which is probably explained by variable methodology and patient selection. Individual-patient-data meta-analysis of high-quality inception studies with long-term follow-up would be the optimal way to investigate the factors influencing mortality.
BackgroundValosin-containing protein (VCP) disease, caused by mutations in the VCP gene, results in myopathy, Paget’s disease of bone (PBD) and frontotemporal dementia (FTD). Natural history and genotype–phenotype correlation data are limited. This study characterises patients with mutations in VCP gene and investigates genotype–phenotype correlations.MethodsDescriptive retrospective international study collecting clinical and genetic data of patients with mutations in the VCP gene.ResultsTwo hundred and fifty-five patients (70.0% males) were included in the study. Mean age was 56.8±9.6 years and mean age of onset 45.6±9.3 years. Mean diagnostic delay was 7.7±6 years. Symmetric lower limb weakness was reported in 50% at onset progressing to generalised muscle weakness. Other common symptoms were ventilatory insufficiency 40.3%, PDB 28.2%, dysautonomia 21.4% and FTD 14.3%. Fifty-seven genetic variants were identified, 18 of these no previously reported. c.464G>A (p.Arg155His) was the most frequent variant, identified in the 28%. Full time wheelchair users accounted for 19.1% with a median time from disease onset to been wheelchair user of 8.5 years. Variant c.463C>T (p.Arg155Cys) showed an earlier onset (37.8±7.6 year) and a higher frequency of axial and upper limb weakness, scapular winging and cognitive impairment. Forced vital capacity (FVC) below 50% was as risk factor for being full-time wheelchair user, while FVC <70% and being a full-time wheelchair user were associated with death.ConclusionThis study expands the knowledge on the phenotypic presentation, natural history, genotype–phenotype correlations and risk factors for disease progression of VCP disease and is useful to improve the care provided to patient with this complex disease.
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