The prevalence and incidence of progressive supranuclear palsy and corticobasal syndrome: a systematic review and meta-analysis

Abstract

Introduction: Progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) are progressive neurodegenerative syndromes characterised by Parkinsonism with additional features including cognitive dysfunction, falls, and oculomotor abnormalities. Understanding the epidemiology of these conditions is critical to planning for future service provision.

Methods: We conducted a systematic review of studies reporting incidence and prevalence of CBS and PSP. A search of the PubMed and EMBASE data bases was conducted from their date of inception to 13th July 2021. Meta-analysis of studies sharing similar methodologies was carried out to generate estimated pooled prevalence and incidence.

Results: We found 32 studies meeting our criteria for inclusion. There were 20 studies with data on prevalence and 12 with incidence data of PSP. Prevalence of CBS was reported in eight studies while seven studies reported incidence. Reported estimates of prevalence for PSP ranged from 1.00 (0.9-1.1) to 18 (8-28) per 100,000 while prevalence rates for CBS ranged from 0.83 (0.1-3.0) to 25 (0-59). Incidence rates for PSP and CBS respectively ranged from 0.16 (0.07-0.39) to 2.6 per 100,000 person-years and 0.03 (0-0.18) to 0.8 (0.4-1.3) per 100,000 person-years. A random effects model meta-analysis of studies with similar methodologies yielded a pooled prevalence estimate for PSP of 6.92 (4.33-11.06, I² = 89%, τ² = 0.3907) and 3.91 (2.03-7.51, I² = 72%, τ² = 0.2573) per 100,000 for CBS.

Conclusion: Studies of the epidemiology of PSP and CBS report highly heterogeneous findings. There is a need for further studies using rigorous phenotyping and the most recent diagnostic criteria to understand the true burden of these conditions.

Keywords: Corticobasal syndrome; Epidemiology; Progressive supranuclear palsy; Tauopathy.

Fig.1

Flowchart of study identification and inclusion

Fig. 2

Unweighted forest plots of crude prevalence and incidence rates for: A PSP and B CBS prevalence per 100,000 population, C PSP and D CBS incidence per 100,000 patient-years with studies reported by region. a = Study restricted to population > 55, b = Study restricted to population > 65, c = Study restricted to population < 65, d  = Study restricted to population > 50. In cases where rates were not reported but could be calculated from provided data (cases and population and/or person-years) this was done

Fig. 3

Incidence of PSP A and CBS B per 100,000 person-years by age bands in Savica (2013), Caslake (2014), and Fleury (2018)

Fig. 4

Meta-analyses of studies reporting prevalence and incidence of PSP and/or CBS

Fig. 5

Pooled proportions in study subgroups be location, study denominator, and condition studied in A PSP prevalence, B PSP Incidence, C CBS incidence