Ethnicity as a predictor of nonmotor symptoms impact on quality of life in patients with Parkinson’s disease: A systematic review

Abstract

AbstractBackgroundParkinson’s disease (PD) is a chronic progressive hypokinetic movement disorder characterised by rigidity, tremor, and bradykinesia in addition to multiple non-motor features. It is increasingly recognised that NMS have a substantial impact on the quality of life (QoL) of people with PD, more than motor features. The prevalence and types of these NMS vary among PD patients from different ethnic groups. Ethnicity has been postulated as a determinant of PD symptoms and quality of life of people with PD. There is paucity of data on the effect of ethnicity on (QoL) of people with PD.AimThe aim of this review is to critically evaluate the literature to (1) identify the variability of NMS that affect QoL of people with PD from different ethnicities, and (2) to examine if ethnicity could determine the impact of these NMS on the QoL of people with PD.MethodsThis review was conducted according to recommendations in preferred reporting Items for Systematic Review and Meta-Analysis (PRISMA). Search was conducted in three databases (PubMed, Ovid Embase and Scopus) in the period between March & July 2023. NMS were assessed by four scales: NMSS, NMQT, MDS-UDPRS I, and HADS. QoL was assessed by PDQ39. Ethnicity has been defined based on the country where the study has been conducted. A best-evidence synthesis was used to summarise the demographics, study designs, NMS features in each ethnic group. The impact of NMS features on QoL in different ethnic groups was assessed by comparing the power of correlations measures between NMS domains and QoL in all studies.ResultsTwenty-one studies with 4246 patients were deemed suitable to be included. Patients in the selected studies were grouped to eight ethnic populations: Caucasian, East Asian, Indian, North African, West African, Hispanic, Mediterranean, and Middle Eastern ethnicities. Heterogeneous protocols and varied statistical methodologies were used in most studies to assess the relation between NMS and QoL of people with PD. Overall depression, fatigue, and sleep and memory problems are the symptoms with the most significant impact on QoL of majority of ethnic populations. Other NMS including cardiovascular, gastrointestinal and urinary Symptoms exhibited a variability in their impact on QoL in different ethnic groups.ConclusionOur study demonstrates that ethnicity may have a significant impact on the correlation between NMS and QoL of patients with PD. There is deficiency in studies assessing the impact of PD NMS on QoL in Africans, Latin Americans, and Middle Eastern populations. Ethnicity is poorly defined and frequently unaddressed in PD studies. Large multicentre, multinational multi-ethnic studies using rigorous unified protocols are required to properly evaluate the effect of ethnicity on PD NMS. Identification of these variabilities is crucial to aid efficient health policy planning based on each population needs and optimize use of local resources.