Association between non-motor symptoms and health-related quality of life for patients with Parkinson’s disease: Evidence from a smartphone-based survey

Background This study aims to explore the association between the total number of non-motor symptoms and the Parkinson’s disease (PD) patients’ health-related quality of life quantitatively, using data from one of the largest smartphone-powered studies and a simplified version of 8-item Parkinson’s disease Quality of life Questionnaire (PDQ-8). Methods The data used for analysis constitutes one part of a dataset derived from the project named ‘100 for Parkinson’s’. 1246 patients were included in the baseline survey. The 30-item Non-Motor Symptom (NMS-30) Questionnaire and PDQ-8 Summary Index (PDQ-8 SI) were used to measure health-related quality of life and a generalized linear model was used to analyze the association of the non-motor symptoms and quality of life. Results The mean number of NMS per patient was 11.81 ± 5.53. For patients with limited ability to work: the key symptoms were urgency (77.4%), sad or blue (71.05%) and difficulty getting to sleep or staying asleep (70.90%). After controlling for the life-style determinants and psychological symptoms prior PD diagnosis determinants, GLM presented the total sum of NMS-30 questions had the strongest positive influence on health-related quality of life as measured by the PDQ-8 SI. Where the sum of NMS scores increases by 1 point, the PDQ-8 SI will increase by 1.33 points (95%CI: 1.13, 1.52; P < 0.001). For patients without limited ability to work: urgency (62.45%), difficulty getting to sleep or staying asleep (59.81%) and getting up regularly at night to pass urine (55.09%) were the most frequent symptoms. GLM showed that where the total sum of NMS scores increases by 1 point, the PDQ-8 SI will increase by 1.56 points (95%CI: 1.37, 1.76; P < 0.001) after controlling for other confounders. Conclusions This smartphone-based study finds a higher total number of non-motor symptoms is related to a lower health-related quality of life for PD patients. It provides useful evidence for the PDQ-8 instrument and is helpful for a multidisciplinary approach to patient care and facilitate the provision of more comprehensive education for patients and caregivers.