The Key Determinants to Quality of Life in Parkinson’s Disease Patients: Results from the Parkinson’s Disease Biomarker Program (PDBP)

Article type: Research Article

Authors: He, Lu^{a; b} | Lee, Eun-Young^a | Sterling, Nicholas W.^a | Kong, Lan^c | Lewis, Mechelle M.^{a; d} | Du, Guangwei^a | Eslinger, Paul J.^a | Huang, Xuemei^{a; d; e; f; g; *}

Affiliations: [a] Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey PA, USA | [b] School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, China | [c] Department of Public School Health, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA, USA | [d] Department of Pharmacology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA, USA | [e] Department of Radiology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA, USA | [f] Department of Neurosurgery, Pennsylvania State University-Milton S. Hershey Medical Center Hershey, PA, USA | [g] Department of Kinesiology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, PA, USA

Correspondence: [*] Correspondence to: Xuemei Huang, M.D., Ph.D., Department of Neurology, Penn State University, H037, 500 University Drive, Hershey, PA 17033-0850, USA. Tel.: +1 717 531 0003/Ext. 287082; Fax: +1 717 531 0266; E-mail: xuemei@psu.edu.

Abstract: Background: The impact of motor- and non-motor symptoms on health-related quality of life (HRQOL) in Parkinson’s disease (PD) has received increasing attention. Objectives: To address this, the study explored a large cohort of patients enrolled in the PD Biomarker Program. Methods: The PD Questionnaire-39 (PDQ-39) measured HRQOL, whereas the Unified PD Rating Scale (UPDRS) assessed motor and non-motor symptoms. Determinants of HRQOL in PD patients were identified by stepwise linear regression analysis. The relationship between the PDQ-39 and UPDRS subscale scores then was explored through structural equation modeling. Results: The mean disease duration was 6.8 years and the mean PDQ-39 summary index (PDQ-39SI) was 18.4. UPDRS-I (non-motor function) and UPDRS-II (motor questionnaire) scores demonstrated the strongest correlations with PDQ-39SI (r Ϡ 0.4, P < 0.05), whereas UPDRS-III (motor exam) and UPDRS-IV (motor complications) scores were correlated moderately with PDQ-39SI (0.3 < r < 0.4, P < 0.05). Multiple linear stepwise regression analyses showed that age (β= –0.13, P < 0.001), education (β= –0.07, P = 0.008), UPDRS-I (β= 0.32, P = 0.000), and UPDRS-II (β= 0.44, P < 0.001) significantly contributed to HRQOL, and cumulatively accounted for 69.1% of the PDQ-39SI variance. UPDRS-II score was the primary predictor of PDQ-39SI, accounting for 57.3% of the variance, whereas UPDRS-I score accounted for 7.5%. UPDRS-III and -IV and other factors measured did not survive stepwise regression. Structural equation modeling confirmed the association of UPDRS-II (β= 0.67, P < 0.001) and UPDRS-I (β= 0.35, P < 0.001) with the PDQ-39SI. Conclusion: Both motor and non-motor function scores impacted significantly HRQOL in PD. UPDRS-III, however, has limited contributions to HRQOL although it is used as a main outcome in many clinical trials.

Keywords: Parkinson’s disease, quality of life, motor symptoms, non-motor symptoms, structural equation modeling, Unified Parkinson’s disease rating scales, structure, review

DOI: 10.3233/JPD-160851

Journal: Journal of Parkinson's Disease, vol. 6, no. 3, pp. 523-532, 2016