Nearly 3 times as many patients with newly diagnosed Parkinson’s disease had dependency in ≥1 activities of daily living (ADLs) compared with a healthy control group, a recent longitudinal, population-based study demonstrated (Bjornestad A, et al. Neurology. 2016;87:1599-1606).
Data showed a dependency rate of 15.9% in patients with Parkinson’s disease compared with 5.7% in the control group, matched for age, sex, and comorbidity. The prevalence of dependency in ADLs increased rapidly in the patients with Parkinson’s disease, affecting more than 50% of patients at 5 years compared with 14% of individuals in the control group. The dependency was irreversible in almost all cases, reported Anders Bjornestad, MD, with the Norwegian Centre for Movement Disorders, Stavanger University Hospital, Norway, and colleagues.
“Our finding that more than half of patients became dependent within 5 years of diagnosis may be considered to challenge the current opinion that PD [Parkinson’s disease] has a benign early phase,” the investigators said. “This view is further substantiated by our observation that even minor functional independence loss appears to be persistent, with a high risk of progression to institutionalization within a few years.”
“Together, these observations may justify the addition of independence loss to the series of the more established clinical milestones in PD,” they added.
Previous studies evaluating the loss of independence in Parkinson’s disease primarily comprised cross-sectional cohorts and patients with advanced disease who were recruited at hospitals or specialty clinics. Only a few longitudinal studies have been conducted, particularly in patients with early-stage Parkinson’s disease. Furthermore, the majority of previous studies assessed independence via the use of disability scales, which are insensitive to the loss of independence.
This prospective study focused on the frequency, risk factors, prognosis of independence loss, and institutionalization in 189 patients with newly diagnosed Parkinson’s disease. These patients were compared with a matched control group of 175 individuals without Parkinson’s disease and followed for 5 years. During follow-up, all patients with Parkinson’s disease received anti-Parkinson’s disease therapy, as determined by the treating physicians.
At baseline, 30 patients with Parkinson’s disease had loss of independence in ADLs compared with 10 individuals in the control group, translating into a relative risk of 2.8 for dependence in patients with Parkinson’s disease versus the control group (P = .004).
Loss of dependence at baseline was associated with older age (74.3 years vs 66.5 years; P <.001), more severe Parkinsonism (Unified Parkinson’s Disease Rating Scale [UPDRS] motor score 33.6 vs 21.4; P <.001), more advanced disease stage (P <.001), lower global cognitive function (P = .021), proportion of patients with mild cognitive impairment (50% vs 17%; P <.001), and higher comorbidity burden (Charlson Comorbidity Index score 0.5 vs 0.25; P = .006) in patients with Parkinson’s disease versus healthy individuals, respectively.
Among the 159 patients with Parkinson’s disease who were independent at baseline, the prevalence of dependence increased over time:
- 6.3% at 1 year
- 25.8% at 3 years
- 40.9% at 5 years.
Compared with the control group, patients with Parkinson’s disease had a relative risk for loss of independence of 2.1 after 1 year, 4.2 after 3 years, and 4.5 after 5 years, all significant differences. The relative risk for home care increased from 2.1 after 1 year, 4.1 after 3 years, and 4.2 after 5 years.
The 2 groups did not differ with respect to institutionalization at 1 year or at 3 years, but significantly more patients with Parkinson’s disease required facility care at 5 years than the control group (12.6% vs 0.6%, respectively; relative risk, 20.6; P = .003).
Logistic regression analysis identified 4 independent predictors of loss of independence during follow-up, including older age (hazard ratio [HR], 1.07 yearly; P = .001), higher motor severity (HR, 1.04 per UPDRS motor score unit; P = .013), shorter motor symptom duration (HR, 0.82 yearly; P = .031), and the presence of mild cognitive impairment (HR, 1.81; P = .048).
“We suggest that future research should focus on identification of biomarkers for independence loss, as dissection of the biological substrates of dependency would be important to reveal the mechanisms responsible for the accelerated neurodegenerative process that probably underlies the earlier entry into the more advanced disease stages,” concluded Dr Bjornestad and colleagues.