Economic aspects of Parkinson’s disease

Abstract

Background: Next to Alzheimer’s disease, Parkinson’s disease (PD) is the second most neurodegenerative disease. As the population structure in the industrialized and industrializing countries is changing, an increasing prevalence of diseases typical for the elderly is projected within the next decades. The burden of disease, cost driving factors and the effectiveness of disease management options are therefore important information, as health and social care systems must prepare for a rising demand for economic resources and trained personnel within the health care sector. Objectives: The objective of this thesis was to describe different aspects of the economic burden of PD as drug costs, institutional care, hospitalization and the cost-effectiveness of the disease management. Subjects: In the first study we evaluated a group of 286 consecutive patients with PD searching free advice in a German counseling program and a group of 152 consecutive Norwegian patients with PD being followed at the outpatient clinic of the Stavanger University Hospital. In the second and third study we included the 108 patients with PD from a population-based prospective longitudinal study in Southern Rogaland, Norway, who were living in the municipality of Stavanger at baseline. Through the National registry we identified eight control subjects for every patient with PD that matched in sex and age and were living in Stavanger at baseline. In the fourth study we included 199 patients participating in a population-based prospective longitudinal study of patients with incident PD from Western and Southern Norway. Among relatives and acquaintances of the patients 205 controls were recruited. We included a subset of 172 control individuals who provided the best possible group match regarding sex, age and education and complete information about their health status. Methods: In the first study data about disease duration, disease severity as measured by Hoehn and Yahr (HY) stage, and drug use were collected for both patient groups in a crosssectional study design. In the second study, for patients with PD data about disease duration, disease severity as measured by HY stage, cognitive functioning as measured by the Mini Mental State Examination (MMSE), date of permanent admission to a nursing home and date of death were collected from the patient files and the municipality’s registration systems during a 12-year observation period. For controls, data about age, date of admission to a nursing home and date of death were collected from the municipality’s registration systems and the National registry. In the third study data about hospital admissions, length of stay and diagnoses at discharge were collected from the files of the Stavanger University Hospital for patients and controls over a 12-year observation period. In the fourth study, for the patients with PD data about disease severity as measured by HY stage and the Unified Parkinson’s Disease Rating Scale (UPDRS), health status as measured by the Short form 36 (SF-36) and drug use was registered during the first year of medical treatment. For controls independency in daily living as measured by the UPDRS part II and the SF-36 were registered during the same period. To evaluate health state values, the data of the SF-36 were converted to the Short Form-6D (SF-6D). Results: We found that drug expenses rose with disease duration and disease severity both in the German and the Norwegian study cohort. However, expenses were markedly higher in the German cohort with Euro 5.78 versus Euro 3.92 per patient and day, partly due to an earlier switch from mono- to multi-drug therapy during the course of the disease. Patients with PD had a five-fold higher risk for living in a nursing home as compared to controls. Based on 2007 prices, the incremental costs for institutional care were Euro 14 897 per person year of survival. There was no significant difference between patients with PD and controls regarding the number of individuals being admitted to hospital, numbers of admission, or length of stay. However, we found that patients with PD were more often admitted for trauma, while cardio-vascular diseases and cancer were markedly more common in control individuals. Patients with PD had significantly lower health state values as compared to controls. Patients starting on antiparkinsonian drugs had an improvement in utility scores of 0.039 from 0.667 to 0.706. The incremental cost-effectiveness ratio (ICER) was Euro 45 259 per quality adjusted life year (QALY) during the first year of treatment, of which two thirds were caused by drugs and one third by costs for clinical consultations. Conclusion: We could show that the use of control cohorts adds valuable information to the evaluation of the burden of disease and helps to discern costs related to a certain disease from costs caused by general age-related morbidity. We could further show that prescription habits may differ markedly from country to country and that the ICER during the first year of treatment is high. Therefore, disease management should be monitored carefully to provide an optimal quality of treatment as well as cost-effectiveness. However, more research is necessary to evaluate the full burden of PD and to explore efficacy and effectiveness of the different disease management options.