The effect of functional status impairment on nursing home admission risk among patients with advanced Parkinson’s disease

Abstract

Aims: To estimate the relationship between functional status (FS) impairment and nursing home admission (NHA) risk in Parkinson’s disease (PD) patients, and quantify the effect of advanced PD (APD) treatment on NHA risk relative to standard of care (SoC).

Materials and methods: PD patients were identified in the Medicare Current Beneficiary Survey (MCBS) (1992–2010). A working definition based on the literature and clinical expert input determined APD status. A logit model estimated the relationship between FS impairment and NHA risk. The effect of levodopa-carbidopa intestinal gel (LCIG) on NHA risk relative to SoC was simulated using clinical trial data (control: optimized oral levodopa-carbidopa IR, ClinicalTrials.gov NCT00660387 and NCT0357994).

Results: Non-advanced PD and APD significantly increased NHA risk when controlling for demographics (p < 0.01). APD status was no longer significant after controlling for FS limitations, implying that FS limitations explain the increased NHA risk in APD patients. Reduced impairment in FS in patients with APD treated with LCIG reduced risk of NHA by 13.5% relative to SoC.

Limitations: This study applies clinical trial results to real-world data. LCIG treatment might have a different effect on NHA risk for the nationally representative population than the effect measured in the trial. Both data sources employ different instruments to measure FS, instrument wording and study follow-up differed, which might bias our estimates. Finally, there lacks consensus on a definition of APD. The prevalence of APD in this study is high, perhaps due to the specific definition used.

Conclusions: Patients with APD experience a higher risk in NHA than those with non-advanced disease. This increased risk in NHA in patients with APD is explained by greater limitations in FS. The relative reduction in risk of NHA for the APD population treated with LCIG is quantitatively similar to doubling Medicaid home care services.

Keywords:

• Long-term care
• disability
• activities of daily living
• functional health status
• Parkinson’s disease
• advanced Parkinson’s disease
• nursing home admission

JEL CLASSIFICATION CODES:

• I00
• I10

Transparency

Declaration of funding

This work was supported by AbbVie (https://www.abbvie.com). The design, study conduct, and financial support for the study were provided by AbbVie.

Declaration of financial/other relationships

Kavita R. Sail, Thomas S. Marshall, and Yash J. Jalundhwala are employees of AbbVie and may own AbbVie stock or stock options. Jeffrey Sullivan and Emma van Eijndhoven are employees of Precision Health Economics (PHE), a consulting firm providing services to the life sciences industry. PHE received compensation from Abbvie to conduct this study. Tiffany M. Shih was a former employee of PHE during the time of the study. Darius N. Lakdawalla holds equity in Precision Medicine Group, parent company of PHE. Cindy Zadikoff currently is an employee of AbbVie and may own AbbVie stock or stock options. When the study was being conducted, Cindy Zadikoff was affiliated with Feinberg School of Medicine, Northwestern University, Chicago, IL, and has previously received honoraria for consulting and lecturing from AbbVie. In addition, she has received consulting honoraria from various biopharmaceutical companies. JME peer reviewers on this manuscript have received an honorarium from JME for their review work, but have no other relevant financial relationships to disclose.

Acknowledgements

We would like to thank Suepattra May-Slater, employee of PHE, and Warren Stevens, Jennifer Benner, and Shalak Gunjal, former employees of PHE, for their support of this study. Financial support for their services was provided by AbbVie. In addition, we would like to thank Dr Kapil Sethi for his clinical advice.

Previous presentations

This work was previously presented at the 2016 AAN Annual Meeting in Vancouver, BC, Canada on April 15–21, 2016.

Data availability

Data was used from the Medicare Current Beneficiary Survey and a 12-week prospective, Phase 3, randomized, double-blind, double-dummy, clinical trial that evaluated the efficacy, safety, and tolerability of LCIG treatment in levodopa-responsive APD subjects who continue to experience persistent motor fluctuations despite receiving optimal treatments for PD (ClinicalTrials.gov NCT00660387 and NCT0357994). The MCBS data is DUA-restricted and the trial data is confidential.