Imo, the excerpt presumes a very narrow concept of PD.
"For example, in a recent report from Australia, the primary reason for hospitalization among 761 admissions of parkinsonian patients was found to be related to PD related symptoms in only 116 instances (15%) [9]. The remaining reasons for admission were: falls (12.6%), pneumonia (12%), cardiac disorders (11.6%), genitourinary infections (11%), gastrointestinal disorders (11%), neoplasia (9.9%), encephalopathy (7%), syncope (4%), stroke (3.6%), and dementia (3%) [9]."
Management of the hospitalized patient with Parkinson’s disease: Current state of the field and need for guidelines.
Michael J. Aminoff, Chad W. Christine, [...], and Michael S. Okun.