Dovepress recommendation based on the four core principles. These parameters were used to perform precise biometric analy- ses to quantify the qualitative principle of the guidelines (Table 1). The parameters were: • Parameter 1. Patients aged ,70 years old in grade II: use of dopamine agonist without L-dopa (L-dopa sparing approach) • Parameter 2. Patients aged ,70 years old in grade III: use of any dopamine agonist as mono- or combination therapy • Parameter 3. Patients aged $70 years old in grade II: use of L-dopa without dopamine agonists • Parameter 4. Patients aged $70 years old in grade III: use of L-dopa without dopamine agonists Hence, for each patient selected for the analyses, one of the four parameters was applicable depending on age and grade of functional impairment. The percentage agreement between the patient’s treatment and the applicable parameter was therefore selected as the key outcome parameter in the main analysis. Secondly, adherence to the parameters was compared within two groups of patients classified according to the claimed guideline adherence by the neurologist: “guideline group” (patients treated according to the national guideline as stated by their neurologists) and the “nonguideline group” (patients not treated according to the national guideline as stated by their neurologists). Chi-square tests for contingency tables were performed to investigate the relative agreement between the guideline and nonguideline groups. If the Parkinson’s disease guideline adherence requirements were not met, Fisher’s exact test was used. The probability criterion for rejecting the hypotheses was p = 0.05. Thirdly, further subgroup analyses were performed focusing on symptom severity, time since diagnosis, and the presence of cognitive impairment/dementia. Since recommendations for treatment initiation differ in patients with mild symptoms, drug use was analyzed according to physician-rated symptom severity (presence/absence of mild symptoms of tremor at rest, rigidity, and bradykinesia) in patients in grade II. Assuming that disease duration may influ- ence therapy in more functionally impaired patients, drug use was also analyzed based on time since diagnosis (,5 years versus $5 years) in patients in grade III. The division was made at 5 years since many patients begin to notice a decline in benefit after about 5 years of dopaminergic therapy.21 Finally, prompted by one of the guideline’s core recom- mendations on the “reluctant use of dopamine agonists in patients with active comorbid medical problems”, drug use was analyzed in patients in grades II and III according to the presence/absence of cognitive impairment as a symptom and/or dementia as a diagnosis, as rated by the physicians according to their clinical standards. All statistical analyses were performed using STATA software (Version 9.1; Stata Corporation, College Station, TX). Results Of the 60 neurologists, 54 were office-based, five hospital- based, and one was based in both an office and a hospital. Table 1 Translation of german national guideline into explicit parameters in idiopathic Parkinson’s disease (n = 451) Without functional impairment (Grade I) n = 5 (2.0%) ,70 years Standard (n = 251) treatment Alternative treatment Patients $70 years Standard (n = 200) treatment Alternative treatment Patients n = 1 (0.5%) Note: Shaded area: patients included in analysis. Abbreviation: DA, dopamine agonist. Lower grade of functional Higher grade of functional impairment without impairment without motor motor fluctuations or fluctuations or complications complications (Grade II) (Grade III) DA (monotherapy) DA (mono or combination therapy) Parameter 1: % DA Parameter 2: % DA without L-dopa L-dopa (if risk of losing job), amantadine/selegiline (if mild symptoms) n = 64 (25.5%) n = 127 (50.6%) L-dopa (monotherapy) L-dopa (monotherapy) Parameter 3: % L-dopa Parameter 4: % L-dopa without DA without DA amantadine/selegiline (if mild symptoms) n = 18 (9.0%) n = 111 (55.5%) L-dopa associated Palliative motor fluctuations phase or complications (Grade IV) (Grade V) complex management (depending on types of motor fluctuations and complications) n = 53 (21.1%) n = 2 (0.8%) complex management (depending on types of motor fluctuations and complications) n = 60 (30.0%) n = 10 (5.0%) Neuropsychiatric Disease and Treatment 2011:7 submit your manuscript | www.dovepress.com Dovepress 105