Dovepress Parkinson’s disease guideline adherence n = 40 n = 64 n = 24 P = 0.12 n = 127 n = 71 n = 56 P = 0.81 n = 7 n = 18 n = 11 P = n.a. n = 111 n = 46 n = 65 60 P = 0.45 Parameter 1 Parameter 2 Parameter 3 Parameter 4 0 20 40 80 100 Percentage of patients treated in accordance with the rule Overall adherence to national guideline Guideline group Nonguideline group Figure 1 Level of adherence to national guideline. Overall adherence and adherence in neurologists who state that they follow the guideline (“guideline group”) and those who do not state that they follow the guideline (“nonguideline group”). Notes: Parameter 1. Patients ,70 years, grade ii (n = 64): use of dopamine agonist without L-dopa. Parameter 2. Patients ,70 years, grade iii (n = 127): use of any dopamine agonists as mono or combination therapy. Parameter 3. Patients $70 years, grade ii (n = 18): use of L-dopa without dopamine agonists. Parameter 4. Patients $70 years, grade iii (n = 111): use of L-dopa without dopamine agonists. impaired patients (grade III), use of L-dopa plus dopamine agonist combination increased with time since diagnosis in those aged ,70 years, but not in those aged $70 years. The presence of cognitive impairment, however, did not have a marked effect on treatment decisions. Discussion Our results showed that neurologists in Germany use dop- amine agonists and L-dopa differently in different patient populations, with treatment being dominated by dopamine agonists in younger patients and L-dopa in older patients. This is an initial indicator of a general adherence to the national guideline. However, if the guideline is translated into strict param- eters, as in the current study, it is apparent that neurologists do not adhere well to recommendations on monotherapy, regardless of the patient’s age and grade of functional impairment. For example, only around half of patients aged Neuropsychiatric Disease and Treatment 2011:7 ,70 years in H&Y stage I received dopamine agonists without L-dopa and, surprisingly, more than a third were already receiving L-dopa. As patients with mild symptoms were less likely to receive L-dopa than those with more severe symptoms, symptom severity might be one reason for early use of L-dopa. Other potential reasons may involve individual patient circumstances and financial considerations reinforced by changes in health reform since, in Germany, L-dopa is much cheaper than dopamine agonists. Mild symptoms in patients with a lower grade of functional impairment were a clear predictor for use of amantadine and the MAO-B inhibitor selegiline; these findings are in line with guideline recommendations. Use of the L-dopa plus dopamine agonist combination increased with disease duration and grade of functional impairment, most notably in younger patients. This suggests that physicians try to adhere to the parameter of an L-dopa-sparing approach in younger patients for as long as possible. In patients aged $70 years, submit your manuscript | www.dovepress.com Dovepress 107