Schröder et al Table 4 Percentage use of L-dopa, dopamine agonists, amantadine, and MAO-B inhibitors in patient subgroups (n = 320) Any dopamine agonist Dopamine agonist + L-dopa L-dopa Amantadine Symptom severity – mild symptoms ,70, grade ii Yes (n = 46) $70, grade ii Disease duration – time since diagnosis ,70, grade iii ,5 years (n = 84) $5 years (n = 43) $70, grade iii ,5 years (n = 71) $5 years (n = 40) Cognitive impairment ,70, grade ii Yes (n = 6) No (n = 18) Yes (n = 12) No (n = 6) No (n = 58) Yes (n = 16) No (n = 111) Yes (n = 3) No (n = 15) Yes (n = 26) No (n = 85) ,70, grade iii $70, grade ii $70, grade iii 31 (67.4%) 14 (77.8%) 6 (50.0%) 1 (16.7%) 71 (84.5%) 36 (83.7%) 30 (42.3%) 19 (47.5%) 4 (66.7%) 41 (70.7%) 13 (81.3%) 94 (84.7%) 0 7 (46.7%) 11 (42.3%) 38 (44.7%) 6 (13.0%) 5 (27.8%) 4 (33.3%) 1 (16.7%) 35 (41.7%) 31 (72.1%) 25 (35.2%) 19 (47.5%) 1 (16.7%) 10 (17.2%) 9 (56.3%) 57 (51.4%) 0 5 (33.3%) 10 (38.5%) 34 (40.0%) 15 (32.6%) 8 (44.4%) 9 (75.0%) 5 (83.3%) 44 (52.4%) 37 (86.0%) 63 (88.7%) 39 (97.5%) 2 (33.3%) 21 (36.2%) 11 (68.8%) 70 (63.1%) 3 (100%) 11 (73.3%) 23 (88.5%) 79 (92.9%) 11 (23.9%) 0 4 (33.3%) 0 19 (22.6%) 15 (34.9%) 12 (16.9%) 15 (37.5%) 1 (16.7%) 10 (17.2%) 6 (37.5%) 28 (25.2%) 0 4 (26.7%) 7 (26.9%) 20 (23.5%) Dovepress MAO-B inhibitor 5 (10.9%) 0 1 (8.3%) 1 (16.7%) 12 (14.3%) 10 (23.3%) 5 (7.0%) 10 (25.0%) 0 5 (8.6%) 1 (6.3%) 21 (18.9%) 0 2 (13.3%) 3 (11.5%) 12 (14.1%) the level of adherence to L-dopa without dopamine agonists was similar in grades II and III, with only limited agreement with the guideline in both cases. Combination therapy with L-dopa plus dopamine agonists increased slightly with longer disease duration and mild symptoms, which might partly explain nonadherence to the recommended mono- therapy in older patients. The small number of patients aged $70 years in grade II, as would be expected in Parkinson’s disease, means that no firm conclusions can be drawn for this patient subgroup. When comparing agreement with the parameters accord- ing to claimed guideline adherence, the differences did not achieve statistical significance. It therefore cannot be con- cluded that neurologists who claimed to follow the guideline did indeed follow it more strictly. As the derivation of statistically testable parameters from any guideline recommendation is not straightforward, there may be a number of methodological reasons that influence the low level of agreement between the physician’s treatment choice and the guideline. One possible reason is that the parameters cannot take into account individua- lized therapy based on patient characteristics as is recom- mended in the guideline. The different possible definitions of key variables are another potential problem. Initiation with and maintenance of monotherapy for as long as pos- sible is one of the core recommendations. When translating the term “monotherapy” directly from the guideline, it is naturally linked to the L-dopa sparing approach in younger patients or the reluctant use of dopamine agonists in older or comorbid patients. However, we chose the more precise 108 submit your manuscript | www.dovepress.com Dovepress Neuropsychiatric Disease and Treatment 2011:7