Dovepress variables “dopamine agonist without L-dopa” and “L-dopa without dopamine agonist” to investigate accordance with the guideline. Another factor that should be taken into account is that we divided the patients according to physician-rated grades of functional impairment based on H&Y stages and L-dopa-associated motor complications, whilst the guideline does not. In particular, if maintenance of monotherapy for as long as possible is recommended, patients’ level of functional impairment must be taken into account when translating the guideline recommendations into explicit parameters since progression across H&Y stages is closely related to the dura- tion of disease.22 Our analyses revealed that monotherapy was only partly followed by neurologists, independently of H&Y stage. In general, and particularly when giving advice on monotherapy, the guideline should be more precise in terms of functional impairment. In the analyses, we used data from a nationwide study aimed at obtaining as representative a sample of real- life Parkinson’s disease patients in Germany as possible. Consequently neurologists were the focus, most of whom were office-based, as the majority of Parkinson’s disease patients in Germany are treated in this setting.2 However, as prescription patterns may change if patients are treated by general practitioners or in outpatient clinics,23,24 it might be of interest to investigate guideline adherence in these set- tings, as well as in more severely ill patients at a later H&Y stage or those treated as in-patients. In contrast to the results of some other studies in which the patient population was restricted, for example, to members of a support group,23 we used data from outpatients typical of those treated in everyday clinical practice. Nevertheless, there may have been an inherent selection bias amongst the neurologists who took part in the study, as only those who were able to provide the necessary information within the required time frame were selected. The 10–13 months between publication of the guideline and performance of the survey should have allowed suffi- cient time to reflect the impact on clinical practice. Indeed, all physicians in the survey reported that they were aware of the content of the guideline. It is worthy of consideration that Parkinson’s disease guidelines are based on evidence-based medicine and, as guidelines take around two years to develop, this evidence may itself be outdated by the time the guidelines are published.25 Many practicing physicians would therefore have also already been exposed to the evidence base during this intervening period. We presume that the physicians were, as they stated, aware of current treatment practices reviewed in Neuropsychiatric Disease and Treatment 2011:7 Parkinson’s disease guideline adherence the guidelines and that this survey can therefore be considered of relevance. We investigated adherence to the first guideline that was issued in Germany in 2003. Updates of the guideline were published in 2005 and 2008,26 and it is possible that the neurologists’ awareness of treatment guidelines might have subsequently changed. Increasing concerns regarding adverse events associated with dopamine agonists, including daytime somnolence, leg edema, impulse control disorders, and valvular heart conditions27 may, for example, have influenced clinical practice since our survey was conducted in 2004. The current guidelines from 2008, however, still follow the same core treatment recommendations, albeit being more restrictive in the use of ergot dopamine agonists. Findings from a study to assess German neurologists’ awareness of the existence of the national guideline were published in 2005.13 This cross-sectional questionnaire was carried out using 181 neurologists in private practice. Surprisingly, only about half of the neurologists claimed to be aware of the guideline. Of these, 60% rated the guideline positively, although 53% reported having problems using it in their general practice. This suggests that implementa- tion strategies may be necessary to improve neurologists’ knowledge and use of the guideline. A study into the attitudes and barriers to the national guideline in Germany indicated that lack of time and an inability to reconcile patient prefer- ences with guideline recommendations were also important reasons for nonadherence.14 Previous researchers have shown that implementation of clinical guidelines is associated with a wide range of problems,28 although their adoption can help to improve the quality of care.29,30 There is, however, a paucity of data on how guideline adherence influences the patient’s outcome. In conclusion, our study of German neurologists can be regarded as a pilot approach to translating a clinical guideline into distinctive parameters to evaluate guideline adherence of neurologists treating patients with Parkinson’s disease. The findings revealed that recommendations were only partially followed. Further research is needed into the reasons for nonadherence and the impact of guideline adher- ence on therapeutic outcomes. Acknowledgments This study was supported by an unrestricted grant from Solvay Pharmaceuticals GmbH, Hannover, Germany, as part of a research project on the management of Parkinson’s disease in Germany conducted at the Institute of Clinical Pharmacology, Charité University of Medicine, Berlin. submit your manuscript | www.dovepress.com Dovepress 109