Clinical trials of add-on medications in Parkinson's disease: Efficacy versus usefulness

Parkinson's disease home diary: Further validation and implications for clinical trials

We provide further validation of a Parkinson's disease (PD) home diary and explore implications for practical use in clinical trials. We previously developed and published a home PD diary that includes the categories ASLEEP, off, on without dyskinesia, on with nontroublesome dyskinesia, and on with troublesome dyskinesia [Hauser et al., J Clin Neuropharmacol 2000;23:75-81] and demonstrated that patients generally consider off time and on time with troublesome dyskinesia "bad time" and on time without dyskinesia or with nontroublesome dyskinesia "good time". We suggested that that on time without dyskinesia or with nontroublesome dyskinesia would be an appropriate outcome measure in clinical trials of advanced PD patients. In the current study, PD patients with motor fluctuations and dyskinesia (present more than 25% of the awake day and at least moderately disabling) completed daily diaries on 3 consecutive days in each of 2 consecutive weeks. In addition, patients provided responses to five questions regarding dyskinesia and their motor response through the day on visual analog scales (VAS). Three hundred two patients from 10 countries participated. Eighty-three percent (n = 252) completed six diaries without missing or duplicate entries. Seventy-six percent of the missing or duplicate entries occurred after Day 3. Mean percent of the awake day on without dyskinesia or with nontroublesome dyskinesia ("good on", ONG%) was observed to be very stable over time (repeated measure analysis of variance, P = 0.99). Coefficients of reliability as calculated by Cronbach's alpha were as follows: 2 days, r = 0.806; 3 days, r = 0.868; 4 days, r = 0.918; 5 days, r = 0.934; 6 days, r = 0.946. The standard error of measurement (SEM) was calculated to be 10.75%. VAS responses to the question, "How much of the day today did you experience a good response?" more strongly correlated with ONG% (0.41) than ON% (0.24). The diary appears to be sufficiently simple and feasible. Test-retest reliability was good, and reliability increased with increasing number of diary days but compliance diminished beyond 3 days. Good on time (ONG = on time without dyskinesia or with nontroublesome dyskinesia) most strongly correlated with patients' perceived duration of a good response through the day and is an important outcome variable.

A home diary to assess functional status in patients with Parkinson's disease with motor fluctuations and dyskinesia

In clinical trials for patients with Parkinson's disease (PD) with motor fluctuations, efficacy is generally ascribed to an intervention if motor function is significantly improved or if "off" time is significantly reduced. However, we have argued that patients might not be improved if off time is reduced only to the extent that unwanted dyskinesia is increased. Therefore, a home diary should include an assessment of dyskinesia to provide an accurate reflection of clinical status over a period of time. We undertook two studies to develop a home diary to assess functional status in patients with PD with motor fluctuations and dyskinesia. In both studies, patients concurrently completed a test and a reference diary. In Study I, we evaluated the impact of different severities of dyskinesia on patient-defined functional status. There were 1,149 evaluable half-hour time periods from 24 patients; 94.3% of off time was considered "bad" time and 90.2% of "on" time without dyskinesia, 72.6% of on time with mild dyskinesia, 43.0% of on time with moderate dyskinesia, and 15.2% of on time with severe dyskinesia was considered "good" time. In Study II, we evaluated a new home diary designed to separate dyskinesia that had a negative impact on patient-defined functional status from dyskinesia that did not. There were 816 evaluable time periods from 17 patients; 84.9% of off time and 89.9% of on time with troublesome dyskinesia was considered bad time while 85.5% of on time without dyskinesia and 93.8% of on time with nontroublesome dyskinesia was considered good time. With this diary (Diary II), the effect of an intervention can be expressed as the change in off time and the change in on time with troublesome dyskinesia (bad time). The sum can be used as an outcome variable and compared to baseline or across groups. In evaluating the efficacy of an intervention, assessment of change in off time and change in on time with troublesome dyskinesia provides a more accurate reflection of clinical response than change in off time alone.