Hauser RA, Koller W, C., Hubble J, P., et al. Time course of loss of clinical benefit following withdrawal of levodopa/carbidopa and bromocriptine in early Parkinson’s Disease. Movement Disorders 2000;15(3):485-89
PubMed link: https://www.ncbi.nlm.nih.gov/pubmed/10830413
| Methods | Study design: Before-and-after study
Number of groups: One group |
| Participants | Number of participants: 31 enrolled
· Active deprescribing group: 6 randomized, 4 completed · Control group: 6 randomized, 5 completed Age: 69.2 ± 1.5 years Sex: Unstated Participants with dementia: No Inclusion criteria: · Parkinson’s Disease at Hoehn and Yahr stage I–III · At least two of three cardinal features of Parkinson’s Disease (bradycardia, rigidity, resting tremor) · Untreated before enrollment in the parent study (a prospective,double-blindrandomized trial with a two-by two-factorial design to determine the effects of selegiline, levodopa, and bromocriptine on the progression of signs and symptoms of early Parkinson’s Disease) Exclusion criteria: · Atypical Parkinson’s Disease · History of exposure of neuroleptic medications · Previous neurosurgical procedures · Clinically significant medical or laboratory abnormalities Country: United States of America Setting: Community |
| Interventions | Medicine: Levodopa/carbidopa or bromocriptine
· Randomized to receive selegiline 10mg or placebo, and randomized to receive levodopa/carbidopa or bromocriptine with the dose titrated to clinical response · Selegiline was withdrawn after 12 months of treatment. At 14 months, levodopa/carbidopa or bromocriptine was withdrawn. This study describes the withdrawal of the levodopa/carbidopa or bromocriptine. Withdrawal schedule: Not described Comparator: None |
| Outcomes | Adverse drug withdrawal effects
Activities of daily living Unified Parkinson’s Disease Rating Scale |
| Dates | Dates: Not described
Follow-up duration: 15 days |
| Funding sources | Supported in part by grants from the National Parkinson Foundation and Somerset Pharmaceuticals |
| Notes |
Risk of bias table
| Bias | Authors’ judgment | Support for judgment |
| Random sequence generation (selection bias) | High risk | This was not a randomized study. |
| Allocation concealment (selection bias) | High risk | Allocation was not concealed. |
| Blinding of participants and personnel (performance bias) | 5 out of 5 | This was an open study. |
| Blinding of outcome assessment (detection bias) | 5 out of 5 | As above. |
| Incomplete outcome data (attrition bias) | 1 out of 5 | There are no drop-outs reported and no missing data. |
| Selective reporting (reporting bias) | 1 out of 5 | A pre-published protocol was not found. However, the authors state in the methods that they are interested in the “changes in Unified Parkinson’s Disease Rating scores among days 1, 8, and 15.”These were reported. |
| Confounding (non-randomized) | 5 out of 5 | There is no control group, and, therefore, it is high risk. |
| Other bias | Low risk | |
| Newcastle-Ottawa scale | ||
| Selection bias | Representativeness of the exposed cohort | The intervention group was somewhat representative of people living with Parkinson’s Disease, who have been treated pharmacologically, however, due to the placebo and Hawthorne Effect from having been involved in a 12-month study immediately before this, they may not be truly representative of their peers. |
| Selection of the non-exposed cohort | There was no concurrent control group.
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| Ascertainment of exposure | Ascertainment of exposure was through secure record.
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| Demonstration that outcome of interest was not present at start of study | It was demonstrated that the outcome of interest was not present at the start of the study. | |
| Comparability bias | Comparability of cohorts on the basis of the design or analysis | The study controls for levodopa or bromocriptine use. |
| Outcome bias | Assessment of outcome | Assessment of outcome was through independent assessment. |
| Was follow-up long enough for outcomes to occur | Follow-up duration should have been sufficient. Two weeks should be sufficient due to the short half-life of levodopa.
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| Adequacy of follow-up of cohorts | Complete follow-up of participants; all subjects accounted for. | |
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