SALZBURG, AUSTRIA – Eradication of Helicobacter pylori in patients with idiopathic parkinsonism modified the syndrome but did not arrest it, according to interim results from a randomized controlled trial presented at an international conference on Alzheimer's and Parkinson's Diseases.
Dr. Sylvia Dobbs presented an interim analysis of a 5-year trial of 30 patients with early disease who were either not on medication or were taking stable, long half-life antiparkinsonism medication. Patients using levodopa were excluded.
All the participants had biopsy-proven H. pylori infection. The researchers randomly and blindly assigned the patients to 1 week of triple therapy to eradicate H. pylori infection or placebo. The antimicrobials used in eradication were chosen according to in vitro sensitivity tests.
Unblinding occurred at 1 year or if the disease had progressed quickly and the researchers thought the patient's lifestyle was unsustainable. Patients on placebo who were breath-test positive at 1 year were given active treatment.
Dr. Dobbs of the Institute of Psychiatry, King's College London, reported follow-up to a mean of 468 days after unblinding. The primary outcome measure was time trend in mean stride length at free-walking speed.
“If you use global scores, which are very insensitive, you require huge numbers of patients,” Dr. Dobbs said in an interview. “If you objectively measure the outcome criteria, you require small numbers. If you do time trends in the outcome criteria, you require even smaller numbers.”
Protocol analysis on the primary outcome showed a clinically relevant effect in favor of biopsy-proven successful, blinded active eradication over placebo (7.3 cm/yr increase in mean stride length [95% confidence interval 1.4,13.2], P less than .01). The presence or absence of antiparkinsonism medication did not affect the results, she said.
Patients in the placebo group who received treatment to eradicate their H. pylori infection unblinding also improved in the primary outcome measure (9.5 cm/yr increase in mean stride length [95% confidence interval 1.2, 20.1], P = .04).
“We have some prima facie evidence pointing to a direct or surrogate but not necessarily unique, response to [H. pylori eradication],” said Dr. Dobbs. “The effect was sustained in the following year.”