new research suggests. Treatment of BPH with terazosin (Hytrin), doxazosin (Cardura), or alfuzosin (Uroxatral), all of which enhance glycolysis, was associated with a lower risk of developing Parkinson’s disease than patients taking a drug used for the same indication, tamsulosin (Flomax), which does not affect glycolysis.
“If giving someone terazosin or similar medications truly reduces their risk of disease, these results could have significant clinical implications for neurologists,” said lead author Jacob E. Simmering, PhD, assistant professor of internal medicine at the University of Iowa, Iowa City.
There are few reliable neuroprotective treatments for Parkinson’s disease, he said. “We can manage some of the symptoms, but we can’t stop it from progressing. If a randomized trial finds the same result, this will provide a new option to slow progression of Parkinson’s disease.”
The pathogenesis of Parkinson’s disease is heterogeneous, however, and not all patients may benefit from glycolysis-enhancing drugs, the investigators noted. Future research will be needed to identify potential candidates for this treatment, and clarify the effects of these drugs, they wrote.
The findings were published online Feb. 1, 2021, in JAMA Neurology.
Time-dependent effects
The major risk factor for Parkinson’s disease is age, which is associated with impaired energy metabolism. Glycolysis is decreased among patients with Parkinson’s disease, yet impaired energy metabolism has not been investigated widely as a pathogenic factor in the disease, the authors wrote.
Studies have indicated that terazosin increases the activity of an enzyme important in glycolysis. Doxazosin and alfuzosin have a similar mechanism of action and enhance energy metabolism. Tamsulosin, a structurally unrelated drug, has the same mechanism of action as the other three drugs, but does not enhance energy metabolism.
In this report, the researchers investigated the hypothesis that patients who received therapy with terazosin, doxazosin, or alfuzosin would have a lower risk of developing Parkinson’s disease than patients receiving tamsulosin. To do that, they used health care utilization data from Denmark and the United States, including the Danish National Prescription Registry, the Danish National Patient Registry, the Danish Civil Registration System, and the Truven Health Analytics MarketScan database.
The investigators searched the records for patients who filled prescriptions for any of the four drugs of interest. They excluded any patients who developed Parkinson’s disease within 1 year of starting medication. Because use of these drugs is rare among women, they included only men in their analysis.
They looked at patient outcomes beginning at 1 year after the initiation of treatment. They also required patients to fill at least two prescriptions before the beginning of follow-up. Patients who switched from tamsulosin to any of the other drugs, or vice versa, were excluded from analysis.
The investigators used propensity-score matching to ensure that patients in the tamsulosin and terazosin/doxazosin/alfuzosin groups were similar in terms of their other potential risk factors. The primary outcome was the development of Parkinson’s disease.
They identified 52,365 propensity score–matched pairs in the Danish registries and 94,883 pairs in the Truven database. The mean age was 67.9 years in the Danish registries and 63.8 years in the Truven database, and follow-up was approximately 5 years and 3 years respectively. Baseline covariates were well balanced between cohorts.
Among Danish patients, those who took terazosin, doxazosin, or alfuzosin had a lower risk of developing Parkinson’s disease versus those who took tamsulosin (hazard ratio, 0.88). Similarly, patients in the Truven database who took terazosin, doxazosin, or alfuzosin had a lower risk of developing Parkinson’s disease than those who took tamsulosin (HR, 0.63).
In both cohorts, the risk for Parkinson’s disease among patients receiving terazosin, doxazosin, or alfuzosin, compared with those receiving tamsulosin, decreased with increasing numbers of prescriptions filled. Long-term treatment with any of the three glycolysis-enhancing drugs was associated with greater risk reduction in the Danish (HR, 0.79) and Truven (HR, 0.46) cohorts versus tamsulosin.
Differences in case definitions, which may reflect how Parkinson’s disease was managed, complicate comparisons between the Danish and Truven cohorts, said Dr. Simmering. Another challenge is the source of the data. “The Truven data set was derived from insurance claims from people with private insurance or Medicare supplemental plans,” he said. “This group is quite large but may not be representative of everyone in the United States. We would also only be able to follow people while they were on one insurance plan. If they switched coverage to a company that doesn’t contribute data, we would lose them.”
The Danish database, however, includes all residents of Denmark. Only people who left the country were lost to follow-up.
The results support the hypothesis that increasing energy in cells slows disease progression, Dr. Simmering added. “There are a few conditions, mostly REM sleep disorders, that are associated with future diagnosis of Parkinson’s disease. Right now, we don’t have anything to offer people at elevated risk of Parkinson’s disease that might prevent the disease. If a controlled trial finds that terazosin slows or prevents Parkinson’s disease, we would have something truly protective to offer these patients.”