Idiopathic Parkinson’s disease: Which dopamine agonist is associated with lower risk of impulse control–related behavioural disorders?

ICRDs are common complications associated with the use of DAs in IPD patients. [Front Neurosci 2021:15;654238] To compare the risk of ICRDs across various DAs, the researchers collected clinical interviews and medical records of 385 Chinese patients with IPD who attended either the PD clinic (n=223) in Pamela Youde Nethersole Eastern Hospital with regular ICRD screening since August 2009, or the neurology clinic (n=162) in Princess Margaret Hospital or Yan Chai Hospital, where a single ICRD screening session was provided in March–December 2020. All screening utilized a short version of the Questionnaire for Impulsive-Compulsive Disorders in PD. [PRDOA 2024:10;100235]

In the cohort, 311 patients (male, 53.1 percent; mean age at IPD onset, 57.1 years; mean duration of IPD, 8.5 years; mean duration of IPD before DA treatment, 3.8 years; median Hoehn-Yahr [HY] stage, 2.5; history of psychiatric disorders, 28.6 percent) received >6 months of first DA monotherapy, including pramipexole (n=82; 26.2 percent), ropinirole (n=89; 28.6 percent), rotigotine (n=40; 12.7 percent), and bromocriptine (n=100; 32.2 percent).

Bromocriptine users had earlier IPD onset vs other DA users (51.8 years vs 58.0–63.3 years of age; p<0.001), while rotigotine users had a longer IPD duration before taking DA vs other DA users (7.2 years vs 3.1–3.4 years; p<0.001). Furthermore, users of bromocriptine or rotigotine had higher levodopa-equivalent daily dose (LEDD) of other anti-PD medications vs pramipexole or ropinirole users (mean dose, 716.9–771.0 mg vs 506.1–544.3 mg; p<0.001).

ICRDs occurred in 43 patients (13.8 percent), with incidence rates of 7.9/1,000 drug-years with rotigotine, 18.6/1,000 drug-years with bromocriptine, 36.6/1,000 drug-years with pramipexole, and 48.9/1,000 drug-years with ropinirole.

Rates of freedom from ICRDs at 5 years differed significantly among DAs (rotigotine, 0.97; bromocriptine, 0.95; pramipexole, 0.83; ropinirole, 0.77; p=0.005). In pairwise comparison, bromocriptine demonstrated higher rates of 5-year ICRD freedom vs ropinirole (p=0.001) and pramipexole (p=0.014). There was a trend for higher 5-year ICRD freedom with rotigotine vs ropinirole (p=0.060) and pramipexole (p=0.16).

“In the rotigotine group, the lower crude incidence rate of ICRDs and higher rate of 5-year ICRD freedom were biased by the pattern of rotigotine prescription in older patients, which was adjusted for in multivariate analysis,” the researchers noted.

After adjustment for DA prescription patterns (eg, gender, age at IPD onset, HY stage, duration of IPD before DA initiation, history of psychiatric disorders) in multivariate analysis, ICRD risk was significantly higher with pramipexole (adjusted hazard ratio [aHR], 7.28; 95 percent confidence interval [CI], 2.46–21.54; p<0.001) and ropinirole (aHR, 6.53; 95 percent CI, 2.67–15.99; p<0.001) vs bromocriptine. Compared with rotigotine, a trend for higher ICRD risk was observed with pramipexole (aHR, 5.01; 95 percent CI, 0.59–42.57; p=0.141) and ropinirole (aHR, 4.50; 95 percent CI, 0.55–36.58; p=0.161).

Other independent ICRD risk factors included male gender (aHR, 2.24; 95 percent CI, 1.07–4.72; p=0.033), IPD onset at age of <50 years (aHR, 2.99; 95 percent CI, 1.44–6.19; p=0.003) and history of psychiatric disorders (aHR, 2.80; 95 percent CI, 1.39–5.62; p=0.004).