Impact of outpatient gastroenterology consult on pharmacotherapy and management of gastrointestinal symptoms in Parkinson's Disease.

Background & aims: Gastrointestinal (GI) symptoms are common in Parkinson's Disease (PD) patients, and GI dysmotility is thought to induce motor fluctuations, requiring escalation of levodopa therapy. The role of GI consultation in managing such symptoms, however, is unclear. In this study, we investigate the possible association between GI dysmotility symptoms and escalated LEDD therapy, as well as factors associated with GI consultation for PD symptom management. Methods: This was a retrospective case-study of 248 PD patients evaluated by outpatient neurology at Massachusetts General Brigham Healthcare from 2018 to 2022. Logistic regression, t-test, and Fisher exact tests were performed to identify factors associated with GI consult, change in LEDD with consult, and association of consultation with GI diagnoses and treatments, respectively. Results: Among 248 PD patients, 12.9% received GI consultation despite 96.8% having GI symptoms. Bloating was the primary symptom associated with receiving GI consultation (OR 3.59 [95% CI 1.47-8.88], p = 0.005). GI consultation increased the odds of receiving GI-specific medications (78.2% vs 46.3%, p = 0.001) and specialized GI diagnoses like gastroparesis (9.4% vs 0.46%, p < 0.001) and pelvic floor dysfunction (15.6% vs 0%, p < 0.0001). Interestingly, LEDD tended not to change after GI consultation, and dysmotility symptoms, including bloating, did not predict need for higher LEDD. Conclusions: While treating symptoms of dysmotility may not ameliorate levodopa-based motor fluctuations as much as previously thought, GI consultations are underutilized in PD, and patients who receive GI consultation are more likely to have changes in GI diagnosis and treatment.