15,000 PD patients were identified using structured ICD codes and PD related keywords in clinical notes from 2.6 million patients in the Axon Registry. All measures were curated from clinical notes with the exception of deep brain stimulation (DBS), which was curated from linked claims data.

PD subtype was determined by calculating the tremor to rigidity/bradykinesia severity ratio at the earliest encounter within one year of the patient’s first PD ICD code. Patients were classified as TD for ratios >=1 and AR for ratios <0.8 (Kang et al., 2005). 

Subtypes were compared by presence and time to first presence of postural instability, motor fluctuations, dyskinesia, and DBS using chi-square and Mann-Whitney U tests, respectively. 

1764 and 693 PD patients were identified as AR and TD, respectively. The AR subtype had a higher proportion of patients with postural instability (61% vs. 53%) and dyskinesia (11% vs. 7%), p-values < .01 and a shorter time to first encounter with dyskinesia (mean 17 vs. 24 months) and motor fluctuations (mean 10 vs. 13 months), p-values < .05. No differences in DBS were found between subtypes. 

Using RWD, we were able to identify AR and TD subtypes and differences in progression profiles consistent with the previous literature, demonstrating that RWD can be leveraged for subtype studies and outcome differences within PD.