Neurological

The PD-PCS: A New Approach to Classifying Pain in Patients with Parkinson’s Disease

The Parkinson Disease-Pain Classification System (PD-PCS) is a valid, reliable instrument for distinguishing Parkinson-related pain from unrelated pain with moderate inter- and intrarateral reliability. This is evident from research published in Pain.

Researchers conducted an international multicenter cross-sectional study with a repeat validation step to test a new mechanism-based classification system that can distinguish Parkinson’s-related pain from unrelated pain. Participants included consecutive inpatients and outpatients with Parkinson’s disease with or without pain.

A total of 159 patients and 37 participants in the healthy control group were recruited in 4 clinical centers in Brazil and Eastern Switzerland. Patients in the Parkinson’s group were more likely to be men who were less active, had higher Hospital Anxiety and Depression Scale (HADS) scores, and higher clockwise drawing test scores.

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In 85% of patients, the full assessment took less than 7 minutes. The results of these assessments indicated that 93% of Parkinson’s disease patients experienced pain as assessed by the Brief Pain Inventory (BPI), compared to 6% of the control group. Parkinson’s-related pain was seen in 77% of patients, 15% of whom had more than one syndrome at the same time.

Nociceptive, neuropathic, or nociplastic pain components were diagnosed in 55%, 16% and 22% of patients, respectively. The most common mixed pain syndromes were nociceptive plus nociplastic pain (12.7%) or neuropathic pain (9.6%).

22% of the patients and 5% of the control group experienced pain that was not related to Parkinson’s disease – that is, it was neither caused nor made worse by Parkinson’s disease.

Nociceptive, neuropathic and nociplastic pain affected body regions 4.8 (± 5.2), 8.5 (± 5.8) and 10.1 (± 8.9), respectively. Ground effects for these 3 types of pain plus total scores were present in 4%, 4%, 20% and 32% of the patients, respectively; Ceiling effects were observed in 6% of patients with nociceptive pain and in no patients with other types of pain.

Samples by geographic region (Brazil and Switzerland) were similar, although Brazilian patients were younger, had higher scores on the Uniform Parkinson’s Disease Part III rating scale, and were more likely to experience levodopa-induced dyskinesia. and Swiss patients had more frequent nociplastic pain and higher PD-PCS total scores.

The researchers rated inter- and intra-rater reliability in patients who came for a second visit and showed no relevant clinical changes in pain. The PD-PCS Overall Severity Score showed statistically significant intrarateral and interrateral reliability (ICC, 0.62 and 0.59, respectively).

The results of a multinomial logistic regression analysis showed that nociceptive pain is related to the results of the wearing-off questionnaire 9 (WOQ-9) (odds ratio) [OR], 1.43) and BPI pain score (OR, 1.27). Neuropathic pain was assessed using the WOQ-9 score (OR, 1.83), the HADS-A score (OR, 1.29), the BPI score (OR, 1.51) and the McGill sensory score Pain questionnaire (OR, 1.19), whereas nociplastic pain was related to the WOQ-9 score (OR, 1.47).

When researchers stratified quality of life by score (low, medium, high, or very high), pain unrelated to Parkinson’s disease had a “somewhat similar distribution across all strata,” while pain associated with Parkinson’s disease was different focused on the more affected layers.

“The PD-PCS is a valid and reliable tool for differentiation [Parkinson disease]-related pain from … unrelated pain, “the researchers wrote. “It recognizes and evaluates mechanistic pain subtypes in a pragmatic and treatment-oriented approach and unifies previous classifications of [Parkinson disease] Pain.”

“The refinement of the characterization of pain in [Parkinson disease] should help to improve pain in [Parkinson disease] Patients more pragmatic and more symptom-oriented, ”they concluded.

Disclosure: This clinical study was supported by Zambon and Mundipharma. For a full list of the authors’ information, see the original reference.

reference

Mylius V., Perez Lloret S., Cury RG, et al. The Pain Classification System for Parkinson’s Disease: Results of an International Mechanism-Based Classification Approach. Pain. 2021; 162 (4): 1201-1. 1210. doi: 10.1097 / j.pain.0000000000002107

This article originally appeared on Clinical Pain Advisor

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