# Incidence of Opioid Use Before and After Parkinson's Disease Diagnosis

## TL;DR

People with Parkinson's disease use more opioids than others, even before diagnosis, suggesting pain is a key issue in early stages.

## Contribution

This study is the first to show increased opioid use in Parkinson's patients years before diagnosis and its progression over time.

## Key findings

- Opioid use was higher in Parkinson's patients (37.0%) compared to non-PD individuals (31.2%).
- Increased opioid initiation was observed 3 years before PD diagnosis and continued afterward.
- Mild opioids were more commonly used before diagnosis, while stronger opioids were used after.

## Abstract

Pain is a common symptom of Parkinson's disease (PD). It occurs also as a prodromal sign of PD. It has not yet been described how the use of analgesics changes over time in persons with PD. We investigated the incidence of opioid use from 5 years before to 5 years after PD diagnosis and compared the incidence to a matched cohort.

This study included 15,763 people diagnosed with incident PD in 2001–2014 and 62,907 matched comparison persons without PD from the Finnish nationwide register‐based study on Parkinson's disease (FINPARK). Initiation rates of opioid use during the follow‐up were calculated in 6‐month time windows, and the difference between persons with and without PD was described using incidence rate ratios (IRRs).

Opioid initiation was more common among persons with PD (37.0%) compared to people without PD (31.2%). The difference between the groups emerged 3 years before the PD diagnosis IRR 1.33 (1.16–1.53), and remained until the end of the follow‐up. Mild opioids, such as tramadol and codeine, were the most commonly initiated opioids, and the largest difference in their use was observed 6 months prior to the diagnosis date, while differences in strong opioids emerged after the PD diagnosis. Initiation rates increased over time and remained above those of the comparison group after the PD diagnosis for all opioid classes.

The findings demonstrate the incidence of moderate/severe pain in PD, which requires treatment with opioid‐class analgesics. Further studies are needed to understand the long‐term impact of opioid use in persons with PD.

Initiation rate of opioids is increased in persons with Parkinson's disease already at premotor or early motor stage, before the diagnosis is confirmed. Shift towards stronger opioids is observed over the disease progress. Further studies are needed to investigate optimized pain management strategies in Parkinson's disease.