Comparing different ways of measuring pain after having a stroke

What is it about?

A stroke is a very serious condition where not enough blood can get to part of your brain. It needs to be treated in hospital as soon as possible. Common symptoms of a stroke include your face dropping on one side, not being able to lift your arms, and slurred speech. Across the world, one in four people over age 25 will have a stroke in their lifetime, but they are more common in older people. While most people recover a lot in the days and weeks after having a stroke, it can take years to fully recover. For some people, long-term care is needed so that they can be independent. There are a range of different ways that doctors can record how much pain a patient is in after having a stroke, based on different combinations of questions.  For example, there is a tool called the ‘5-level EQ-5D’ which has various specific topics called domains, such as ‘self care’.  For each domain, there are five possible answers (levels) which are presented in order of severity: for self-care this ranges from ‘I have no problems washing or dressing myself’ to ‘I am unable to wash or dress nyself’.  But as different tools have different questions, and different options for answers, it can be hard to know how to compare different answers. In this study, we looked at different ways of recording pain after stroke in multiple research studies, recorded in the Virtual International Stroke Trials Archive (VISTA). Pain scores were available in 10 studies in VISTA, totalling 10,002 people with stroke. Despite having different questions and answers, there was a general trend across all tools tested that higher scores from one tool were *correlated* with high scores on another – that is, the tools were all capturing the same amount of pain generally.  However, some tools were more closely linked than others.  We made a pathway for turning scores from one tool to another, so we can compare results from studies using different tools. We also tried to add in other information to some of the scales, such as information about how easily people could move around, and whether they were feeling depressed or anxious, to see if this improved how we could compare between different tools, but we didn’t find it helped. Overall, we found that it was okay to compare different tools for capturing pain after stroke, and found a good way to change one tool’s score into another.  This means that researchers can combine together data from different studies to make a larger dataset for further studies, and with more people we can be more confident in anything we find.

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