Many people report pain for a long time after a stroke

Research question How many people are in pain after a stroke and for how long?

Answer One third of patients report moderate or severe pain in the first few months after a stroke. About one fifth are still in pain after 16 months.

Why did the authors do the study? Pain is often underdiagnosed and undertreated after a stroke. These authors wanted to find out how common it is among unselected patients recruited from the community. They also wanted to find out how and where patients experience pain after a stroke and what happens to their pain over time.

What did they do? For one year they registered all 416 patients who had their first stroke within the catchment area of a single university hospital, including those treated in the community. They interviewed the 297 survivors four months and 16 months after their stroke using 100 mm visual analogue scales to assess pain, the Barthel index to assess dependence, the geriatric depression score to assess mood, and the mini-mental state examination to assess cognitive function. They also asked patients to describe their pain and asked them whether they thought it was caused by the stroke. Moderate or severe pain was defined as a visual analogue score of more than 40.

Almost all the participants were living independently before their stroke, and most were still independent at both interviews afterwards. They were younger and had less serious strokes than the 119 patients who died or were otherwise unable to complete one or both interviews.

What did they find? 96 of the 297 survivors (32%) reported moderate or severe pain four months after their first stroke. By 16 months, that proportion had dropped to 21% (62/297). Late pain seemed more severe than earlier pain (median score 70 v 60, P = 0.016), and about half the patients with late pain said it was constant (47% of 62) and disturbed their sleep (58%).

More patients complained of moderate or severe pain in their upper limbs than anywhere else, often in the shoulder. Headache was uncommon. Only four patients had central post-stroke pain, and none had pain from pressure sores or deep vein thrombosis. Lasting pain was significantly associated with a worse depression score, better cognitive function, impaired glucose tolerance, and being female.

What does it mean? Many people have clinically important pain after a stroke and for about a fifth it goes on for at least 16 months. The causes of pain are unclear from this analysis. A substantial minority (about 40%) of participants with pain said it had started before they had a stroke.

Whatever its cause, pain is likely to be undertreated in this population. Less than half the patients in this study were successfully treated with analgesics, and only a fifth had tried physiotherapy. The patients were relatively fit survivors of a first stroke. The findings may not apply to older, sicker, patients or those who have had previous strokes.