May 7, 2010 (Baltimore) -- People with diabetes-related nerve damage may experience worse pain in the evening hours, preliminary research suggests.
"It could be that patients need more [pain] medication at night or that if they are taking a once-a-day medication, it should be taken in the evening," says Brett Stacey, MD, medical director of the Comprehensive Pain Center at Oregon Health & Science University in Portland.
But it’s too early to make recommendations on the basis of this study, he tells WebMD.
The new findings were presented at the annual meeting of the American Pain Society.
Diabetes Nerve Damage: More Pain at Night
Previous research has shown that people with rheumatoid arthritis often experience worse pain when they wake up than at other times of the day; people with osteoarthritis have worse pain at night.
To begin to investigate whether the pain of diabetic peripheral neuropathy also has a daily pattern, researchers recruited 647 people who reported they'd been diagnosed with the condition.
For seven days, participants kept a diary recording the intensity of their pain every three hours, starting at 8 a.m. They were asked to rate their pain on a 10-point scale, where 10 equals the worst pain imaginable.
The average age of the participants was 54, and 58% were female. Nearly all (92%) were taking prescription or over-the-counter pain medication.
Results showed that average pain scores were highest at 11 p.m. and 8 p.m., when they were 4.65 and 4.53 points, respectively. They dropped to their daily low at 11 a.m., when they averaged 4.21 points.
The association between worse pain and evening hours remained after factors such as age, gender, and other health conditions were taken into account.
Still, the difference between the lowest and highest pain scores was too small to draw any firm conclusions, researchers say.
Diabetes Pain Study: "Hypothesis Generating"
The study has other limitations too, including the fact that participants were recruited via email and that they rated their own pain.
"It's hypothesis-generating," says Michael Clark, PhD, a pain specialist at the Haley VA Medical Center in Tampa, Fla.
Studies like this "tell us whether a hypothesis is worth pursuing," Clark tells WebMD.
"With pain management, we're trying to get away from treating patients based on averages, asking instead when do patients function best and when do they function worst," he says.
The new study was funded by GlaxoSmithKline, for whom Stacey serves as a consultant.