Women feel more pain: study

Women feel pain more intensely than men, according to a new study conducted by medical researchers at the Stanford University School of Medicine in the US.

A study of the electronic medical records (EMRs) of more than 72,000 adult patients found that women felt pain more intensely across practically all 250 different disease categories examined.

Researchers looked at 160,000 disease-associated pain scores among patients, reported on scales of 1-to-10, zero being equivalent to "no pain", while 10 indicating the "worst imaginable."

"To the best of our knowledge, this is the first-ever systematic use of data from electronic medical records to examine pain on this large a scale, or across such a broad range of diseases," said the study's senior author Dr Atul Butte.

"We're certainly not the first to find differences in pain among men and women," he added, "but we focused on pain intensity, whereas most previous studies have looked at prevalence: the percentage of men versus women with a particular clinical problem who are in pain."

The research team then separately analysed only the first pain-scores initially reported to hospital-associated healthcare professionals, before the patients had been treated.

"If someone's reporting that they're in pain, they're probably going to be given medication, which might reduce any subsequently measured pain score," explained Butte.

This analysis identified 47 diagnostic categories, which were further broken down into 16 disease clusters including "musculoskeletal and connective tissue", "circulatory", and so on.

Of the 11,000 adults examined in this sample, "We saw higher pain scores for female patients practically across the board," said Butte.

"Those reported differences were not only statistically significant, but also clinically significant," he added. "In many cases, the reported difference approached a full point on the 1-to-10 scale. How big is that? A pain-score improvement of one point is what clinical researchers view as indicating that a pain medication is working."

The biggest gender differences were observed in females reportedly suffering greater fibromyalgia (migraine) pain than men, and also in diseases such as acute sinusitis and "cervical spine disorders" (neck pain).

Butte acknowledged that the research was conducted under a number of assumptions, including that patients had not already self-medicated with over-the-counter painkillers, and were not influenced by other factors such as setting and environment.

"Will an 18-year-old male report the same pain intensity with or without his mum present, or in the presence of a male versus a female nurse?" said Butte. "We can't be sure, but the sheer size of the study probably washes these concerns out at least to some extent."

The most controversial element of the study, which was published this week in the Journal of Pain, remains the fact that "It's still not clear if women actually feel more pain than men do, but they're certainly reporting more pain than men do," said Butte.

The next step for Butte and the research team is to attempt to find more objective measurements in the EMRs, such as an existing and commonly measured blood-test variable that can act as a "biomarker" for reported pain.

Currently EMRs are only used in one to two percent of hospitals in the US, "but that should approach 100 percent within the next few years as the United States continues to move toward EMRs," said Butte. "Thus, large-scale research using clinically collected data will become increasingly feasible."