The study conducted by Stanford University School of Medicine investigators suggests that stronger efforts should be made to recruit women subjects in population and clinical studies in order to find out why this gender difference exists.
It also revealed the value of EMR data mining for research purposes.
Using a novel database designed especially for research, the Stanford scientists examined more than 160,000 pain scores reported for more than 72,000 adult patients. From these, they extracted cases where disease-associated pain was first reported, and then stratified these findings by disease and gender.
"None of these data were initially collected for research, but this study shows that we can use it in that capacity," said Atul Butte, MD, PhD, the study's senior author.
The medical literature contains numerous reports indicating that women report more pain than men for one or another particular disease, noted Butte, a professor of systems medicine in pediatrics.
"We're certainly not the first to find differences in pain among men and women. But we focused on pain intensity, whereas most previous studies have looked at prevalence: the percentage of men vs. women with a particular clinical problem who are in pain. 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," he added.
The search identified 47 separate diagnostic categories for which there were more than 40 pain reports for each gender. The sample included more than 11,000 individual adult patients, of which 56 percent were women and 51 percent of them white.
The researchers were able to further analyze these 47 categories by condensing them into 16 disease clusters: "musculoskeletal and connective tissue" (in which the biggest gender differences in reported pain intensity were observed), "circulatory" and so forth.
"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.
"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," he explained.
While the overall results tended to confirm previous clinical findings - for example, that female fibromyalgia or migraine patients report more pain than their male counterparts - the search also unearthed previously unreported gender differences in pain intensity for particular diseases, for example acute sinusitis and "cervical spine disorders," more commonly known as neck pain.
The finding has been published online Jan. 23 in the Journal of Pain.