Women report more intense pain than men in virtually every disease category, according to investigators who mined a vast collection of electronic medical records to establish the broad gender difference at a high level of statistical significance.
The study, by researchers with Stanford University School of Medicine, suggests that stronger efforts should be made to recruit women subjects in population and clinical studies to find out why this gender difference exists.
The study also shows the value of electronic medical record data mining for research purposes. Using a database designed especially for research, the scientists extracted cases where disease-associated pain was first reported, 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," Atul Butte, MD, PhD, the study's senior author, said in a news release.
The medical literature contains numerous reports indicating that women report more pain than men for one or another particular disease, said Butte, a professor of systems medicine in pediatrics.
"We're certainly not the first to find differences in pain among men and women," Butte said. "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."
Butte's team examined adult records, looking for gender-related differences in pain intensity as reported on 10-point scales in which 0 stands for "no pain" and 10 for "worst imaginable." Their search algorithm combed through unprotected EMR data for more than 72,000 patients and came up with more than 160,000 instances, ranging across some 250 disease categories, in which a pain score had been reported.
To minimize confounding of pain estimates by subsequent pain-relief medications or procedures, the group analyzed only the first pain-intensity score reported by a patient per encounter with a hospital-associated health professional.
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 whom 56% were women and 51% were 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 researchers observed the biggest gender differences in reported pain intensity), "circulatory" and so forth.
"We saw higher pain scores for female patients practically across the board," Butte said. Those reported differences were not only statistically significant, but also clinically significant, he said: "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."
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, such as acute sinusitis and cervical spine disorders.
The study's results come with a few caveats. The investigators assumed that patients' pain had not already been treated by they time they arrived at the ED, doctor's office or health clinic.
More fundamentally. Butte said, the study clarified that women report more pain than men but not that they actually feel more pain. The team plans to search EMRs for some kind of objective measurement that correlates highly with reported pain. "We want to find a biomarker for pain," Butte said.
The study appears in the Jan. 23 issue of the Journal of Pain. To access the study via subscription or purchase, visit http://bit.ly/zqp2bx.
The study, by researchers with Stanford University School of Medicine, suggests that stronger efforts should be made to recruit women subjects in population and clinical studies to find out why this gender difference exists.
The study also shows the value of electronic medical record data mining for research purposes. Using a database designed especially for research, the scientists extracted cases where disease-associated pain was first reported, 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," Atul Butte, MD, PhD, the study's senior author, said in a news release.
The medical literature contains numerous reports indicating that women report more pain than men for one or another particular disease, said Butte, a professor of systems medicine in pediatrics.
"We're certainly not the first to find differences in pain among men and women," Butte said. "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."
Butte's team examined adult records, looking for gender-related differences in pain intensity as reported on 10-point scales in which 0 stands for "no pain" and 10 for "worst imaginable." Their search algorithm combed through unprotected EMR data for more than 72,000 patients and came up with more than 160,000 instances, ranging across some 250 disease categories, in which a pain score had been reported.
To minimize confounding of pain estimates by subsequent pain-relief medications or procedures, the group analyzed only the first pain-intensity score reported by a patient per encounter with a hospital-associated health professional.
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 whom 56% were women and 51% were 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 researchers observed the biggest gender differences in reported pain intensity), "circulatory" and so forth.
"We saw higher pain scores for female patients practically across the board," Butte said. Those reported differences were not only statistically significant, but also clinically significant, he said: "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."
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, such as acute sinusitis and cervical spine disorders.
The study's results come with a few caveats. The investigators assumed that patients' pain had not already been treated by they time they arrived at the ED, doctor's office or health clinic.
More fundamentally. Butte said, the study clarified that women report more pain than men but not that they actually feel more pain. The team plans to search EMRs for some kind of objective measurement that correlates highly with reported pain. "We want to find a biomarker for pain," Butte said.
The study appears in the Jan. 23 issue of the Journal of Pain. To access the study via subscription or purchase, visit http://bit.ly/zqp2bx.
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