There are few estimates of the incidence and prevalence of inflammatory bowel disease (IBD) in North American communities.
Dr Lisa Herrinton and colleagues from California, USA estimated the incidence and prevalence of inflammatory bowel disease, including Crohn's disease and ulcerative colitis, among 3.2 million members of Kaiser Permanente, Northern California, between 1996 and 2002.
|In 2000, the point prevalence per 100,000 was 96 for Crohn's disease|
|The American Journal of Gastroenterology|
The team identified all health plan members who had one or more diagnoses of Crohn's disease or ulcerative colitis on computerized records during the study period.
There were 12,059 health plan members who had at least 12 months of membership as possible inflammatory bowel disease cases.
The team randomly sampled 24% of these for chart review to confirm the diagnosis and obtain the initial diagnosis date.
Incidence rates and the point prevalence at the end of 2002 were standardized to the 2000 USA Census.
The researchers found that the annual incidence rate per 100,000 persons was 6 for Crohn's disease, and 12 for ulcerative colitis.
In 2000, the point prevalence per 100,000 was 96 for Crohn's disease, and 156 for ulcerative colitis.
The research team noted that point prevalence increased to 100 and 206 per 100,000, respectively, when hospital discharge data from 1985 to 1995 were included.
The age-specific incidence of Crohn's disease was bimodal, while ulcerative colitis incidence rose in early adulthood and remained elevated with advancing age.
Dr Herrinton's team concluded, "The incidence we estimated for Crohn's disease was similar to the previous USA estimate."
"Our incidence estimate for ulcerative colitis was much higher than the previous USA estimate, but similar to that of recent Canadian and European studies."
"The prevalence we estimated for Crohn's disease was somewhat lower than previous estimates."