麻豆传媒

Although life expectancy has increased for inflammatory bowel disease (IBD) patients, a mortality gap between those with and without IBD remains, a Canadian population study reported. And with the adverse effect of pain on daily functioning contributing to reduced health-adjusted life expectancy, better pain mitigation strategies are needed.

The matched cohort study led by Eric Benchimol, MD, PhD, of the University of Toronto and Toronto's Hospital for Sick Children, found the following patterns in almost 230,000 IBD patients from 1996, 2000, 2008 and 2011:

• Life expectancy increased for females by 2.9 years from 75.5 to 78.4 years (95% CI 1.3-4.5) and by 3.2 years for males from 72.2 to 75.5 (95% CI 2.1- 4.4).
• Health-adjusted life expectancy decreased among males by 3.9 years (95% CI 1.2-6.6) but remained relatively stable for females, with no statistically significant change: difference 2.0 years (95% CI –1.6 to 5.7).
• Differences in life expectancy between IBD patients and non-IBD controls ranged from 6.6 to 8.1 years in females and 5.0 to 6.1 years in males, depending on year.
• Differences in health-adjusted life expectancy for these two groups ranged from 9.5 to 13.5 years in females and 2.6 to 6.7 years in males.
• By IBD type, life expectancy increased significantly for females with Crohn's disease but not for females with ulcerative colitis.

The findings were , the Canadian Medical Association journal.

"While life expectancy in IBD patients has improved over the past 15 to 20 years, it's worrying that despite all of our advances in the treatment of IBD, life expectancy is still lower than in people without IBD," Benchimol told 麻豆传媒. "Furthermore, health-adjusted life expectancy, a measure of quality of life, is substantially lower in people with IBD. This has either remained stable for females or declined for males, so our treatments still aren't achieving all the goals we were hoping for."

The gap in health-adjusted life expectancy between those with and without IBD was especially large, he said, when evaluated both by general well-being and the effect of pain – despite the introduction during the study period of two biologics, infliximab (Remicade, in 2001) and adalimumab (Humira, in 2004).

The retrospective cohort study drew on information from health administrative, demographic, and health survey data available from Ontario databases.

To calculate life expectancy, the investigators matched people diagnosed with IBD to those without using period life tables based on age- and sex-specific 5-year mortality for 1996, 2000, 2008, and 2011. They also incorporated data from the Health Utility Index (National Population Health Study and Canadian Community Health Survey) to estimate health-adjusted life expectancy for 1996, 2000, and 2008.

Over the four index years, a total of 227,254 IBD patients were matched to a total 970,164 non-IBD controls. Mean age of patients with prevalent IBD increased from 42.4 to48.3 years, and the proportion of female cases remained stable, ranging from 52% to 53%.

Testifying to the negative impact of pain, the study found that using the pain-attributed utility, health-adjusted life expectancy among females was 65.7 years (95% CI 61.9-69.6) in 1996, 62.2 in 2000 (95% CI 59.1-65.2), and 66.1 in 2008 (95% CI 63.6-68.7), all considerably lower than for non-IBD controls. Health-adjusted life expectancy calculated with the pain-attribute utility remained relatively stable, however, for males with IBD.

The authors noted that earlier studies have found mortality to be elevated in Crohn's patients versus the general population, especially in those with childhood-onset disease, while studies in have been inconclusive.

Michael D. Kappelman, MD, MPH, of the University of North Carolina at Chapel Hill, who was not involved in the study, agreed with the authors' conclusions and said the findings parallel what he sees in the United States.

Benchimol and colleagues cited a number of limitations to the analysis:

• Results may have been confounded by disease phenotype or severity, information that was not available in health administrative data. Active or severe disease may have prevented some people from responding to surveys and hence the study may have underestimated the effect of IBD on health-adjusted life expectancy.
• Population-based data on medication use for those younger than 65 years of age were not available, and data on potential environmental or other confounders such as smoking and ethnicity were available only for the small proportion responding to a Statistics Canada survey.
• Life expectancy among people with IBD may vary depending on age at IBD diagnosis, a difference that the study may have missed by not comparing the life expectancies of individuals diagnosed at various ages. And mortality may increase with disease duration, which counters the assumption of life tables that age- and sex-specific mortality rates remain constant over a person's lifetime.
• The analysis was based on prevalent rather than incident cases and thus lacked data on the age of diagnosis or disease duration, and it may also have been prone to if patients with IBD died before meeting the full case definition required by the validated algorithms.

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