Study Highlights Wide Variation in Mortality of Spondyloarthritis, IBD Across the Globe

Significant geographic disparities exist among mortality rates for spondyloarthritis (SPA) and inflammatory bowel disease (IBD) across the globe, according to a new study, which found that over a decade, mortality rates did not change significantly for ankylosing spondylitis (AS) but decreased for IBD.

The researchers drew on data from the World Health Organization, which found that in 2015, the global age-standardized mortality rate (ASMR) for AS was 0.13 deaths per million people and for psoriatic arthritis (PsA) was 0.04, significantly lower than the ASMR for Crohn disease (CD) (0.86) and for ulcerative colitis (UC) (0.76).

“On the one hand, it should be noted that the prevalence as well as the incidence of IBD is higher than that of SpA, which may explain higher direct mortality rates for IBD,” detailed the researchers. “On the other hand, IBD directly causes death in 25-50% of cases for CD, and 18% for UC. In France, from 2000 to 2009, AS was considered the main cause of death in only 3.1% of cases. In AS and PsA, there is an excess of infectious and cardiovascular mortality, the latter partly related to a high prevalence of metabolic syndrome. The WHO data only provide information on the main cause of death. Thus, some causes of death may have been favoured by SpA, but not identified in this analysis.”

Looking at mortality over time, the researcher found that ASMR for AS did not significantly change between 2001 and 2015. Meanwhile, ASMR of PsA stabilized between 2001 and 2004 before increasing significantly through 2015. During the same time period, mortality rates of CD and UC significantly decreased.

The data showed wide variations in mortality rates among the different conditions geographically, which the researchers said could be attributed to various factors, including the heterogeneity of the diseases globally, socioeconomic inequalities, and a lack of data. For example, data from Africa was only available from Egypt and South Africa for AS, CD, and US, and there were no data from China and India.

“Interpretation of these data, particularly for comparisons between continents, must remain cautious in view of the risk of confounding and misclassification,” noted the researchers of their findings. “Further studies seem to be needed to better understand the evolution of mortality over the last twenty years.”

Global ASMR for AS ranged from 0.017 in Japan to 1.89 in Iceland. ASMR for AS in Europe (0.17) was statistically significantly higher than that in North American (0.12), South America (0.09), and Asia (0.08), and was comparable with that in Africa (0.10) and Oceania (0.08).

ASMR for PsA ranged from 0.008 in Mexico to 0.135 in Greece, and ASmR in Europe (0.05) was statistically significantly higher than in South American (0.02) and similar to North America (0.03) and Oceania (0.02).

The ASMR in Europe for CD (1.12) was significantly lower than that in North America (1.31), was significantly higher than that in Africa (0.74), Latin America (0.57), and Asia (0.27), and was similar to that in Oceania (0.87).

For UC, ASMR ranged from 0.03 in Thailand to 5.48 in Saint Lucia. Compared with North America (0.64), Africa (0.57), South Africa (0.84), Asia (0.47), and Oceania (0.58), the ASMR of Europe was significantly higher (1.00).

Reference

Fakih O, Wendling D, Verhoeven F, Prati C. World mortality of ankylosing spondylitis, psoriatic arthritis and inflammatory bowel disease in 2015 and its evolution from 2001 to 2015. Joint Bone Spine. 2022;89(6):105452. doi:10.1016/j.jbspin.2022.105452