Immune-Mediated Inflammatory Diseases Increase Despite Available Treatment

Lai-Shan Tam, MD

Credit: Spectra Collaboration

Findings from a study of immune-mediated inflammatory diseases are providing an overview of global incidence patterns and trends.

The observed increase in the age standardized incidence rate of rheumatoid arthritis and surge in cases of asthma, inflammatory bowel disease, multiple sclerosis, psoriasis, and atopic dermatitis are calling attention to the need for a better understanding of prevention and mitigation strategies for immune-mediated inflammatory diseases.¹

“Given that [immune-mediated inflammatory diseases] represent a significant health concern, a refined trend analysis of [immune-mediated inflammatory diseases] will aid in identifying and addressing the underlying causes of disparities in the diagnosis, treatment, and management of these diseases,” wrote investigators.¹

Both host and environmental factors contribute to the risk of immune-mediated diseases, which cause the immune system to act abnormally and attack the body. The result is a damaging inflammatory response. Due to these varying factors, ranging from age and sex to environmental pollution and allergen levels, some people may be disproportionately affected by these diseases.^2,3

To estimate immune-mediated inflammatory disease patterns, trends, and their causes, senior investigator Lai-Shan Tam, MD, of the department of medicine and therapeutics at the Chinese University of Hong Kong, and a team of investigators examined data on asthma, inflammatory bowel disease, multiple sclerosis, rheumatoid arthritis, psoriasis, and atopic dermatitis derived from the Global Burden of Disease study in 2019. A comprehensive source of epidemiological data, the Global Burden of Disease study provides estimates for 369 diseases and injuries across 204 countries and territories from 1990 to 2019.¹

Investigators collected annual incident cases and age standardized incidences of immune-mediated inflammatory diseases by sex, region, country, and cause from 1990 to 2019 from the Global Health Data Exchange query tool. Data was categorized into 5 regions by socio-demographic index, including low, low-middle, middle, high-middle, and high, and were further subdivided into 21 geographic regions. The average annual percent change in number of incidents and age standardized incidence rate on immune-mediated inflammatory diseases were calculated to quantify temporal trends.¹

Upon analysis, most incident cases were observed in individuals under the age of 25 years for atopic dermatitis, in the age group of 20 to 59 years for inflammatory bowel disease, 15 to 54 years for multiple sclerosis, 30 to 69 years for rheumatoid arthritis, and in individuals under the age of 69 for psoriasis. For all 6 examined immune-mediated inflammatory diseases, the average annual percent change of incident cases increased with age.¹

The global incidence of overall immune-mediated inflammatory diseases in 2019 was approximately 67,586,168 cases, with an age standardized incidence rate of 908.69 per 100,000 population. From 1990 to 2019, the global incident cases increased with an average annual percent change of 0.68 (95% confidence interval [CI], 0.59 to 0.77), but the age standardized incidence rates decreased with an average annual percent change of −0.34 (95% CI, −0.46 to −0.22).¹

Investigators noted the age standardized incidence rates decreased in all 5 socio-demographic index regions from 1990 to 2019, with the quickest decline in the low-middle socio-demographic index region (average annual percent change, −0.27; 95% CI, −0.41 to −0.14). Across regions, the most rapid increase of age standardized incidence rate was observed in high-income North America (average annual percent change, 0.21; 95% CI, 0.10 to 0.31) while the most rapid increase of incident cases was in Western Sub-Saharan Africa (average annual percent change, 2.59; 95% CI, 2.52 to 2.65).¹

From 1990 to 2019, the global age standardized incidence rate significantly increased for rheumatoid arthritis (average annual percent change, 0.21; 95% CI, 0.18 to 0.25) while the age standardized incidence rate significantly decreased for atopic dermatitis (average annual percent change, −0.15; 95% CI, −0.16 to −0.14), asthma (average annual percent change, −0.41; 95% CI, −0.59 to −0.23), multiple sclerosis (average annual percent change, −0.26; 95% CI, −0.27 to −0.24), psoriasis (average annual percent change, −0.77; 95% CI, −0.78 to −0.76), and inflammatory bowel disease (average annual percent change, −0.32; 95% CI, −0.77 to −0.67).¹

Global new cases increased the fastest for:

• rheumatoid arthritis (average annual percent change, 2.22; 95% CI, 2.19 to 2.25)
• multiple sclerosis (average annual percent change, 1.21; 95% CI, 1.20 to 1.23)
• inflammatory bowel disease (average annual percent change, 1.11; 95% CI, 1.06 to 1.16)
• atopic dermatitis (average annual percent change, 0.84; 95% CI, 0.82 to 0.86)
• psoriasis (average annual percent change, 0.81; 95% CI, 0.80 to 0.82)
• asthma (average annual percent change, 0.53; 95% CI, 0.37 to 0.70).

In 2019, the age standardized incidence rate of overall immune-mediated inflammatory diseases increased with the socio-demographic index across 21 regions and 204 countries and territories. Throughout all regions and countries, those with higher socio-demographic index experienced a more rapid increase in age standardized incidence rate of overall immune-mediated inflammatory diseases from 1990 to 2019.¹

“The magnitude of incident cases of [immune-mediated inflammatory diseases] has increased significantly over the past few decades. As a result, there is an urgent need for an integrative management strategy to address the increasing [age standardized incidence rate] of rheumatoid arthritis and the upsurge in new cases of the other five [immune-mediated inflammatory diseases] studied,” investigators concluded.¹

References:

1. Wu D, Jin Y, Xing Y, et al. Global, regional, and national incidence of six major immune-mediated inflammatory diseases: findings from the global burden of disease study 2019. eClinicalMedicine. doi:https://doi.org/10.1016/j.eclinm.2023.102193
2. Adapa D, Sai YRKM, Anand SY, et al. A Brief Review on Immune Mediated Diseases. Journal of Clinical & Cellular Immunology. doi:10.4172/2155-9899.S11-001
3. National Multiple Sclerosis Society. What’s an Immune-Mediated Disease? Immune-Mediated Disease and MS. Accessed September 28, 2023. https://www.nationalmssociety.org/What-is-MS/Definition-of-MS/Immune-mediated-disease