To the Editor: Chronic urticaria (CU) is a prevalent dermatologic condition, yet its risk factors in Asian populations remain insufficiently understood.1 This study aims to thoroughly assess the potential risk factors influencing the incidence of CU among Asians.
Our study is registered on PROSPERO (CRD420250643142) and reported following Cochrane Handbook and preferred reporting items for systematic reviews and meta-analyses guidelines (Supplementary I, available via Mendeley at https://data.mendeley.com/datasets/hkssw9tmh4/2). We searched PubMed, Embase, and the Cochrane Library for studies published up to October 19, 2024. The search strategy included terms such as “urticaria” or “chronic urticaria” or “angioedema” and “Asia,” along with a series of Asian countries. Studies examining risk factors for CU in Asian populations were included (Fig 1). Due to clinical heterogeneity, we selected the random-effects model to calculate the pooled ORs. Subgroup and sensitivity analyses were conducted to assess heterogeneity and robustness.
Fig 1.
preferred reporting items for systematic reviews and meta-analyses flow diagram of study selection.
Twenty studies involving 6,025,605 participants met the inclusion criteria (Supplementary II, available via Mendeley at https://data.mendeley.com/datasets/hkssw9tmh4/2). We identified 6 patient-related factors: female gender (OR 1.17, 95% confidence interval [CI] 1.01-1.35), allergic rhinitis (OR 2.47, 95% CI 1.19-5.13), systemic lupus erythematosus (OR 3.39, 95% CI 1.62-7.11), rheumatoid arthritis (OR 3.71, 95% CI 1.36-10.11), Helicobacter pylori (HP) infection (OR 2.64, 95% CI 1.59-4.37) and diabetes mellitus (OR 1.79, 95% CI 1.06-3.02), along with one social factor, nonintermediate education level (OR 1.16, 95% CI 1.06-1.27) (Table I). However, neither asthma nor advanced education showed significant associations with CU (Supplementary II, available via Mendeley at https://data.mendeley.com/datasets/hkssw9tmh4/2).
Table I.
Significant and nonsignificant factors associated with chronic urticaria
| Significant factors | No of studies | No of patients | Chronic urticaria OR (95% CI) | Pooled P value | I2, % | P value for Cochran’s Q test | Egger's test P value |
|---|---|---|---|---|---|---|---|
| Gender | |||||||
| Male | Ref. | ||||||
| Female | 11 | 5,979,567 | 1.17 (1.01 to 1.35) | .036 | 95.3 | <.001 | .575 |
| Allergic rhinitis | |||||||
| No | Ref. | ||||||
| Yes | 3 | 5,786,947 | 2.47 (1.19 to 5.13) | .015 | 99.9 | <.001 | .232 |
| Systemic lupus erythematosus | |||||||
| No | Ref. | ||||||
| Yes | 3 | 5,731,952 | 3.39 (1.62 to 7.11) | .001 | 93.7 | <.001 | .896 |
| Rheumatoid arthritis | |||||||
| No | Ref. | ||||||
| Yes | 3 | 5,731,952 | 3.71 (1.36 to 10.11) | .01 | 98.5 | <.001 | .955 |
| Hp infection | |||||||
| No | Ref. | ||||||
| Yes | 5 | 5,916,290 | 2.64 (1.59 to 4.37) | <.001 | 23.7 | .263 | .914 |
| Diabetes | |||||||
| No | Ref. | ||||||
| Yes | 5 | 5,994,735 | 1.79 (1.06 to 3.02) | .003 | 98.5 | <.001 | .446 |
| Non-middle educational level | |||||||
| Yes | Ref. | ||||||
| No | 3 | 187,938 | 1.16 (1.06 to 1.27) | .001 | 0 | .695 | .171 |
| Nonsignificant factors | No of studies | No of patients | Chronic urticaria OR (95% CI) | Pooled P value | I2, % | P value for Cochran’s Q test | Egger's test P value |
|---|---|---|---|---|---|---|---|
| Asthma | |||||||
| No | Ref. | ||||||
| Yes | 3 | 5,786,947 | 2.08 (0.84 to 5.13) | .111 | 99.9 | <.001 | .034 |
| High educational level | |||||||
| No | Ref. | ||||||
| Yes | 3 | 187,938 | 0.97 (0.86 to 1.09) | .483 | 86.4 | .001 | .54 |
Effect sizes were pooled using the DerSimonian-Laird random-effects model; heterogeneity among studies was assessed via the Q test and I2 statistic, with P < .05 indicating statistically significant heterogeneity; publication bias was detected using Egger’s test, with P < .05 indicating significant publication bias. 95% CI, 95% Confidence interval; Hp, Helicobacter pylori; OR, odds ratio; Ref., reference group.
A retrospective study showed approximately 17% of CU patients have autoimmune diseases, with female patients developing such diseases within 10 years of urticaria diagnosis.2 Thus, we recommend clinical screening of suspected patients for the early detection of severe systemic diseases like systemic lupus erythematosus. Notably, HP infection is also strongly associated with CU3, and HP prevalence in the Southeast Asia is higher than the global average.4 Despite eradication remains controversial3,5, HP is linked to gastric cancer4 and can cause chronic inflammation (eg, gastritis) that impacts CU treatment. We therefore suggest HP screening for patients with digestive symptoms and eradication therapy if positive, consistent with guideline recommendations.1
Our study has the following limitations. First, inconsistent outcome reporting, incompatible definitions, and insufficient studies per factor precluded us from conducting subgroup analysis and meta-regression. Notably, the small number of included studies and heterogeneity may affect the robustness of our findings, and subsequent investigations with large-sample sizes and homogeneous methodologies are warranted to validate these results. Second, all included studies are observational in nature, which intrinsically precludes the establishment of a causal relationship between the identified factors and CU. We performed evidence grading and publication bias analysis, with the results presented in Supplementary I, available via Mendeley at https://data.mendeley.com/datasets/hkssw9tmh4/2.
Conflicts of interest
None disclosed.
Footnotes
Drs Peng and Li authors contributed equally to this work.
Funding sources: This work was supported by the National Natural Science Foundation of China (Grant No. 82473532, 82173424).
Patient consent: Not applicable.
IRB approval status: Not applicable.
Data availability statement: The data underlying this article will be shared on reasonable request to the corresponding author.
References
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