A Systematic Review of Findings on Comorbidities of Chronic Urticaria

 Findings on Comorbidities of Chronic Urticaria
Systematic Review


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A Systematic Review of Findings on Comorbidities of Chronic Urticaria (Asthma, Atopic Dermatitis, and Allergic Rhinitis)

Abstract

The relationship between the occurrence of chronic urticaria (CU) and asthma, atopic dermatitis (AD), and allergic rhinitis (AR) has remained unclear over the years. Our aim was to provide an update on knowledge from observational studies determining the prevalence of asthma, AR and AD in patients with CU from PubMed, EMBASE, Clinicaltrials.org, and Cochrane Library databases. The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines were used in the identification of literature for analysis. The quality of included studies was assessed using the Newcastle–Ottawa Scale (NOS) which revealed that the selected articles are of good quality. A total of 12 studies met the criteria and were included in this review. Two of the publications were prospective, six retrospectives, and four were cross-sectional studies. Except for one article, all the studies reported data on the occurrence of asthma, AR, and AD. AR was the most prevalent co-morbidity with its frequencies ranging between 16.5%-48%, followed by asthma that occurred in 4.7%-25.8% of patients, and finally, AD was the least reported condition among CU patients (1%-22.5%), particularly among the elderly. Nonetheless, 50% of the selected articles were based on archived data or analysis of medical records which are likely to be biased. Therefore, there is a need for additional longitudinal studies to explore the role of age in the occurrence of AD, AR, and asthma among CU patients.

Results

Study Characteristics

The electronic search yielded n=867 studies, including n=597 from PubMed, n=174 EMBASE, n=1 Clinicaltrials.org, and n=95 Cochrane Library. An additional n=4 records were identified through the hand search. After elimination of n=321 duplicates, another n=429 were excluded based on abstract and title screening. In addition, of the n=113 full-text publications which were assessed for eligibility, n=101 were removed for not reporting on AR, AD, or asthma. Therefore, a total of n=12 studies were included in the systematic review. The selected studies were carried out in various countries across the world, including two in the United States1, 2, three in Thailand 3, 4 , two in Germany 5, 6, two in Korea 7, 8, one in Israel 9, one in Taiwan 10, and another one involved patients in Denmark, Norway, and Sweden 11. Two of the publications were prospective 11, 6, six retrospective 2 3 4 7 10 12, while four were cross-sectional studies.1, 5, 8, 9.  

Whereas six of the investigations focused on describing the baseline features of AWARE patients with CU or CSU 11, 6, 7, 2, 1, 12, another five concentrated on the prevalence of the comorbidities (AR, AD, and asthma) of CU 5, 3, 12, 8, 4, 9, and one explored the correlation between dry eye disease (DED) and asthma.10  In total, the number of patients in each of the study ranged between 93 to 74,335, while in four studies which involved controls 8, 9, 5, 10 the number vacillated between 4,053-1,318,043. In a majority of the studies (66.7%), identification of CU was done primarily through doctor diagnosis 3, 1, 12, 4, 7, 6, 11, 9, in 25% of the studies by ICD 9/10 codes 10, 2, 8, and 8% used a combination of DLQ1 questionnaire, interviews personal interviews, and physical examination 5. Owing to the significant heterogeneities available in the investigations, in terms of methodology, design, and location, pooled analyses were not carried out.

Except for one study7 , all the remaining reported data on the occurrence of asthma, AR, and AD. AR was the most prevalent co-morbidity with its frequencies ranging between 16.5%-48%; followed by asthma that occurred in 4.7%-25.8% of cases; and finally, AD was reported among CU patients (1%-22.5%). Nonetheless, the remaining retrospective study7 that explored the clinical feature and prevalence of CU among geriatric patients reported no data on AR and asthma but found significantly high AD (37.8%).

Prevalence of Allergic Rhinitis in CU Patients

As stated earlier, AR was reported as the most prevalent co-morbidity among CU patients. For example, n=158 AWARE adult patients in a prospective study11 were engaged to investigate the baseline data for CU and it was found that 16.5% of the respondents had AR. In similar prospective research6 it was reported that 18.2% of the n=1539 AWARE patients in Germany were diagnosed with AR. In four retrospective analyses 2, 4, 12, 3 it was reported of AR prevalence of 48%, 20.4%, 20%, and 17%, respectively. The mean ages of the respondents in these studies were between 36.4 and 43.5, and the majority of the patients were female (>69%). Another retrospective research10, unlike the investigations mentioned above, matched the prevalence of DED among