The prevalence of clinical features and comorbidities in patients prior to giant cell arteritis diagnosis: a systematic review

Problem

Giant cell arteritis (GCA) is the most common form of medium and large vessel vasculitis. In the UK, incidence is 10 per 10,000 people, with highest rates being found in women aged between 70 and 80 years old. GCA is often typified by headache, fever, weight loss, and visual impairment. Diagnosis remains difficult since there are a multitude of symptoms experienced by patients with GCA. Prompt diagnosis is important as GCA is classed as a medical emergency. Due to the high risk of permanent visual loss, it is crucial that the time to diagnosis is as short as possible. The aim of this systematic review is to find pooled estimates of prevalence and odds for common GCA symptoms.

Approach

Four medical literature databases were searched (Medline, Ovid, CiNAHL, and Web of Science) from their respective inception dates until December 2017. A defined search strategy was used to search the databases, which included known symptoms of GCA such as headache and comorbidities prior to diagnosis. Title review was completed by one reviewer; abstracts and full-text articles were reviewed by two. Quality assessment was performed using a modified version of the Newcastle-Ottowa scale by two reviewers. Data such as sample size, and demographics was extracted from articles, along with the clinical features recorded for patients. A random-effects meta-analysis will be conducted, stratified by symptoms recorded in 4 or more articles.

Findings

The search strategy found 10,192 articles; 7,581 were unique. 589 were included for abstract review, whilst 90 were kept for full-text. A total of 43 articles were included in the final review. All articles reported prevalence of symptoms within the study population, the most commonly reported were headache, PMR, jaw claudication, abnormal temporal artery, and any kind of visual impairment. However, no symptom was reported in all 43 articles. The variability of GCA populations in the articles was large, with as many as 92% reporting headache to as few as none. There was large heterogeneity between studies.Only 18 articles had the necessary information to calculate odds ratios. Jaw claudication, elevated ESR, and anorexia had the highest pooled ORs, indicating that they were indicative of a GCA diagnosis.

Consequences

Our review illustrates that there are many clinical features associated with a GCA diagnosis with large variation between patients and populations. It was also shown that visual disturbances, often thought to be highly associated with GCA, are only present in less than 50% of the disease population. This review shows that systemic/constitutional symptoms such as fever and weight loss have a high prevalence in patients prior to their GCA diagnosis. This compounds the problem of diagnosing GCA quickly, as these symptoms are often indicative of another, more common, condition. Our review indicates that further research is needed into the clinical features experienced by GCA patients prior to their diagnosis.