BackgroundGiant cell arteritis (GCA), if untreated, can lead to blindness and stroke. The study’s objectives were to (1) determine a new evidence-based benchmark of the extent of diagnostic delay for GCA and (2) examine the role of GCA-specific characteristics on diagnostic delay.MethodsMedical literature databases were searched from inception to November 2015. Articles were included if reporting a time-period of diagnostic delay between onset of GCA symptoms and diagnosis. Two reviewers assessed the quality of the final articles and extracted data from these. Random-effects meta-analysis was used to pool the mean time-period (95% confidence interval (CI)) between GCA symptom onset and diagnosis, and the delay observed for GCA-specific characteristics. Heterogeneity was assessed by I 2 and by 95% prediction interval (PI).ResultsOf 4128 articles initially identified, 16 provided data for meta-analysis. Mean diagnostic delay was 9.0 weeks (95% CI, 6.5 to 11.4) between symptom onset and GCA diagnosis (I 2 = 96.0%; P < 0.001; 95% PI, 0 to 19.2 weeks). Patients with a cranial presentation of GCA received a diagnosis after 7.7 (95% CI, 2.7 to 12.8) weeks (I 2 = 98.4%; P < 0.001; 95% PI, 0 to 27.6 weeks) and those with non-cranial GCA after 17.6 (95% CI, 9.7 to 25.5) weeks (I 2 = 96.6%; P < 0.001; 95% PI, 0 to 46.1 weeks).ConclusionsThe mean delay from symptom onset to GCA diagnosis was 9 weeks, or longer when cranial symptoms were absent. Our research provides an evidence-based benchmark for diagnostic delay of GCA and supports the need for improved public awareness and fast-track diagnostic pathways.Electronic supplementary materialThe online version of this article (doi:10.1186/s12916-017-0871-z) contains supplementary material, which is available to authorized users.

BackgroundThe diagnosis of giant cell arteritis (GCA) remains difficult, with patients often presenting with non-specific and atypical symptoms. Such ambiguity can lead to delays in the diagnosis of GCA, which in-turn may result in the patient experiencing preventable and life-altering outcomes, including blindness. Despite the seriousness of such diagnostic delay, the extent of this, though frequently highlighted, has seldom been the primary focus of GCA research. Without a clear understanding of the extent to which GCA diagnosis is delayed, it is difficult to quantify the current problem and how this may then impact on patient outcomes.ObjectivesTo determine the average time-period between the onset of GCA symptoms and receiving a GCA diagnosis.MethodsWe conducted a systematic review and meta-analysis to identify research literature which has examined diagnostic delay of GCA and to determine the extent of this delay. Literature searches were conducted in the following bibliometric databases; MEDLINE, EMBASE, CINAHL, PsycInfo and ISI web of knowledge. A single reviewer (HR) initially performed a title screen; abstracts were then reviewed by two reviewers (HR & JP) and finally, two reviewers (JP & CM) assessed the remaining articles in full. Final article selection was based on pre-specified inclusion criteria and from these data on a multitude of factors was extracted. The primary outcome of interest was the “average number of weeks between onset of GCA symptoms and GCA diagnosis”, with other extracted data including; lead author, year of publication, sample size, gender, age, country, healthcare setting, method of GCA diagnosis and the definition of diagnostic delay. Where diagnostic delay was reported as “days” or “months”, data were converted to “weeks” to provide a standardised dataset for analysis. Standard deviations were also converted to standard errors (SE) for use in a meta-analysis. Random-effects meta-analysis was used to report the mean number of weeks (95% confidence interval (CI)) between symptom onset and GCA diagnosis.Results4,128 articles were initially identified, 185 were reviewed in full and 34 articles were included in the final systematic review. Of these, the average age ranged from 65.2 to 81.6 years and GCA samples from 31 articles were recruited from secondary care. GCA diagnosis was defined by a positive temporal artery biopsy in 25 articles, using the 1990 ACR criteria in 4 articles, with the remaining articles either using clinical judgement or not providing a definition. Delay was determined by the article reporting “how many days, weeks or months had occurred between GCA symptom onset and receiving a diagnosis of GCA”. 16 articles were included in the meta-analysis, resulting in a mean number of weeks between symptom onset and GCA diagnosis of 8.87 (95% CI 6.4 to 11.3) (I2 =95.8%, p<0.001).ConclusionsOn average, patients experience approximately a 9-week delay between the onset of their symptoms and receiving a diagnosis of GCA. The reasons for this are yet to be understood, but co...