Evaluation for clinical predictors of positive temporal artery biopsy in giant cell arteritis

A Diagnostic Algorithm Based on a Simple Clinical Prediction Rule for the Diagnosis of Cranial Giant Cell Arteritis

Background: Risk stratification based on pre-test probability may improve the diagnostic accuracy of temporal artery high-resolution compression sonography (hrTCS) in the diagnostic workup of cranial giant cell arteritis (cGCA). Methods: A logistic regression model with candidate items was derived from a cohort of patients with suspected cGCA (n = 87). The diagnostic accuracy of the model was tested in the derivation cohort and in an independent validation cohort (n = 114) by receiver operator characteristics (ROC) analysis. The clinical items were composed of a clinical prediction rule, integrated into a stepwise diagnostic algorithm together with C-reactive protein (CRP) values and hrTCS values. Results: The model consisted of four clinical variables (age > 70, headache, jaw claudication, and anterior ischemic optic neuropathy). The diagnostic accuracy of the model for discrimination of patients with and without a final clinical diagnosis of cGCA was excellent in both cohorts (area under the curve (AUC) 0.96 and AUC 0.92, respectively). The diagnostic algorithm improved the positive predictive value of hrCTS substantially. Within the algorithm, 32.8% of patients (derivation cohort) and 49.1% (validation cohort) would not have been tested by hrTCS. None of these patients had a final diagnosis of cGCA. Conclusion: A diagnostic algorithm based on a clinical prediction rule improves the diagnostic accuracy of hrTCS.

Steroid Use is Associated with Clinically Irrelevant Biopsies in Patients with Suspected Giant Cell Arteritis

Temporal artery biopsy (TAB) is the diagnostic gold standard for giant cell arteritis (GCA). GCA is treated by high-dose corticosteroids. In cases of high clinical suspicion, steroids may be administrated despite negative TAB, making TAB clinically irrelevant. We assessed the role of TAB in clinical decision-making in patients with suspected GCA and to identify factors associated with clinically irrelevant TAB. Charts of patients who underwent TAB from 2005 to 2010 were reviewed for clinical parameters potentially associated with GCA and clinically irrelevant TAB. We studied 143 patients with 99 negative (69%), 34 positive (24%), and 10 undefined (7%) TABs. Eventually 26 patients (18% of the entire cohort and 26% of the patients with a negative TAB) received steroid treatment for GCA despite negative TAB. The start of steroid treatment before TAB was associated with clinically irrelevant TABs. If clinical suspicion of GCA is high, a TAB can be considered clinically irrelevant.

The Impact of Temporal Artery Biopsy at a UK Tertiary Plastic Surgery Unit

Guidelines recommend temporal artery biopsy (TAB) for patients suspected of having giant cell arteritis (GCA). We evaluated the impact of TAB on the diagnosis and management of patients with suspected GCA at a tertiary plastic surgery unit.

Methods

A retrospective review of all TAB procedures performed at our centre over 7 years was performed. One hundred and one patients were included in the study. Patients were classified into 3 diagnostic groups: confirmed (positive TAB), presumed (negative TAB with high clinical suspicion) and unlikely (negative TAB with low clinical suspicion). The clinical presentation and management for each group were compared.

Results

The average American College of Rheumatology (ACR) score was 3.07. The number of patients with an ACR score of ≥3 before TAB was 72 (71.3%) and remained the same after TAB. The number of patients who remained on steroid therapy was lower in the group with an unlikely diagnosis of GCA compared to the group with a confirmed diagnosis (p<0.05). Conversely, there was no significant difference in steroid therapy between those with a presumed and confirmed diagnosis (p>0.05).

Conclusions

This study found a significant difference in steroid treatment between those with confirmed GCA and those where the diagnosis was unlikely showing that TAB may support decisions regarding steroid therapy. However, TAB was inappropriately requested for patients whose pre-TAB ACR score was ≥3 as this score is sufficient for the diagnosis of GCA. Therefore, the use of TAB should be limited to cases of diagnostic uncertainty.

The Use of a Nomogram to Visually Interpret a Logistic Regression Prediction Model for Giant Cell Arteritis

OBJECTIVE

To illustrate the utility of a nomogram for the prediction of giant cell arteritis (GCA).

METHOD

A nomogram was constructed from a multivariable logistic regression prediction model with 10 covariates: age, sex, clinical temporal artery abnormality, new-onset headache, jaw claudication, vision loss, diplopia, erythrocyte sedimentation rate, C-reactive protein, and platelet level.

RESULTS

The magnitude and location of the nomogram scale for each predictor variable graphically illustrates the net effect of each covariate and is especially useful for continuous variables such as age and bloodwork values.

CONCLUSIONS

Nomograms allow integration and synthesis of the relative importance of clinical variables and provide a graphic representation of the odds ratios, p values, and confidence intervals of logistic regression prediction models. Although nomograms and prediction rules cannot substitute for clinical judgment, they help objectify and optimize the individualized risk assessments for patients with suspected GCA.

Multivariable prediction model for suspected giant cell arteritis: development and validation

Purpose

To develop and validate a diagnostic prediction model for patients with suspected giant cell arteritis (GCA).

Methods

A retrospective review of records of consecutive adult patients undergoing temporal artery biopsy (TABx) for suspected GCA was conducted at seven university centers. The pathologic diagnosis was considered the final diagnosis. The predictor variables were age, gender, new onset headache, clinical temporal artery abnormality, jaw claudication, ischemic vision loss (VL), diplopia, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and platelet level. Multiple imputation was performed for missing data. Logistic regression was used to compare our models with the non-histologic American College of Rheumatology (ACR) GCA classification criteria. Internal validation was performed with 10-fold cross validation and bootstrap techniques. External validation was performed by geographic site.

Results

There were 530 complete TABx records: 397 were negative and 133 positive for GCA. Age, jaw claudication, VL, platelets, and log CRP were statistically significant predictors of positive TABx, whereas ESR, gender, headache, and temporal artery abnormality were not. The parsimonious model had a cross-validated bootstrap area under the receiver operating characteristic curve (AUROC) of 0.810 (95% CI =0.766–0.854), geographic external validation AUROC’s in the range of 0.75–0.85, calibration p_H–L of 0.812, sensitivity of 43.6%, and specificity of 95.2%, which outperformed the ACR criteria.

Conclusion

Our prediction rule with calculator and nomogram aids in the triage of patients with suspected GCA and may decrease the need for TABx in select low-score at-risk subjects. However, misclassification remains a concern.

Baseline clinical predictors of an ultimate giant cell arteritis diagnosis in patients referred to temporal artery biopsy

The diagnosis of giant cell arteritis (GCA) is based on clinical grounds and confirmed by characteristic histological findings on temporal artery biopsy (TAB). Patients may be diagnosed with GCA based on clinical grounds only, despite negative histological findings. We aimed to investigate which baseline clinical and laboratory features best predict an ultimate diagnosis of giant cell arteritis among patients referred to TAB. We retrospectively analyzed 224 patients who underwent TAB in our hospital between 2000 and 2014. Patients were diagnosed with GCA if TAB was positive for GCA, or by clinical grounds only despite a negative biopsy, provided they fulfilled the American College of Rheumatology 1990 criteria. Baseline clinical and laboratory features were obtained from medical records. Predictors of an ultimate GCA diagnosis were investigated. Overall, 82 patients were diagnosed with GCA-57 had histological evidence of GCA and 25 were diagnosed with GCA despite a negative biopsy. One hundred and forty-two patients were not diagnosed with GCA. Predictors of an eventual diagnosis of GCA in a multivariate logistic regression analysis were headache (OR = 6; p < 0.001), jaw claudication (OR 4.5; p = 0.007), erythrocyte sedimentation rate (ESR) (OR = 1.5; p = 0.032) and platelet count (OR = 1.74; p = 0.004). Among patients referred to TAB, headache, jaw claudication, ESR, and thrombocyte levels are predictors for an ultimate diagnosis of GCA. These clinical and laboratory features should be considered when contemplating the diagnosis and treatment of GCA.

Factors associated to temporal artery biopsy result in suspects of giant cell arteritis: a retrospective, multicenter, case-control study

PURPOSE

To evaluate the positivity rate of temporal artery biopsies (TAB) performed in suspects of giant cell arteritis (GCA) and to study the epidemiological and clinical factors associated to the biopsy result.

METHODS

A retrospective, multicenter, case-control study was performed, including three hundred and thirty-five patients who underwent TAB for a suspicion of GCA from 2001 to 2010. Clinical, epidemiological and pathology data were recovered from the patients' clinical records. Histologic diagnosis of GCA was made when active inflammation or giant cells were found in the arterial wall.

RESULTS

Eighty-one biopsies (24.2%) were considered positive for GCA. Clinical factors independently associated to TAB result in a logistic regression analysis were temporal cutaneous hyperalgesia (OR = 10.8; p < 0.001), jaw claudication (OR = 4.6; p = 0.001), recent-onset headache (OR = 4.4; p = 0.001), decreased temporal pulse (OR = 2.8; p = 0.02), pain and stiffness in neck and shoulders (OR = 2.3; p = 0.05), unintentional weight loss (OR = 1.33; p = 0.003) and age (OR = 1.085; p = 0.004). Other factors such as length of the surgical specimen (OR = 1.079; p = 0.028) and erythrocyte sedimentation rate (OR = 1.042; p < 0.001) were also statistically significant. The model was accurate (C-index = 0.921), reliable (pHosmer-Lemeshow = 0.733) and consistent in the bootstrap sensitivity analysis. No significant association was detected between TAB result and number of days of previous systemic corticosteroid treatment (p = 0.146). However, an association was observed between TAB result and the total accumulated dose of previous systemic corticotherapy (p = 0.043).

CONCLUSIONS

Exhaustive anamnesis and clinical examination remain of paramount importance in the diagnosis of GCA. To improve the yield of TAB, it should be performed specially in older patients with GCA-compatible clinic. TAB could be avoided in patients with an isolated elevation of acute phase reactants, without GCA-compatible clinic.

Calcification of the external carotid arteries and their branches

This patient had longstanding hypercalcaemia and hyperphosphataemia owing to chronic renal disease, then finally failure, inducing tertiary hyperparathyroidism. He also had long histories of diabetes mellitus type II, hypertension and hypercholesterolaemia. He then reported a painful expansile swelling of the anterior mandible which was diagnosed as a "brown tumour". Subsequent review of the CT data set by an oral and maxillofacial radiologist revealed two patterns of calcification of the carotid arteries. A pipestem pattern was observed bilaterally along almost the entire lengths of the external carotid artery, a muscular artery, and its branches whereas plaque-like calcification was observed in the common and internal carotid arteries (elastic arteries). The pipestem pattern, hitherto an unreported feature affecting the external carotid artery, may represent a metastatic calcified deposit owing to hypercalcaemia and hyperphosphataemia in the tunica media of muscular arteries, resulting in arteriosclerosis, which maintains a patent lumen. The plaque-like pattern is representative of lumen-occluding calcified atherosclerosis associated with the long histories of diabetes mellitus type II, hypertension and hypercholesterolaemia. As this patient did not have any symptoms and/or signs of myofacial pain, facial dysfunction or numbness, the calcification of his external carotid arteries and branches were considered as arteriosclerosis. The brown tumour responded to the parathyroidectomy and the renal transplant.