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.

Neural network and logistic regression diagnostic prediction models for giant cell arteritis: development and validation.

PURPOSE: To develop and validate neural network (NN) vs logistic regression (LR) diagnostic prediction models in patients with suspected giant cell arteritis (GCA). Design: Multicenter retrospective chart review. METHODS: An audit of consecutive patients undergoing temporal artery biopsy (TABx) for suspected GCA was conducted at 14 international medical centers. The outcome variable was biopsy-proven GCA. The predictor variables were age, gender, headache, clinical temporal artery abnormality, jaw claudication, vision loss, diplopia, erythrocyte sedimentation rate, C-reactive protein, and platelet level. The data were divided into three groups to train, validate, and test the models. The NN model with the lowest false-negative rate was chosen. Internal and external validations were performed. RESULTS: Of 1,833 patients who underwent TABx, there was complete information on 1,201 patients, 300 (25%) of whom had a positive TABx. On multivariable LR age, platelets, jaw claudication, vision loss, log C-reactive protein, log erythrocyte sedimentation rate, headache, and clinical temporal artery abnormality were statistically significant predictors of a positive TABx (P≤0.05). The area under the receiver operating characteristic curve/Hosmer-Lemeshow P for LR was 0.867 (95% CI, 0.794, 0.917)/0.119 vs NN 0.860 (95% CI, 0.786, 0.911)/0.805, with no statistically significant difference of the area under the curves (P=0.316). The misclassification rate/false-negative rate of LR was 20.6%/47.5% vs 18.1%/30.5% for NN. Missing data analysis did not change the results. CONCLUSION: Statistical models can aid in the triage of patients with suspected GCA. Misclassification remains a concern, but cutoff values for 95% and 99% sensitivities are provided (https://goo.gl/THCnuU).

Meta-analysis of randomized controlled trials in dacryocystorhinostomy with and without silicone intubation.

OBJECTIVE: To determine the effect of bicanalicular silicone intubation (SI) on dacryocystorhinostomy (DCR) success rate in adult primary acquired nasolacrimal duct obstruction. DESIGN: Meta-analysis of randomized controlled trials (RCTs). METHODS: PubMed, Embase, Cochrane CENTRAL, Ovid Medline, Google Scholar, and grey literature search was performed from inception to June 2017. All prospective DCR trials with randomization of SI were considered. Cases with non-SI or adjunctive mitomycin were excluded. Where possible we analysed only 1 eye from each subject. Random effects meta-analysis was performed. RESULTS: We retrieved 1142 articles and after filtering there were 14 RCTs with a total of 1311 DCR cases. There were 444 external DCRs and pooled estimate showed risk ratio (RR) was 1.08 (95% confidence interval [CI] 1.01-1.15). There were 867 predominantly endonasal DCR with RR 1.04 (95% CI 0.99-1.09). When all DCR modalities were combined the RR was 1.05 (95% CI 1.01-1.09). CONCLUSIONS: Overall, there was a 5% statistically significant improvement in DCR success rate with SI, but more endonasal DCR RCTs are required.

Does herpes zoster predispose to giant cell arteritis: a geo-epidemiologic study.

PURPOSE: Giant cell arteritis (GCA) is the most common systemic vasculitis in the elderly and can cause irreversible blindness and aortitis. Varicella zoster (VZ), which is potentially preventable by vaccination, has been proposed as a possible immune trigger for GCA, but this is controversial. The incidence of GCA varies widely by country. If VZ virus contributes to the immunopathogenesis of GCA we hypothesized that nations with increased incidence of GCA would also have increased incidence of herpes zoster (HZ). We conducted an ecologic analysis to determine the relationship between the incidence of HZ and GCA in different countries. METHODS: A literature search for the incidence rates (IRs) of GCA and HZ from different countries was conducted. Correlation and linear regression was performed comparing the disease IR of each country for subjects 50 years of age or older. RESULTS: We found the IR for GCA and HZ from 14 countries. Comparing the IRs for GCA and HZ in 50-year-olds, the Pearson product-moment correlation (r) was -0.51, with linear regression coefficient (ß) -2.92 (95% CI -5.41, -0.43; p=0.025) using robust standard errors. Comparing the IRs for GCA and HZ in 70-year-olds, r was -0.40, with ß -1.78, which was not statistically significant (95% CI -4.10, 0.53; p=0.12). CONCLUSION: Although this geo-epidemiologic study has potential for aggregation and selection biases, there was no positive biologic gradient between the incidence of clinically evident HZ and GCA.

Quantitative analysis of the text and graphic content in ophthalmic slide presentations.

OBJECTIVE: To determine the characteristics of ophthalmic digital slide presentations. DESIGN: Retrospective quantitative analysis. METHODS: Slide presentations from a 2015 Canadian primary eye care conference were analyzed for their duration, character and word count, font size, words per minute (wpm), lines per slide, words per slide, slides per minute (spm), text density product (wpm × spm), proportion of graphic content, and Flesch Reading Ease (FRE) score using Microsoft PowerPoint and Word. The median audience evaluation score for the lectures was used to dichotomize the higher scoring lectures (HSL) from the lower scoring lectures (LSL). A priori we hypothesized that there would be a difference in the wpm, spm, text density product, and FRE score between HSL and LSL. Wilcoxon rank-sum tests with Bonferroni correction were utilized. RESULTS: The 17 lectures had medians of 2.5 spm, 20.3 words per slide, 5.0 lines per slide, 28-point sans serif font, 36% graphic content, and text density product of 136.4 words × slides/minute2. Although not statistically significant, the HSL had more wpm, fewer words per slide, more graphics per slide, greater text density, and higher FRE score than LSL. There was a statistically significant difference in the spm of the HSL (3.1 ± 1.0) versus the LSL (2.2 ± 1.0) at p = 0.0124. CONCLUSION: All presenters showed more than 1 slide per minute. The HSL showed more spm than the LSL. The descriptive statistics from this study may aid in the preparation of slides used for teaching and conferences.

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 pH-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.