Ernesto Tovar-Sugrañes, Mcarmen Lopez-Gonzalez, Cristina Rodriguez-Alvear, Elisabet Perea-Martínez, Mariano Andrés
Affiliation(s):
Dr. Balmis General University Hospital, Alicante
Background: Standard cardiovascular (CV) risk assessment scales (score, framingham heart study) showed an inaccurate prediction of patients with gout and carotid atheroma plaques (thus, at high CV risk) [1]. An updated version of the european scale (score2) and a calibration for population aged >70years (score2-op) have been recently developed. Whether score2 improves the prediction of subclinical atherosclerosis in people with gout remains unknown.
Aim: To assess the discriminative value of score2 and score2-op for carotid plaques in patients with gout.
Methods: We studied newly seen patients with crystal-proved gout enrolled in our inception cohort for structured CV assessment (1). The enrolment period was june 2014-february 2018. For the present analysis, we selected participants: a) eligible for score2/score2-op calculation (absence of established CV disease, diabetes with vascular involvement, severe renal disease); and b) with available results of carotid ultrasound. Score2/score2-op provides the 10-year risk of fatal and non-fatal CV events. To assess the discriminative value of score2/score2-op scale to detect individuals with carotid plaque, 2×2 tables were built to match high-risk score2 (≥7.5% in <50years; ≥10% in 50-69years; ≥15% in >69years) versus the presence of atheroma plaques at carotid ultrasound. Sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios were then calculated with their 95% confidence intervals (CI). Afterwards, receiver operating characteristic curves were plotted, allowing an estimation of the area under the curve (auc) with 95%CI for the scale.
Results: From the initial sample of 356 patients, 193 (54.2%) were eligible for this study. The group consisted mainly of middle-aged men (mean age 56.8, 94.8% male), had a mean of 8.2 years since first gout flare, and nearly every four patients showed subcutaneous tophi. Almost all patients were born in low CV risk regions. Only 32 patients (16.6%) had high-risk score2, while atheroma plaques were detected in 93 patients (48.2%). The results (with 95%CI) for sensitivity, specificity, positive and negative predictive values were 26.9% (17.3 to 36.4%), 93.0% (87.5 to 98.5%), 78.1% (62.2 to 94.0%), 57.8% (49.8 to 65.7%), respectively. Accordingly, positive and negative likelihood ratios were 3.8 (1.7 to 8.5) and 0.8 (0.7 to 0.9), respectively. We estimated an auc of 0.599 (0.519 to 0.680).
Conclusions: Recently updated score2 is an inaccurate tool to predict the presence of atheroma plaques in patients with gout. Despite new calibrations, the absence of inflammatory variables (among others) in risk assessment tools probably limits their discriminative value.
Reference: (1) Ann Rheum Dis. 2017;76(7):1263-8.