Validation of a clinical prediction rule for the prediction of renal artery stenoses in hypertension resisting to treatment.

Purpose: to perform an external validation of: the clinical prediction rule established by Krijnen et al. (Ann intern Med 1998; 129 : 705-11) designed to identify renal artery stenoses (RAS) in hypertensive patients. Methods: we included 102 patients with a refractory hypertension treated wi th at least two antihypertensive drugs. All subjects had the research of RA S by renal angiography, or angio-computed tomography, or doppler ultrasound . Probability to detect RAS was calculated with Krijnen's algorithm (Pre-te st probability) from the following parameters: age, smoking status, diffuse atherosclerosis, recent hypertension (<2 y), obesity (BMI>25), abdominal b ruit, hypercholesterolemia (>6,5 mmol/L), creatinine. ROC curves were plott ed for each pre-test probability value. A "post-test probability" was obtai ned from the likelihood ratio calculated at each pre-test probability level . Results: RAS prevalence in this population was 49%. Area under the ROC curv e was 0.79 and Youden index was maximal for a pre-test probability of 15%. Maximal likelihood ratio was obtained for a pre-test probability of 46%. Ta ble shows post-test probability as a function of pre-test probability obtai ned with Krijnen's algorithm. [GRAPHICS] Conclusion: Krijnen's algorithm is valid in a population of resistant hyper tensives treated with a bitherapy. This external validation obtained on a p opulation with a high prevalence of RAS should also be tested on a populati on with a lower prevalence of SAR.