Chiu R C, Lidstone D, Blundell P E
J Vasc Surg. 1986 Sep;4(3):251-6.
To evaluate the diagnostic power of penile/brachial index (PBI) in patients studied for male sexual impotence, we prospectively interviewed 503 patients referred to our vascular laboratory for PBI measurements. Since the predictive values of diagnostic tests are affected by the prevalence of the disease in the population studied, we calculated the independent likelihood ratio for various PBI levels obtained. For the purpose of this analysis, "organic" impotence was defined as occurring in patients who had no nocturnal erections, whereas "clinical" impotence was defined as occurring in those patients who could not achieve penetration during intercourse. The patients were divided into four groups by the presence or absence of risk factors, including peripheral vascular disease (PVD) and diabetes mellitus. Patients taking medications that may affect potency (n = 175) were excluded from this analysis. The results show that the predictive power of PBI is less in diabetic patients with PVD and least in those without either PVD, diabetes, or drugs. In patients with PVD but no other risk factors, PBI is highly diagnostic with a sharp cut-off point at 0.6. Thus, the diagnostic power of PBI can be improved by considering the risk factors in the patients studied.
为评估阴茎/肱动脉指数（PBI）在男性性功能障碍患者中的诊断效能，我们前瞻性地访谈了503名被转介至我们血管实验室进行PBI测量的患者。由于诊断试验的预测值受所研究人群中疾病患病率的影响，我们计算了所获得的不同PBI水平的独立似然比。为进行此项分析，“器质性”阳痿定义为发生在无夜间勃起的患者中，而“临床”阳痿定义为发生在性交时无法插入的患者中。根据是否存在包括外周血管疾病（PVD）和糖尿病在内的危险因素，将患者分为四组。正在服用可能影响性功能药物的患者（n = 175）被排除在本分析之外。结果显示，PBI在患有PVD的糖尿病患者中的预测效能较低，而在既无PVD、糖尿病也未服用药物的患者中最低。在患有PVD但无其他危险因素的患者中，PBI具有高度诊断价值，在0.6处有一个明显的临界点。因此，通过考虑所研究患者中的危险因素，可以提高PBI的诊断效能。
