A Nomogram for Predicting the Risk of Critical Limb Ischemia in Adults with Hypertension: A Retrospective Study

Dong Xu,1 Xu Zhu,2 Junyu Huo,2 Xupin Xie,1 Changpin Huang,1 Xin Fang,1 Ting Yin3 1Department of Vascular Surgery, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of China; 2Department of Cardiology, Jiangsu Province Hospital and Nanjing Medical University, First Affiliated Hospital, Nanjing, Jiangsu, People’s Republic of China; 3Intensive Care Unit, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, People’s Republic of ChinaCorrespondence: Ting Yin, Intensive Care Unit, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310000, People’s Republic of China, Tel +86 13777879077, Fax +86 56005600, Email ameliyt@163.com Xin Fang, Department of Vascular, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310000, People’s Republic of China, Tel +86 13867478324, Fax +86 56005600, Email fangxin324@hotmail.comPurpose: Peripheral arterial disease (PAD) presenting with underlying hypertension (HTN) poses a higher risk of bilateral lower limb amputation than PAD patients without HTN. While the role of HTN management of PAD patients has received limited attention. We analyzed the clinical characteristics of PAD in adults with HTN and explored risk factors for PAD to construct a nomogram for evaluating critical limb ischemia (CLI) and lesion severity.Methods Patients and Methods: Between January 2014 and December 2019, we retrospectively evaluated 1886 patients with peripheral artery disease with coexisting HTN. Patients were randomly divided into training (n = 1320, 70%) and validation cohorts (n = 566, 30%), and according to the subjective experience of PAD [Fontaine classification (I–II vs III–IV)], patients were further classified into intermittent claudication (IC) and CLI groups. LASSO regression and multivariate Cox proportional hazard analyses were used to construct a nomogram using variables defined in the training cohort, which was validated in the validation cohort. The evaluation of the predictive discriminative, accuracy and clinical application are further analyzed.Results: In the training cohort, optimal independent factors included age, male sex, body mass index, diabetes mellitus, heart rate, triglyceride, and uric acid (AM-BDHTU), which were included in the nomogram predicting the CLI risk (all P < 0.05). The C-index values for CLI risk in PAD with HTN patients were 0.729 (95% CI: 0.704– 0.807) and 0.728 (95% CI: 0.652– 0.744) in the training and validation sets, respectively. Calibration curves indicated good consistency between predicted and actual outcomes. DCA confirmed the clinical utility of the diagnostic model.Conclusion: The AM-BDHTU nomogram, constructed and validated using simple to obtain clinical variables, when combined with the Fontaine classification, effectively predicts the risk of CLI among PAD patients with HTN.Keywords: peripheral arterial disease, hypertension, vascular-related complications, LASSO regression, nomogram, predictive diagnosis