A nomogram including serum ions to screen for new-onset hypertension in rural Chinese populations over a short-term follow-up period: a prospective cohort study

Background: This study aimed to establish a clinically useful nomogram to evaluate the probability of hypertension onset in a Chinese population. Methods: A prospective cohort study was conducted in 2012/2013, and followed up in 2015 to identify new-onset hypertension in 4123 participants. The dataset was divided into development (n=2748) and verification (n=1375) cohorts. After screening risk factors by lasso regression, a multivariate Cox regression risk model as well as a nomogram were established. Results: Among 4123 patients, 818 (19.8%) developed hypertension. The model identified 10 risk factors: age, waist-to-hip ratio, systolic blood pressure, diastolic blood pressure, high pulse rate, history of diabetes mellitus, family history of hypertension and stroke, intake frequency of bean products, and physical labour intensity. The C-indexes of this model were 0.744 and 0.768 in the development and validation cohorts, respectively. After the inclusion of serum calcium and magnesium levels, the C-indexes were 0.764 and 0.791, respectively. The areas under the curve of the updated model in the development and validation cohorts were 0.907 and 0.917, respectively. The calibration curve showed that the nomogram predicted the hypertension probability accurately. The updated nomogram was clinically beneficial across thresholds of 10%–60%. Conclusions: The newly developed nomogram has good predictive ability and may effectively assess hypertension risk in high-risk rural areas in China.