Hypertension, an important risk factor for the health of human being, is often accompanied by various comorbidities. However, the incidence patterns of those comorbidities have not been widely studied. Applying big-data techniques on a large collection of electronic medical records, we investigated sex-specific and age-specific detection rates of some important comorbidities of hypertension, and sketched their relationships to reveal the risk for hypertension patients.

Hypertension, or high blood pressure, is one of the most important risk factors that can lead to cardiovascular diseases, and is thus regarded as a serious public health problem. The prevalence of hypertension has been increasing in most areas worldwide [1, 2]. In China, hypertension is the leading preventable risk factor for death among Chinese adults aged 40 years and older [3, 4]. Moreover, hypertension has a large number of comorbidities, which greatly affect hypertension patients' quality of life [5-7]. In previous years, researchers and medical practitioners have made a tremendous effort to study the comorbidities of hypertension [8-10]. Specifically, heart disease [2, 11], diabetes [12, 13], and obesity [14, 15] are the most widely studied comorbidities of hypertension. Some other diseases, such as allergic respiratory disease [9], sleep-disordered breathing [16], and chronic kidney disease [17], have also been studied as potential comorbidities of hypertension. Hypertension and some of its comorbidities have shown high correlations in terms of their prevalence. An example of this type of correlations is that the prevalence of hypertension in patients with diabetes is as high as 92.7% [18].

Moreover, the sex-specific and age-specific analyses of comorbidities of hypertension have resulted in various important findings [1, 19-21]. Specifically, the incident rates of comorbidities in hypertension patients with a different sex and age can significantly differ. An example of this difference is that the incidence of hypertension and hypercholesterolemia combined is 20% for women versus 16% for men, and ranges from 1.9% for those aged 20-29 to 56% for those aged 80 years and older [22]. Additionally, patient's age and sex need to be considered for treatment of these comorbidities [23, 24]. An example of the situation is that treatment for hypertension patients who are 80 years or older with indapamide has been proved to be effective and can also reduce the patient's risk of stroke [23]. Research has shown that untreated male hypertension patients are more likely to suffer from cognitive impairment than untreated female hypertension patients do [25]. Thus, hypertension should be treated and controlled as early as possible for male patients before they encounter dementia.