The effect of prehypertension and hypertension on the incidence of cardiovascular disease: A population‐based cohort study in Kharameh, a city in the South of Iran

BACKGROUND AND AIM: Prehypertension and hypertension are important risk factors for cardiovascular diseases. This study was carried out to evaluate the effect of prehypertension and hypertension on the development of cardiovascular diseases. METHODS: This prospective cohort study was performed on 9442 people aged 40−70 in Kharameh, southern Iran. Individuals were divided into three groups: normal blood pressure (N = 5009), prehypertension (N = 2166), and hypertension (N = 2267). In this study, demographic data, disease histories, behavioral habits, and biological parameters were studied. At first, the incidence density was calculated. Then Firth's Cox regression models were used to investigate the association between prehypertension and hypertension with the incidence of cardiovascular diseases. RESULTS: The incidence density in the three groups of individuals with normal blood pressure, prehypertension, and hypertension was 1.33, 2.02, and 3.29 cases per 100,000 person‐days, respectively. The results of multiple Firth's Cox regression by controlling all factors showed that the risk of occurrence of cardiovascular disease in people with prehypertension was 1.33 times (hazard ratio [HR] = 1.32, 95% confidence interval [CI]: 1.01−1.73, p = 0.03) and those with hypertension were 1.85 times higher (HR = 1.77, 95% CI: 1.38−2.29, p < 0.0001) than the individuals with normal blood. CONCLUSION: Prehypertension and hypertension have played an independent role in the risk for developing cardiovascular diseases. Therefore, early detection of individuals with these factors and control of other risk factors in them can contribute to reducing the occurrence of cardiovascular diseases.