Levels and Trends of Hypertension at National and Subnational Scale in Iran from 1990 to 2016: A Systematic Review and Pooled Analysis

BACKGROUND: Raised blood pressure is a serious risk factor for several non-communicable diseases (NCDs) in Iran. In this study, we aimed to estimate the mean of systolic blood pressure (SBP) and diastolic blood pressure (DBP) and subsequently, the prevalence of hypertension by sex, age, province, and year in Iran. METHODS: We conducted a systematic review using PubMed, Web of Science, and Scopus databases through December 2017. We also used individual level data from eight national surveys, aggregated data from seven subnational population-based studies, and extracted data reported in 52 published studies. We used a two-stage model including Age-Spatio-Temporal and Gaussian process regression (GPR) to estimate mean systolic and diastolic blood pressure and used a crosswalk model to estimate the prevalence of hypertension by sex, age, province, and year. RESULTS: The number of hypertensive adults increased in Iran from 1.8 million (882 thousand in women) in 1990 to 13.6 million (7.2 million in women) in 2016. The national age-standardized prevalence of hypertension increased from 8.7% (7.8-9.7) to 28.8% (27.7-30.0) in women and from 8.0% (7.2-8.9) to 24.2% (23.1-25.3) in men from 1990 to 2016. Mean systolic and diastolic blood pressures show a similar increasing trend. CONCLUSION: During the past 27 years, we observed an increase in the age-standardized prevalence and mean levels of blood pressure. If the current trend in levels of blood pressure and prevalence of hypertension continue in the coming years, Iran will not achieve the sixth target of the Global Action Plan by 2020 and the Sustainable Development Goals (SDGs) by 2030.