1999–2009 Trends in Prevalence, Unawareness, Treatment and Control of Hypertension in Geneva, Switzerland

BACKGROUND There are no time trends in prevalence, unawareness, treatment, and control of hypertension in Switzerland. The objective of this study was to analyze these trends and to determine the associated factors. METHODS/FINDINGS Population-based study conducted in the Canton of Geneva, Switzerland, between 1999 and 2009. Blood pressure was measured thrice using a standard protocol. Hypertension was defined as mean systolic or diastolic blood pressure ≥ 140/90 mmHg or self-reported hypertension or anti-hypertensive medication. Unawareness, untreated and uncontrolled hypertension was determined by questionnaires/blood pressure measurements. Yearly age-standardized prevalences and adjusted associations for the 1999-2003 and 2004-2009 survey periods were reported. The 10-year survey included 9,215 participants aged 35 to 74 years. Hypertension remained stable (34.4%). Hypertension unawareness decreased from 35.9% to 17.7% (P<0.001). The decrease in hypertension unawareness was not paralleled by a concomitant absolute increase in hypertension treatment, which remained low (38.2%). A larger proportion of all hypertensive participants were aware but not treated in 2004-2009 (43.7%) compared to 1999-2003 (33.1%). Uncontrolled hypertension improved from 62.2% to 40.6% between 1999 and 2009 (P = 0.02). In 1999-2003 period, factors associated with hypertension unawareness were current smoking (OR = 1.27, 95%CI, 1.02-1.59), male gender (OR = 1.56, 1.27-1.92), hypercholesterolemia (OR = 1.31, 1.20-1.44), and older age (OR 65-74 yrs vs 35-49 yrs = 1.56, 1.21-2.02). In 1999-2003 and 2004-2009, obesity and diabetes were negatively associated with hypertension unawareness, high education was associated with untreated hypertension (OR = 1.45, 1.12-1.88 and 1.42, 1.02-1.99, respectively), and male gender with uncontrolled hypertension (OR = 1.49, 1.03-2.17 and 1.65, 1.08-2.50, respectively). Sedentarity was associated with higher risk of hypertension and uncontrolled hypertension in 1999-2003. CONCLUSIONS Hypertension prevalence remained stable since 1999 in the canton of Geneva. Although hypertension unawareness substantially decreased, more than half of hypertensive subjects still remained untreated or uncontrolled in 2004-2009. This study identified determinants that should guide interventions aimed at improving hypertension treatment and control.