Ambulatory blood pressure profile in hypertensive patients with β-thalassemia minor

Abstract

β-thalassemia trait (β-TT) is a common genetic disorder in Mediterranean countries, including Greece. Previous studies have shown the protective effect of β-TT against myocardial infarction. However, the ambulatory blood pressure (BP) profile of such patients has not yet been investigated. Thus, the purpose of the present study was to investigate the ambulatory BP monitoring (ABPM) profile of hypertensives with β-TT, in comparison with all-cause anemic and non-anemic essential hypertensive patients. The study ultimately comprised of 8861 essential hypertensive, nondiabetic patients who were divided into three groups: group I (n=191, with β-TT), group II (n=655, anemic) and group III (n=8015, nonanemic). All patients underwent full clinical, laboratory and echocardiographic evaluations, whereas all were subjected to ABPM. Anemia was defined as Hb <12 g per 100 ml for women and <13 g per 100 ml for men, whereas patients with β-TT were self-referred. The distribution of dipping patterns among the three groups was 61.3 vs. 41.2 vs. 45.8% (P<0.001), whereas for nondippers it was 20.4 vs. 31.5 vs. 27.7% (P<0.001), for extreme-dippers it was 15.7 vs. 15.0 vs. 17.5% (P<0.001) and for reverse dippers it was 2.6 vs. 12.4 vs. 9.0% (P<0.001). Furthermore, mean daytime systolic BP (SBP) among the three groups was 140.13 ± 7.79 vs. 142.02 ± 11.61 vs. 141.99 ± 9.87 mm Hg (P=0.03), and mean nighttime SBP was 125.87 ± 10.4 vs. 131.13 ± 15.7 vs. 129.62 ± 13.31 mm Hg (P<0.001). In the multiple regression analysis, after adjustments for age, body mass index and lipid levels, the differences among daytime and nighttime SBP remained significant at 140.18 ± 9.84 vs. 142.02 ± 9.85 vs. 141.99 ± 9.85 mm Hg (P=0.04) and 125.99 ± 13.07 vs. 131.19 ± 13.08 vs. 129.61 ± 13.07 mm Hg (P<0.001), respectively. Hypertensive patients with β-TT present with a better 24-h BP profile in comparison with anemic and nonanemic hypertensives. Thus, β-TT may function protectively in their total cardiovascular risk profile.