CORONARY ARTERY CALCIUM SCORE AND HOME BLOOD PRESSURE VARIABILITY IN A MIDDLE-AGED SAMPLE OF THE SWEDISH POPULATION

Objective: The aim of this study was to explore associations between coronary artery calcium (CAC) score and home blood pressure variability (HBPV) in a Swedish population sample. Design and method: In this cross-sectional study, we analysed data from a Swedish population-based cohort (n = 5057). We included all participants (n = 4262) who as part of the baseline examination had undergone a CAC scoring, and who also during a seven-day period had performed systolic home blood pressure measurements thirteen times (each in triplicate). Mean home systolic blood pressure (HSBP) was calculated, and its standard deviation (SD) and coefficient of variation (CV = 100 X SD / HSBP) were used as measures of HBPV. Participants were divided in four groups: group 1 had CAC score zero (n = 2578), group 2 had CAC score 1–99 (n = 1180), group 3 had CAC score 100–399 (n = 352) and group 4 had CAC score > = 400 (n = 152). One-way analysis of variance was used to test for statistically significant between-group differences. Post-hoc pairwise comparisons were adjusted for multiple comparisons as described by Bonferroni. Results: Overall, there were significant associations between CAC score groups and SD, CV and HSBP, (P < 0.001 for all comparisons). Average SD in group 1 (7.0 ± 2.4 mmHg) was significantly lower than in group 2 (7.3 ± 2.6 mmHg), group 3 (8.1 ± 3.0 mmHg) and group 4 (8.4 ± 3.3 mmHg), P for pairwise comparisons: 0.006, <0.001 and <0.001, respectively. Average CV in group 1 (5.9 ± 1.9) was not significantly different from group 2 (6.0 ± 2.0, P = 1.00) but was significantly lower than in group 3 (6.3 ± 2.1, P = 0.005) and group 4 (6.5 ± 2.4, P = 0.003). Average HSBP in group 1 (117.9 ± 13.6 mmHg) was significantly lower than in group 2 (122.6 ± 13.0 mmHg), group 3 (127.3 ± 12.5) and group 4 (129.1 ± 12.2 mmHg), P for all pairwise comparisons <0.001. Conclusions: In this middle-aged sample of the Swedish population, CAC score was modestly but significantly associated with HBPV. The prognostic performance of HBPV remains to be determined in this cohort.