Cardiovascular protection by initial and subsequent combination of antihypertensive drugs in daily life practice.

Guidelines recommend a combination of 2 drugs to be used as first-step treatment strategy in high-risk hypertensive individuals to achieve timely blood pressure control and avoid early events. The evidence that this is associated with cardiovascular (CV) benefits compared with initial monotherapy is limited, however. The objective of this study was to assess whether, compared with antihypertensive monotherapy, a combination of antihypertensive drugs provides a greater CV protection in daily clinical practice. A population-based, nested case-control study was carried out by including the cohort of 209 650 patients from Lombardy (Italy) aged 40 to 79 years who were newly treated with antihypertensive drugs between 2000 and 2001. Cases were the 10 688 patients who experienced a hospitalization for CV disease from initial prescription until 2007. Three controls were randomly selected for each case. Logistic regression was used to model the CV risk associated with starting on and/or continuing with combination therapy. A Monte-Carlo sensitivity analysis was performed to account for unmeasured confounders. Patients starting on combination therapy had an 11% CV risk reduction with respect to those starting on monotherapy (95% CI: 5% to 16%). Compared with patients who maintained monotherapy also during follow-up, those who started on combination therapy and kept it along the entire period of observation had 26% reduction of CV risk (95% CI: 15% to 35%). In daily life practice, a combination of antihypertensive drugs is associated with a great reduction of CV risk. The indication for using combination of blood pressure drugs should be broadened.