[Influence of compliance on the incidence of cardiovascular events and health costs when using single-pill fixed-dose combinations for the treatment of hypertension]

Abstract

Background and objective: To determine the incidence of cardiovascular events (CVE) and health care costs in relation to compliance, persistence and level of blood pressure control when comparing patients treated with single-pill combinations (SPC) or free combinations (FC) for the treatment of hypertension.

Patients and methods: Observational, multicenter study that included patients>30 years old, from six primary care teams and two hospitals, who started pharmacological treatment for hypertension during 2006. Two study groups were established: SPC (ACEIs/diuretics; ARBs/diuretics) and FC (ACEIs+DIU; ARB+DIU, separately). Main variables studied were sociodemographic data, comorbidity, Charlson-index, compliance, persistence and achievement of therapeutic goals (ESH-ESC criteria). The cumulative incidence of CVE and a total-cost model were determined (differentiating: health/direct; non-health/indirect). Patients were followed for two years. Statistical analysis included logistic regression, Cox proportional hazards model and analysis of covariance. Statistical signification: p<0.05.

Results: 1,605 patients were recruited, 1,112 (69.3%) receiving SPC and 493 (30.7%) receiving FC, p<0.001; mean age: 69.4 (12.2) years; women: 55.5%. FC treatments were associated with ischaemic heart disease (OR=1.4; 95% CI: 1.1-2.0) and organ failure (OR=1.5; 95% CI: 1.2-2.1), p<0.031. Patients on SPC showed better therapeutic compliance (77.6% vs 71.9%; p<0.001) and longer persistence of treatment (62.1% on-treatment at 24-months [95% CI: 56.3-67.9] vs 49.7% [95% CI: 38.5-60.9]; p<0.001). Optimal control of blood pressure was higher in SPC (48.9% [95% CI: 43.0-54.8] vs 46.7% [95% CI: 35.6-57.8]; p<0.001). Cumulative incidence of cerebrovascular accidents in FC was 4.6% vs 2.4% in SPC; p=0.041. The total health care costs were lower in SPC (1,650.7 € vs 1,674.8 €; p<0.001), including lower specialized care costs (316.1 € vs 382.9 €; p<0.001), fewer hospital admissions and less loss of labour productivity (44.5 € vs 88.4 €; p<0.001).

Conclusions: Better compliance and persistence with antihypertensive fixed-dose combinations improves therapeutic control, leading to a significant reduction of cerebrovascular accidents and total health care costs.