Adherence with antihypertensive drug therapy and the risk of heart failure in clinical practice

Corrao G, Rea F, Ghirardi A, et al.
Hypertension. Published online before print July 27, 2015; DOI:10.1161/HYPERTENSIONAHA.115.05463

Background

The increased risk of heart failure (HF) associated with hypertension [1] appears reversible, since in randomised clinical trials (RCTs) antihypertensive treatment was accompanied with a reduction in HF incidence [2,3]. The observation that a lower HF incidence was seen with several antihypertensive drug classes, suggests that the lowering of blood pressure (BP) per se is beneficial [2].
Adherence to antihypertensive treatment is generally low, with consequential effects on the BP-lowering effect and cardiovascular (CV) protection. It is unclear to date how adherence to antihypertensive medication affects HF risk in real life.
This population-based case-control study, nested in a large cohort of patients on antihypertensive treatment, assessed the relationship between long-term adherence to the prescribed treatment regimen and risk of first hospitalisation for HF. Data of 622 first hospital admissions for HF, matched to 3110 controls, were included. Adherence was assessed based on the number of days that the prescribed drugs were available as compared to the number of days of follow-up (PDC value). Categories of very low (≤ 25%), low (26%–50%), intermediate (51%–75%), and high (>75%) PDC values were considered.

Main results

• Most patients had a very low adherence to antihypertensive medication during follow-up.
• A marked progressive reduction in risk of HF hospitalisation was seen with increasing adherence, as compared with those in the very low-adherence group (low adherence: OR: 0.83 {95%CI: 0.63-1.10}, intermediate: OR: 0.73 [95%CI: 0.55-0.98}, high: OR: 0.66 {95%CI: 0.52-0.83], P(trend)<0.001).
• Patients who used a larger variety of antihypertensive agents (2: OR: 1.28, >3: OR: 1.99), those who switched between drug classes (OR: 1.61), those with >1 prescribing physician (OR: 1.22) and those who added other CV medicaments during follow-up, showed a significantly higher risk of HF hospitalisation.
• While statin-users showed a significantly decreased risk (OR: 0.71), the opposite was true for those on antidiabetic agents (OR: 1.69).
• Significant linear trends of decreasing risk of HF hospitalisation with increasing adherence were seen in strata based on age (40-70 and 70-80 years). When stratifying by gender, only men showed progressively lower HF hospitalisation risk with low/intermediate and high vs. very low adherence.
• A significant progressive decrease of HF risk was seen with increasing adherence to diuretic, ACE-inhibitor, and ARB treatment, but not with betablockers and calcium channel blockers.

Conclusion

In patients newly treated with antihypertensive drugs in daily clinical practice, the risk of hospitalisation for HF decreases markedly and progressively as adherence to most types of prescribed antihypertensive treatment improves. Thus, the protective effect of antihypertensive treatment on HF as seen in RCTs, appears to translate to real life conditions. Improving adherence with antihypertensive treatment regimens should therefore be a fundamental goal to protect patients against HF.

Find this article online at Hypertension

References

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2. Turnbull F, Neal B, Pfeffer M, et al Blood Pressure Lowering Treatment Trialists’ Collaboration. Blood pressure-dependent and independent effects of agents that inhibit the renin-angiotensin system. J Hypertens. 2007;25:951–958.
3. Zanchetti A, Thomopoulos C, Parati G. Randomized controlled trials of blood pressure lowering in hypertension: a critical reappraisal. Circ Res. 2015;116:1058–1073. doi: 10.1161/CIRCRESAHA.116.303641.