Poor 'Real-world' Adherence to BP Meds Ups Heart-Failure Risk

Marlene Busko

August 07, 2015

MILAN, ITALY — Although nonadherence to medication is common in patients with newly diagnosed hypertension, those with greater compliance may have a lower risk of early heart failure, according to a new study from Italy[1].

Specifically, in 6.6 years of follow-up, compared with patients who filled their prescriptions less than a quarter of the time (very low adherence), those who filled their prescriptions more than three-quarters of the time (high adherence) had a 34% lower risk of being hospitalized for heart failure.

The inverse relationship between drug adherence and hospitalization for heart failure was similar in 71- to 80-years-olds vs 40- to 70-year-olds. ACE inhibitors, angiotensin-receptor blockers (ARBs), and diuretics protected patients against heart failure, but calcium-channel blockers did not.

This research shows that "in the real-life setting, achieving a suitable adherence with antihypertensive medicaments is effective for the primary prevention of hospitalization for heart failure," Dr Giovanni Corrao (University Milano-Bicocca, Milan, Italy) and colleagues write in their study, published July 27, 2015 in Hypertension.

Thus, adherence to antihypertensive medications needs to be improved, which should be "a fundamental goal to pursue for protecting patients against HF," the authors write.

Real-world Antihypertensive Adherence and HF

Randomized clinical trials have previously shown that antihypertensive drugs are effective in lowering the risk of heart failure, but there is limited information about how this translates to real-world clinical practice, the researchers write.

They performed a nested case-control study to examine how adherence with antihypertensive therapy affects new heart failure, based on data from 76,017 patients living in Lombardy, Italy, who were 40 to 80 years old in 2005 when they were diagnosed with hypertension and newly treated with antihypertensive drugs.

Patients who had signs of CV disease or had filled a prescription for an antihypertensive drug in the previous 5 years and those who filled a prescription for digitalis in the first year of follow-up were excluded.

During an average follow-up of 6.6 years, 622 patients were newly hospitalized for heart failure, and these patients were randomly matched with 3110 control patients.

The case patients and control patients had a mean age of 67, and 54% were men. The case patients were most often prescribed ACE inhibitors (37%), followed by calcium-channel blockers (19%), ARBs (18%), beta-blockers (14%), and diuretics (12%). Control patients received similar agents, but somewhat fewer (only 8%) received initial therapy with diuretics.

Patients were classed as having antihypertensive adherence that was:

  • Very low—prescriptions filled for <25% of days (46% of case patients).

  • Low—prescriptions filled for 26% to 50% of days (15% of case patients).

  • Intermediate—prescriptions filled for 51% to 75% of days (13% of case patients).

  • High—prescriptions filled for >75% of days (26% of case patients).

The rates for different levels of adherence to therapy were similar in the control patients.

The risk of hospitalization for heart failure decreased stepwise with increasing treatment compliance.

Risk of Hospitalization for Heart Failure, Higher vs Very Low Adherence to Antihypertensive Therapy

Adherence to antihypertensive therapy Odds ratio (95% CI)*
Low 0.83 (0.63–1.10)
Intermediate 0.73 (0.55–0.98)
High 0.66 (0.52–0.83)
*Compared with very low adherence

Perhaps surprisingly, adherence to antihypertensive medication was less beneficial for reducing the risk of hospitalization for heart failure in women than in men—which needs to be investigated further, the researchers say.

Future studies should also investigate how to achieve better patient compliance with antihypertensive therapy (especially among patients at high risk of cardiovascular events) and look at clinical and economic implications of better adherence, they conclude.

Corrao received research support from the European Community, the Italian Medicines Agency, and the Italian Ministry of Education, University, and Research. He has received funding from Novartis and GlaxoSmithKline and is on the advisory board of Roche. Disclosures for the coauthors are listed in the article.

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