WASHINGTON — Use of ACE inhibitors in patients hospitalized with acute myocardial infarction has increased over the past 15 years, but there is still room for improvement, Chyke A. Doubeni, M.D., said at a conference on cardiovascular disease epidemiology and prevention sponsored by the American Heart Association.
Use of ACE inhibitors (ACEIs) in the early treatment of acute MI has indeed risen since their use was recommended in the 1996 Joint American College of Cardiology/American Heart Association guidelines (J. Am. Coll. Cardiol. 1996;28:1328–428). But results of a large community study suggest that the agents are still underutilized in the elderly, patients with renal disease, those with prior acute MI, and patients who were not using ACEIs prior to hospitalization.
“Clinicians should be vigilant about appropriately considering the use of this therapy in all patients with acute myocardial infarction,” commented Dr. Doubeni of the department of family medicine and community health at the University of Massachusetts, Worcester.
Of a total 7,989 Worcester residents hospitalized between 1990 and 2003 with acute MI at 16 acute care hospitals, 44% (3,545) received ACEIs. But of the 1,733 patients who had already been on ACEI therapy prior to hospitalization, 87% continued to receive it while in the hospital. In contrast, 33% of the 6,256 who had not previously been taking ACEIs were newly initiated on the therapy during hospitalization, Dr. Doubeni reported at the conference, also sponsored by the National Heart, Lung, and Blood Institute.
Patients who were on ACEI prior to the index hospitalization were older (73 years vs. 69 years) and were significantly more likely than were those not previously taking these drugs to have hypertension (73% vs. 69%), diabetes (48% vs. 25%), and/or heart failure (41% vs. 15%). The patient population was mostly white.
Overall, receipt of ACEI therapy in hospitalized MI patients rose from just 23% in 1990 to 34% in 1995, then jumped to 50% in 1997, the year after the ACC/AHA guidelines were published. Although the rate of ACEI use remained unchanged between 1997 and 1999, it rose to 68% by 2003.
But these proportions differed substantially between prior users of ACEIs, in whom use during an MI hospitalization rose from 80% to 93% over the 14 year period, and new users, who accounted for just 15% of MI hospitalizations in 1990 and 57% in 2003.
Comparing 1990–1991 with 2001–2003, ACEI use more than doubled in several other subgroups, including those younger than 55 years and those with left ventricular ejection fractions less than 0.40, he reported.
Patients with diabetes, anterior acute MI, left ventricular dysfunction, and heart failure were significantly more likely to receive ACEIs during the entire study period, while there were no differences with regard to age or gender. Patients who had a history of renal disease were only about half as likely (adjusted odds ratio 0.55) to receive ACEI treatment. This is of concern, given recent data suggesting that the agents are protective in patients who have chronic kidney disease (Circulation 2004;110:3667–73).
During the hospitalization, patients who were also on aspirin or β-blockers and those undergoing cardiac catheterizations or percutaneous coronary intervention were all more likely to receive ACEIs, while those undergoing coronary artery bypass grafting and those receiving calcium channel blockers were less likely to have received them.
Overall, 8% of patients receiving ACEI therapy died while in the hospital, compared with 16% of those not on ACEIs. This survival benefit remained after the investigators factored in age, gender, medical history, characteristics of the incident MI, in-hospital complications, and study year. Similar though somewhat attenuated benefits were observed when the analysis was repeated in patients surviving beyond 24 hours of hospitalization, and remained for all subgroups examined.