Author + information
- Received February 11, 2013
- Revision received April 10, 2013
- Accepted April 23, 2013
- Published online November 5, 2013.
- Suzanne V. Arnold, MD, MHA∗,†∗ (, )
- John A. Spertus, MD, MPH∗,†,
- Frederick A. Masoudi, MD, MSPH‡,
- Stacie L. Daugherty, MD, MSPH‡,
- Thomas M. Maddox, MD, MSc§,
- Yan Li, PhD∗,
- John A. Dodson, MD‖ and
- Paul S. Chan, MD, MSc∗,†
- ∗Saint Luke's Mid America Heart Institute, Kansas City, Missouri
- †University of Missouri-Kansas City, Kansas City, Missouri
- ‡University of Colorado Anschutz Medical Campus, Denver, Colorado
- §VA Eastern Colorado Health Care System, Denver, Colorado
- ‖Brigham and Women's Hospital, Boston, Massachusetts
- ↵∗Reprint requests and correspondence:
Dr. Suzanne V. Arnold, Saint Luke’s Mid America Heart Institute, Cardiovascular Research, 4401 Wornall Road, Kansas City, Missouri 64111.
Objectives The aim of this study was to examine the prescribing patterns of medications quantified by the performance measures for acute myocardial infarction (AMI).
Background Current performance measures for AMI are designed to improve quality by quantifying the use of evidence-based treatments. However, these measures only assess medication prescription. Whether patients receive optimal dosing of secondary prevention medications at the time of and after discharge after AMI is unknown.
Methods We assessed treatment doses of beta-blockers, statins, and angiotensin-converting enzyme inhibitors (ACEI)/angiotensin II receptor blockers (ARBs) at discharge and 12 months after AMI among 6,748 patients from 31 hospitals enrolled in 2 U.S. registries (2003 to 2008). Prescribed doses were categorized as none, low (<50% target [defined from seminal clinical trials]), moderate (50% to 74% target), or goal (≥75% target). Patients with contraindications were excluded from analyses for that medication.
Results Most eligible patients (>87%) were prescribed some dose of each medication at discharge, although only 1 in 3 patients were prescribed these medications at goal doses. Of patients not discharged on goal doses, up-titration during follow-up occurred infrequently (approximately 25% of patients for each medication). At 12 months, goal doses of beta-blockers, statins, and ACEI/ARBs were achieved in only 12%, 26%, and 32% of eligible patients, respectively. After multivariable adjustment, prescription of goal dose at discharge was strongly associated with being at goal dose at follow-up: beta-blockers, adjusted odds ratio (OR): 6.08 (95% confidence interval [CI]: 3.70 to 10.01); statins, adjusted OR: 8.22 (95% CI: 6.20 to 10.90); ACEI/ARBs, adjusted OR: 5.80 (95% CI: 2.56 to 13.16); p < 0.001 for each.
Conclusions Although nearly all patients after an AMI are discharged on appropriate secondary prevention medications, dose increases occur infrequently, and most patients are prescribed doses below those with proven efficacy in clinical trials. Integration of dose intensity into performance measures might help improve the use of optimal medical therapy after AMI.
In an effort to standardize and improve the quality of care provided to patients with acute myocardial infarction (AMI), the American College of Cardiology and American Heart Association developed performance measures to quantify the use of evidence-based treatments (1). The goal of these measures is to promote the widespread and uniform application of best practices in AMI care and, in turn, improve survival and quality of life of patients (2). Current performance measures assess whether patients are prescribed certain medications (i.e., yes/no) but not the potency of treatment (i.e., dose). However, trials comparing low versus high doses of these medications have demonstrated that optimal dosing is necessary to achieve the full clinical benefit of these therapies (3–7). Thus, it is possible that a large number of treated patients are receiving relatively ineffective therapy but yet still fulfill the requirements of current performance measures.
Initiating lower doses of secondary prevention medications at hospital discharge might be reasonable, particularly in patients with marginal hemodynamic status (e.g., low blood pressure or heart rate) or left ventricular (LV) systolic dysfunction. It is desirable, however, for these therapies to be up-titrated shortly after discharge to the levels with established benefit in clinical trials, but the degree to which providers are intensifying treatment during outpatient follow-up also is not currently known. If patients are being sub-optimally dosed with secondary prevention medications at hospital discharge and if medication up-titration occurs infrequently during subsequent follow-up, this might explain why the findings from clinical trials (where there was clear evidence of benefit for each medicine promoted by performance measures) have been discordant from those in clinical practice (where the impact of performance measures on reducing mortality has been underwhelming [8–10]).
Accordingly, we examined the prescribing patterns of medications quantified by the performance measures (beta-blockers, statins, and angiotensin-converting enzyme inhibitor [ACEI] or angiotensin II receptor blocker [ARB]) in a large multi-center cohort of patients hospitalized with AMI. We explored prescribing patterns at the time of hospital discharge and 12 months after discharge as well as outpatient intensification of therapy among those initially discharged on medication dose regimens that were below goal.
Study population and protocol
Patients were enrolled in either of 2 multicenter, prospective cohort studies of unselected patients hospitalized with AMI in the United States. Between January 2003 and June 2004, 2,498 patients with AMI were recruited from 19 U.S. hospitals into the PREMIER (Prospective Registry Evaluating Myocardial Infarction: Events and Recovery) (11). Similarly, between June 2005 and December 2008, 4,340 patients with AMI from 24 U.S. hospitals were enrolled into the TRIUMPH (Translational Research Investigating Underlying disparities in acute Myocardial infarction Patients’ Health status) study (12 hospitals participated in both registries) (12). Both registries employed identical inclusion and exclusion criteria and were coordinated by the Mid America Heart Institute. Patients were required to have biomarker evidence of myocardial necrosis and additional clinical evidence supporting the diagnosis of an AMI, including prolonged ischemic signs/symptoms (≥20 min) or electrocardiographic ST-segment changes during the initial 24 h of admission. Baseline data, including discharge medications and doses, were obtained through chart abstraction and a structured interview by trained research staff within 24 to 72 h after admission. To be eligible for the current study, patients had to survive to hospital discharge and not be discharged against medical advice or to hospice (90 patients excluded). Thus, our study sample included 6,748 patients from 31 hospitals, 12 of which participated in both the PREMIER and TRIUMPH studies (Fig. 1).
Detailed follow-up interviews were attempted on all survivors at 1, 6, and 12 months after AMI. In addition to a report of interval events and an assessment of health status, participants were asked to read the names and doses of their medications from their prescription bottles and to report the number of outpatient visits to cardiologists, cardiac surgeons, and primary care providers (for care related to their “heart condition”). For follow-up analyses of this study, we excluded 503 patients who participated in the interview but reported taking zero medications of any type (cardiac or otherwise), because we believed that the therapeutic decisions in these cases were not likely under the control of a physician.
For each of the 3 medication classes, we excluded patients with chart-documented contraindications (e.g., heart rate <50 beats/min or systolic blood pressure [SBP] <100 mm Hg for beta-blockers, SBP <100 mm Hg or a glomerular filtration rate <30 ml/min/1.73 m2 for ACE/ARBs, patient sensitivities/allergies for each medication class), which were prospectively abstracted from the medical records of patients. Furthermore, for analyses of ACEI/ARBs, we included only patients with LV systolic dysfunction at the time of AMI (ejection fraction <40%) (Fig. 1). Each participating hospital obtained Institutional Research Board approval, and all patients provided written informed consent for baseline and follow-up assessments.
Medication dose assessment
Our primary outcome was whether a patient reported taking a goal dose of beta-blocker, statin, and ACEI/ARB at 12 months after AMI. To standardize comparisons of medications within the same class (e.g., metoprolol and carvedilol for beta-blockers), we classified medication doses into categories, relative to the target dose for that medication. The target dose for each medication was defined by the landmark clinical trials that established clinical benefit for each medication in AMI (see Online Tables 1 to 3 for target doses for each medication, the clinical trials demonstrating clinical efficacy, and the mean achieved doses in the trials). Beta-blockers, statins, and ACEI/ARBs that were not indicated by U.S. Food and Drug Administration labeling for patients after AMI or with concurrent heart failure (and thus did not have a target dose for these conditions) were considered “other” and excluded from the respective analyses. For example, medications such as labetalol and losartan are only indicated for the treatment of hypertension and thus do not have established target doses for secondary prevention in AMI. Overall, this exclusion affected 1% of patients taking beta-blockers, 0% of patients taking statins, and 6% of patients taking ACEI/ARBs.
A person was considered to be taking a goal dose of a medication if the dose was at least 75% of the target dose. A dose that was 50% to 74% of target was considered moderate intensity, whereas doses below 50% of target were considered low. Although we excluded patients with SBP <100 mm Hg from the beta-blocker and ACEI/ARB analyses, because these patients would be difficult to get on any dose regime of these medications, patients with SBP <110 mm Hg might similarly be difficult to up-titrate. As such, a fifth category of patients was created for the beta-blocker and ACEI/ARB analyses that included these patients, which was labeled “on medication/unable to titrate.” The percentages of patients at the various dose categories (goal, moderate, low, none, on medication/unable to titrate) of beta-blockers, statins, and ACEI/ARBs were examined at the time of hospital discharge and at 12-month follow-up.
We also examined rates of up-titration during the first year of follow-up, which was defined as an increase in the dose category of a medication from discharge to follow-up (e.g., increasing from a low dose to a moderate or goal dose). Although 12-month follow-up was examined, some patients (20% of cohort) only had 6-month follow-up data, in which case the medications reported at 6 months were used for the follow-up analyses. Because up-titration of medications requires active decision making on the part of a physician, we examined outpatient follow-up intensity (defined as the patient-reported monthly rate of outpatient visits to cardiologists, cardiac surgeons, or primary care providers) for cardiologists and for all physicians (cardiologists and primary care physicians) to determine its association with achieving a goal dose of each medication at follow-up.
Baseline characteristics of patients treated with beta-blockers, statins, and ACEI/ARBs were summarized with proportions for categorical variables, mean ± SD for non-skewed continuous variables, and medians with interquartile ranges for skewed continuous variables. The percentage of patients at the various dose categories (goal, moderate, low, none) of beta-blockers, statins, and ACEI/ARBs were summarized at the time of hospital discharge and at 12-month follow-up, and the percentage of patients at goal at each time point was compared with the McNemar’s test. The mean outpatient follow-up rate was compared between those who did versus those who did not achieve goal dose of each medication at follow-up Student t tests.
For each of the 3 medication classes, we constructed multivariable logistic regression models to identify factors associated with achieving goal dose at follow-up. Patients on medications/unable to titrate were excluded from these analyses. We used hierarchical random effects models to adjust for patient clustering by site. Variables included in the model were selected a priori on the basis of clinical judgment of factors that might impact medication titration. All 3 models included the following variables: discharge dose, age, sex, race, hypertension, diabetes mellitus, chronic lung disease, depression (as assessed with the 9-item Patient Health Questionnaire ), type of AMI (ST- or non–ST-segment elevation), Global Registry of Acute Coronary Events score (14), and the intensity of outpatient follow-up (monthly rate of physician visits). In addition to these variables, the beta-blocker model included SBP, heart rate, and LV systolic dysfunction at hospital discharge, whereas the ACEI/ARB model included SBP and estimated glomerular filtration rate at hospital discharge.
We conducted a number of sensitivity analyses. First, we evaluated the distribution of discharge SBPs to determine whether most patients who were discharged on low-dose regimens of beta-blockers and ACEI/ARBs had lower blood pressures. Second, because it is recommended that beta-blockers be more slowly up-titrated in patients with LV systolic dysfunction, we repeated the analyses, restricting the model for only patients with normal or mild LV dysfunction (ejection fraction ≥40%). Third, for the statin model, even though data supports treating all patients after AMI with high statin doses (6,15), we added low-density lipoprotein cholesterol (LDL-C) levels to the multivariable model to assess whether in-hospital LDL-C levels were associated with physician dosing of statins at follow-up. Fourth, we additionally adjusted for follow-up intensity to cardiologists specifically, to evaluate whether type of provider visited was associated with a greater likelihood of goal dosing at follow-up. For each of these sensitivity analyses and for the main models, cubic splines were considered to account for non-normality of data on age, heart rate, SBP, and LDL.
Missing data analysis
Among patients who survived 12 months, 4% of study participants were contacted but refused to participate in the interview, and 11% were lost to follow-up (Fig. 1). To account for potential bias attributable to those with missing follow-up data, we calculated a non-parsimonious propensity score with successful follow-up as the dependent variable. An inversely weighted propensity score was assigned to each responder (16) to provide greater weight to the data of patients who were most like those without follow-up. Results were comparable with and without weighting, so only the unweighted analyses are presented.
All analyses were conducted with SAS (version 9.2, SAS Institute, Inc., Cary, North Carolina), and evaluated at a 2-sided significance level of <0.05.
Of the 6,838 patients enrolled in the PREMIER and TRIUMPH studies, 41 did not survive to hospital discharge, and 49 were discharged to hospice or left the hospital against medical advice. Of the remaining 6,748 patients, 1,413 (20.9%) had left ventricular systolic dysfunction that was at least moderate in severity and were thus eligible for the ACEI/ARB analyses (Fig. 1). Baseline characteristics of the patients in the study cohort who were eligible for beta-blocker, statin, and ACEI/ARB therapy are shown in Table 1. The mean age of patients was approximately 60 years, and two-thirds were male and of white race. The mean SBP was >120 mm Hg in each group, and most patients underwent either percutaneous or surgical coronary revascularization.
At hospital discharge, most eligible patients were discharged on some dose of the 3 secondary prevention medications: beta-blockers, 93%; statins, 88%, and ACEI/ARB, 88% (Fig. 2). However, 40% of patients were discharged on low doses of beta-blockers, despite SBPs ≥110 mm Hg, and only 19% of patients considered eligible for titration were discharged on goal doses. Patients without LV systolic dysfunction were discharged on goal doses of beta-blockers at similar rates as those with LV dysfunction (14.6% vs. 16.3%, p = 0.18). One-third of patients were discharged on goal doses of statins, and 19% were on low doses. Among patients with LV dysfunction, 21% of patients were discharged on a low or moderate dose of ACEI/ARB but were considered unable to titrate due to marginal blood pressures. Among the remainder, 17% were discharged on low doses despite reasonable SBP and 40% were discharged on goal doses of ACEI/ARBs.
The distribution of SBPs for patients within each discharge dose category for beta-blockers and ACEI/ARBs is shown in Figure 3. Although patients with higher SBPs were more likely to be discharged on higher doses of these medications, 46% of patients on low doses and 59% of patients on moderate doses of beta-blockers had SBPs of at least 120 mm Hg just before hospital discharge to allow for a potentially higher dose. Similarly, for those eligible for ACEI/ARB therapy, 34% of patients on low doses and 45% on moderate doses had a SBP of at least 120 mm Hg just before hospital discharge.
Up-titration during outpatient follow-up
Twelve months after AMI, only 60% to 70% of patients reported taking any dose of beta-blockers, statins, or ACEI/ARBs, compared with approximately 90% at hospital discharge (Fig. 2). Goal doses of medications were achieved less frequently at 12 months than at discharge, with only 12% (p < 0.001 for change from discharge to 12 months), 26% (p < 0.001), and 32% (p = 0.74) of eligible patients on goal doses of beta-blockers, statins, and ACEI/ARBs, respectively. Patients with LV systolic dysfunction were more likely to be on goal doses of beta-blockers at 12 months than those without LV systolic dysfunction (16.2% vs. 9.2%, p < 0.001). Up-titration of medication dose during outpatient follow-up occurred infrequently, with dose increases in only 20.4% of patients on a regimen of beta-blockers, 24.4% of patients on a regimen of statins, and 31.9% of patients on a regimen of ACEI/ARB (Online Table 4).
For each of the 3 medications, the frequency of physician follow-up for patients who were and were not at goal doses is shown in Figure 4 (frequency of follow-up to a cardiologist or cardiac surgeon is shown in Online Fig. 1). There was a modestly higher follow-up frequency in patients who achieved a goal beta-blocker dose at follow-up compared with those who did not (mean frequency: every 7.5 weeks vs. every 8.2 weeks, respectively; p = 0.014). For statins and ACEI/ARBs, there were no significant differences in the mean frequency of physician visits during follow-up among patients who did and who did not achieve goal doses of treatment (statins: 8.2 weeks vs. 8.0 weeks, p = 0.76; ACEI/ARBs: 6.6 weeks vs. 7.1 weeks, p = 0.35). Patients who achieved goal doses at follow-up had more frequent visits to cardiologists than those who did not (beta-blockers: 14.0 weeks vs. 16.0 weeks, p < 0.001; statins: 14.4 weeks vs. 16.0 weeks, p = 0.022; ACEI/ARBs: 12.4 weeks vs. 14.0 weeks, p = 0.13).
In site-level hierarchical logistic regression models adjusting for sociodemographic and clinical factors, including intensity of outpatient follow-up, a patient who was discharged on a goal dose of medication was 6 to 8 times more likely to be on a goal dose at the 12-month follow-up as compared with those not discharged on goal medication doses: beta-blockers (adjusted odds ratio [OR]: 6.08 [95% CI: 3.70 to 10.01]), statins (adjusted OR: 8.22 [95% CI: 6.20 to 10.90]), and ACEI/ARBs (adjusted OR: 5.80 [95% CI: 2.56 to 13.16]); all p < 0.001 (Table 2). Results were similar when adjusted for cardiac-specific follow-up intensity: beta-blockers (adjusted OR: 6.06 [95% CI: 3.68 to 9.97]), statins (adjusted OR: 8.21 [95% CI: 6.20 to 10.90]), and ACEI/ARBs (adjusted OR: 5.42 [95% CI: 2.40 to 12.23]); all p <0.001.
In these models, patients with hypertension and diabetes were more likely to be on goal doses of beta-blockers at follow-up. In addition, patients with LV systolic dysfunction at the time of AMI were nearly 2 times more likely to be on goal doses of beta-blockers at follow-up than those without LV dysfunction (OR: 1.88 [95% CI: 1.40 to 2.53], p < 0.001). No other patient factors, other than discharge dose, were significantly associated with being on a goal dose of any of the 3 medications at follow-up. Notably, follow-up intensity was not significantly associated with being on goal dose for any medication at follow-up. However, when follow-up was restricted to cardiologists, follow-up intensity was significantly associated with achieving goal dose at follow-up for cardiology follow-up rate [per 1 visit/month]; beta-blockers: adjusted OR: 1.69 [95% CI: 1.05 to 2.72], p = 0.031; statins: adjusted OR: 1.37 [95% CI: 1.03 to 1.83], p = 0.033; ACEI/ARBs: adjusted OR: 2.48 [95% CI: 0.99 to 6.22], p = 0.053). In sensitivity analyses, the strong association between goal dose of medication at discharge and follow-up was not materially altered, including additional adjustment for in-hospital LDL-C levels (statin analysis) or limiting the study sample to only those patients without LV systolic dysfunction (Online Table 5).
In a large prospective cohort of patients hospitalized with AMI, we found that the use of evidence-based medications at hospital discharge was high, with approximately 90% of all eligible patients treated with beta-blockers, statins, and ACEI/ARBs. However, the prescribed doses for these medications were below those examined in clinical trials, with nearly 85% of patients discharged on beta-blocker doses and two-thirds of patients discharged on statin and ACEI/ARB doses that were substantially below (<75%) the doses with established efficacy. This is particularly concerning in the case of statins, where there should be few clinical reasons not to start a patient on a goal statin dose early in the AMI hospital stay. Although discharging patients on sub-optimal doses of beta-blockers and ACEI/ARBs might be appropriate clinical care if these doses are then actively increased to goal doses during outpatient follow-up, up-titration was uncommon during the 12 months after AMI—occurring in only 25% of patients—and was not influenced by blood pressure or heart rate during hospital stay. In fact, the strongest predictor of being on a goal dose for any of the 3 medications during follow-up was being on a goal medication dose at hospital discharge. Collectively, our findings suggest most patients with AMI might be undertreated, despite meeting criteria for performance measures for secondary prevention medications. These findings highlight the limitation of current performance measures that credit providers for using any dose of medication, even if well below doses with established clinical benefit.
Actively titrating secondary prevention therapy to goal doses is particularly important, because the efficacy of these medications has been demonstrated to be dose-related. For statins, 2 large clinical trials have shown that higher statin doses are superior in reducing the risk of repeat hospital stay and death after an AMI (6,7,17). A trial comparing low versus high doses of lisinopril and a second comparative effectiveness study of different doses of losartan and candesartan both demonstrated that higher doses of these classes of medications reduced the risk of heart failure, hospital stays, and death (4,5). Finally, for beta-blockers, 2 trials of heart failure patients showed that target doses of bucindolol and carvedilol were associated with more improvement in ejection fraction (3,18), fewer hospital stays (3), and lower mortality compared with low or moderate doses (3). Although there has been some conflicting evidence published from an observational registry in which patients treated with low doses of beta-blockers had lower mortality than those discharged on high doses (19), most studies—and, in particular, clinical trials that do not have inherent treatment bias found in registries—have demonstrated that the higher treatment doses are most effective in reducing morbidity and mortality after an AMI.
Although several studies have reported rates of medication treatment among patients hospitalized with AMI at discharge and follow-up (20–23), these studies have not examined treatment doses or intensification of therapy over time. Therefore, they did not establish whether patients were being treated at doses with established efficacy from clinical trials. Studies that have examined medication dosing are limited; however, these have demonstrated patterns of medication dosing similar to what we found. A study of 606 patients admitted with AMI from 4 hospitals in 1995 found that, although 58% of patients without contraindications were discharged on some dose of beta-blocker, 76% were discharged on doses ≤25% of the target doses from clinical trials, and only 11% were discharged on doses of >50% of the target doses (24). Although these authors did not have information on follow-up, our study highlights that, despite 15 years of quality improvement, little has changed with regard to optimal dosing of secondary prevention medications. A second study of 382 patients with AMI from 41 hospitals found that 76% of patients discharged on a statin were on the same dose 1 year later, with intensification of therapy occurring in only 12% (25). Our data both support and extend the findings of prior studies by examining patterns of medication prescription and dosing at both hospital discharge and outpatient follow-up, evaluating 3 proven therapies in AMI, and including data from over 30 centers for greater generalizability.
There are several potential reasons as to why patients might have been treated at doses far lower than those with established efficacy. First, some patients who are on lower doses of medications are truly receiving their maximally tolerated dose (e.g., low blood pressure for beta-blockers and ACEI/ARBs). Furthermore, there might be some patients who were not up-titrated due to side effects, such as light-headedness or myalgias, or due to patient preference. However, given our sensitivity analyses, it is unlikely that low blood pressure or other dose-limiting side effects were the primary limiting factors in achieving goal doses in most patients.
Second, as hospital stays for AMI have continued to decrease over the past decade (26), clinicians today have less time to optimize medical therapy during the index hospital stay and thus defer intensification of medication therapy until outpatient follow-up. However, we found that medication up-titration occurred infrequently, suggesting there is significant clinical inertia in intensifying treatment during the outpatient period. Interestingly, we found that outpatient follow-up intensity was not associated with an increased likelihood of achieving goal dose at follow-up. However, when we restricted follow-up to cardiologists, there was a modest association between follow-up intensity and goal dose at follow-up, indicating that specialists might be more aggressive in up-titrating these medications. The general lack of active up-titration in the outpatient setting might be because some clinicians do not view up-titration of these medications as an important therapeutic goal, are unaware of the target medication doses (i.e., the doses with proven clinical efficacy), or have other competing medical issues that they need to address during follow-up visits (27). Because current performance measures evaluate only whether patients are on a medication, clinicians also might mistakenly equate being on a treatment as being on effective treatment. This inertia has been shown to be pervasive in the outpatient management of other chronic medical conditions such as hypertension (28) and diabetes (29). Thus, strategies such as improved care coordination at discharge (30) or outpatient tools that assist providers with automating medication titrations (e.g., pharmacist-assisted monitoring, clinical reminders, education, and feedback ) might lead to greater success in treatment intensification during follow-up. Because the protective effects of these medications have been shown to be dose-related (4–7), the inability to achieve goal doses at discharge or to intensify treatment during follow-up represents an important gap in the current quality of AMI care.
The findings of our study have important implications for performance measurement in AMI. The current measures do not distinguish between those hospitals that make robust or meager efforts to optimize medical therapy dosing in patients with AMI. Rates of medication use at clinically proven doses might be improved if performance measures incorporated assessments of medication dosing. Inclusion of optimal drug dosing at discharge has the potential to improve outcomes, although this would understandably be more challenging in terms of data collection. There is also a need to further our understanding of outpatient care, because the current practice of evaluating AMI care only at hospital discharge has substantial limitations in comprehensively capturing the quality of care of AMI patients. Outpatient registries, such as the PINNACLE (Practice Innovation And Clinical Excellence) program (32), might provide additional insights into how best to track and optimize outpatient cardiac care.
First, our analyses on medication up-titration during follow-up used information from vital signs, creatinine, and adverse side effects at hospital discharge. As a result, some patients might have been misclassified as not being at their maximally tolerated dose of medication at follow-up (either due to new or worsening medical factors [e.g., new heart failure or renal dysfunction], side effects [e.g., light-headedness, myalgias], or patient preferences). However, because we excluded patients with SBP <110 mm Hg from these up-titration analyses, we suspect this is relevant to a minority of patients and does not diminish our finding that most patients are not on goal doses of these important medications 12 months after discharge. More in-depth qualitative research, with detailed interviews of patients and physicians, would be particularly useful in deepening our understanding of why up-titration did not occur more frequently in many patients.
Second, medications without a specific indication for treatment of post-AMI or heart failure patients were excluded in the study (e.g., nebivolol, olmesartan) but might be appropriate for particular patients. However, these excluded patients only represented 1% of patients taking beta-blockers and 6% taking ACEI/ARBs and therefore were unlikely to have affected our findings. Third, we did not have follow-up data on approximately 15% of surviving patients; however, we performed a sensitivity analysis in which we weighted the responses of participants by the inverse of their likelihood to follow-up, to provide greater weight to the data of patients who were most like those without follow-up. Because results were comparable with and without weighting, it is unlikely that our results were significantly biased by loss-to-follow-up. Finally, although we identified gaps in achieving optimal dosing of secondary prevention medications in post-MI patients, we did not evaluate the effectiveness of optimal dosing of these medications because of the likelihood of significant bias by indication with such analyses, whereby patients at higher risk of adverse outcomes [e.g., LV dysfunction] are more likely to receive goal doses of medication or undergo more frequent medication up-titration than lower-risk patients.
We found that most patients hospitalized with an AMI were routinely discharged on secondary prevention medications at doses substantially below the levels proven to be efficacious in clinical trials. These doses were infrequently increased as outpatients, even after 1 year. Because being on a target medication dose at discharge was the strongest predictor of being on a target dose at follow-up, our findings suggest that clinicians should attempt to maximize the doses of secondary prevention therapy during the index hospital stay and to up-titrate these medications during outpatient follow-up. More in-depth qualitative research is necessary to deepen our understanding of why up-titration did not occur more frequently and could provide important insights as to mechanisms by which care can be improved. Performance measures, in turn, might need to incorporate doses of medications to better achieve their goal of truly optimal medical therapy.
The TRIUMPH study was sponsored by a grant from the National Institutes of Health (National Heart, Lung, and Blood Institute): SCCOR Grant #P50HL077113. The PREMIER study (Prospective Registry Evaluating Myocardial Infarction: Events and Recovery) was principally supported by a grant from Cardiovascular Therapeutics, Inc., Palo Alto, California. The funding organizations did not play a role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; or preparation, review, or approval of the manuscript. Dr. Spertus is supported by a Clinical and Translational Science Award (1UL1RR033179); discloses industry relationships with Lilly, Genentech, Amgen, EvaHeart, and Amorcyte; and has served on the United Healthcare Scientific Advisory Board. Dr. Masoudi discloses a contract with the American College of Cardiology Foundation. Dr. Daugherty is supported by a Career Development Grant Award (K08HL103776) from the National Heart, Lung, and Blood Institute. Dr. Maddox is supported by a Career Development Grant Award from the Veterans Affairs Health Services Research and Development Service. Dr. Chan is supported by a Career Development Grant Award (K23HL102224) from the National Heart, Lung, and Blood Institute. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- angiotensin-converting enzyme inhibitor
- acute myocardial infarction
- angiotensin II receptor blocker
- confidence interval
- low-density lipoprotein cholesterol
- left ventricular
- odds ratio
- systolic blood pressure
- Received February 11, 2013.
- Revision received April 10, 2013.
- Accepted April 23, 2013.
- American College of Cardiology Foundation
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