MI guideline adherence spotty with some high-risk patients

A study found that hospital adherence with six evidence-based guidelines for treatment of MI declined based on age, gender, congestive heart failure, atrial fibrillation, chronic renal insufficiency and chronic dialysis. Hypertension, hyperlipidemia, hospitals with full interventional capabilities and calendar year all were associated with increased guideline adherence.

The study was published in the January issue of the American Journal of Medicine.

Dharam J. Kumbhani, MD, of Brigham and Women’s Hospital in Boston, and colleagues used the Get With the Guidelines-Coronary Artery Disease Registry (GWTG-CAD) to assess rates of adherence with evidence-based guidelines for therapies to treat acute MI: aspirin within 24 hours; aspirin and beta-blockers at discharge; patients with low ejection fraction discharged on angiotensin-converting enzyme (ACE) inhibitor/angiotensin receptor blocker; smoking-cessation counseling; and use of lipid-lowering medications. They hoped to determine the overall rate of adherence, calculate any temporal changes in rates of adherence and identify patterns of nonadherence that might be the foci of intervention to increase use of evidence-based therapies.

The researchers analyzed the records of 148,654 patients admitted to 405 hospitals between Jan. 1, 2002, and Dec. 31, 2009. They assigned a value of 1 to each evidence-based treatment for which the patient was eligible. For example, patients who were not smokers were deemed not eligible for smoking-cessation intervention; patients who did not present with high cholesterol were not eligible for lipid-lowering medication. The mean number of eligible measures per patient was 3.1.

Overall, the researchers found that guideline adherence was high and increased over time, so that by 2007 the composite score for the six measures, and the score for each measure individually, was 90 percent or higher. However, adherence was markedly lower in some high-risk populations—age and female gender adversely affected adherence in all six variables, and atrial fibrillation, congestive heart failure, chronic renal insufficiency and chronic dialysis adversely affected adherence in at least four of the six measures. Facilities with full interventional capabilities had the highest adherence rates overall and across all individual measures.

Noting that age and female gender have long been associated with poor outcomes and decreased adherence to evidence-based therapies, the authors termed the continued persistence of this pattern “sobering.” They advocated tailored interventions such as increased efforts to increase awareness among physicians and patients, universal referral to cardiac rehabilitation, expanding the role of non-physicians in the post-MI care plan and imposing incentives and penalties to spur greater adherence.  

Kumbhani et al discussed the dichotomy of impacts specific comorbidities had on guideline adherence. Hypertension, hyperlipidemia, prior MI and prior PCI all were associated with greater adherence, while renal impairment was associated with decreased adherence. The study authors hypothesized that this could be attributed in part to concerns that ACE inhibitors or aspirin may cause adverse events in this population, yet “[i]t is unclear why medication such as lipid-lowering agents would be withheld. Moreover, risk-benefit studies with aspirin and ACE inhibitors in these patients demonstrate benefits similar or even greater than in those with normal renal function.”  

Similarly, atrial fibrillation patients were not only less likely to receive ACE inhibitors and aspirin, but also less likely to receive lipid-lowering medication or smoking-cessation counseling.

“Programs to further improve evidence-based care for acute MI should consider interventions specifically targeting and tailored to non-interventional facilities and patients who are older and female, and who have comorbid conditions identified in this study. This may help these high-risk patient populations to realize the full potential of these treatments,” the authors wrote.