Danish Study Looks at Impact of Socioeconomic Status on Primary PCI Outcomes

A Denmark-based observational study has found that, even in a country with a universal, tax-financed health care system, patients with lower socioeconomic status undergoing primary percutaneous coronary intervention (PCI) have worse outcomes than those with more resources. The findings were published online October 2, 2012, ahead of print in Circulation: Cardiovascular Interventions.

Lars Jakobsen, MD, of Aarhus University Hospital (Aarhus, Denmark), and colleagues analyzed the outcomes of 7,385 Danish STEMI patients who received PCI within 12 hours of symptom onset from 2002 to 2008. The researchers considered individual-level socioeconomic data on employment status, income, and education and collected information on each patient’s baseline characteristics as well as hospital stay and medication use within 2 years of discharge.

Baseline Factors, Employment Status Matter

Compared with high socioeconomic-status patients, those with low socioeconomic status were more likely to be women, older, and have comorbidities including diabetes, impaired renal function, and hypertension. Procedural factors also varied, with lower status patients less likely to receive glycoprotein IIb/III inhibitors during treatment and more likely to have complications and to receive angioplasty alone vs. stenting as well as BMS vs. DES.

Over the course of follow-up (maximum 8.8 years, mean 3.7 years), 1,357 patients (18.4%) experienced MACE (cardiac death, recurrent MI, and TVR). Cumulative risk of MACE was elevated in patients with low vs. high income and in unemployed or pensioner vs. employed patients. Adjustment for patient characteristics muted those effects, though employment status remained associated with outcome (table 1). Length of education had no impact on MACE in either unadjusted or adjusted analyses.

Table 1. MACE Risk at Maximum Follow-up

 

Unadjusted HR (95% CI)

Adjusted HR (95% CI)

Low vs. High Income

1.68 (1.47-1.92)

1.12 (0.93-1.33)

Unemployed vs. Employed

1.75 (1.46-2.10)

1.27 (1.03-1.56)

Pensioner vs. Employed

1.78 (1.58-2.01)

1.14 (0.95-1.36)

 

The difference in MACE risk was driven primarily by cardiac death, though again differences were attenuated after adjustment for patient-level factors (table 2).

Table 2. Cardiac Death Risk at Maximum Follow-up

 

Unadjusted HR (95% CI)

Adjusted HR (95% CI)

Low vs. High Income

3.92 (3.11-4.94)

1.30 (0.97-1.73)

Unemployed vs. Employed

4.09 (2.95-5.69)

1.70 (1.17-2.46)

Pensioner vs. Employed

5.37 (4.18-6.89)

1.45 (1.04-2.01)

Short vs. Long Education

1.66 (1.25-2.20)

0.93 (0.69-1.25)

 

Further adjustment for hospital- and procedure-related factors and for medical therapy during follow-up did not significantly alter the relationships.

Findings Call for More Prevention

“The fact that the poor outcome related to low [socioeconomic status] was primarily explained by differences in baseline characteristics, including higher comorbidity, highlights the need for primary prevention strategies [aimed at this population],” the researchers conclude. As to the lack of association between education level and outcome, they suggest that the “healthy choices . . . inculcated early in the Danish school system experience” may be responsible.

Harlan M. Krumholz, MD, SM, of the Yale School of Medicine (New Haven, CT), told TCTMD in a telephone interview that health care systems such as Denmark’s present a unique opportunity for studying how socioeconomic status influences outcome.

“If we were doing [such an analysis in the United States], we’d wonder if [differences in outcome were] in some way related to the quality of their insurance or the way their health care is organized,” he explained. Looking at Denmark, “we can say that even with [a more comprehensive system] there are these gaps occurring. That doesn’t mean we ought not [seek] a more just system here; it means that [simply] having that system still may not be enough to eliminate the disparity.”

But the findings do offer some positive news, Dr. Krumholz said, in that the study “reinforces our general feeling that we give good care to people when they come in with acute disease regardless of their background.”

Echoing the paper, Dr. Krumholz stressed that better prevention is key. “To make progress, we have to focus on that earlier period [before people get sick],” he said, adding that the social determinants are so strong that “we can’t just provide equitable health care. We’ve got to be more proactive than that if we’re going to address the problems in people who are most vulnerable.”

 

Source:

Jakobsen L, Niemann T, Thorsgaard N, et al. Dimensions of socioeconomic status and clinical outcome after primary percutaneous coronary intervention. Circ Cardiovasc Interv. 2012;Epub ahead of print.

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Disclosures
  • The study was supported by the Danish Heart Foundation, the Western Danish Research Forum for Health Sciences, and the Central Denmark Research Foundation.
  • Drs. Jakobsen and Krumholz report no relevant conflicts of interest.

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