The association between socioeconomic position, use of revascularization procedures and five-year survival after recovery from acute myocardial infarction

Abstract

Background: Patients living under better socioeconomic circumstances often receive more active treatments after an acute myocardial infarction (AMI) compared to less affluent patients. However, most previous studies were performed in countries with less comprehensive coverage for medical services. In this Swedish nation-wide longitudinal study we wanted to evaluate long-term survival after AMI in relation to socioeconomic position (SEP) and use of revascularization.

Methods: From the Swedish Myocardial Infarction Register we identified all 45 to 84-year-old patients (16,041 women and 30,366 men) alive 28 days after their first AMI during the period 1993 to 1996. We obtained detailed information on the use of revascularization, cumulative household income from the 1975 and 1990 censuses and 5-year survival after the AMI.

Results: Patients with the highest cumulative income (adding the values of the quartile categories of income in 1975 and 1990) underwent a revascularization procedure within one month after their first AMI two to three times as often as patients with the lowest cumulative income and had half the risk of death within five years. The socioeconomic differences in the use of revascularization procedures could not be explained by differences in co-morbidity or type of hospital at first admission. Patients who underwent revascularization showed a similar lowered mortality risk in the different income groups, while there were strong socioeconomic differences in long-term mortality among patients who did not undergo revascularization.

Conclusion: This nationwide Swedish study showed that patients with high income had a better long-term survival after recovery from their AMI compared to patients with low income. Furthermore, even though the use of revascularization procedures is beneficial, low SEP groups receive it less often than high SEP groups.

Figure 1

Adjusted odds ratios (OR) of the use of revascularization procedures in all 30,366 men and 16,041 women aged 45 to 84 years that were hospitalized for their first acute myocardial infarction in Swedish acute care facilities from 1993 to 1996 and who survived the first 28 days after admission, by hospital at admission and cumulative income in 1975 and 1990. Adjustments were made for age, sex and previous hospitalizations. Income was obtained by summing the values of the quartile categories of income in 1975 and in 1990. This variable has the minimum value of two if the patient belonged to the low income group (1) in both 1975 and 1990 (i.e., value = 1 + 1), and the maximum value of eight if the patient belonged to the high income group (i.e., value = 4 + 4). The lower borders of the 95% confidence intervals are marked.