Table 2.
Age-adjusted baseline characteristics of male patients aged 45 to 84 years that were hospitalized for first-time acute myocardial infarction in Swedish acute care facilities from 1993 to 1996 and who survived the first 28 days after admission (n = 30,366) according to cumulative income in the years 1975 and 1990.
| Cumulative income* | ||||||||
| 2 (n = 1,472) | 3 (n = 2,489) | 4 (n = 3,928) | 5 (n = 5,750) | 6 (n = 6,135) | 7 (n = 5,914) | 8 (n = 4,678) | p for trend | |
| Percentage of patients with previous hospitalizations (ICD codes): | ||||||||
| Cancer (140–239) | 6.7 | 7.6 | 8.9 | 9.5 | 8.7 | 8.2 | 7.3 | 0.25 |
| Diseases of the respiratory system (460–519) | 10.7 | 10.2 | 10.0 | 9.5 | 8.7 | 7.6 | 7.4 | < 0.001 |
| Diabetes (250) | 9.2 | 9.1 | 8.0 | 6.5 | 5.9 | 5.0 | 4.4 | < 0.001 |
| Hypertension (401–405) | 6.4 | 7.1 | 7.4 | 7.0 | 6.8 | 6.7 | 6.7 | 0.38 |
| Angina pectoris/other ischemic heart disease (413–414) | 17.3 | 16.7 | 16.1 | 16.2 | 15.5 | 13.8 | 14.0 | < 0.001 |
| Cerebrovascular disease (430–438) | 8.1 | 7.6 | 8.0 | 7.4 | 7.2 | 6.6 | 6.4 | 0.001 |
| University hospital, (%) | 11.1 | 11.5 | 11.9 | 12.4 | 13.8 | 16.9 | 20.1 | < 0.001 |
| Hospital volume | ||||||||
| 0 – 500 | 15.8 | 13.4 | 12.3 | 12.1 | 11.4 | 11.3 | 8.7 | < 0.001 |
| 500 – 1500 | 32.9 | 34.3 | 35.1 | 34.3 | 32.8 | 31.8 | 28.7 | < 0.001 |
| 1500 – 2500 | 46.4 | 47.5 | 48.2 | 48.2 | 49.1 | 48.5 | 52.9 | < 0.001 |
| > 2500 | 6.3 | 5.7 | 6.0 | 6.5 | 7.9 | 9.9 | 11.4 | < 0.001 |
| Revascularization† (%) | 1.3 | 1.8 | 2.3 | 2.8 | 2.9 | 2.9 | 3.4 | < 0.001 |
* By adding the values of the quartile categories of income in 1975 and 1990 for each patient, we created a cumulative income variable ranging from 2–8.
† Coronary revascularization was defined as discharge with any operation code '3066', '3067','3105', '3127', '3158', '3080', '3092' 'FNA', 'FNB', 'FNC', 'FND', 'FNE', 'FNF' or 'FNG' within one month after the first acute myocardial infarction.