Background
Methods
Study cohort
Data source
Study outcomes
Statistical analyses
Ethics
Results
Event characteristics
All IHD (n = 5,377 events) | MI only (n = 1,823 events) | |||||
---|---|---|---|---|---|---|
Aboriginal | Non-Aboriginal | Aboriginal | Non-Aboriginal | |||
n = 1,059 events (794 patients) | n = 4,318 events (3,587 patients) | p value | n = 365 events (342 patients) | n = 1,458 events (1,386 patients) | p value | |
Age groups | <0.001 | <0.001 | ||||
25-34 years | 53 (5.0) | 31 (0.7) | 25 (6.8) | 10 (0.7) | ||
35-44 years | 222 (21.0) | 312 (7.2) | 83 (22.7) | 111 (7.6) | ||
45-54 years | 353 (33.3) | 760 (17.6) | 116 (31.8) | 295 (20.2) | ||
55-64 years | 247 (23.3) | 1,073 (24.8) | 87 (23.8) | 359 (24.6) | ||
65-74 years | 117 (11.0) | 1,051 (24.3) | 36 (9.9) | 333 (22.8) | ||
75-84 years | 67 (6.3) | 1,091 (25.3) | 18 (4.9) | 350 (24.0) | ||
Sex: female (%) | 465 (43.9) | 1,419 (32.9) | <0.001 | 120 (34.2) | 368 (25.2) | 0.001 |
Residential area (%) | <0.001 | <0.001 | ||||
Regional | 424 (40.0) | 3,431 (79.5) | 125 (34.2) | 1,128 (77.4) | ||
Remote | 635 (60.0) | 887 (20.5) | 240 (65.8) | 330 (22.6) | ||
SES (%) | <0.001 | <0.001 | ||||
1st quartile(a)
| 576 (54.4) | 1,218 (28.2) | 209 (57.3) | 401 (27.5) | ||
2nd quartile | 209 (19.7) | 1,205 (27.9) | 63 (17.3) | 425 (29.1) | ||
3rd quartile | 166 (15.7) | 1,388 (32.1) | 50 (13.7) | 465 (31.9) | ||
4th quartile(b)
| 108 (10.2) | 507 (11.7) | 43 (11.8) | 167 (11.5) | ||
Risk factors (%) | ||||||
Alcohol | 311 (29.4) | 234 (5.4) | <0.001 | 96 (26.3) | 59 (4.0) | <0.001 |
Smoking | 756 (71.4) | 2,388 (55.3) | <0.001 | 263 (72.1) | 779.(53.4) | <0.001 |
Comorbidities (%) | ||||||
Chronic pulmonary disease | 204 (19.3) | 483 (11.2) | <0.001 | 56 (15.3) | 128 (8.8) | <0.001 |
Diabetes | 608 (57.4) | 1,113 (25.8) | <0.001 | 205 (56.2) | 340 (23.3) | <0.001 |
HF | 238 (22.5) | 666 (15.4) | <0.001 | 79 (21.6) | 230 (15.8) | 0.008 |
Kidney disease | 175 (16.5) | 316 (7.3) | <0.001 | 67 (18.4) | 110 (7.5) | <0.001 |
First ever IHD/MI event in 2005–09 (%) | 591 (55.8) | 3,035 (70.3) | <0.001 | 263 (72.1) | 1,241 (85.1) | <0.001 |
Private insurance (%) | 52 (4.9) | 1,181 (27.4) | <0.001 | 21 (5.8) | 470 (32.2) | <0.001 |
IHD category (%) | 0.497 | |||||
MI | 365 (33.8) | 1,458 (33.8) | ||||
Unstable angina | 340 (32.1) | 1,468 (34.0) | ||||
Other IHD | 354 (33.4) | 1,392 (32.2) | ||||
MI type (%)(c)
| ||||||
Transmural | 167 (45.8) | 641 (44.0) | 0.078 | |||
Subendocardial | 144 (39.5) | 527 (36.1) | ||||
Other | 54 (14.8) | 290 (19.9) |
Aboriginal disparity in receipt of coronary angiography
IHD | MI | |||
---|---|---|---|---|
Aboriginal status = yes | RR (95% CI) | p value | RR (95% CI) | p value |
(i) Receipt of coronary angiography
| ||||
Unadjusted | 0.88 (0.80-0.97) | 0.010 | 0.94 (0.87-1.02) | 0.162 |
Model 1 | 0.77 (0.69-0.85) | <0.001 | 0.79 (0.73-0.86) | <0.001 |
Model 2 | 0.76 (0.70-0.83) | <0.001 | 0.81 (0.75-0.89) | <0.001 |
Model 3 | 0.87 (0.80-0.95) | 0.002 | 0.93 (0.86-1.01) | 0.096 |
Model 4 | 0.95 (0.88-1.04) | 0.283 | 0.96 (0.88-1.05) | 0.366 |
Model 5 | 0.93 (0.84-1.03) | 0.166 | 0.97 (0.87-1.07) | 0.510 |
(ii) Transfer to metropolitan hospital
| ||||
Unadjusted | 0.96 (0.89-1.04) | 0.366 | 1.02 (0.95-1.09) | 0.597 |
Model 1 | 0.86 (0.79-0.94) | 0.001 | 0.88 (0.83-0.94) | <0.001 |
Model 2 | 0.84 (0.78-0.91) | <0.001 | 0.89 (0.83-0.95) | 0.001 |
Model 3 | 0.91 (0.84-0.98) | 0.012 | 0.96 (0.90-1.03) | 0.256 |
Model 4 | 0.99 (0.92-1.07) | 0.758 | 0.99 (0.93-1.06) | 0.804 |
Model 5 | 0.97 (0.89-1.06) | 0.543 | 1.00 (0.92-1.08) | 0.939 |
(iii) Receipt of coronary angiography if transferred to metropolitan hospital
| ||||
Unadjusted | 0.92 (0.87-0.96) | <0.001 | 0.92 (0.88-0.97) | 0.003 |
Model 1 | 0.88 (0.84-0.93) | <0.001 | 0.89 (0.84-0.95) | <0.001 |
Model 2 | 0.89 (0.85-0.94) | <0.001 | 0.91 (0.86-0.97) | 0.003 |
Model 3 | 0.97 (0.92-1.02) | 0.188 | 0.97 (0.92-1.03) | 0.304 |
Model 4 | 0.98 (0.93-1.03) | 0.346 | 0.97 (0.92-1.03) | 0.382 |
Model 5 | 0.97 (0.91-1.03) | 0.300 | 0.98 (0.91-1.05) | 0.546 |
Aboriginal disparity in transfer to metropolitan hospital
Aboriginal disparity in receipt of coronary angiography if transferred to metropolitan hospital
Individual characteristics associated with outcomes
Coronary angiography | Transfer to metropolitan hospital | Coronary angiography if transferred to metropolitan hospital | ||||
---|---|---|---|---|---|---|
RR (95% CI) | p value | RR (95% CI) | p value | RR (95% CI) | p value | |
Aboriginal status | ||||||
Non-Aboriginal | 1.00 | 1.00 | 1.00 | |||
Aboriginal | 0.96 (0.88-1.05) | 0.366 | 0.99 (0.93-1.06) | 0.804 | 0.97 (0.92-1.03) | 0.382 |
Age groups | ||||||
25-34 years | 1.11 (0.93-1.31) | 0.244 | 1.04 (0.91-1.20) | 0.559 | 1.07 (0.99-1.17) | 0.107 |
35-44 years | 1.04 (0.97-1.12) | 0.298 | 1.05 (0.98-1.12) | 0.141 | 1.00 (0.95-1.05) | 0.900 |
45-54 years | 1.00 | 1.00 | 1.00 | |||
55-64 years | 0.98 (0.92-1.05) | 0.541 | 1.00 (0.95-1.05) | 0.959 | 0.98 (0.94-1.02) | 0.331 |
65-74 years | 0.86 (0.79-0.94) | 0.001 | 0.87 (0.80-0.93) | <0.001 | 1.00 (0.95-1.04) | 0.870 |
75-84 years | 0.52 (0.45-0.60) | <0.001 | 0.59 (0.52-0.66) | <0.001 | 0.88 (0.82-0.96) | 0.002 |
Sex | ||||||
Male | 1.00 | 1.00 | 1.00 | |||
Female | 0.98 (0.91-1.06) | 0.648 | 0.97 (0.91-1.03) | 0.290 | 1.01 (0.97-1.05) | 0.786 |
Residential area | ||||||
Regional | 1.00 | 1.00 | 1.00 | |||
Remote | 1.03 (0.96-1.09) | 0.488 | 1.06 (1.00-1.12) | 0.035 | 0.97 (0.93-1.01) | 0.147 |
SES quartiles | ||||||
1st quartile(a)
| 1.00 | 1.00 | 1.00 | |||
2nd quartile | 1.06 (0.99-1.15) | 0.115 | 1.05 (0.98-1.12) | 0.153 | 1.01 (0.97-1.05) | 0.691 |
3rd quartile | 1.08 (1.00-1.17) | 0.049 | 1.05 (0.99-1.13) | 0.126 | 1.02 (0.98-1.07) | 0.313 |
4th quartile(b)
| 1.08 (0.98-1.18) | 0.107 | 1.11 (1.04-1.19) | 0.003 | 0.97 (0.91-1.03) | 0.278 |
MI type(c)
| ||||||
Transmural | 1.00 | 1.00 | 1.00 | |||
Subendocardial/other | 0.96 (0.91-1.01) | 0.131 | 0.96 (0.92-1.01) | 0.128 | 0.99 (0.96-1.02) | 0.656 |
Chronic pulmonary disease | ||||||
No | 1.00 | 1.00 | 1.00 | |||
Yes | 0.79 (0.67-0.93) | 0.005 | 0.85 (0.74-0.97) | 0.019 | 0.94 (0.85-1.04) | 0.183 |
Diabetes | ||||||
No | 1.00 | 1.00 | 1.00 | |||
Yes | 0.97 (0.90-1.04) | 0.404 | 0.99 (0.93-1.05) | 0.758 | 0.98 (0.94-1.02) | 0.304 |
HF | ||||||
No | 1.00 | 1.00 | 1.00 | |||
Yes | 0.67 (0.57-0.78) | <0.001 | 0.74 (0.66-0.84) | <0.001 | 0.89 (0.81-0.98) | 0.014 |
Kidney disease | ||||||
No | 1.00 | 1.00 | 1.00 | |||
Yes | 0.63 (0.51-0.79) | <0.001 | 0.89 (0.76-1.03) | 0.106 | 0.71 (0.60-0.84) | <0.001 |
Private insurance | ||||||
No | 0.84 (0.79-0.88) | <0.001 | 0.85 (0.81-0.89) | <0.001 | 0.98 (0.95-1.01) | 0.124 |
Yes | 1.00 | 1.00 | 1.00 |
Sensitivity analyses
IHD | MI | |||
---|---|---|---|---|
Method of identifying Aboriginal status | RR (95% CI) | p value | RR (95% CI) | p value |
(i) Coronary angiography
| ||||
≥25% of admissions: 28-day event | 0.94 (0.86-1.03) | 0.186 | 0.94 (0.86-1.03) | 0.195 |
First admission for event: 28-day event | 0.97 (0.88-1.06) | 0.473 | 0.96 (0.88-1.06) | 0.431 |
Any admission: 90-day event | 0.94 (0.86-1.02) | 0.119 | 0.96 (0.89-1.04) | 0.371 |
(ii) Transfer to metropolitan hospital
| ||||
≥25% of admissions: 28-day event | 0.96 (0.88-1.04) | 0.305 | 0.98 (0.91-1.05) | 0.579 |
First admission for event: 28-day event | 0.97 (0.90-1.06) | 0.535 | 0.99 (0.92-1.07) | 0.888 |
Any admission: 90-day event | 1.00 (0.93-1.07) | 0.942 | 1.00 (0.94-1.07) | 0.958 |
(iii) Receipt of coronary angiography if transferred to metropolitan hospital
| ||||
≥25% of admissions: 28-day event | 0.98 (0.93-1.04) | 0.569 | 0.97 (0.91-1.03) | 0.275 |
First admission for event: 28-day event | 1.02 (0.94-1.05) | 0.900 | 0.97 (0.91-1.04) | 0.423 |
Any admission: 90-day event | 0.95 (0.90-1.03) | 0.061 | 0.97 (0.92-1.03) | 0.338 |