We aimed to determine whether gender and race are independently associated with in-hospital major adverse cardiac and cerebrovascular events (MACCE) and hospital length of stay in chronic dialysis patients undergoing percutaneous coronary intervention (PCI). Cardiovascular disease is the leading cause of mortality in patients with end-stage renal disease requiring dialysis. Whether gender or race independently influences the outcomes in patients undergoing PCI is not fully understood. The study population included 474 chronic dialysis patients who underwent PCI at 4 New York State teaching hospitals from January 1, 2004 to December 31, 2007. The primary end point of the study was the composite of in-hospital MACCE, defined as all-cause mortality, nonfatal myocardial infarction, and nonfatal stroke. The secondary end points included in-hospital all-cause mortality and hospital length of stay. Of the 474 chronic dialysis patients, 172 (36.3%) were women. The women undergoing PCI were more likely to be black or Hispanic and had a greater left ventricular ejection fraction. The women had significantly greater rates of in-hospital MACCE (5.8% vs 1.7%, p = 0.013) and mortality (4.7% vs 0.7%, p = 0.006). No significant difference in the MACCE rates was found between the black and white patients (4.9% vs 2.2%, respectively, p = 0.125), although black patients showed a trend toward greater in-hospital mortality (4.1% vs 1.2%, p = 0.069). After adjustment for the baseline clinical and procedural characteristics, female gender was an independent predictor of MACCE (odds ratio 7.41, 95% confidence interval 1.81 to 30.27) and all-cause mortality (odds ratio 13.23, 95% confidence interval 1.55 to 113.25), but race was not. No significant difference in the hospital length of stay was observed by either gender or race. In conclusion, in this study, female gender was independently associated with a greater risk of MACCE and all-cause mortality in dialysis-dependent patients undergoing PCI. Although being a black woman was an independent predictor of mortality, race per se was not an independent predictor of in-hospital mortality.
It is unknown whether gender or race affects the outcomes in dialysis-dependent patients undergoing percutaneous coronary intervention (PCI). Racial disparity studies have demonstrated that although black patients are 4 times more likely to develop kidney failure than whites, black patients receiving chronic dialysis appear to have a survival advantage that can likely be attributed to a decreased prevalence of cerebrovascular disease in these patients compared to dialysis-dependent whites. Although minority patients tend to be referred less for PCI, no difference in the post-PCI outcomes have been previously demonstrated among whites and blacks with cerebrovascular disease. Regarding gender, most studies comparing the outcomes after PCI in men versus women have demonstrated worse outcomes for women. The aim of the present analysis was to determine whether gender and race are independent predictors of in-hospital major adverse cardiac and cerebrovascular events (MACCE) and hospital length of stay among dialysis-dependent patients undergoing PCI.
Methods
The data were prospectively collected from all patients who underwent PCI from January 1, 2004 to December 31, 2007 at 4 New York State academic medical centers that participate in the New York State Percutaneous Coronary Interventions Reporting System. The data elements in the registry include patient demographic information, insurance status, baseline clinical, angiographic, and procedural characteristics, and in-hospital outcomes. To protect the anonymity of patients, all data were stripped of the 20 potential identifiers by each individual center and submitted to a central databank for analysis. The institutional review boards of each participating institution approved the present study. The demographic and medical history data extracted included age, gender, race, ethnicity, ejection fraction, previous coronary artery bypass graft surgery, previous PCI, previous myocardial infarction (defined as myocardial infarction occurring >72 hours before PCI), stable angina, previous stroke or cerebrovascular accident, diabetes, peripheral vascular disease, chronic obstructive pulmonary disease, congestive heart failure, and serum creatinine. The presentation and procedural characteristics recorded included the priority of PCI, unstable angina, acute myocardial infarction, ST-segment elevation myocardial infarction, stent thrombosis, stent placement, stent type (bare metal or drug-eluting), and coronary arteries treated. The coronary arteries (and their respective branches) were grouped as the left main, left anterior descending, left circumflex, right coronary artery, vein graft, and arterial graft.
The primary outcome for the present analysis was in-hospital MACCE, defined as a combined end point of in-hospital all-cause mortality, nonfatal myocardial infarction, and nonfatal stroke. The secondary outcomes included all-cause in-hospital mortality and length of stay measured in days.
The data were summarized using descriptive statistics. Univariate analyses were performed to compare the characteristics of male and female dialysis-dependent patients and white and black dialysis-dependent patients. The chi-square test (or Fisher’s exact test, when applicable) was used to compare the differences in the categorical variables. Student’s t test was used for continuous variables. Multivariate logistic regression analysis was used to evaluate the influence of gender on adverse cardiac events and inpatient mortality in PCI patients, controlling for demographic characteristics, medical history, clinical presentation, and procedural characteristics. The predictors for the logistic and linear regression analyses were selected according to the statistical significance on the univariate analysis (p <0.2) and previous clinical data and included age, gender, race, left ventricular ejection fraction, previous coronary artery bypass graft surgery, previous myocardial infarction, peripheral vascular disease, diabetes, congestive heart failure, myocardial infarction within the previous 72 hours, and ST-segment elevation myocardial infarction. The Statistical Package for Social Sciences, version 17.0 (SPSS, Chicago, Illinois) was used for data analysis, and a 2-tailed p value of 0.05 was statistically significant.
Results
Complete data were available for 25,025 patients who had undergone PCI from January 1, 2004 to December 31, 2007. Of the 474 patients with end-stage renal disease requiring dialysis replacement therapy who constituted the study population, 302 (63.7%) were men and 172 (36.3%) were women. The clinical characteristics are summarized in Table 1 . The dialysis-dependent women undergoing PCI had a greater left ventricular ejection fraction, lower baseline creatinine, and lower rates of previous coronary artery bypass graft surgery compared to their male counterparts. However, a greater percentage of the female patients were either black or Hispanic. The female patients also had a greater prevalence of chronic lung disease. The clinical presentation and procedural characteristics are listed in Table 2 . After exclusion of 26 patients listed as nonwhite and nonblack, the clinical characteristics of the 325 white (72.5%) and 123 black (27.5%) patients were subsequently compared. The clinical characteristics are summarized in Table 3 . The dialysis-dependent black patients undergoing PCI were more likely to be women and less likely to be Hispanic. The black patients had lower rates of previous coronary artery bypass graft surgery and congestive heart failure and a greater baseline creatinine. The clinical presentation and procedural characteristics are listed in Table 4 . No significant difference in clinical presentation was found between the races. Black patients tended to have less saphenous vein graft interventions.
| Variable | Male (n = 302) | Female (n = 172) | p Value |
|---|---|---|---|
| Age (years) | 66 ± 12 | 67 ± 12 | 0.342 |
| Race | 0.003 | ||
| White | 221 (73.2%) | 104 (60.5%) | 0.029 |
| Black | 65 (21.5%) | 58 (33.7%) | |
| Other | 16 (5.3%) | 10 (5.8%) | |
| Hispanics | 30 (9.9%) | 34 (19.8%) | 0.003 |
| Insurance | 0.460 | ||
| Medicare | 212 (70.2%) | 132 (76.7%) | — |
| Medicaid | 19 (6.3%) | 11 (6.4%) | — |
| Managed Care | 38 (12.6%) | 15 (8.7%) | — |
| Private | 29 (9.6%) | 14 (8.1%) | — |
| Uninsured | 2 (0.7%) | 0 (0.0%) | — |
| Other | 2 (0.7%) | 0 (0.0%) | — |
| Ejection fraction (%) | 45 ± 13 | 51 ± 13 | <0.001 |
| Previous bypass graft surgery | 100 (33.1%) | 38 (22.1%) | 0.011 |
| Previous percutaneous coronary intervention | 145 (48.0%) | 73 (42.4%) | 0.242 |
| Previous myocardial infarction | 63 (20.9%) | 35 (20.3%) | 0.895 |
| Stable angina | 51 (16.9%) | 31 (18.0%) | 0.753 |
| Peripheral vascular disease | 82 (27.2%) | 34 (19.8%) | 0.072 |
| Chronic lung disease | 18 (6.0%) | 19 (11.0%) | 0.047 |
| Congestive heart failure | 112 (37.1%) | 58 (33.7%) | 0.463 |
| Cerebrovascular accident | 55 (18.2%) | 26 (15.1%) | 0.389 |
| Diabetes mellitus | 172 (57.0%) | 103 (59.9%) | 0.534 |
| Serum creatinine (mg/dl) | 6.9 ± 3.0 | 6.3 ± 2.5 | 0.030 |
| Variable | Male (n = 302) | Female (n = 172) | p Value |
|---|---|---|---|
| Clinical presentation | |||
| Myocardial infarction | 59 (19.5%) | 24 (14.0%) | 0.124 |
| ST-segment elevation | 7 (2.3%) | 5 (2.9%) | 0.695 |
| Unstable angina | 196 (64.9%) | 113 (65.7%) | 0.861 |
| Stent thrombosis | 1 (0.3%) | 0 (0.0%) | 1.000 |
| Priority of percutaneous coronary intervention | 0.970 | ||
| Emergent | 17 (5.6%) | 10 (5.8%) | |
| Urgent | 151 (50.0%) | 84 (48.8%) | |
| Elective | 134 (44.4%) | 78 (45.3%) | |
| Stent type and coronary vessel intervention | |||
| Left main | 23 (7.6%) | 11 (6.4%) | 0.620 |
| Left anterior descending | 216 (71.5%) | 118 (68.6%) | 0.503 |
| Left circumflex | 174 (57.6%) | 89 (51.7%) | 0.216 |
| Right | 197 (65.2%) | 102 (59.3%) | 0.198 |
| Arterial graft | 9 (3.0%) | 4 (2.3%) | 0.777 |
| Saphenous vein graft | 55 (18.2%) | 12 (7.0%) | 0.001 |
| Bare metal stent | 56 (18.5%) | 29 (16.9%) | 0.646 |
| Drug-eluting stent | 204 (67.5%) | 123 (71.5%) | 0.370 |
| Variable | Whites (n = 325) | Blacks (n = 123) | p Value |
|---|---|---|---|
| Age (years) | 67 ± 12 | 65 ± 10 | 0.073 |
| Men | 221 (68.0%) | 65 (52.8%) | 0.003 |
| Hispanics | 49 (15.1%) | 9 (7.3%) | 0.029 |
| Insurance | 0.122 | ||
| Medicare | 242 (74.5%) | 88 (71.5%) | |
| Medicaid | 14 (4.3%) | 12 (9.8%) | |
| Managed care | 38 (11.7%) | 11 (8.9%) | |
| Private | 29 (8.9%) | 11 (8.9%) | |
| Uninsured | 0 (0.0%) | 1 (0.1%) | |
| Other | 2 (0.6%) | 0 (0.0%) | |
| Ejection fraction | 46 ± 13% | 48 ± 14% | 0.150 |
| Previous bypass graft surgery | 105 (32.3%) | 25 (20.3%) | 0.013 |
| Previous percutaneous coronary intervention | 155 (47.7%) | 55 (44.7%) | 0.573 |
| Previous myocardial infarction | 75 (23.1%) | 20 (16.3%) | 0.115 |
| Stable angina | 62 (19.1%) | 15 (12.2%) | 0.085 |
| Peripheral vascular disease | 85 (26.2%) | 27 (22.0%) | 0.359 |
| Chronic lung disease | 28 (8.6%) | 8 (6.5%) | 0.463 |
| Congestive heart failure | 131 (40.3%) | 32 (26.0%) | 0.005 |
| Cerebrovascular event | 61 (18.8%) | 19 (15.4%) | 0.413 |
| Diabetes | 188 (57.8%) | 71 (57.7%) | 0.981 |
| Serum creatinine (mg/dl) | 6.2 ± 2.7 | 7.9 ± 2.8 | <0.001 |
| Variable | Whites (n = 325) | Blacks (n = 123) | p Value |
|---|---|---|---|
| Clinical presentation | |||
| Myocardial infarction | 57 (17.5%) | 20 (16.3%) | 0.749 |
| ST-segment elevation myocardial infarction | 5 (1.5%) | 4 (3.3%) | 0.267 |
| Unstable angina | 210 (64.6%) | 85 (69.1%) | 0.371 |
| Stent thrombosis | 1 (0.3%) | 0 (0.0%) | 1.000 |
| Priority of percutaneous coronary intervention | 0.250 | ||
| Emergent | 18 (5.5%) | 6 (4.9%) | |
| Urgent | 169 (52.0%) | 54 (43.9%) | |
| Elective | 138 (42.5%) | 63 (51.2%) | |
| Stent type and coronary vessels intervened | |||
| Left main | 24 (7.4%) | 4 (3.3%) | 0.128 |
| Left anterior descending | 232 (71.4%) | 80 (65.0%) | 0.192 |
| Left circumflex | 176 (54.2%) | 71 (57.7%) | 0.498 |
| Right | 202 (62.2%) | 81 (65.9%) | 0.469 |
| Arterial graft | 9 (2.8%) | 3 (2.4%) | 1.000 |
| Saphenous vein graft | 58 (17.8%) | 7 (5.7%) | 0.001 |
| Bare metal stent | 62 (19.1%) | 18 (14.6%) | 0.273 |
| Drug-eluting stent | 225 (69.2%) | 87 (70.7%) | 0.758 |
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