Unraveling the paradox: the impact of one or more traditional risk factors on short-term mortality following acute coronary syndromes.

Abstract Background It has been recently suggested that individuals without exposure to any standardized modifiable risk factors may have an increased risk of all-cause mortality from acute coronary syndromes (ACS) compared with their counterparts with one or more risk factors, including diabetes. Purpose To estimate the individual contribution of the four traditional risk factors to the risk of adverse outcomes from first ACS. Methods We analyzed data from 70,953 Caucasian patients presenting with first ACS, but without prior coronary heart disease in the International Survey of Acute Coronary Syndromes (ISACS) Archives registry network from October 2005 to January 2021. The primary outcome was all-cause mortality within 30 days after hospital admission. We calculated sex-specific risk ratios (RRs) stratifying traditional risk factors, current smoking, diabetes, hypercholesterolemia and hypertension into mutually exclusive categories using a balancing strategy by inverse probability weighting. Results Compared with patients presenting without risk factors, those with diabetes had significantly higher 30-day mortality in both women (RR, 1.29; 95% CI, 1.06-1.57) and men (RR, 1.40; 95% CI, 1.16-1.69). By contrast, patients who were current smokers or presented with a history of hypercholesterolemia or hypertension had significantly lower 30-day mortality than patients with no risk factors with RRs ranging from 0.53; 95% CI 0.42–0.67 in women who were smokers to 0.46; 95% CI 0.37–0.59 in men with hypercholesterolemia. The impact of diabetes on mortality was obscured in patients who concomitantly presented with diabetes and one more traditional risk factor. The RRs in combination with current smoking were 1.39; 95% CI 0.92 -2.09 in women and 0.89; 95% CI 0.68 -1.17 in men; with hypercholesterolemia: 0.91; 95% CI 0.66 -1.25 in women and 0.75; 95% CI 0.53–1.06 in men; with hypertension: 1.14; 95% CI 0.99–1.32 in women and 1.12; 95% CI 0.96–1.31 in men. Conclusions Diabetes confers a significant independent excess mortality risk at 30 days following ACS. Dilution bias in this setting refers to the weakening of the observed effect of diabetes because of the inclusion of "one more" risk factor with lower risk profile. Potential misinterpretation of the relationship between diabetes and death from ACS may negatively affect healthcare organization