Comparative Discrimination of Life's Simple 7, Life's Essential 8, and Life's Crucial 9: Evaluating the impact of added complexity on mortality prediction.

Background: Cardiovascular health (CVH) is a key determinant of mortality, but the comparative effectiveness of different CVH metrics remains uncertain. Life's Simple 7 (LS7) evaluates seven domains: smoking, body mass index, physical activity, total cholesterol, blood pressure, fasting glucose, and diet. Life's Essential 8 (LE8) adds sleep health, while Life's Crucial 9 (LC9) further includes mental health. This study aimed to assess whether the additional components in LE8 and LC9 enhance mortality prediction compared to LS7.

Methods: Data from 22,382 participants in the NHANES 2005-2018 were analyzed. Cox proportional hazards regression models were used to evaluate the associations between the scores of these metrics and all-cause, cardio-cerebrovascular disease (CCD), and CVD mortality. The predictive performance of each metric was assessed via receiver operating characteristic (ROC) curves and area under the curve (AUC) values.

Results: The participants had a mean age of 45.23 ± 0.23 years, and 51.53% were female. During a median follow-up of 7.75 (4.42-11.08) years, there were 1,483 all-cause deaths, 405 CCD deaths, and 337 CVD deaths. Compared with participants with LS7 scores ≤ 4, those with scores ≥ 11 had a 65% (HR = 0.35 [0.25-0.50]) lower risk of all-cause mortality, a 66% (HR = 0.34 [0.16-0.73]) lower risk of CCD mortality, and a 61% (HR = 0.39 [0.18-0.85]) lower risk of CVD mortality. Similar trends were observed for LE8 and LC9. The AUC for LS7 (0.68 [0.66-0.70]) was slightly greater than that for LE8 (0.67 [0.65-0.69], P = 0.007) and LC9 (0.67 [0.65-0.69], P = 0.019) in predicting all-cause mortality at 5 years; however, the overall predictive performance was nearly identical across all three metrics. Furthermore, the addition of LS7 (AUC = 0.84 [0.82-0.86], P < 0.001), LE8 (AUC = 0.84 [0.82-0.86], P < 0.001), and LC9 (AUC = 0.84 [0.83-0.86], P < 0.001) to the baseline model (AUC = 0.83 [0.82-0.85]) significantly improved all-cause mortality predictions at 5 years; however, the actual gains in predictive performance were marginal.

Conclusions: LS7, LE8, and LC9 all predict mortality effectively. Given its simpler scoring and fewer components, LS7 demonstrates comparable predictive performance to LE8 and LC9, making it a more practical tool for clinical and public health applications.