Association of frailty index with all-cause and cardiovascular mortality with different diabetic status: NHANES 1999-2018

Aims The relationship between frailty and mortality among individuals with varying diabetic statuses represents a burgeoning area of concern and scholarly interest within the medical community. However, there are limited studies that explore the relationship between frailty and mortality, as well as cause-specific mortality among individuals with non-diabetes, prediabetes, and diabetes patients. Hence, this study aims to investigate the relationship between the frailty statues and all-cause mortality, as well as cause-specific mortality in individuals with varying diabetic statuses using the data in the NHANES database. Methods The study utilized data from the National Health and Nutrition Examination Survey (NHANES) 1999-2018, incorporating a final sample size of 57, 098 participants. Both univariable and multivariable-adjusted logistic regression analyses, as well as Cox regression analysis were employed to examine the relationship between frailty index (FI) and mortality. Results This study, found a significant positive correlation between the frailty and the increased risk of all-cause mortality non-diabetic [OR 4.277, 95%CI (3.982, 4.594), P < 0.001], prediabetic [OR 2.312, 95%CI (2.133, 2.506), P < 0.001], and diabetic patients [OR 3.947, 95%CI (3.378, 4.611), P < 0.001]. This correlation still existed even after adjusting for confounding factors including age, sex, BMI, poverty, fasting insulin, education, smoke, alcohol drink, waist, hypertension, hyperlipidemia, fasting glucose, HbA1c, eGFR, creatinine and total bilirubin. Our result also suggested a significant positive correlation between the frailty index and the increased risk of CVD mortality among non-diabetic [OR 3.095, 95%CI (2.858, 3.352), P < 0.001] and prediabetic [OR 5.985, 95%CI (5.188, 6.904), P < 0.001] individuals. However, in patients with diabetes, the correlation between frailty and CVD mortality lost significance after adjusting for possible confounding factors [OR 1.139, 95%CI (0.794, 1.634), P > 0.05]. Conclusion A nonlinear relationship has been identified between the FI and all-cause mortality, as well as CVD mortality in non-diabetic and pre-diabetic population. In diabetic patients, there was a significant positive correlation between the frailty and the increased risk of all-cause mortality, but not with CVD mortality. Renal function and liver function might potentially acted as an intermediary factor that elevated the risk of CVD mortality in frail patients with diabetes.