| Background:In recent years,with the development of reperfusion therapy and the improvement of comprehensive cardiac rehabilitation in patients with acute coronary syndrome(ACS),the prognosis of ACS patients in China has improved;however,the long-term prognosis of ACS patients is still poor.Therefore,accurate risk prediction in ACS patients is critically important.The nutritional index,a tool to evaluate the nutritional risks of patients,is a predictive factor for the prognosis of ACS patients.However,there are many different nutrient indices for nutritional risk evaluation,and the evaluation of nutritional risk was not included in the commonly used prognostic risk prediction models for risk stratification assessment in ACS patients.Objective:This study aimed to compare the prognostic prediction value of the geriatric nutritional risk index(GNRI)and prognostic nutritional index(PNI)in predicting the long-term all-cause mortality in patients with ACS who underwent percutaneous coronary intervention(PCI),and whether GNRI or PNI could improve the predictive value of the Global Registry of Acute Coronary Events(GRACE)score-based prognostic models for predicting long-term all-cause death in ACS patients.Methods:Patients with ACS who underwent PCI in the Third People’s Hospital of Chengdu from May 2018 to December 2019 were included.According to the occurrence of all-cause death during the follow-up,the enrolled patients were divided into the all-cause death group and the survival group for baseline data comparison.According to the GNRI score,the patients were divided into four groups with different nutritional risks:a normal nutrition group(GNRI>98),a mild malnutrition risk group(GNRI 92-98),a moderate malnutrition risk group(GNRI 82～91),and a severe malnutrition risk group(GNRI<82),observed the distribution of patients in each group,and the long-term prognosis was compared between four groups.According to the PNI score,the patients were divided into three groups:a normal nutrition group(PNI>38);a moderate malnutrition risk group(PNI 35～38);and a severe malnutrition risk group(PNI<35),observed the distribution of patients in each group,and the long-term prognosis was compared between three groups.According to the GRACE score,the patients were divided into a non-high-risk group(GRACE score<118)and a high-risk group(GRACE score>118),observed the distribution of patients in each group,and the long-term prognosis was compared between the two groups.Kaplan-Meier survival curves were used to estimate the cumulative incidence of all-cause death during the follow-up and compared using the Log-Rank test.Furthermore,univariate and multivariate Cox regression analyses were conducted to evaluate the prognostic values of GNRI and PNI for the occurrence of long-term all-cause death in ACS patients after PCI.Calculating and comparing the concordance index(C-index)of the GNRI and PNI in predicting long-term all-cause death.Calculating and comparing the C-index of the GRACE Score,GNRI combining GRACE score,and PNI combining GRACE score in predicting long-term all-cause death.Finally,the integrated discrimination improvement(IDI)and net reclassification improvement(NRI)were used to evaluate the predictive value of adding moderate to severe malnutrition risk(GNRI<92)or moderate to severe malnutrition risk(PNI<38)to the classification of high-risk GRACE score(GRACE score>118).Results:A total of 831 ACS patients who underwent PCI were enrolled in this study.the mean age of the patient group was 66.28 ± 11.27 years,and 601(72.3%)patients were male.The median follow-up time was 30(26,35)months,a total of 46 all-cause deaths occurred during the follow-up period.1.Comparison of Clinical Features at BaselineAccording to the prognosis,the patients were divided into the all-cause death group(n=46)and the survival group(n=785).PNI(43.86±5.35 vs.47.83±5.75,P<0.001)and GNRI[96.94(92.33,101.71)vs.100.37(95.42,104.13),P=0.001]were significantly lower in the all-cause death group than in the survival group,but GRACE scores were higher[165(136,186)vs.130(108,160),P<0.001].Among the nutrition-related indicators used in the nutritional index in this study,serum albumin and total lymphocyte count in the all-cause death group were significantly lower(P<0.05).However,there was no significant difference in the proportion of weight loss between the two groups.2.Comparison of cumulative incidence of all-cause death during follow-up(1)According to the GNRI score,the patients were divided into normal nutrition group(GNRI>98),n=517(62.2%);mild malnutrition risk group(GNRI 92～98),n-213(25.6%);moderate malnutrition risk group(GNRI 82～91),n=94(11.3%);and severe malnutrition group risk(GNRI<82),n=7(0.8%).In Kaplan-Meier analysis,patients in the mild to severe malnutrition risk group had a significantly higher cumulative incidence of all-cause death than those in the normal nutrition group(Log-Rank P=0.011).(2)According to the PNI score,the patients were divided into normal nutrition group(PNI>38),n=792(95.3%);a moderate malnutrition risk group(PNI 35～38),n=27(3.3%);and a severe malnutrition risk group(PNI<35),n=12(1.4%),KM curve showed that patients with moderate and severe malnutrition risk had a significantly worse prognosis than patients without malnutrition risk(Log-Rank P<0.001).(3)According to the GRACE score,the patients were divided into the non-high-risk group(GRACE score≤118),n=547(65.8%),and a high-risk group(GRACE score>118),n=284(34.2%).And the Kaplan-Meier testing showed the cumulative incidence of all-cause death in the high-risk group was higher than that in the non-high-risk group(Log-Rank P=0.012).3.Multivariate Cox regression analysis for all-cause deathMultivariable Cox proportional hazards regression revealed that GRACE score[HR 1.013,95%CI(1.005-1.020)],PNI[HR 0.921,95%CI(0.865-0.979),P=0.009],moderate and severe malnutrition risk(PNI<38)[HR 2.975,95%CI(1.266-6.993),P=0.012]and total lymphocyte count[HR 0.562,95%CI(0.321-0.983),P=0.043]were independent predictors for long-term all-cause death in ACS patients who underwent PCI.In addition,although GNRI was associated with all-cause death in this study,it was not an independent predictor of all-cause death in ACS patients undergoing PCI.4.Comparison of the predictive value of GNRI and PNI for all-cause deathThe performance of PNI in predicting long-term all-cause death[C-index 0.681,95%CI(0.607-0.755)]was better than that of GNRI[C-index 0.642,95%CI(0.655-0.719)],and the difference was statistically significant(P<0.001).5.Effects of GNRI or PNI on GRACE risk prediction modelThis study showed that the addition of PNI to the GRACE score significantly improved the prediction of long-term all-cause death,increasing the C-index from 0.675(95%CI:0.594-0.756)to 0.721(95%CI:0.649-0.792)(P=0.005).And compared with the GRACE score,the addition of GNRI could also improve the predictive performance of long-term all-cause death[C-index 0.702,95%CI(0.632-0.783)],however,the difference was not statistically significant(P=0.091).Adding moderate to severe malnutrition risk(PNI≤38)to the classification of high-risk GRACE Score(GRACE Score>118)improved the predictive value of GRACE score classification for all-cause death in ACS patients undergoing PCI[NRI 0.129,95%CI(0.049-0.216),P=0.022;IDI 0.030,95%CI(0.002-0.182),P<0.001],however,the addition of moderate to severe malnutrition risk(GNRI<92)did not significantly improve the ability of the GRACE classification to predict long-term all-cause death.Conclusion:PNI was an independent predictor of long-term all-cause death in ACS patients undergoing PCI,and PNI was superior to GNRI in predicting long-term all-cause death.Therefore,it is effective and feasible to use PNI for nutritional risk assessment in ACS patients undergoing PCI.And the addition of PNI to the GRACE score could significantly improve the predictive value of long-term all-cause death. |
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