Cardiovascular Journal of Africa: Vol 35 No 2 (MAY/AUGUST 2024)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 35, No 2, May – August 2024 AFRICA 85 were found to be co-independent predictors in both the whole population and in patients with STEMI and NSTEMI. While a 100-unit increase in SII level in STEMI patients increased the risk of MACE 1.05 times [hazard ratio (HR): 1.05; p < 0.001], this increase in risk was found to be 1.02 times in NSTEMI patients (HR: 1.02; p < 0.001) (Table 4). The SII level showed superior diagnostic performance than WBC, CRP, NLR and PLR in predicting MACE in the whole population (Fig. 1A). The predictive value of SII level in predicting MACE in the whole population was found to be > 955.8 with 79.5% sensitivity and 87.9% specificity [area under the curve (AUC) ± standard error (SE): 0.876 ± 0.02; positive predictive value: 58.5%, negative predictive value: 95.2%; p < 0.001]. MACE risk was found to be 48.7 times higher in those with SII level > 955.8 compared to those with a level ≤ 955.8 [HR: 48.7; 95% confidence interval (CI) = 33.8–69.9; p < 0.001] (Fig. 1B). The predictive value of SII level in predicting MACE in STEMI patients were found to be > 916.7, with 82.9% sensitivity and 83.2% specificity (AUC ± SE: 0.880 ± 0.02; positive predictive value: 53.4%, negative predictive value: 95.4%; p < 0.001). MACE risk was found to be 24.6 times higher in patients with SII level > 916.7 compared to those with a level ≤ 916.7 (HR: 24.6; 95% CI = 14.4–42.1; p < 0.001) (Fig. 1C). The predictive value of SII level in predicting MACE in NSTEMI patients was found to be > 986 with 78.2% sensitivity and 90.7% specificity (AUC ± SE: 0.873 ± 0.02; positive predictive value: 63.3%, negative predictive value: 95.3%; p < 0.001). MACE risk was found to be 97.1 times higher in those with SII level > 986 compared to those with a level ≤ 986 (HR: 97.1; 95% CI = 59.2–159.1; p < 0.001) (Fig. 1D). Table 3. Demographic and clinical findings associated with MACE in the NSTEMI patients Variables Total NSTEMI (n = 700) MACE Univariate regression No (n = 581) Yes (n = 119) HR 95% CI p-value Gender, n (%) Men 455 (65.0) 379 (65.2) 76 (63.9) ref Women 245 (35.0) 202 (34.8) 43 (36.1) 1.03 0.71–1.5 0.879 Age, years 68.5 ± 12.2 66.5 ± 11.6 78.4 ± 9.8 1.08 1.06–1.1 < 0.001* Smoker, n (%) 103 (14.7) 95 (16.4) 8 (6.7) 0.39 0.19–0.79 0.009* Hypertension, n (%) 400 (57.1) 335 (57.7) 65 (54.6) 0.83 0.58–1.19 0.312 Diabetes mellitus, n (%) 210 (30.0) 174 (29.9) 36 (30.3) 1.09 0.73–1.61 0.675 CHD, n (%) 142 (20.3) 114 (19.6) 28 (23.5) 1.20 0.78–1.83 0.409 Hyperlipidaemia, n (%) 386 (55.1) 329 (56.6) 57 (47.9) 0.77 0.54–1.11 0.156 CHF, n (%) 6 (0.9) 2 (0.3) 4 (3.4) 5.30 1.95–14.41 0.001* CRF, n (%) 9 (1.3) 6 (1.0) 3 (2.5) 1.72 0.54–5.42 0.357 WBC (×10³ cells/µl) 9.1 (7.4–10.9) 8.8 (7.1–10.3) 11.8 (9.7–14.1) 1.26 1.21–1.31 < 0.001* Haemoglobin (g/dl) 13.8 ± 1.8 13.9 ± 1.8 12.9 ± 1.8 0.75 0.67–0.83 < 0.001* Neutrophils (×10³ cells/µl) 5.9 (4.4–7.4) 5.6 (4.2–6.8) 9.4 (7.3–11.3) 1.02 1.01–1.03 0.006* Lymphocytes (×10³ cells/µl) 2.3 (1.6–3) 2.4 (1.8–3.1) 1.5 (1–2.1) 0.35 0.28–0.45 < 0.001* Platelets (×10³ cells/µl) 220 (183–266) 219 (183–263) 224 (176–275) 1.00 0.98–1.02 0.400 LDL-C (mg/dl) 113 (89–141) 115 (92–143) 100.5 (78–134) 0.98 0.97–0.99 0.006* (mmol/l) 2.93 (2.31–3.65) 2.98 (2.38–3.70) 2.60 (2.02–3.47) Creatinine (mg/dl) 0.9 (0.8–1.1) 0.9 (0.8–1.1) 1.1 (0.9–1.3) 1.00 0.96–1.03 0.886 CRP (mg/dl) 4.6 (2.2–11) 4.2 (2–9.4) 9.6 (3.8–26) 1.03 1.01–1.06 < 0.001* NLR 2.4 (1.7–4) 2.1 (1.6–3.1) 6.3 (4.1–9.4) 1.02 1.01–1.04 < 0.001* PLR 96.5 (74.1–135) 91.7 (70.9–122.5) 151.4 (116.9–215.7) 1.03 1.01–1.05 < 0.001* SII 530.8 (370–884) 482.2 (341.4–702.5) 1325 (1005.1–2109.8) 1.02 1.01–1.02 < 0.001* Follow-up events (MACE) Mortality, n (%) 111 (15.9) – 111 (93.3) – – – TVR, n (%) 7 (1.0) – 7 (5.9) – – – RMI, n (%) 8 (1.1) – 8 (6.7) – – – CHD: chronic heart disease, CHF: chronic heart failure, CRF: chronic renal failure, WBC: white blood cell, TVR: target-vessel revascularisation, RMI: re-myocardial infarction, LDL-C: low-density lipoprotein cholesterol, CRP: C-reactive protein, NLR: neutrophil–lymphocyte ratio, PLR: platelet–lymphocyte ratio, SII: serum immune–inflammation index, HR: hazard ratio, CI: confidence interval. Numerical variables are shown as mean ± standard deviation or median (min–max). and categorical variables as numbers (%). Levels of SII are divided into 100. *p < 0.05 indicates statistical significance. Table 4. Independent predictors of MACE Variables Univariate regression HR 95% CI p-value All patients Age 1.07 1.05–1.08 < 0.001* WBC 1.19 1.15–1.23 < 0.001* CRP 1.06 1.01–1.10 0.011* SII 1.02 1.01–1.03 < 0.001* –2 log likelihood = 2211.0; p < 0.001 STEMI patients Age 1.04 1.02–1.07 < 0.001* Hyperlipidaemia 0.49 0.30–0.79 0.004* WBC 1.12 1.05–1.20 0.001* CRP 1.05 1.01–1.11 0.047* SII 1.05 1.02–1.07 < 0.001* –2 log likelihood = 734.5; p < 0.001 NSTEMI patients Age 1.07 1.06–1.10 < 0.001* WBC 1.23 1.17–1.29 < 0.001* CRP 1.07 1.01–1.13 0.011* SII 1.02 1.01–1.03 < 0.001* –2 log likelihood = 1207.9; p < 0.001 WBC: white blood cells, CRP: C-reactive protein, SII: serum immune–inflammation index, HR: hazard ratio, CI: confidence interval. Levels of SII are divided into 100. *p < 0.05 indicates statistical significance.

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