Table 1 Summary of clinical studies included in meta-analysis
Author (year)CountryStudy designPatients (% male)Age (years)Baseline LVEF (%)Comparison of CYC (mg/l)Outcome measures HR or RR (95% CI)Follow-up durationAdjustment for covariatesOverall NOS
Shlipak et al. (2005) [19]U.S.A.Prospective cohort studyChronic HF 279 (49.5)76.6 ± 6NPQuartile 4 compared with1; ≥1.56 compared with ≤1.03Total deaths:1826.5 yearsAge, gender, BMI, stroke, cancer, hypertension, anemia, and lipid-lowering medication7
2.15 (1.30–3.54)
Lassus et al. (2007) [20]FinlandProspective studyAHF 480 (50.0)74.8 ± 10.445 ± 16>1.3 compared with <1.3Total deaths: 1221.0 yearAge, gender, SBP, DBP, hyponatremia, anemia, creatinine, and NT-proBNP6
3.2 (2.0–5.3)
Campbell et al. (2009) [21]U.S.A.Prospective cohort studyAHF 240 (50.0)63 ± 1435 ± 20Quartile 4 compared with 1–3Total deaths: 531.0 yearAge, race, gender, type of HF, QRS duration, LVRF, cancer, cirrhosis, and DM6
2.0 (1.03–3.88);
Death/rehospitalization: 153;
1.94 (1.27–2.95)
Manzano-Fernández et al. (2011) [22]SpainProspective studyAHF 220 (54)72.2 ± 11.946.4 ± 16.6>1.05 compared with <1.05Death/rehospitalization: 1161.37 yearsAge, NYHA, glucose, ST-segment elevation MI, leukocytes, β-trace protein, in-hospital inotrope use, creatinine, eGFR, urea nitrogen, troponin-T, and NT-proBNP6
1.73 (1.15–2.62)
Carrasco-Sánchez et al. (2011) [23]SpainProspective studyAHF 218 (49.9)75.6 ± 8.7LVEF >45%Quartile 4 compared with 1; >2.06 compared with ≤1.12Total deaths: 701.0 yearAge, creatinine, urea nitrogen, HB, NT-proBNP, hyponatremia,and NYHA7
8.14 (2.33–28.4);
Death/rehospitalization: 126; 3.40 (1.86–6.21)
Pérez-Calvo et al. (2012) [24]SpainProspective studyAHF 526 (45)76 (70–81)80.7% cases LVEF ≥45%>1.25 compared with <1.25Total deaths: 661.0 yearAge, gender, NT-proBNP, total cholesterol, urea, HF with preserved EF, NYHA, AF, DM and hypertension7
2.86 (1.72–4.77);
Carrasco-Sánchez et al. (2014) [25]SpainProspective studyAHF 195 (42.2)76.3 ± 8.271.8% cases LVEF ≥45%≥1.32 compared with <1.32Total deaths: 401.0 yearAge, NT-proBNP, anemia, hyponatremia, LVEF, serum creatinine, and NYHA7
4.87 (1.92–12.36)
Ruan et al. (2014) [26]ChinaProspective cohort studyAHF with AKI 162 (53.7)51.9 ± 15.439.1 ± 11.6Tertile 3 compared with 1; >1.46 compared with <1.11Total deaths: 451.0 yearMultivariate logistic regression analysis5
2.72 (1.92–4.28)
Jackson et al. (2016) [27]U.K.Prospective studyAHF 628 (58.4)70.8 ± 10.640.1 ± 12.1>1.6 compared with <1.6Total deaths: 2903.2 yearsAge, gender, smoking, NYHA, LVEF, HR, SBP, BMI, peripheral edema, bilirubin, urate, creatinine, HB, HbA1c, lymphocyte/red cell distribution width, and BNP7
1.13 (0.81–1.57)
Breidthardt et al. (2017) [28]SwitzerlandProspective studyAHF 207 (59%)80 (74–85)40 (25–55)≥1.5 compared with <1.5Total deaths: 951.72 yearsEarly AKI, SBP, urea at presentation, creatinine, serum sodium and BNP7
1.41 (1.02–1.95)
  • Abbreviations: AF, atrial fibrillation; AKI, acute kidney injury; BMI: body mass index; DBP, diastolic blood pressure; DM, diabetes mellitus; EF, ejection fraction; eGFR, estimated glomerular filtration rate; HB, hemoglobin; HbA, glycosylated HB; LVEF, left ventricular EF; NP, not reported; NT-proBNP, N-terminal B-type natriuretic peptide; SBP, systolic blood pressure.