title: Non-thyroidal illness syndrome in patients with cardiovascular diseases: A systematic review and meta-analysis.
abstract: BACKGROUND
  Non-thyroidal illness syndrome (NTIS) is characterized by decreased serum triiodothyronine level without increased thyroid-stimulating hormone level during critical illness. The summary data on the prevalence of NTIS in cardiovascular patients are lacking, and its prognostic role in cardiovascular patients is also unclear.
  
  
  METHODS
  We performed a systematic review and meta-analysis to comprehensively determine the prevalence and the prognostic role of NTIS in cardiovascular patients. The prevalence of NTIS was pooled using random-effect meta-analysis and the hazard ratios (HRs) for all-cause mortality, cardiac mortality and major adverse cardiovascular events (MACE) were also pooled.
  
  
  RESULTS
  Forty-one studies were finally included. The pooled prevalence of NTIS in cardiovascular patients was 21.7% (95% CI 18.4%-25.3%). Subgroup by the types of cardiovascular diseases showed the prevalence of NTIS was highest in patients with heart failure (24.5%), followed by acute myocardial infarction (18.9%) and acute coronary syndrome (17.1%). Meta-analysis of studies using strict diagnostic criteria of NITS showed that the pooled prevalence of NTIS in cardiovascular patients was 17.6% (95% CI 14.5%-21.2%). NTIS was independently associated with increased risks of all-cause mortality (HR=2.52, 95% CI 1.87-3.40, P<0.001) and cardiac mortality (HR=2.06, 95% CI 1.58-2.69, P<0.001) in cardiovascular patients. NTIS was also an independent predictor of MACE in cardiovascular patients (HR=1.73, 95% CI 1.32-2.26, P<0.001).
  
  
  CONCLUSIONS
  NTIS is very common in patients with cardiovascular diseases. NTIS is an independent prognostic factor in cardiovascular patients and is associated with increased risks of all-cause mortality, cardiac mortality and MACE.
authors: Department of Endocrinology, Jinshan Hospital of Fudan University, Shanghai 201508, China.
authors: Bin
authors: B
authors: Wang
authors: Department of Nephrology, Xi'an Central Hospital, Xi'an 710003, China.
authors: Suijun
authors: S
authors: Liu
authors: Department of Endocrinology, Jinshan Hospital of Fudan University, Shanghai 201508, China.
authors: Ling
authors: L
authors: Li
authors: Department of Endocrinology, Jinshan Hospital of Fudan University, Shanghai 201508, China.
authors: Qiuming
authors: Q
authors: Yao
authors: Department of Endocrinology, Jinshan Hospital of Fudan University, Shanghai 201508, China.
authors: Ronghua
authors: R
authors: Song
authors: Department of Endocrinology, Jinshan Hospital of Fudan University, Shanghai 201508, China.
authors: Xiaoqing
authors: X
authors: Shao
authors: Department of Endocrinology, Jinshan Hospital of Fudan University, Shanghai 201508, China.
authors: Qian
authors: Q
authors: Li
authors: Department of Endocrinology, Jinshan Hospital of Fudan University, Shanghai 201508, China.
authors: Xiaohong
authors: X
authors: Shi
authors: Department of Endocrinology, Jinshan Hospital of Fudan University, Shanghai 201508, China. Electronic address: zhangjinan@hotmail.com.
authors: Jin-An
authors: JA
authors: Zhang
mesh_terms: D002318:Cardiovascular Diseases / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D005067:Euthyroid Sick Syndromes / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology*; D006801:Humans; D011446:Prospective Studies; D012307:Risk Factors; D013963:Thyroid Hormones / Q000097:blood
chemical_list: D013963:Thyroid Hormones
keywords: Cardiovascular disease; Meta-analysis; Non-thyroidal illness syndrome