Biomarkers to guide the use of antibiotics for acute exacerbations of COPD (AECOPD): a systematic review and meta-analysis

Table 8 Description of studies assessing the properties of Tumour Necrosis Factor-alpha [TNF-α) for identifying bacterial vs non-bacterial AECOPD

Author	Setting	Antibiotics or Steroids in the exclusion criteria (length of exclusion)	GOLD Stage of Cohort	Definition of Bacterial Cause of Exacerbation	Number of Exacerbations	Number of Exacerbations with Bacterial Cause	Mean TNF-α (SD; pg/mL) Bacterial Exacerbation	Mean TNF-α (SD; pg/mL) Non-bacterial Exacerbation
Aaron [47]	OP	Steroids	–	Positive sputum culture of pathogen not cultured at baseline	14	1	–	–
Bafadhel [39]	OP	Antibiotics & Steroids	I–IV	Positive sputum culture OR total aerobic count > 10⁷ CFU	158	84	89.7 [61.9 to 129.9]	7.5 [5.2 to 10.8]
Bathoorn [40]	OP	Steroids	–	High semi-quantitative growth density of PPM on sputum culture	37	8	56.8 (43.3–69.7)*	3.43 (1.60–7.73)*
Dal Negro [16]	H	Antibiotics	II	Positive sputum culture > 10⁶ CFU/mL	124	CB = 28 PA = 20	CB = 721.6 (1186.0)^$ PA = 2417.6 (1485.3)^$	NI = 112.1 (119.5)^$ V = 181.8 (125.6)^$
Sethi [46]	OP	–	I–IV	Positive sputum culture	150	84	–	–

5 studies were identified to evaluate the relationship between TNF-α and AECOPD aetiology
OP outpatient, H hospital, CFU colony forming units, PPM potentially pathogenic microorganisms. *, Median (IQR); -, information not provided; ^$, mean (IQR); [x] where x = 95% confidence intervals

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