TABLE 3.

Quality of evidence of the association between systemic immune-inflammation index (SII) and cardiovascular disease (CVD).

Certainty assessment							Effect		Certainty	Importance
No. of studies	No. of participants	Risk of bias	Inconsistency	Indirectness	Imprecision	Other considerations*	Relative (95% CI)	Absolute (95% CI)
Coronary heart disease
3 Observational studies	99,478	Seriousa	Very seriousb	Not serious	Not serious	None	HR 1.13 (0.94 to 1.36)	1 fewer per 1,000 (from 1 fewer to 1 fewer)	⊕○○○ Very low	CRITICAL
Stroke
3 Observational studies	139,753	Seriousa	Very seriousb	Not serious	Not serious	None	HR 1.31 (1.07 to 1.60)	7 more per 1,000 (from 2 more to 14 more)	⊕○○○ Very low	CRITICAL
Peripheral arterial disease
1 Observational studies	6,576	Not serious	Not serious	Not serious	Not serious	None	HR 1.51 (1.18 to 1.93)	2 fewer per 1,000 (from 2 fewer to 1 fewer)	⊕⊕○○ Low	CRITICAL
Venous thrombosis
2 Observational studies	1,329	Seriousa	Very seriousb	Not serious	Not serious	None	HR 4.65 (0.66 to 32.71)	5 fewer per 1,000 (from 33 fewer to 1 fewer)	⊕○○○ Very low	CRITICAL
Cerebral small vessel disease
1 Observational studies	3,052	Not serious	Not serious	Not serious	Not serious	None	HR 1.09 (0.95 to 1.25)	1 fewer per 1,000 (from 1 fewer to 1 fewer)	⊕⊕○○ Low	CRITICAL

CI, confidence interval; HR, hazard ratio.

^aStudies with some risks of bias were included in this analysis (NOS < 7).

^bConsiderable heterogeneity (I² > 75%).

*Publication bias, large effect, plausible confounding, and dose response gradient.

High quality: Further research is very unlikely to change our confidence in the estimate of effect.

Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.

Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.

Very low quality: Any estimate of effect is very uncertain.