Table 3.

Assessment of evidence for the risk of studied outcomes based on Grades of Recommendations, Assessment, Development, and Evaluation framework

Risk	Quality of study limitations: ↓	Indirectness of evidence: ↓	Inconsistency: ↓	Imprecision, range CI effect size >2.0: ↓	Publication bias, yes or unclear: ↓	Effect estimate >2.0: ↑ >5.0: ↑↑	Dose–response effect: ↑	Residual confounding: ↑	Overall certainty (high, moderate, low)
In-hospital mortality	No (−)*	No (−)	No (−)†	No (−)	Unclear ↓	Yes ↑↑‡	Yes ↑	No (−)	High
Case mortality	No (−)*	No (−)	No (−)§	No (−)	Unclear ↓	Yes ↑↑¶	Yes ↑	No (−)	High
Hospitalisation	No (−)*	No (−)	Yes ↓**	No (−)	Unclear ↓	Yes ↑↑††	Yes ↑	No (−)	High

*High-quality studies also reported a significant association between age and risk of outcome.

†Moderate heterogeneity (I²=64.1%) was observed on studies using age as a continuous variable and on high-quality studies (I²=58.7%).

‡Although per age RR is 1.057, when comparing different adult groups can have an effect size of greater than 5.0 (ie, a 54-year difference, 18 years vs 72 years results in a RR of 20.0).

§Moderate heterogeneity (I²=68.7%) was observed on studies using age as a continuous variable and on high-quality studies heterogeneity was very low (I²=0%).

¶Although per age RR is 1.074, when comparing different adult groups can have an effect size of greater than 5.0 (ie, a 54-year difference, 18 years vs 72 years results in a RR of 47.2).

**High heterogeneity observed (I² >85%).

††Although per age RR is 1.034, when comparing different adult groups can have an effect size of greater than 5.0 (ie, a 54-year difference, 18 years vs 72 years results in a RR of 6.08).