Table 3

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

RiskQuality 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 mortalityNo (−)*No (−)No (−)†No (−)Unclear ↓Yes ↑↑‡Yes ↑No (−)High
Case mortalityNo (−)*No (−)No (−)§No (−)Unclear ↓Yes ↑↑¶Yes ↑No (−)High
HospitalisationNo (−)*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).