Table 3. Risk of bias assessment for 20 included studies.

Study	Study design			Comparability			Assessment of outcomes					Overall risk of bias
	Were participants selected to be representative of the wider population?	Were there clear selection criteria for those with and without DIR?	Risk of bias	Are patients with and without DIR managed to standardised protocol?	Are outcomes reported after adjustment for important confounding variables?	Risk of bias	Were procedures for measuring outcome sufficient?	Was follow-up long enough for outcome detection?	Were incomplete outcome data adequately assessed?	Are outcomes reported in full and not selectively reported?	Risk of bias
BAKER [50]	Yes	Yes	Low	Yes	Unclear	High	Yes	Yes	Unclear	Yes	High	High
BATISTE [63]	Yes	Yes	Low	Yes	Yes	Low	Yes	Yes	No	Yes	High	High
DRONDA [51]	Yes	Yes	Low	Yes	No	High	Yes	Yes	Yes	Yes	Low	High
ENGSIG [52]	No	Yes	High	Yes	No	High	Yes	Yes	Unclear	Yes	High	High
FALSTER [53]	Yes	Yes	Low	Yes	No	High	Yes	Yes	Unclear	Yes	High	High
GILSON [6]	Yes	Yes	Low	Yes	Yes	Low	Yes	Yes	Unclear	Yes	High	High
GRABAR [54]	Yes	Yes	Low	Yes	Yes	Low	Yes	Yes	Unclear	Yes	High	High
GUTERRIEZ [55]	Yes	Yes	Low	Yes	Yes	Low	Yes	Yes	Yes	Yes	Low	Low
HUNT [4]	Yes	Yes	Low	Yes	Yes	Low	Yes	Yes	Yes	Yes	Low	Low
KAUFMANN [56]	No	Yes	High	Yes	No	High	Unclear	Yes	No	Yes	High	High
LOUTFY [57]	Yes	Yes	Low	Yes	Yes	Low	Unclear	Yes	No	Yes	High	High
MOORE [7]	Yes	Yes	Low	Yes	Yes	Low	Yes	Yes	Yes	Yes	Low	Low
NAKANJAKO [58]	Yes	Yes	Low	Yes	No	High	Yes	Yes	No	Yes	High	High
NICASTRI [61]	Yes	Yes	Low	Yes	Yes	Low	Yes	Yes	Yes	Yes	Low	Low
PACHECO [59]	Yes	Yes	Low	Yes	Yes	Low	Yes	Yes	No	Yes	High	High
TAKUVA [64]	Yes	Yes	Low	Yes	Yes	Low	Yes	Yes	Yes	Yes	Low	Low
TAN [8]	Yes	Yes	Low	Yes	Yes	Low	Yes	Yes	Yes	Yes	Low	Low
TAIWO [62]	Yes	Yes	Low	Yes	Yes	Low	Yes	Unclear	Unclear	Yes	High	High
TUBOI [9]	Yes	Yes	Low	Yes	Yes	Low	Yes	Yes	Yes	Yes	Low	Low
ZOUFALY [10]	Yes	Yes	Low	Yes	Yes	Low	Yes	Yes	Unclear	Yes	High	High