Summary of findings 2. Comparison between different types of standard valves.

Comparison between different types of standard valves
Patient or population: participants with hydrocephalus Setting: hospital procedure ‐ outpatient follow‐up (Mexico and Uganda) Intervention and comparison: distal cleft valve (Biomed), Hakim ball‐in‐cone and spring, Chhabra and Codman‐Hakim
Outcomes	Impact	№ of participants (studies)	Certainty of the evidence (GRADE)
Treatment failure: morbidity associated with shunt placement that led to shunt revision Follow‐up: see each study	There is uncertainty about the incidence of treatment failure in participants with different types of standard valves: Garcia 1988(84 participants) reported a similar incidence of early treatment failure (7% vs 21% at 30 days) with the standard distal cleft valve and the standard Hakim ball‐in‐cone and spring valve (RR 0.41, 95% CI 0.13 to 1.27). Warf 2005(90 participants) reported a similar incidence of treatment failure (46% vs 42% at 12 months) with the Chhabra valve and the Codman‐Hakim micro precision valve (RR 1.17, 95% CI 0.72 to 1.92).	174 (2 RCTs)	⊕⊝⊝⊝ VERY LOW 1 2
Adverse events: morbidity related to the shunt placement that has not led to shunt revision Follow‐up: not applicable	None of the included studies reported this outcome beyond those included under "treatment failure".	(0 RCTs)	‐
Mortality In the early postoperative period (≤ 30 days)	There is uncertainty about the effects of different types of standard valves on mortality. Warf 2005 reported a 2% mortality with the Chhabra valve and 0% with the Codman‐Hakim micro precision valve (RD 0.02%, 95% CI ‐0.04% to 0.09%). Garcia 1988 reported a 9% mortality with the standard distal cleft valve and 0% mortality with the standard Hakim ball‐in‐cone and spring valve in the early postoperative period (RD 0.09%, 95% CI ‐0.00% to 0.18%).	174 (2 RCT)	⊕⊝⊝⊝ VERY LOW 1 2
Mortality Beyond the early postoperative period (> 30 days)	We are uncertain about the effects of different types of standard valves on mortality > 30 days. Warf 2005 reported a 14% mortality with the Chhabra valve and 17% with the Codman‐Hakim micro precision valve.	90 (1 RCT)	⊕⊝⊝⊝ VERY LOW 1 2
Quality of life	Not reported	‐	‐
*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; RCT: randomised controlled trial; RD: Risk difference; RR: Risk ratio.
GRADE Working Group grades of evidence High certainty: We are very confident that the true effect lies close to that of the estimate of the effect Moderate certainty: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low certainty: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect Very low certainty: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect

¹ Downgraded two levels due to high or unclear risk of bias in multiple domains of the included studies

² Downgraded one level due to few participants and events in the included studies