Summary of findings 4. External differential programmable pressure valve compared to non‐programmable valves.

External differential programmable pressure valve compared to non‐programmable valves for hydrocephalus
Patient or population: participants with hydrocephalus Setting: inpatient treatment ‐ outpatient follow‐up (USA) Intervention: external differential programmable pressure valve Comparison: other types of valve (any non‐programmable valve pressure fixed pressure available on the market: Delta (Medtronic PS Medical, Goleta Ca): 10%, other Medtronic PS Medical: 57%, other Codman/Johnson & Johnson: 8%, Orbis‐Sigma (Cordis, Miami Lakes, FL): 3%, others: 22%)
Outcomes	Impact	№ of participants (studies)	Certainty of the evidence (GRADE)
Treatment failure: morbidity associated with shunt placement that led to shunt revision Follow‐up: 2 years	The incidence of treatment failure is probably similar in those with programmable valves and the non‐programmable valves (RR 1.02, 95% CI 0.84 to 1.24). Programmable valve: 52% Other non‐programmable fixed pressure valves: 52%	377 (1 RCT)	⊕⊕⊝⊝ LOW 1 2
Adverse events: morbidity related to the shunt placement that has not led to shunt revision Follow‐up: 2 years	The incidence of adverse events may be similar in those with programmable valves and non‐programmable valves (RR 0.97, 95% CI 0.44 to 2.15). Programmable valve: 6.19% Other non‐programmable fixed pressure valves: 6.01%	377 (1 RCT)	⊕⊕⊝⊝ LOW 1 2
Mortality In the early postoperative period (≤30 days)	Not reported	‐	‐
Mortality Beyond the early postoperative period (>30 days)	Not reported	‐	‐
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; 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 one level due to high or unclear risk of bias in multiple domains in the included study

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