What do systematic reviews say?

Mucolytic vs placebo

Mucolytic showed no clear difference in death during study period compared with placebo (moderate certainty).

• Mucolytic agents versus placebo for chronic bronchitis or chronic obstructive pulmonary disease 2019 · Cochrane Headline outcomes only
  Peto OR 0.98 [0.51, 1.87]
  11 studies · 3527 participants
  Moderate

Oxygen‐guided lung‐recruitment maneuver vs usual care

Oxygen‐guided lung‐recruitment maneuver showed no clear difference in mortality by hospital discharge compared with routine care (low certainty).

• Positive end‐expiratory pressure for preterm infants requiring conventional mechanical ventilation for respiratory… 2019 · Cochrane Headline outcomes only
  RR 1 [0.17, 5.77]
  2 studies · 44 participants
  Low

Oxygen‐guided lung‐recruitment maneuver vs usual care

• Positive end‐expiratory pressure for preterm infants requiring conventional mechanical ventilation for respiratory… 2019 · Cochrane Headline outcomes only
  no estimate extracted
  2 studies · 44 participants
  Low

NIPPV vs no NIPPV

NIPPV showed no clear difference in rate of intubation compared with no NIPPV (moderate certainty).

• Non‐invasive positive pressure ventilation for prevention of complications after pulmonary resection in lung cancer… 2019 · Cochrane Headline outcomes only
  RR 0.55 [0.25, 1.2]
  2 studies · 69 participants
  Moderate

NIPPV vs no NIPPV

NIPPV showed no clear difference in mortality compared with no NIPPV (moderate certainty).

• Non‐invasive positive pressure ventilation for prevention of complications after pulmonary resection in lung cancer… 2019 · Cochrane Headline outcomes only
  RR 0.6 [0.24, 1.53]
  4 studies · 151 participants
  Moderate

NIPPV vs no NIPPV

• Non‐invasive positive pressure ventilation for prevention of complications after pulmonary resection in lung cancer… 2019 · Cochrane Headline outcomes only
  no estimate extracted
  2 studies · 69 participants
  Low

NIPPV vs no NIPPV

• Non‐invasive positive pressure ventilation for prevention of complications after pulmonary resection in lung cancer… 2019 · Cochrane Headline outcomes only
  no estimate extracted
  3 studies · 101 participants
  Very low

Maize flour or maize flour products fortified with folic acid alone vs no intervention

• Fortification of wheat and maize flour with folic acid for population health outcomes 2019 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 38 participants
  Very low

Wheat flour or wheat flour products fortified with folic acid plus other vitamins and minerals vs unfortified wheat flours or wheat flour products (not containing folic acid nor any other vitamins and minerals)

It is very uncertain whether wheat flour or wheat flour products fortified with folic acid plus… changes spina bifida compared with unfortified wheat flours or wheat flour products (not containing… (very low certainty).

• Fortification of wheat and maize flour with folic acid for population health outcomes 2019 · Cochrane Headline outcomes only
  RR 0.29 [0.16, 0.56]
  8037 participants
  Very low

Wheat flour or wheat flour products fortified with folic acid plus other vitamins and minerals vs unfortified wheat flours or wheat flour products (not containing folic acid nor any other vitamins and minerals)

It is very uncertain whether wheat flour or wheat flour products fortified with folic acid plus… changes encephalocoele compared with unfortified wheat flours or wheat flour products (not containing… (very low certainty).

• Fortification of wheat and maize flour with folic acid for population health outcomes 2019 · Cochrane Headline outcomes only
  RR 0.26 [0.13, 0.56]
  8037 participants
  Very low

Wheat flour or wheat flour products fortified with folic acid plus other vitamins and minerals vs unfortified wheat flours or wheat flour products (not containing folic acid nor any other vitamins and minerals)

It is very uncertain whether wheat flour or wheat flour products fortified with folic acid plus… changes fatal anencephaly compared with unfortified wheat flours or wheat flour products (not containing… (very low certainty).

• Fortification of wheat and maize flour with folic acid for population health outcomes 2019 · Cochrane Headline outcomes only
  RR 0.47 [0.21, 1.07]
  8037 participants
  Very low

Wheat flour or wheat flour products fortified with folic acid plus other vitamins and minerals vs unfortified wheat flours or wheat flour products (not containing folic acid nor any other vitamins and minerals)

• Fortification of wheat and maize flour with folic acid for population health outcomes 2019 · Cochrane Headline outcomes only
  no estimate extracted
  657 participants
  Very low

Wheat flour or wheat flour products fortified with folic acid plus other vitamins and minerals vs unfortified wheat flours or wheat flour products (not containing folic acid nor any other vitamins and minerals)

It is very uncertain whether wheat flour or wheat flour products fortified with folic acid plus… changes anaemia compared with unfortified wheat flours or wheat flour products (not containing… (very low certainty).

• Fortification of wheat and maize flour with folic acid for population health outcomes 2019 · Cochrane Headline outcomes only
  RR 0.87 [0.68, 1.11]
  657 participants
  Very low

Maize flour or maize flour products fortified with folic acid alone vs no intervention

• Fortification of wheat and maize flour with folic acid for population health outcomes 2019 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 38 participants
  Very low

Maize flour or maize flour products fortified with folic acid plus other vitamins and minerals vs unfortified maize flours or maize flour products

• Fortification of wheat and maize flour with folic acid for population health outcomes 2019 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 35 participants
  Very low

Maize flour or maize flour products fortified with folic acid plus other vitamins and minerals vs unfortified maize flours or maize flour products

• Fortification of wheat and maize flour with folic acid for population health outcomes 2019 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 35 participants
  Very low

Wheat flour or wheat flour products fortified with folic acid alone vs unfortified wheat flours or wheat flour products (not containing folic acid nor any other vitamins and minerals)

• Fortification of wheat and maize flour with folic acid for population health outcomes 2019 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 30 participants
  Very low

Wheat flour or wheat flour products fortified with folic acid alone vs unfortified wheat flours or wheat flour products (not containing folic acid nor any other vitamins and minerals)

• Fortification of wheat and maize flour with folic acid for population health outcomes 2019 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 30 participants
  Very low

Wheat flour or wheat flour products fortified with folic acid plus other vitamins and minerals vs unfortified wheat flours or wheat flour products (not containing folic acid nor any other vitamins and minerals)

Wheat flour or wheat flour products fortified with folic acid plus… showed no clear difference in anaemia compared with unfortified wheat flours or wheat flour products (not containing… (low certainty).

• Fortification of wheat and maize flour with folic acid for population health outcomes 2019 · Cochrane Headline outcomes only
  RR 1.07 [0.74, 1.55]
  1 study · 334 participants
  Low

Wheat flour or wheat flour products fortified with folic acid plus other vitamins and minerals vs unfortified wheat flours or wheat flour products (not containing folic acid nor any other vitamins and minerals)

• Fortification of wheat and maize flour with folic acid for population health outcomes 2019 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 334 participants
  Low