What do systematic reviews say?

Metformin vs clomiphene

Metformin showed no clear difference in ovulation rate per woman fParticipants with BMI < 30 kg/m2 compared with clomiphene citrate (low certainty).

• Metformin for ovulation induction (excluding gonadotrophins) in women with polycystic ovary syndrome 2019 · Cochrane Headline outcomes only
  OR 0.8 [0.52, 1.25]
  5 studies · 352 participants
  Low
• Insulin‐sensitising drugs (metformin, rosiglitazone, pioglitazone, D‐chiro‐inositol) for women with polycystic ovary… 2017 · Cochrane Headline outcomes only
  OR 0.81 [0.51, 1.28]
  4 studies · 312 participants
  Low

Metformin vs clomiphene

Metformin may leads to lower ovulation rate per woman fParticipants with BMI ≥ 30 kg/m2 compared with clomiphene citrate (low certainty).

• Metformin for ovulation induction (excluding gonadotrophins) in women with polycystic ovary syndrome 2019 · Cochrane Headline outcomes only
  OR 0.29 [0.2, 0.43]
  2 studies · 500 participants
  Low
• Insulin‐sensitising drugs (metformin, rosiglitazone, pioglitazone, D‐chiro‐inositol) for women with polycystic ovary… 2017 · Cochrane Headline outcomes only
  OR 0.29 [0.2, 0.43]
  2 studies · 500 participants
  Low

Metformin combined with clomiphene citrate vs clomiphene

Metformin combined with clomiphene citrate showed no clear difference in live birth rate per woman compared with clomiphene citrate alone (low certainty).

• Metformin for ovulation induction (excluding gonadotrophins) in women with polycystic ovary syndrome 2019 · Cochrane Headline outcomes only
  OR 1.27 [0.98, 1.65]
  10 studies · 1219 participants
  Low
• Insulin‐sensitising drugs (metformin, rosiglitazone, pioglitazone, D‐chiro‐inositol) for women with polycystic ovary… 2017 · Cochrane Headline outcomes only
  OR 1.21 [0.92, 1.59]
  9 studies · 1079 participants
  Low

Metformin combined with clomiphene citrate vs clomiphene

Metformin combined with clomiphene citrate probably leads to higher adverse events (gastrointestinal) per woman compared with clomiphene citrate alone (moderate certainty).

• Metformin for ovulation induction (excluding gonadotrophins) in women with polycystic ovary syndrome 2019 · Cochrane Headline outcomes only
  OR 4.26 [2.83, 6.4]
  6 studies · 852 participants
  Moderate
• Insulin‐sensitising drugs (metformin, rosiglitazone, pioglitazone, D‐chiro‐inositol) for women with polycystic ovary… 2017 · Cochrane Headline outcomes only
  OR 3.97 [2.59, 6.08]
  3 studies · 591 participants
  Moderate

Metformin combined with clomiphene citrate vs clomiphene

Metformin combined with clomiphene citrate probably leads to higher clinical pregnancy rate per woman compared with clomiphene citrate alone (moderate certainty).

• Metformin for ovulation induction (excluding gonadotrophins) in women with polycystic ovary syndrome 2019 · Cochrane Headline outcomes only
  OR 1.62 [1.32, 1.99]
  19 studies · 1790 participants
  Moderate
• Insulin‐sensitising drugs (metformin, rosiglitazone, pioglitazone, D‐chiro‐inositol) for women with polycystic ovary… 2017 · Cochrane Headline outcomes only
  OR 1.59 [1.27, 1.99]
  16 studies · 1529 participants
  Moderate

Metformin combined with clomiphene citrate vs clomiphene

Metformin combined with clomiphene citrate may leads to higher ovulation rate per woman compared with clomiphene citrate alone (low certainty).

• Metformin for ovulation induction (excluding gonadotrophins) in women with polycystic ovary syndrome 2019 · Cochrane Headline outcomes only
  OR 1.65 [1.35, 2.03]
  22 studies · 1601 participants
  Low
• Insulin‐sensitising drugs (metformin, rosiglitazone, pioglitazone, D‐chiro‐inositol) for women with polycystic ovary… 2017 · Cochrane Headline outcomes only
  OR 1.57 [1.28, 1.92]
  21 studies · 1624 participants
  Moderate

Short‐acting insulin analogues vs regular human insulin

Short‐acting insulin analogues showed no clear difference in all‐cause mortality (N) compared with regular human insulin (moderate certainty).

• Short‐acting insulin analogues versus regular human insulin for adult, non‐pregnant persons with type 2 diabetes… 2018 · Cochrane Headline outcomes only
  Peto OR 1.66 [0.41, 6.64]
  6 studies · 2519 participants
  Moderate
• Short‐acting insulin analogues versus regular human insulin for adults with type 1 diabetes mellitus 2016 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Short‐acting insulin analogues vs regular human insulin

• Short‐acting insulin analogues versus regular human insulin for adult, non‐pregnant persons with type 2 diabetes… 2018 · Cochrane Headline outcomes only
  no estimate extracted
  6 studies · 2509 participants
  Low
• Short‐acting insulin analogues versus regular human insulin for adults with type 1 diabetes mellitus 2016 · Cochrane Headline outcomes only
  OR 0.89 [0.71, 1.12]
  7 studies · 2459 participants
  Very low

Short‐acting insulin analogues vs regular human insulin

• Short‐acting insulin analogues versus regular human insulin for adult, non‐pregnant persons with type 2 diabetes… 2018 · Cochrane Headline outcomes only
  no estimate extracted
  9 studies · 2608 participants
  Low
• Short‐acting insulin analogues versus regular human insulin for adults with type 1 diabetes mellitus 2016 · Cochrane Headline outcomes only
  no estimate extracted
  9 studies · 2608 participants
  Low

Short‐acting insulin analogues vs regular human insulin

• Short‐acting insulin analogues versus regular human insulin for adult, non‐pregnant persons with type 2 diabetes… 2018 · Cochrane Headline outcomes only
  no estimate extracted
  2 studies · 2 participants
  Very low
• Short‐acting insulin analogues versus regular human insulin for adults with type 1 diabetes mellitus 2016 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Intensive glycaemic control vs conventional glucose control

Intensive glycaemic control showed no clear difference in mortality compared with standard glycaemic control (moderate certainty).

• Effect of the treatment of Type 2 diabetes mellitus on the development of cognitive impairment and dementia 2017 · Cochrane Headline outcomes only
  RR 1 [0.79, 1.26]
  3 studies · 15888 participants
  Moderate
• Targeting intensive glycaemic control versus targeting conventional glycaemic control for type 2 diabetes mellitus 2013 · Cochrane Headline outcomes only
  RR 1 [0.92, 1.08]
  24 studies · 34325 participants
  Moderate

Zuclopenthixol dihydrochloride vs placebo

It is very uncertain whether zuclopenthixol dihydrochloride changes leaving the study early (any reason) compared with placebo (very low certainty).

• Zuclopenthixol dihydrochloride for schizophrenia 2017 · Cochrane Headline outcomes only
  RR 0.29 [0.01, 6.6]
  2 studies · 100 participants
  Very low
• Zuclopenthixol versus placebo for schizophrenia 2015 · Cochrane Headline outcomes only
  RR 0.93 [0.06, 13.54]
  1 study · 29 participants
  Very low

Prophylactic platelet transfusion at threshold of 10,000 vs higher transfusion threshold (20,000 or 30,000)

• Comparison of different platelet count thresholds to guide administration of prophylactic platelet transfusion for… 2015 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 255 participants
  Low
• Prophylactic platelet transfusion for prevention of bleeding in patients with haematological disorders after… 2012 · Cochrane Headline outcomes only
  RR 1.72 [1.33, 2.22]
  2 studies · 94205 participants
  Moderate

Prophylactic platelet transfusion at threshold of 10,000 vs higher transfusion threshold (20,000 or 30,000)

• Comparison of different platelet count thresholds to guide administration of prophylactic platelet transfusion for… 2015 · Cochrane Headline outcomes only
  no estimate extracted
  2 studies · 333 participants
  Low
• Prophylactic platelet transfusion for prevention of bleeding in patients with haematological disorders after… 2012 · Cochrane Headline outcomes only
  no estimate extracted
  2 studies · 333 participants
  Moderate