Table 2

 Risk of bias in studies from more developed versus less developed countries based on reported features

TopicExperimental interventionOutcomeRandomisation sequence generationAllocation concealmentBlinding
Trials from more developed countries*Trials from less developed countries*Trials from more developed countries*Trials from less developed countries*Trials from more developed countries*Trials from less developed countries*
Antenatal prevention in preterm birth33CorticosteroidsFetal and neonatal deaths7/100/37/101/35/101/3
Antioxidant supplements for prevention39AntioxidantsMortality†14/582/712/581/76/580/7
Multiple pregnancy42Admission to hospital for bed restPerinatal death1/30/41/31/43/30/4
Treatment of sepsis and septic shock34CorticosteroidsAll cause mortality at 28 days†4/160/34/160/35/160/3
Prevention of gastrointestinal cancers40AntioxidantsMortality0/80/50/80/50/80/5
Non-neutropenic critically ill patients35Systemic antifungalsMortality†4/91/13/90/11/90/1
Treatment of non-small cell lung cancer41Postoperative radiotherapyMortality†0/80/25/81/28/82/2
Aneurysmal subarachnoid haemorrhage36Calcium antagonists aloneCase fatality0/101/13/101/15/101/1
Prevention of infection in preterm or low birthweight infants37Intravenous immunoglobulinAll cause mortality7/105/51/104/56/105/5
Unresectable hepatocellular carcinoma38Transarterial chemoembolisation or transarterial embolisationAll cause mortality†1/81/12/80/18/81/1
Oral cavity and oropharyngeal cancer43Altered fractionation radiotherapyTotal mortality†3/131/13/131/113/131/1
Cirrhosis with upper gastrointestinal bleeding44AntibioticsBacterial infections†1/73/53/74/57/75/5
Peripheral arterial disease of leg45Lipid lowering regimensCardiovascular events†5/60/24/60/20/60/2
Pneumococcal infection in adults46VaccinationAll cause pneumonia†4/92/47/93/45/93/4
Prevention of pre-eclampsia47AntioxidantsPre-eclampsia†1/42/41/42/40/41/4
Vitamin E supplementation in pregnancy48Vitamin EClinical pre-eclampsia†1/21/11/21/10/20/1
Prevention of gastrointestinal cancers40AntioxidantsIncidence of gastrointestinal cancers†0/65/110/65/110/60/11
Hypertension during pregnancy49β blockersCaesarean section†7/111/17/110/17/110/1
Hepatic encephalopathy52ProbioticsNo recovery from hepatic encephalopathy†0/11/31/13/31/13/3
Prevention of pre-eclampsia51Antiplatelet agentsProteinuric pre-eclampsia†13/305/1020/307/1026/308/10
Tuberculosis prevention in non-HIV infected people53IsoniazidActive tuberculosis†0/60/41/61/40/60/4
Prophylactic antifungal agents in very low birthweight infants54FluconazoleInvasive fungal infection†1/40/11/40/10/40/1
Prevention of infection in preterm or low birthweight infants37Intravenous immunoglobulinSepsis†5/73/30/72/33/73/3
Antenatal care for low risk pregnancy50Reduced number of visits or goal oriented visitsPreterm birth†2/42/32/41/34/41/3
Diarrhoea prevention55Rotavirus vaccineEpisodes of rotavirus diarrhoea†7/141/610/141/64/140/6

*Numbers represent trials with unclear or high risk of bias/total number of trials.

†The primary binary outcomes of the respective systematic reviews.