Table 2

Case control and cohort studies

Author and year of publicationCountry and settingQuality assessmentStudy findingsOutcome of quality assessment
Study designSelectionComparabilityExposure/outcomeOther issuesComparisonSample sizeOutcomes
Ballot 201014South Africa
Tertiary neonatal unit
Case control
Consecutive cases—controls from the same group
Prospective data collection, retrospective analysis
All admissions with BW <1500 g within a given time period (2006–2007)
Exposure to CPAP determined from records
Babies needing MV and CPAP were classified as MV
Statistically significant differences in GA, BW, and 5 min Apgar scoreOutcome (mortality) data collected from records
Mortality beyond discharge not determined, duration and completeness of follow-up unclear
Same method of ascertainment for both groups
No description of those for whom data were missing
Neonates who died before leaving birth suite not mentioned
No detail on type of CPAP (bubble vs ventilator)
CPAP use between survivors vs non-survivors
Large number of variables in multivariate analysis
474 babies:
334 survivors
140 non-survivors
Logistic regression
Overall 140/474 (29.5%)
28/99 who received IPPV died (28%)
16/96 who received CPAP died (16%)
Low quality
Kawaza 201436Malawi
Regional referral hospital
No MV available
X-ray not consistently available
Case control
Quasi-randomised allocation to CPAP based on availability of equipment
Prospective data collection
Male:Female 6:4
All admissions presenting to neonatal unit BW>1000 g without congenital abnormalities or severe asphyxiaGroups were similar across all important variables except for the proportion who received bag and mask ventilation (resuscitation) in the birth suite, which was much higher in the bubble CPAP groupMortality
Mortality beyond discharge not determined
Same method of ascertainment for both groups
9 patients from control group received CPAP as it became available—these were analysed in CPAP group, not by intention-to-treat analysisBubble CPAP vs nasal prong oxygen (O2)87 babies:
62 bubble CPAP
25 nasal O2
Intended numbers were not recruited to control group
Bubble CPAP: 18/62 (29%)
14/25 (56%)
Minimal complications in either group
Koyamaibole 200538Fiji
Tertiary neonatal unit
High quality for this methodology
MV available
Higher GA and BW than other studies
Cohort study, Preintroduction and Postintroduction of CPAP
Prospective data collection
Predominately term babies or late preterm
Case definition was clear
Consecutive cases with hospital based controls over two 18 month time periods
A higher proportion of infants 1000–1500 g were admitted in the second time periodIndependently verifiable outcomes based on prospectively collected data
Ascertainment consistent between groups
Controlled for BW in analysis
No record of any missing dataPreintroduction of bubble CPAP vs postintroduction of bubble CPAP596 infants needing respiratory support pre- CPAP
556 needing respiratory support post-CPAP
Reduction in need for MV by 50%
113 needed MV pre-CPAP
70 needed MV post-CPAP
75 deaths (12.5%) pre-CPAP vs 63 deaths (11.3%) post-CPAP
Low-moderate quality
Pieper 200333South Africa
Tertiary neonatal unit
O2 available
No access to MV for babies in the study
Initially randomised then based on availability of CPAP (quasirandomised/case control) Not analysed according to intention-to-treat
Prospective data collection
Clear case definition and exclusion criteria
All admissions to a unit with
BW <1200 g
Babies that died in birth suite excluded from study
Gender ratio significantly skewed (CPAP group Male 4:Female 7, vs non-CPAP group M1:F9)100% follow-up for mortality outcome, to discharge
1 baby lost to long-term follow-up in treatment group
Ascertainment of treatment was adequate
Jet CPAP was used, not bubble
Protocol deviations were significant
CPAP vs no-CPAP21 babies
10 No CPAP
Survival of initial respiratory distress
9/11 vs 2/10
Survival to discharge
5/11 vs 2/10
Low to moderate quality
Rezzonico 201239Nicaragua
Tertiary neonatal unit
CPAP used prior to introduction of bubble CPAP but method not specified
MV available
Cohort study, preintroduction and postintroduction of bubble CPAPIncluded term and late preterm babies
Range of gestations and BW represented
Consecutive cases with hospital-based controls over two 12-months time periods (2006 and 2008)
Significant differences between groups include: higher caesarean section rate and lower BW in the second time period, higher rate of need for resuscitation in first time periodNeed for MV (no clear criteria for CPAP failure)
No detail on follow-up duration
No case definition
No description of missing data or protocol violations
Preintroduction of bubble CPAP vs postintroduction of bubble CPAP230 infants needing respiratory support prebubble CPAP
383 needing respiratory support postbubble CPAP
166 needed MV in 2006
150 needed MV in 2008
Reported reduction in mortality of 17.7% after bubble CPAP introduced
Low quality
  • Assessed according to the Newcastle-Ottawa Quality Assessment scale.

  • BW, birth weight; CPAP, continuous positive airway pressure; GA, gestational age; MV, mechanical ventilation; IPPV, intermittent positive pressure ventilation.