Case control and cohort studies
| Author and year of publication | Country and setting | Quality assessment | Study findings | Outcome of quality assessment | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Study design | Selection | Comparability | Exposure/outcome | Other issues | Comparison | Sample size | Outcomes | |||
| Ballot 201014 | South 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 score | Outcome (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 Mortality: Overall 140/474 (29.5%) 28/99 who received IPPV died (28%) 16/96 who received CPAP died (16%) | Low quality |
| Kawaza 201436 | Malawi 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 asphyxia | Groups 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 group | Mortality 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 analysis | Bubble CPAP vs nasal prong oxygen (O2) | 87 babies: 62 bubble CPAP 25 nasal O2 Intended numbers were not recruited to control group | Mortality: Bubble CPAP: 18/62 (29%) O2: 14/25 (56%) Minimal complications in either group | Moderate |
| Koyamaibole 200538 | Fiji 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 period | Independently verifiable outcomes based on prospectively collected data Ascertainment consistent between groups Controlled for BW in analysis | No record of any missing data | Preintroduction of bubble CPAP vs postintroduction of bubble CPAP | 596 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 Mortality: 75 deaths (12.5%) pre-CPAP vs 63 deaths (11.3%) post-CPAP | Low-moderate quality |
| Pieper 200333 | South 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-CPAP | 21 babies 11 CPAP 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 201239 | Nicaragua Tertiary neonatal unit CPAP used prior to introduction of bubble CPAP but method not specified MV available | Cohort study, preintroduction and postintroduction of bubble CPAP | Included 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 period | Need 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 CPAP | 230 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.