Erasmus 2002.
| Methods | Randomized, double‐blind, controlled trial Blinding of randomization? ‐ Yes Blinding of intervention? ‐ Yes Blinding of outcome measure assessment? ‐ Yes Completeness of follow‐up? Yes ‐ see Notes section | |
| Participants | 130 preterm infants (PMA 26 to 34 weeks) admitted to one NICU in Saskatoon, Saskatchewan, Canada were enrolled between April 1997 and July 2000 Entry characteristics expressed as mean and SEM 66 infants were assigned to the lactase group (numbers indicate mean ± SEM); PMA (weeks) 31.4 ± 0.3; BW (grams) 1394.0 ± 49.1; Age at study entry (d) 11.2 ± 0.9; Weight at study entry (grams) 1408.8 ± 41.6; Body length at study entry (cm) 40.7 ± 0.5; Head circumference at study entry (cm) 27.9 ± 0.3 64 infants were assigned to the placebo group; PMA (weeks) 31.4 ± 0.2; BW (grams) 1420.9 ± 56.3; Age at study entry (d) 10.8 ± 0.9; Weight at study entry (grams) 1434.2 ± 48.7; Body length at study entry (cm) 41.0 ± 0.4; Head circumference at study entry (cm) 27.9 ± 0.3 | |
| Interventions | Infants randomly assigned to the lactase group received feeds treated with Lactacid drops (McNeil Consumer Products Company) which according to Carlson et al (Carlson 1991) would result in a 70% decrease in lactose concentration. A study placebo solution composed of the identical carrier agent as in Lactacid was used in the control group. The enzyme and matched placebo solutions were packaged in identical bottles labelled "lactase study drops" and were identifiable only by the research nurse according to assigned code numbers. Researchers and care givers remained blinded for the duration of the study. |
|
| Outcomes | Primary outcome was weight gain (grams per day). Secondary outcomes included gains in length and head circumference, biochemical indexes of nutritional status, feeding intolerance, NEC | |
| Notes | 52 of 66 infants assigned to the lactase group reached study day 14; 50 of 64 infants assigned to the control group reached study day 14.
One of the authors of the study was contacted and confirmed that outcomes were reported as per the numbers of infants randomized.
The study intervention started when enteral feedings provided > 75% of the daily intake. The study was terminated when the infant reached 36 weeks or was discharged from the unit, whichever came first. Study infants were fed according to parental choice. Infants fed human milk received human milk alone on study day 1 and 2. On study day 3, each infant received a 1:1 ratio of human milk and a liquid human milk fortifier (Natural Care, Ross Laboratories) (providing 81 kcal/100 mL) and continued with this feeding regimen for the duration of the study. Infants fed formula received the preterm formula Similac Special Care (SSC) (Ross Laboratories). On study days 1 and 2 these infants received SSC 20 (68 kcal/100 mL) and on study day 3 they were advanced to SSC 24 (81 kcal/100 mL). |
|
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | No information provided |
| Allocation concealment (selection bias) | Unclear risk | Infants were randomly assigned |
| Blinding (performance bias and detection bias) All outcomes | Low risk | "Researchers and care givers remained blinded for the duration of the study; only the research nurse and central food production staff had access to randomization information and did not participate in patients care" |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | "Researchers and care givers remained blinded for the duration of the study; only the research nurse and central food production staff had access to randomization information and did not participate in patients care" |
| Blinding of outcome assessment (detection bias) All outcomes | Low risk | "Researchers and care givers remained blinded for the duration of the study; only the research nurse and central food production staff had access to randomization information and did not participate in patients care" |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Sixty‐six infants were randomly assigned to the lactase group, 52 reached study day 14. Sixty‐four infants were randomly assigned to the control group, of which 50 reached study day 14 |
| Selective reporting (reporting bias) | Unclear risk | The study protocol was not available to us |
BW = birth weight; d = days; NEC = necrotizing enterocolitis; NICU = neonatal intensive care unit; PMA = postmenstrual age; SEM = standard error of the mean.