Are feed thickeners an effective treatment for the symptoms of gastroesophageal reflux (GER) in formula-fed infants?
Feed thickeners decrease the number of reflux episodes in full-term formula-fed infants (mean difference [MD] = −1.97; 95% confidence interval [CI], −2.32 to −1.61). Additionally, full-term formula-fed infants with GER who are given thickeners are more than twice as likely to be asymptomatic compared with infants not receiving thickeners at one to eight weeks of follow-up (number needed to treat [NNT] = 5).1 (Strength of Recommendation: A, based on consistent, good-quality patient-oriented evidence.)
GER is characterized as reflux of gastric contents into the esophagus caused by lower esophageal sphincter dysfunction. It affects at least 40% of infants.2 Although GER is a normal physiologic process in healthy infants, symptoms of GER—including regurgitation, vomiting, posseting (i.e., milk or formula being regurgitated immediately after feeding), irritability, and disordered sleep—can be distressing to parents and account for frequent office visits, medication use, and subspecialist referral. Thickened infant feeds are thought to prevent symptoms of GER by increasing the “stickiness” of formula in the stomach and preventing retrograde movement of stomach contents into the esophagus. The authors of this review sought to evaluate the effectiveness of feed thickeners in formula-fed infants up to six months of age with GER.1
This Cochrane review included eight randomized controlled trials and 637 participants up to six months of age. Most participants were healthy, formula-fed infants. However, breastfed infants were included, as were preterm infants until their corrected age was six months. Trials including participants with congenital, gastrointestinal tract, or neurologic abnormalities were excluded. Carob bean gum, rice cereal, cornstarch, and alginate feed thickeners were compared with standard formula in most of the trials. One study used 25% thickened formula as the control, whereas another used a matching placebo. One study included two intervention groups that used carob bean gum–thickened formula and cornstarch-thickened formula. Primary outcomes included symptoms or signs of GER and measurement of gastric and esophageal acidity using pH probe studies. Assessment of symptoms or signs of GER and adverse effects were based on parental report.1
A meta-analysis of six studies including 442 participants showed that use of thickened feeds was associated with fewer episodes of regurgitation, posseting, or vomiting per day (MD = −1.97; 95% CI, −2.32 to −1.61). Data combined from two separate trials including 186 participants demonstrated that infants with GER receiving thickened feeds were more likely to be without regurgitation or vomiting after one to eight weeks compared with the control group (relative risk = 2.50; 95% CI, 1.38 to 4.51; NNT = 5). No type of feed thickener was statistically superior to another.1
The authors of this Cochrane review note that parents were likely to notice the viscosity of thickened formula, thus complicating attempts at blinding. One study reported diarrhea as an adverse effect, but most of the studies showed no significant differences in adverse effects between the control and treatment groups. Despite the inclusion of preterm infants in this review, the authors caution against applying these results to this patient population due to potentially different clinical presentations and nutritional requirements. Furthermore, because most of the participating infants were formula-fed, these results may not be generalizable to breastfed infants.1 Initiation of complementary solid foods before four months of age is associated with childhood obesity.3–5 Although feed thickeners increase the caloric density of infant feeds, larger trials with longer follow-up periods are necessary to adequately assess the long-term risk of weight gain.1
Guidance from the American Academy of Pediatrics recommends against introducing solid foods before six months of age.6 Current guidelines by the National Institute for Health and Care Excellence (NICE) recommend reassurance and parental education for initial treatment of GER, and suggest the modification of feeds—to include decreasing feed volumes; using smaller, more frequent feeds; and using thickened formula—only for infants exhibiting signs and symptoms of distress or frequent episodes of regurgitation.2 Pharmacologic management is indicated for infants who do not respond to conservative management or who meet criteria for gastroesophageal reflux disease. The findings in this Cochrane review1 support the NICE guidelines.2