Diagnostic interpretation of extended pH monitoring: is there a single best method?

Pharmacodynamics and safety of pantoprazole in neonates, preterm infants, and infants aged 1 through 11 months with a clinical diagnosis of gastroesophageal reflux disease

BACKGROUND

Limited data on proton pump inhibitors in infants led regulatory agencies to request sponsors to conduct pediatric studies.

AIM

To determine the pharmacodynamic response to pantoprazole in infants with GERD to aid the dose selection for an efficacy study.

METHODS

In two open-label studies, neonates and preterm infants (study 1, ~1.2 mg/kg [high dose]) and infants 1 through 11 months (study 2, ~0.6 [low dose] or ~1.2 mg/kg [high dose]) received once-daily pantoprazole. Twenty-four-hour dual-electrode pH-metry parameters were compared between predose and steady state (≥5 days) (two-sided paired t test). Treatment was administered for ≤6 weeks.

RESULTS

In studies 1 and 2, 21 and 24 patients, respectively, were enrolled for pharmacodynamic evaluation. The high dose provided similar responses in the two studies and improved these parameters significantly: mean gastric pH and percent time gastric pH > 4 increased (p < 0.05 both studies), normalized area under the curve (AUC) of gastric H(+) activity decreased (p < 0.05 study 2), and normalized AUC of esophageal H(+) activity decreased (p < 0.05 both studies). The AUC of esophageal pH < 4 decreased. Normalized AUC of esophageal H(+) activity decreased (p < 0.05 both studies), indicating refluxate pH increased, although this was not reflected in any change in mean esophageal pH or reflux index. The normalized AUC of esophageal H(+) activity was a more sensitive measure of changes in esophageal pH.

CONCLUSIONS

In neonates, preterm infants, and infants aged 1 through 11 months, pantoprazole (high dose) improved pH-metry parameters after ≥5 consecutive daily doses, and was generally well tolerated for ≤6 weeks.

Ethnicity and gender related differences in extended intraesophageal pH monitoring parameters in infants: a retrospective study

Background

Gastroesophageal reflux disease (GERD) is believed to be more common in adult males as compared to females. It also has been shown in adults to be more common in Caucasians. We wanted to determine ethnicity and gender related differences for extended pH monitoring parameters in infancy.

Methods

Extended pH monitoring data (EPM) from infants <1 year of age were reviewed. Results were classified in two groups, as control and Gastroesophageal reflux disease (GERD) group based on the reflux index (RI). The GERD group had RI of equal to or more than 5% of total monitoring period. The parameters of RI, total number of episodes of pH < 4, and the number of episodes with pH < 4 lasting more than 5 minutes were compared by genders and by ethnic groups, Caucasians and African American (AA).

Results

There were 569 infants, 388 controls, 181 with GERD (320 males, 249 females; 165 Caucasians, 375 AA). No statistical difference in EPM parameters was detected between genders in both groups. However, Caucasian infants had a significantly higher incidence of GERD than AA infants (p = 0.036). On stratifying by gender, Caucasian females had a significantly higher number of reflux episodes >5 minutes as compared to AA females in the control group (p = 0.05). Furthermore, Caucasian females with GERD showed an overall higher trend for all parameters. Caucasian males had a trend for higher mean number of reflux episodes as compared to AA males in the control group (p = 0.09).

Conclusion

Although gender specific control data do not appear warranted in infants undergoing EPM, ethnic differences related to an overall increased incidence of pathologic GERD in Caucasian infants should be noted.