In this study, we report a rise in pediatric acute pancreatitis evaluated at a single tertiary care center on the basis of a 12-year retrospective analysis. There was a 53% increase in cases from the latter half of the 1990s to the first half of the current decade. This was largely accounted for by an increase in pediatric ED visits in general for patients during the same time period. To further evaluate the increase we examined several factors.
The increasing BMIs of children have been well documented (12
) and an association has been noted between obesity and severity of pancreatitis in adults (13
). However, the contribution of BMI to the frequency of pancreatitis in children has not been previously investigated. Thirty percent of patients in the study had BMIs at the 85th percentile or higher, indicating at-risk status or clinical obesity. This observation was consistent with trends in the pediatric population of Connecticut (12
). However, there was no statistically significant increase in BMI percentiles between patients in 1995 to 2000 and 2001 to 2006. This was confirmed with weight-for-age data.
The cohort was ethnically similar to the patient population seen at our hospital and this did not change over time. Careful etiologic analysis could not account for the increase in frequency and showed the most common etiologies in both time groups to be biliary tract disease, medications, and idiopathic.
Increased clinical awareness or referral bias can account for rising disease rates in retrospective studies. A national trend toward regionalization of pediatric emergency care among tertiary centers has created increased referral load at children’s hospitals throughout the United States. (14
). The effect of this phenomenon on the incidence of pediatric pancreatitis has not been previously investigated. We found that pediatric ED visits increased by more than 25%, whereas pancreatitis cases rose by 53% between 1995 to 2000 and 2001 to 2006. To assess the effect of referral patterns, we calculated incidence by dividing annual case frequency by ED visits. As a result, the observed increase between 1995 to 2000 and 2001 to 2006 was reduced by more than half, to 22%. Concurrent reanalysis of data collected over a similar time period from the Children’s Hospital of Wisconsin corroborated the effect of referral bias. At Wisconsin, a previously reported rise in pediatric pancreatitis was reduced by nearly half after normalizing for a concurrent increase in ED visits (8, S. Werlin, personal communication, 2008).
To date there are no population-based studies assessing pediatric acute pancreatitis. Reports are limited to a handful of case series and retrospective studies (5
). Because of the effect on our data of increasing visits to our ED during the time periods studied, we are unable to compare our results with those of other retrospective studies not reporting simultaneous changes in ED visits. These studies were done during similar time periods in Dallas (9
), Wisconsin (8
), Melbourne (7
), and Mexico (18
). The Melbourne study (7
) found a significant increase in incidence between 1993 to 1997 and 1998 to 2002. This was attributed to an absolute rise in systemic-associated and idiopathic etiologies. There were no differences in etiology subsets between the 2 time groups in our study. The Dallas study (9
) reported a significant increase in cases per year from 1993 to 1998. They examined the hypothesis of increased clinical awareness by assessing amylase and lipase testing rates. However, they noted a paradoxical decrease in testing per 100 ED visits from 1993 to 1998. This suggests that the rise in disease could not be attributed to an increase in testing. Because of the nature of laboratory databases at our institution, we were unable to study biochemical testing rates over time. A potential testing bias not previously assessed is radiography. However, there were no significant changes in CT and U/S scanning rates between 1995 to 2000 and 2001 to 2006.
Another unique aspect of the present report is the analysis of etiologies by age subsets. Under the age of 6 years, etiologies were highly diverse and idiopathic pancreatitis was uncommon, with most children obtaining a diagnosis. After age 11 years, biliary was the most common etiology and more than half of these cases were due to gallstones. The higher diversity of etiologies we observed in comparison with adults is consistent with other pediatric studies. However, our findings overall are in contrast to most pediatric reports, which have typically found acute pancreatitis in children most often associated with systemic or “multisystem” disease (5
). Kandula et al (17
) analyzed etiologies in children 0 to 3 years in a retrospective analysis and found that systemic disease was the most common cause of pancreatitis, followed by infections, idiopathic, medications, trauma, and biliary disease. We analyzed 0 to 2 years and 3 to 5 years patients separately, hence a direct comparison is difficult. In our 0 to 2 years cohort, there were no idiopathic cases and biliary disease was the primary etiology. However, the number of patients in our 0 to 2 years cohort was small compared to the number of patients in the Kandula study (12 vs 87).
There are several important limitations of this study. First, it is a retrospective analysis and suffers from the limitations inherent in such a study design. Also, we were unable to calculate true incidence because the pediatric population in our region has historically been divided among several referral centers whose catchment areas overlap. Only 1 other study in this field has been able to calculate true incidence (7
), and it was outside the United States.
Our finding that referral patterns may account for a rise in pancreatitis is limited because the data are confined to Yale-New Haven Children’s Hospital. However, there were no shifts in patient flow among the pediatric referral centers in our area during the study. No centers opened or closed, nor were there expansions or eliminations of service at existing institutions. In addition, the referral pattern cannot be attributed to overall growth in the pediatric population because the number of children in Connecticut decreased during the study period (19
Etiologic classifications and inclusion criteria vary widely among previous reports in this field because unlike adults, there is no evidence-based standard in diagnosis and treatment of children with pancreatitis. Our inclusion parameters were modified from definitions by the Acute Pancreatitis Classification Working Group (10
) to deemphasize clinical features because abdominal pain “characteristic” of pancreatitis is problematic to assess in children and there are data to suggest that patients can be diagnosed by biochemical changes alone (21
). Our etiologic classifications were not mutually exclusive, on the basis of the emerging concept that acute pancreatitis is the result of multiple factors that sensitize the pancreas to injury (17
Despite its limitations, the study confirms that acute pancreatitis in children evaluated at a single tertiary care center has been increasing during the last 2 decades. It is the first to assess the role of BMI and referral patterns in this regard, finding that the observed rise may be partly explained by higher referral rates at tertiary care centers. Regionalization of pediatric care has been encouraged by the National Institutes of Medicine (14
) and, therefore, our report may have wider applicability to other areas of the country. Subsequent studies from tertiary centers may need to control for referral patterns or include nontertiary institutions. Additional studies, population based if possible, are necessary to further confirm the rising frequency of pancreatitis. Our work also highlights the need for an evidence-based standard in diagnosis and etiologic classification of pediatric pancreatitis, particularly at a time when it appears that there is a rising burden of disease.