A description of the study sample is provided in . The mean age of the children was 9.0 years, with 69% being female. Age, ethnic distributions, and mother’s level of education did not significantly differ between the CGI and CP groups.
Child-Reported Diary Data
Group comparisons of child-reported, 2-week diary data reflected no significant differences between the CGI and CP groups with regard to any pain characteristic, interference with activities because of pain, or stooling characteristics (). Pain location trended toward significance (P = .05), with children in the CGI group more often indicating their pain as periumbilical and children in the CP group more often indicating pain as epigastric.
Group Comparison of Child-Reported Pain and Stooling Characteristics
Mother-Reported Telephone Screening Data
Evaluation of the mothers’ screening data () reflected that mothers in the CGI group reported their children as having higher maximum pain intensity in the previous year compared with mothers in the CP group. Mothers did not differ significantly with respect to retrospective ratings of pain frequency or whether pain interfered with the child’s activities.
Group Comparison of Retrospective Mothers’ Report of Child Pain
lists all diagnostic tests that were recorded, as well as the percentage of children in each group documented as receiving each test at least once.
Percentage of the Sample Receiving Diagnostic Tests According to Group
Differences in Cost of Medical Evaluation
Because the amount of variance in cost was significantly different between groups (with significantly greater variation in the CGI group), t tests assuming unequal variances were examined for all group comparisons of cost. Evaluation of group differences in cost of medical evaluation began with independent sample t tests comparing the 2 groups on total cost of evaluation. Because endoscopy procedures could only be performed on children in the CGI group, total cost of evaluation was compared both excluding and including the endoscopy procedure cost (). When endoscopy costs were excluded, costs for the CGI group were significantly (fivefold) higher than those for the CP group. Understandably, this difference increased further (ninefold) when endoscopy costs were included.
To further explore what types of medical evaluation might be contributing to differences in total cost, group comparisons also were examined separately for cost of blood work, urine testing, stool studies, breath testing, and diagnostic imaging (). Children in the CGI group incurred more cost than the CP group for all categories of testing except urine testing, which was not significantly different between groups.
Prediction of Cost of Medical Evaluation
A series of multiple regression analyses were conducted to explore if child-reported pain characteristics, child-reported stool characteristics, or mother-report of child symptoms predicted total cost of evaluation in either the CGI or CP groups. For the CGI group, regression analyses were conducted both with and without endoscopy procedures included in the total cost of evaluation.
Child-reported pain characteristics (mean pain, maximum pain, number of pain episodes, average interference rating for pain episodes, and child-report of typical pain location) did not significantly predict cost for the CGI group when endoscopy procedures were excluded (F5,41 = 1.38, P = .25, R2 = 0.16, adjusted R2 = 0.05) or included (F5,41 = 0.62, P = .68, R2 = 0.08, adjusted R2 = −0.05). Similarly, for the CP group, pain characteristics did not predict cost of evaluation (F5,40 = 1.07, P = .40, R2 = 0.13, adjusted R2 = 0.01).
Child-reported stooling characteristics (mean number of bowel movements per day, percent rated as watery, and percent rated as hard) also did not significantly predict cost for the CGI group when endoscopy procedures were excluded (F3,45 = 1.29, P = .29, R2 = 0.08, adjusted R2 = 0.02) or included (F3,45 = 1.05, P = .38, R2 = 0.07, adjusted R2 = −0.00). Similarly, for the CP group, stooling characteristics did not predict cost of evaluation (F3,42 = 0.76, P = .52, R2 = 0.06, adjusted R2 = −0.02).
Mother screening data (number of pain episodes per month, rating of worst pain in the previous year, whether pain interfered with activities) did not significantly predict cost for the CGI group when endoscopy procedures were excluded (F3,43 = 0.82, P = .49, R2 = 0.06, adjusted R2 = −0.01) or included (F3,43 = 1.19, P = .34, R2 = 0.08, adjusted R2 = 0.01). Finally, for the CP group, mother screening data did not predict cost of evaluation (F3,42 = 0.43, P = .73, R2 = 0.03, adjusted R2 = −0.04).