Development and validation of a childhood self-efficacy for functional constipation questionnaire

BACKGROUND

Children with functional constipation fear painful bowel movements leading to stool withholding behavior. Self-efficacy is the belief that an individual can accomplish a given goal. If children with constipation avoid defecation because they think that they are unable defecate comfortably, this low self-efficacy may prevent treatment success. The aim of the current study was to develop and validate a constipation specific self-efficacy scale.

METHODS

The self-efficacy for functional constipation questionnaire (SEFCQ) was developed by the authors and evaluated by 10 children and seven experts. Ninety-nine healthy children and 122 children with functional constipation completed the SEFCQ and three other questionnaires measuring related constructs.

KEY RESULTS

Minor changes were made in wording based on feedback from experts and children. Factor analysis showed two scales, a 7 item Action scale (Cronbach's α = 0.88) and a 7 item Emotion scale (Cronbach α = 0.86). The SEFCQ total scale correlated positively with general self-efficacy (r = .32, P < .001) and quality of life (r = .20; P < .01) and negatively with anxiety (r = -.15; P < .05). Scores on the SEFCQ were higher in children without functional constipation compared to those with functional constipation (53.33 + 3.38 vs 39.34 + 7.19, P < .001).

CONCLUSIONS & INFERENCES

We developed a constipation specific self-efficacy questionnaire with good initial internal reliability, excellent face validity and adequate content validity. A low self-efficacy for defecation, may make the child resist their physical urge to defecate and hence, the need for further studies to assess its effect on treatment outcomes.

Serological confirmation of Chagas' disease by a recombinant and peptide antigen line immunoassay: INNO-LIA chagas

Although screening for Trypanosoma cruzi antibodies is mandatory in most South American countries, current tests are insensitive and have poor specificity. A recently optimized line immunoassay (the INNO-LIA Chagas assay) for the serological confirmation of Chagas' disease was evaluated at a large blood bank in São Paulo, Brazil. Sera from blood donors who reacted in at least one of three serological screening assays (n = 1,604) and who returned for a follow-up were retested, and the donors were interviewed to assess their epidemiological risk. The results obtained by the confirmatory assay evaluated in this study were compared to those obtained by the three different screening assays. Upon consideration of the consensus results obtained by the three different screening assays as a "gold standard," the INNO-LIA Chagas assay showed a sensitivity of 99.4% (95% confidence interval [CI], 98.3 to 99.9) and a specificity of 98.1% (95% CI, 96.6 to 99.0) for positive (n = 503) and negative (n = 577) sera. The INNO-LIA Chagas assay confirmed the results for significantly larger numbers of positive samples of at-risk individuals independent of the number of positive screening tests (P = 0.017, Mantel-Haenszel test). In conclusion, the INNO-LIA Chagas assay reliably confirmed the presence of antibodies to T. cruzi and can be implemented as a confirmatory assay for Chagas' disease serology.

A recombinant peptide antigen line immunoassay optimized for the confirmation of Chagas' disease

BACKGROUND

The transfusion of contaminated blood has become the major route of transmission for Chagas' disease in Brazil. Current screening tests are insensitive and yield conflicting results, while confirmatory assays do not exist. A line immunoassay (INNO-LIA Chagas Ab [INNO-LIA]) combining relevant, immunodominant recombinant and synthetic antigens on a single nylon membrane strip was evaluated for the serologic confirmation of Chagas' disease.

STUDY DESIGN AND METHODS

Sera from 1062 patients and healthy residents of four Brazilian regions endemic for Chagas' disease were used for test optimization. The established confirmation algorithm was evaluated with an independent set of positive (n = 75) and negative (n = 148) samples.

RESULTS

In the optimization phase, without an established comparative gold standard, the results with the INNO-LIA were compared with those obtained in four other screening assays. In the validation phase, the INNO-LIA showed a sensitivity of 100 percent (95% CI, 95.21-100) and a specificity of 99.32 percent (95% CI, 96.29-99.98) for well-characterized sera. Moreover, its specificity reached 100 percent with a set of 40 sera obtained from patients with documented leishmaniasis. The interpretation criteria defined in this study indicated that the INNO-LIA accurately detected the presence of antibodies to various specific antigens of Trypanosoma cruzi.

CONCLUSION

The INNO-LIA Chagas Ab assay may become the first commercial assay to reliably confirm the presence of antibodies to T. cruzi.