[Cultural adaptation to Spanish and validation of the Gastrointestinal Short Form Questionnaire].
OBJECTIVE
To describe the process followed for the cultural and psychometric adaptation (validation) to Spanish of the Gastrointestinal Short Form Questionnaire (GSFQ), used to measure the interference of symptoms of gastroesophageal reflux disease GERD and to report the psychometric properties of this instrument.


METHODS
The adaptation process was supervised by a five-member expert panel. After forward and backward translations in duplicate, a Spanish version was obtained, which was administered to two samples; a five-patient pilot sample to check comprehension and face validity, and a 4,000-patient sample to check structural validity (factor analysis and reliability), construct validity, and discriminative validity.


RESULTS
The questionnaire showed a unique dimension that matched that of the original questionnaire. Reliability was high (alpha=0.83), and the correlation between even-odd items was good (r=0.69). The overall score correlated with generic health-related quality of life measures evaluated by the EQ-5D tariff (r=0.499) and VAS (r=-0.481). The scale discriminated between GERD severity levels (p<0.008) as measured by the Savary-Miller scale, except for the most severe level with respect to the levels immediately below. The questionnaire was able to detect differences between diverse concomitant diseases and antecedents. Sensitivity with respect to the GERD clinician criterion was 60.5% and specificity was 68.3%. Normative comparison scaling values are reported.


CONCLUSIONS
The results show acceptable psychometric properties. A new instrument to assess the interference of GERD symptoms is thus available to health professionals. This instrument takes the patient's perspective into account.
Ruiz Díaz
Miguel A
MA
Facultad de Psicología, Universidad Autónoma de Madrid, España. miguel.ruiz@uam.es
Suárez Parga
José Manuel
JM
Pardo Merino
Antonio
A
García Vargas
Mercedes
M
Pascual Renedo
Virginia
V
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D003430:Cross-Sectional Studies; D003469:Culture; D005260:Female; D005764:Gastroesophageal Reflux / Q000453:epidemiology / Q000523:psychology*; D006801:Humans; D007802:Language; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011237:Predictive Value of Tests; D011594:Psychometrics; D011788:Quality of Life; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D055815:Young Adult