Application of the general health status questionnaire SF36 to patients with gastrointestinal dysfunction: initial validation and validation as a measure of change

Objective: To determine whether the Short Form (SF36) Health Status Survey is a valid measure of health status and health change for patients with irritable bowel syndrome (IBS). Methods: The SF36 was self-administered by 116 patients with IBS at the commencement and end of a controlled clinical trial. Patients were recruited through two Sydney teaching hospitals and through private gastroenterologists during 1997 and treated with Chinese herbal medicine. Results: The SF36 health concepts demonstrated internal consistency, construct validity and concurrent validity when applied to patients with significant bowel dysfunction. Patient scores on two health scales of the SF36 (bodily pain, general health) correlated significantly with the bowel symptom scores recorded by patients and gastroenterologists at the beginning and end of the trial period. Actively treated patients significantly improved their scores in four out of eight of the health scales of the SF36 and reported overall improvement compared with inactively treated patients. Conclusions: The SF36 is a valid measure of general health status in IBS patients, is sensitive to the presence of IBS, and is adequately sensitive to gastrointestinal change in IBS patients. Implications: While the SF36 general health measure is used by the Australian Bureau of Statistics and widely overseas, until recently no data have been available on the sensitivity of the SF36 to gastrointestinal dysfunction or numerous other disorders. The SF36 is not only sensitive to the presence of IBS, it also provides a useful adjunct to current methods of evaluating treatment outcomes for IBS, and potentially other disorders.