Validation of a derived version of the IPF-specific Saint George's Respiratory Questionnaire.

The SGRQ-Ider is a valid, reliable and responsive HRQL instrument in patients with IPF and has psychometric properties comparable to SGRQ-I. Thus, SGRQ results can reliably be transformed into the SGRQ-Ider. The MCID estimates were calculated for improvement and deterioration separately. Increasing SGRQ-Ider score was associated with increased mortality.