[Design and validation of a satisfaction questionnaire in patients with urolithiasis treated by extracorporeal shock wave lithotripsy (ESWL).]

Studying the psychosocial sphere of patients who undergo any treatment allows to have more information about its repercussion and can help the choice of an appropriate and personalized treatment. Due to the absence of specific instruments at present, the objective is to design and validate a health questionnaire regarding the treatment received with ESWL.

It was carried out in 6 phases using a sampleof 50 patients treated with ESWL in 2015 in ourcenter, whom we interviewed by telephone. In phase1 the items were proposed based on bibliographic review,in phase 2 those that scored below 7 were eliminatedaccording to the evaluation from 0 to 10 on theitems made by specialists. In phase 3, values of 1 to 5were assigned to each item and those with correctedcorrelation more than 0.2 and not significant (p>0.05)discriminant power with U-Mann Whitney were eliminated.In phase 4 the reliability of the questionnaire waschecked with two indexes (Cronbach's alpha and twoGuttman's halves). In phase 5, the factor analysis withVarimax rotation was performed to calculate the constructvalidity and in stage 6, the scores were analyzedto establish reference values.

50 patients (32 men, 18 women). Medianage 59 years (27-79). In phase 1, 35 items were proposed,9 of which were eliminated in phase 2. The initialquestionnaire with 26 items was distributed, with 18being eliminated in phase 3. The final questionnaire wasformed with 8 items. In phase 4 the results of Cronbach'salpha and Guttman's two halves index were 0.44 and0.323 respectively. In phase 5 after factor analysis, wefound 4 factors with 2 items each (background, impactof the acute picture, post-treatment, quality of life) able toexplain 71.19% of the variance. The median scores ofthe scale, extreme values and quartiles studied in phase6 were respectively: P50: 17 (minimum-maximum 9-25),P25: 14 and P75: 20.

The study carried out has provided anew instrument for assessing satisfaction after treatmentwith ESWL with adequate reliability and validity values.Future studies will be necessary to contrast its true clinicalusefulness.