Validating the incontinence symptom severity index: a self-assessment instrument for voiding symptom severity in women.
OBJECTIVE
Most voiding symptom self-assessment instruments assess either symptom bother or effect on quality of life. The Incontinence Symptom Severity Index is an instrument for self-assessment of severity of female urinary storage and voiding symptoms, rather than symptom bother or effects of symptoms on quality of life. We assessed the validity of the Incontinence Symptom Severity Index for female voiding symptom self-assessment.


METHODS
The Incontinence Symptom Severity Index assesses 8 symptom domains, including emptying, urgency, urge incontinence, nocturia, daytime frequency, stress incontinence, leakage with physical activity and pad use. Three separate cohorts of women with a mean age of 59, 60 and 63 years, respectively, who underwent evaluation for urinary complaints associated with incontinence and vaginal prolapse were analyzed. Internal consistency was assessed via item-total correlations and Cronbach's alpha. Concurrent validity against the Urogenital Distress Inventory and Pelvic Floor Distress Inventory-Short Form were studied by correlating similar symptom domains of the Incontinence Symptom Severity Index with both instruments. We assessed criterion validity by comparison with the objective measures of post-void residual urine, voiding logs and self-reported pad use. Response to change was assessed by comparing pretreatment and posttreatment Incontinence Symptom Severity Index scores.


RESULTS
Significant item total correlations were seen for each Incontinence Symptom Severity Index item and Cronbach's alpha was 0.69. All Incontinence Symptom Severity Index items significantly correlated with similar items of the Urogenital Distress Inventory and Pelvic Floor Distress Inventory-Short Form. Significant posttreatment reductions were also observed for all 8 Incontinence Symptom Severity Index items. Progressively higher post-void residual urine was noted for the 4 severity scores of Incontinence Symptom Severity Index item 1 (emptying) (p = 0.07). Incontinence Symptom Severity Index items 3 (nocturia) and 4 (daytime frequency) showed significantly increasing nighttime and daytime voids with worsening severity scores for each (p <0.0001 and <0.0041, respectively). Incontinence Symptom Severity Index items 5 to 8 (stress incontinence, urge incontinence, leakage with activity and pad use) showed significantly increasing trends in mean daily pad use (p <0.0001, 0.022, <0.0001 and <0.0001, respectively) among the 4 severity scores for each.


CONCLUSIONS
The Incontinence Symptom Severity Index demonstrates good reliability and validity. It is a useful instrument for assessment of female incontinence and voiding symptom severity in clinical and research settings.
Twiss
Christian
C
Department of Surgery, University of Arizona School of Medicine, Tucson, Arizona 85724-5077, USA. ctwiss@surgery.arizona.edu
Triaca
Veronica
V
Anger
Jennifer
J
Patel
Mayank
M
Smith
Ariana
A
Kim
Ja-Hong
JH
Raz
Shlomo
S
Rodríguez
Larissa V
LV
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008875:Middle Aged; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D014549:Urinary Incontinence / Q000175:diagnosis*