The Pilonidal Sinus Disease-Specific Quality of Life Questionnaire (SQoL): Reliability, Validity, and Utilisation.

Background: Pilonidal sinus disease is an inflammatory condition characterised by formations ranging from minor cysts to extensive sinus tracts in the natal cleft in the sacrococcygeal area. Due to its complex and unique symptoms, the condition may not be adequately captured by the generic quality of life (QoL) instruments. In this study, we evaluated a newly developed pilonidal sinus disease-specific quality of life (SQoL) questionnaire, valuating its validity and applicability for measuring postoperative outcomes of pilonidal sinus disease. Materials and Methods: The study involved developing a SQoL. A total of 116 adult patients with chronic and acute symptomatic disease at the Kaunas Hospital of the Lithuanian University of Health Sciences (LUHS) were asked to complete both the SQoL and the SF-36v2 questionnaire. Key evaluation criteria for the SQoL questionnaire included internal consistency, measurement stability, as well as construct and discriminant validity. Results: 2 months after the procedure, 103 patients (response rate 88.79%) completed both questionnaires. Internal consistency was assessed 1 week after surgery, with the overall questionnaire achieving a Cronbach's α coefficient of 0.919. The Spearman correlation coefficient for the total questionnaire score in the test-retest validation was 0.55 (CI 0.406-0.679), indicating a moderately significant correlation for all questions. Construct validity was evaluated by comparing the SQoL questionnaire with the results from various SF-36v2 domains 1 week after surgery. The highest inverse correlations were found between the corresponding domains of Physical Functioning and Role Physical Functioning (-0.770 and -0.600), with all correlations being statistically significant. Conclusions: A newly developed SQoL questionnaire has shown promise in assessing the impact of the disease and its treatment, particularly by addressing disease-specific symptoms. Standardising outcome measures can improve the reliability of meta-analyses and systematic reviews, which in turn helps to create more personalised care plans. The trial was registered in ClinicalTrials.gov with the identifier of NCT05982028.