Associations of smoking and obesity with chronic pain, physical functioning, and quality of life following primary ventral hernia repair: a register- and survey-based nationwide study

This Statistical Analysis Plan (SAP) outlines the statistical methodologies and data-related specifics for a planned register- and survey-based observational cross-sectional study. The study's objective is to investigate the relationship between the common risky lifestyle factors smoking and obesity and the patient-reported outcomes chronic pain, physical functioning, and improvement in quality of life following primary ventral hernia repair. The dataset comprises a nationwide Danish cohort of patients who underwent primary ventral hernia repair from January 2014 to March 2024. The study hypothesizes that smoking and obesity are associated with a higher risk of chronic pain, poorer physical functioning scores, and a lower probability of postoperative improvement in quality of life, and that the combined effect of smoking and obesity exceeds additivity.