This study is a secondary interim analysis of 'Perioperative Database of Chinese Elderly Patients,' an ongoing prospective observational cohort study that began in 2020 at the muti-center in China with the primary aim of complications in older adults before and after surgery. The investigators described the demographics, comorbidities, and assessment scores as n (percentage) or mean (SD), as appropriate. Unadjusted bivariate analyses included t-test or χ2 test to compare differences between minimal pain and intrusive pain at 3 months after surgery based on demographics, preoperative status, baseline pain status and perioperative serum potassium. The investigators then created a logistic regression model with the outcome of persistent pain at 3 months after surgery and serum potassiumas the main predictor, adjusting for baseline pain, surgery type and surgery part and frailty status based on the hypothesis and association. The investigators also tested for the interaction between baseline pain and serum potassiumas.
Perioperative serum potassium in patients over 65 impacts recovery, quality of life and physical functioning. While perioperative serum potassium is an important preoperative risk factor for poor surgical outcomes in older adults, the relationship between perioperative serum potassium and postsurgical pain in this population has not been investigated. The investigators hypothesized that preoperative serum potassium would be associated with greater odds of postsurgical chronic pain.