[Nested case-control study on risk factors of postoperative hyperactive-type delirium in geriatric orthopedic patients]

Objective: To investigate the risk factors of postoperative hyperactive-type delirium(PHTD) in geriatric orthopedic patients using nested case-control study. Methods: Seventy-four patients who underwent orthopedic surgeries in the Second Affiliated Hospital of Wenzhou Medical University from January 2008 to December 2013, aged 65 or above, American Society of Anesthesiologists (ASA) physical status Ⅰ-Ⅳ, with complete medical records and confirmed diagnosis of PHTD were selected as case group. A control group of 444 patients, on the basis of 1∶6 versus nested case group, from the same cohort but without PHTD was established. Data patterns such as patient age, gender, ASA classification, status of preoperative/postoperative electrolytes, preoperative blood glucose, preoperative/postoperative plasma albumin and preoperative/postoperative hematocrit(Hct), uses of non-steroidal analgesics, anticholinergic drugs and benzodiazepines drugs, type of anesthesia, anesthesia duration, difference in postoperative analgesia were collected and analyzed. Results: Univariate Logistic regression analysis showed that gender, age, ASA grade, preoperative electrolytes, anesthesia duration, operative duration, intraoperative hypotension and the difference of postoperative analgesia were risk factors for PHTD. Multiple Logistic regression analysis showed that gender (OR=2.562, 95%CI: 1.438-4.564, P=0.001), age (OR=3.929, 95%CI: 1.788-8.633, P=0.001), preoperative electrolytes(OR=3.714, 95%CI: 2.068-6.670, P<0.001)were the independent risk factors for PHTD. Conclusion: Male, elderly patients and abnormalities of preoperative electrolyte are the independent risk factors for PHTD in geriatric orthopedic patients.