Predictive value of American Society of Anesthesiologists classification on prognosis of elderly patients with hip fracture

Abstract

Objective To explore the predictive effect of American Society of Anesthesiologists (ASA) classification on prognosis of elderly patients with hip fracture. Methods A retrospective case-control study was conducted to analyze the clinical data of 814 elderly patients with hip fracture admitted to the 7th Medical Center of the General Hospital of the PLA from January 2012 to December 2015. There were 272 males and 542 females, with the age range of 60-99 years [(80.0±8.0)years]. According to ASA classification, the patients were divided into four groups: 23 cases (2.8%) of ASA grade I, 380 cases (46.7%) of ASA grade II, 389 cases (47.8%) of ASA grade III and 22 cases (2.7%) of ASA grade IV. Data compared among the groups included gender, age, comorbidities, fracture type, anesthesia methods, surgical methods, length of hospital stay, complications, and 30-day and 1-year mortality rates. Multiple Logistic analysis was conducted to seek independent risk factors for 1-year mortality. Results There were no significant difference among the four groups with regards to gender, fracture type, surgical methods (P>0.05 ). With the improvement of ASA classification, the age of patients increased gradually, the length of hospital stay increased, and the rate of nerve block anesthesia increased ( allP<0.01). Incidence of complications of ASA grade IV patients was the highest [59%(13/22)], followed by 31.4%(122/389) of ASA grade Ⅲ patients, 17.6%(67/380) of ASA grade II patients, 4%(1/23) of ASA grade I patients (all P<0.01). The 30-day and 9-0day mortality of ASA grade IV patients were 32% (7/22), 64% (14/22), ASA grade III patients were 4.6% (18/389), 17.0% (66/389), ASA grade II patients were 3.4% (13/380), 12.1% (46/380), and ASA grade I patients were 0 and 4% (1/23), respectively. The differences between these groups were significantly different ( allP<0.01). Univariate analysis showed that male, advanced age, coronary heart disease, pulmonary infections, chronic obstructive pulmonary diseases (COPD), renal insufficiency, ASA classification, anesthesia methods, and length of hospital stay were related to postoperative 1-year death (P<0.05 or 0.01). A total of 127 patients (15.6%) died within 1 year after operation. Multivariate Logistic regression analysis showed age (OR=1.037, 95%CI 1.007-1.068), ASA grade(ASA grade II : OR=1.851, 95%CI 1.238-14.386; ASA grade III : OR=2.092, 95%CI 1.266-16.482; ASA grade IV: OR=15.368, 95%CI 1.626-145. 283), length of hospital stay (OR=1.038, 95%CI 1.015-1.061) were independent risk factors for 1-year mortality. Conclusions The outcome of the elderly hip fracture is poor. The ASA classification is closely related to the incidence of complications, 30-day mortality, and 1-year mortality. Advanced age, ASA grade II, III and IV, hospital length of stay are the independent risk factors for poor prognosis of hip fractures. The ASA classification can be used as a screening tool to intervene for the high-risk population as early as possible. Key words: Hip fractures; Prognosis; Aged