Musculoskeletal Research Unit, Translational Health Sciences, Bristol Medical School, 1st Floor Learning & Research Building, Southmead Hospital, Bristol, BS10 5NB, United Kingdom.
National Institute for Health Research Bristol Biomedical Research Centre, University of Bristol, Bristol, United Kingdom.
Sci Rep. 2018 Oct 9;8(1):15026. doi: 10.1038/s41598-018-33314-0.
Observational studies have identified surgical factors that are associated with a reduced risk of mortality after joint replacement. It is not clear whether these are causal or reflect patient selection. Data on the first primary hip (n = 424,156) and knee replacements (n = 469,989) performed for osteoarthritis in the National Joint Registry were analysed. Flexible parametric survival modelling was used to determine if risk factors for mortality in the perioperative period persisted. To explore selection bias, standardised mortality ratios were calculated for all-cause, respiratory and smoking related cancer mortality using population rates. Selection was apparent for hip resurfacing, combined spinal and general anaesthetic and unicondylar knee implants; reduced mortality was observed for many years for both all and other causes of mortality with a waning effect. Mechanical thromboprophylaxis was also suggestive of selection although patients receiving aspirin had sustained reduced mortality, possibly due to to a cardioprotective effect. Posterior approach for hips was ambiguous with a possible causal component. Spinal anaesthesia was suggestive of a causal effect. We are reliant on observational data when it is not feasible to undertake randomised trials. Our approach of looking at long term mortality risks for perioperative interventions provides further insights to differentiate causal interventions from selection. We recommend the use of aspirin chemothromboprophylaxis, the posterior approach and spinal anaesthetic in total hip replacement due to the apparent causal effect on reduced mortality.
观察性研究已经确定了与关节置换术后死亡率降低相关的手术因素。目前尚不清楚这些因素是因果关系还是反映了患者选择。对国家关节登记处（National Joint Registry）中因骨关节炎进行的初次髋关节（n=424156）和膝关节置换术（n=469989）的数据进行了分析。采用灵活参数生存模型来确定围手术期死亡风险因素是否持续存在。为了探讨选择偏倚，使用人群比率计算了全因、呼吸和吸烟相关癌症死亡率的标准化死亡率比。髋关节表面置换术、联合脊椎和全身麻醉以及单髁膝关节植入物存在选择偏倚；全因和其他死因的死亡率多年来持续降低，效果逐渐减弱。机械血栓预防也表明存在选择偏倚，尽管接受阿司匹林治疗的患者死亡率持续降低，可能是因为具有心脏保护作用。对于髋关节的后路入路结果不明确，可能存在因果关系。脊髓麻醉提示存在因果关系。当无法进行随机试验时，我们依赖观察性数据。我们采用观察长期围手术期干预的死亡率风险的方法，提供了进一步的见解，以区分因果干预和选择。我们建议在全髋关节置换术中使用阿司匹林化学血栓预防、后路入路和脊髓麻醉，因为它们对降低死亡率有明显的因果作用。
