Abstract
Introduction
Renal impairment following major surgery is a formidable complication. There is recent evidence suggesting increasing risk of progression to chronic kidney disease and mortality after transient renal impairment. We aimed to evaluate the impact of pre-operative comorbidities on long-term outcomes of renal-function following hip arthroplasty.
Method
Patients listed for hip arthroplasty were pre-assessed according to the Charlson-Comorbidity-index (CCI) in May 2017. Demographic data, established risk factors and preoperative renal-function were collected. Pre-existing renal dysfunction was classified using KDIGO CKD criteria. RIFLE AKIN scores were used to document post-operative renal impairment based on 7-day serum creatinine. Renal function was assessed at 30 day and 1 year. Risk for early and long-term-complications were determined by univariate and multivariate analysis. Mortality and kidney-disease-progression were estimated using Kaplan Meier plots
Results
839 patients were included in our study. Mean pre-assessment data was calculated; age = 71 years (Range = 44 – 93), length of stay = 4.46 days (SD 3.43), CCI = 3.1 (SD 2.54), 69% had an elevated BMI (BMI>25) and ASA grade = 2.55 (SD 1.03). Preoperative eGFR was 74ml/min/1.73m2 [SD-14.31]. The prevalence of pre-existing CKD was 8.5% (n=70).
89 patients developed postoperative AKI (11%), 31 patients developed persistent AKI (35%) and 58 patients developed transient AKI (65%). Mean recovery time for transient AKI was 1.9 days [SD 1.20]. Within this group 43% developed CKD at 1 year [HR = 2.2]. Transient AKI had an average CCI of 4 [SD-2.9], of which 31 patients (20%) progressed to CKD at 1 year; HR = 1.5 [95% CI 1.0–1.5].
Discussion and Conclusion
We highlight the benefits of using the Charlson Comorbidity Index as a preoperative tool in risk stratification. We note the significance of managing post-operative AKI promptly. CCI and AKIN scoring systems are useful adjuncts to perioperative risk stratification, decision making and counselling of patients susceptible to worsening renal function and increased mortality.
