ACUTE KIDNEY INJURY FOLLOWING SURGERY FOR HIP FRACTURE

Factors that influence the mortality of patients following hip hemiarthroplasty

INTRODUCTION

Hip hemiarthroplasty (HHA) is one of the most common types of orthopedic surgery. With the prevalence and utilization of the surgery increasing year after year, this procedure is found to be associated with severe postoperative complications and eventually mortality. Thus, it is crucial to understand the factors that increase the risk of mortality following HHA.

METHODS

Using the Nationwide Inpatient Sample (NIS) database, patients undergoing HHA from 2016 to 2019 were identified. This sample was stratified into a mortality group and a control group. The data regarding patients' demographics, co-morbidities, and associated complications were compared between the groups.

RESULTS

Of the 84,067 patients who underwent the HHA procedures, 1,327 (1.6%) patients died. Additionally, the mortality group had a higher percentage of patients who were non-electively admitted (P < 0.001) and diabetic patients with complications (P < 0.001), but lower incidences of tobacco-related disorders (P < 0.001). Significant differences were also seen in age (P < 0.001), length of stay (P < 0.001), and total charges (P < 0.001) between the two groups. Preoperatively, those aged > 70 years (OR: 2.11, 95% CI [1.74, 2.56], P < 0.001) had diabetes without complications (OR: 0.32, 95% CI [0.23, 0.44], P < 0.001), tobacco-related disorders (OR: 0.24, 95% CI [0.17, 0.34], P < 0.001) and increased rates of mortality after HHA. Postoperatively, conditions, such as pulmonary embolisms (OR: 6.62, 95% CI [5.07, 8.65], P < 0.001), acute renal failure (OR: 4.58 95% CI [4.09, 5.13], P < 0.001), pneumonia (95% CI [2.72, 3.83], P < 0.001), and myocardial infarctions (OR: 2.65, 95% CI [1.80, 3.92], P < 0.001) increased likelihood of death after undergoing HHA. Patients who were electively admitted (OR: 0.46 95% CI [0.35, 0.61], P < 0.001) had preoperative obesity (OR: 0.67, 95% CI [0.44, 0.84], P = 0.002), and a periprosthetic dislocation (OR: 0.51, 95% CI [0.31, 0.83], P = 0.007) and were found to have a decreased risk of mortality following THA.

CONCLUSIONS

Analysis of pre- and postoperative complications relating to HHA revealed that several comorbidities and postoperative complications increased the odds of mortality. Old age, pulmonary embolisms, acute renal failure, pneumonia, and myocardial infraction enhanced the odds of post-HHA mortality.

Incidence and predictors of postoperative acute kidney injury in older adults with hip fractures

OBJECTIVES

Main Purpose: To clarify the incidence and predictors of acute kidney injury (AKI) after hip fracture surgery; Secondary Purpose: To investigate the impact of AKI on the length of stay (LOS) and mortality of patients.

METHODS

We retrospectively evaluated data from 644 hip fracture patients at Peking University First Hospital from 2015 to 2021, and divided the patients into AKI and Non-AKI groups according to whether AKI occurred after surgery. Logistic regression was used to clarify the risk factors for AKI, draw ROC curves, and analyze the odds ratio (OR) for LOS and death at 30 days, 3 months, and 1 year for patients with AKI.

RESULTS

The prevalence of AKI after hip fracture was 12.1%. Age, BMI, and postoperative brain natriuretic peptide (BNP) levels were risk factors for AKI after hip fracture surgery. The risk of AKI in underweight patients, overweight patients and obese patients was 2.24, 1.89, and 2.58 times. Compared to patients with BNP levels <800 pg/ml, the risk of AKI was 22.34-fold for postoperative BNP levels>1500 pg/ml. The risk of a one-grade increase in LOS was 2.84 times higher in the AKI group and the mortality of patients with AKI were higher.

CONCLUSION

The incidence of AKI after hip fracture surgery was 12.1%. Advanced age, low BMI, and postoperative high level BNP were risk factors for AKI. Surgeons need to pay more attention to patients with older age, low BMI and high postoperative BNP levels in order to proactively prevent the development of postoperative AKI.

Incidence and risk factors of acute kidney injury after femoral neck fracture in elderly patients: a retrospective case-control study

Background

Hip fracture is highly associated with disability and consequently, mortality in the elderly population. Postoperative acute kidney injury (AKI) is not unusual and is associated with considerable morbidity and mortality. We aimed to determine the incidences and potential risk factors for postoperative AKI in elderly patients with femoral neck fracture.

Methods

We retrospectively evaluated patients over 65 years of age who had been subjected to surgery for femoral neck fracture at Peking University People's Hospital from January 2015 to December 2019. Demographic characteristics and potential risk factors were collected. AKI was defined according to the Kidney Disease Improving Global Outcomes Guidelines (KDIGO).

Results

A total of 308 elderly patients with femoral neck fracture were included in the study. The overall incidence of postoperative AKI was 12% (37 cases). Through binary logistic regression analysis, adjusted for age, intraoperative blood loss and BMI, we identified that early postoperative albumin levels, hemoglobin changes and intraoperative hypotension are independent risk factors for postoperative AKI. The model considering the three factors can improve accuracy of predicting the possibility of developing AKI. The patients with AKI had a significantly higher mortality of 40.5% than those without AKI (24.0%, p < 0.001)

Conclusion

The incidence of postoperative AKI in elderly patients with femoral neck fracture was 12%. Independent risk factors for postoperative AKI included hemoglobin changes, early postoperative hypoalbuminemia and intraoperative hypotension. At the same time, postoperative AKI significantly increased mortality in elderly patients with femoral neck fracture. Taking multiple possible factors into consideration can better predict the possibility of elderly patients developing AKI after surgery.

Blood Urea Nitrogen to Serum Albumin Ratio in the Prediction of Acute Kidney Injury of Patients with Rib Fracture in Intensive Care Unit

Background

We hypothesized that the blood urea nitrogen (BUN) to serum albumin ratio (BAR) could serve as an independent predictor for incident acute kidney injury (AKI) in intensive care unit (ICU) patients with rib fracture.

Methods

Rib fracture patients in ICU were extracted from Medical Information Mart for Intensive Care IV (MIMIC-IV v1.0) database. The primary outcome in this study was the incidence of AKI. Univariate and multivariate logistic regression analyses were used to determine the relationship between BAR and AKI and propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were also applied to assure the robustness of our results.

Results

The optimal cut-off value for BAR was 5.26 based on receiver operator characteristic curve. Among the 953 patients who diagnosed with rib fracture, 197 high-BAR group (≥5.26) patients and 197 low-BAR group (<5.26) patients who had similar propensity scores were finally included in the matched cohort. High-BAR group patients had a significantly higher incidence of AKI (odds ratio, OR, 3.85, 95% confidence index, 95% CI, 2.58–5.79, P<0.001) in the original cohort, in the matched cohort (OR, 4.47, 95% CI 2.71–7.53, P<0.001), and in the weighted cohort (OR, 4.28, 95% CI 2.80–6.53, P<0.001). Furthermore, BAR was superior to that of acute physiology score III for predicting AKI and could add more net benefit for incident AKI in critical care patients with rib fracture.

Conclusion

As an easily access and cost-effective parameter, BAR could serve as a good diagnostic predictor for AKI in ICU patients with rib fracture.

The effect of intra-operative hypotension on acute kidney injury, postoperative mortality and length of stay following emergency hip fracture surgery

The association between intra-operative hypotension and postoperative acute kidney injury, mortality and length of stay has not been comprehensively evaluated in a large single-centre hip fracture population. We analysed electronic anaesthesia records of 1063 patients undergoing unilateral hip fracture surgery, collected from 2015 to 2018. Acute kidney injury, 3-, 30- and 365-day mortality and length of stay were evaluated to assess the relationship between intra-operative hypotension absolute values (≤ 55, 60, 65, 70 and 75 mmHg) and duration of hypotension. The rate of acute kidney injury was 23.7%, mortality at 3-, 30- and 365 days was 3.7%, 8.0% and 25.3%, respectively, and median (IQR [range]) length of stay 8 (6-12 [0-99]) days. Median (IQR [range]) time ≤ MAP 55, 60, 65, 70 and 75 mmHg was 0 (0-0.5[0-72.1]); 0 (0-4.4 [0-104.9]); 2.2 (0-8.7 [0-144.2]); 6.6 (2.2-19.7 [0-198.8]); 17.5 (6.6-37.1 [0-216.3]) minutes, and percentage of surgery time below these thresholds was 1%, 2.5%, 7.9%, 12% and 21% respectively. There were some univariate associations between hypotension and mortality; however, these were no longer evident in multivariable analysis. Multivariable analysis found no association between hypotension and acute kidney injury. Acute kidney injury was associated with male sex, antihypertensive medications and cardiac/renal comorbidities. Three-day mortality was associated with delay to surgery ? 48 hours, whilst 30-day and 365-day mortality was associated with delay to surgery ≥ 48 hours, impaired cognition and cardiac/renal comorbidities. While the rate of acute kidney injury was similar to other studies, use of vasopressors and fluids to reduce the time spent at hypotensive levels failed to reduce this complication. Intra-operative hypotension at the levels observed in this cohort may not be an important determinant of acute kidney injury, postoperative mortality and length of stay.