Complications and 30-Day Mortality Rate After Hip Fracture Surgery in Superobese Patients

Is High Body Mass Index Protective or Detrimental in Surgical Fixation of Hip Fractures?: A Spline Regression Analysis of 22,388 Patients

OBJECTIVE

We aimed to characterize the association between BMI as a continuous variable and 30-day postoperative outcomes following hip fracture surgery through (1) 30-day readmission and reoperation; (2) local wound-related; and (3) systemic complications.

METHODS

The National Surgical Quality Improvement Program database (January 2016-December 2019) was queried for patients undergoing hip fracture open reduction and internal fixation. Baseline patient demographics, comorbidities, and patient outcomes were recorded. Multivariable regression models accounted for baseline demographics, comorbidities, and fracture patterns. Significant associations were analyzed using spline regression models to evaluate the continuous association between BMI and the aforementioned outcomes.

RESULTS

Spline models demonstrated a U-shaped curve for the odds of 30-day readmission and 30-day reoperation with nadirs at the BMI of 27.5 and 22.0 kg/m 2 . The odd ratios of superficial infection, deep infection, any wound complication, and inability to weight bear on POD 1 rose progressively starting at a BMI of 25.6, 35.5, 25.6, and 32.7 kg/m 2 respectively. Odds of 30-day mortality, transfusion, pneumonia, and delirium were greatest at the lowest recorded BMI (11.9 kg/m 2 ).

CONCLUSION

BMI has a U-shaped association with 30-day readmission and reoperation. Conversely, the highest risk of mortality and systemic complications (transfusion, pneumonia, and delirium) were within the lower BMI range, with diminishing risk as BMI increased. Local wound complications and systemic sepsis exhibited a third unique pattern with progressive rise in odds as BMI increased. The odds of any complications demonstrated a U-shaped pattern with a nadir in the overweight to obese I categories, suggesting that patients may be at lowest risk within this range.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Timing of Adverse Events Within 90 Days of Hip Fracture Surgery: A Database Study

INTRODUCTION

Hip fracture surgery is associated with notable morbidity. Understanding the timing of adverse events can inform strategies for prevention and management. Owing to database limitations, many studies have limited postoperative follow-up to 30 days. However, adverse events may not have plateaued by this time. This study evaluated adverse events after hip fracture surgery out to 90 days.

METHODS

Hip fracture surgeries in patients 65 years or older were identified in the 2010 to 2020 Q3 M91Ortho PearlDiver data set using administrative codes. The 90-day incidence and time of diagnosis of 10 common adverse events were determined and used to calculate median, interquartile range, and middle 80% for time of diagnosis. The number of events occurring before and after 30 days was also determined.

RESULTS

A total of 258,834 hip fracture surgery patients were identified. On average, 70% of adverse events occurred in postoperative days 0 to 30 and 30% occurred in days 31 to 90. The percentage of events in days 31 to 90 ranged from 8% (transfusion) to 42% (wound dehiscence). Compared with patients with a 0- to 30-day adverse event, those with 31- to 90-day adverse events had higher average Elixhauser Comorbidity Index scores (8.6 vs. 7.8, P < 0.001) and a slightly greater proportion of men (31.5% vs. 30.2%, P < 0.001).For specific adverse events, the time of diagnosis (median; interquartile range; middle 80%) were as follows: transfusion (2 days; 1 to 4 days; 1 to 24 days), acute kidney injury (5; 2 to 26; 1 to 55), cardiac event (9; 3 to 35; 1 to 64), urinary tract infection (13; 3 to 39; 1 to 65), hematoma (14; 6 to 28; 3 to 52), pneumonia (15; 5 to 39; 2 to 66), venous thromboembolism (16; 5 to 40; 2 to 64), surgical site infection (23; 14 to 37; 7 to 56), sepsis (24; 9 to 48; 3 to 71), and wound dehiscence (26; 15 to 41; 7 to 64).

DISCUSSION

Nearly one-third of 90-day adverse events after hip fracture surgery were found to occur after postoperative day 30. An understanding of the timing of adverse events is important for improving patient counseling and optimizing patient care.

Obese elderly patients with hip fractures may have better survival outcomes after surgery

BACKGROUND

In recent years, there has been an increasing amount of research on the "obesity paradox". So our primary objective was to explore whether this phenomenon exists in our study, and secondary objective was to determine the effect of body mass index (BMI) on major complications, and the incidence of acute kidney injury (AKI) after hip fracture surgery after controlling for confounding factors.

METHODS

We included patients over 70 years old with hip fracture who were admitted to the Department of Orthopedics, Peking University First Hospital between 2015 and 2021. Patients were classified as underweight (UW, < 18.5 kg/m²), normal weight (NW, 18.5-24.9 kg/m²), overweight (OW, 25.0-29.9 kg/m²) and obese (OB, ≥ 30.0 kg/m²). We analyzed demographic characteristics, operation information and postoperative outcomes. Using multivariate regression with normal-weight patients as the reference, we determined the odds of 1-year mortality, major complications, and AKI by BMI category.

RESULTS

A total of 644 patients were included. Nine percent of patients died after 1 year, 18% had major postoperative complications, and 12% had AKI. There was a U-shaped relationship between BMI and the rates of major complications or AKI. However, there was a linear decreasing relationship between 1-year mortality and BMI. After controlling for confounding factors, multivariate regression analysis showed that the risk of 1-year mortality after surgery was 2.24 times higher in underweight patients than in normal-weight patients (P < 0.05, OR: 2.24, 95% CI 1.14-4.42). Compared with normal-weight patients, underweight patients had a 2.07 times increased risk of major complications (P < 0.05, OR 2.07, 95% CI 1.21-3.55), and the risk of major complications in obese patients was 2.57 times higher than that in normal-weight patients (P < 0.05, OR 2.57, 95% CI 1.09-6.09). Compared with normal-weight, underweight patients had a 2.18 times increased risk of AKI (P < 0.05, OR 2.18, 95% CI 1.17-4.05).

CONCLUSIONS

The 1-year mortality risk of patients with higher BMI was significantly reduced. Besides, compared with normal-weight patients, underweight patients and obese patients have a higher risk of major complications; low-weight and obese patients are at higher risk for AKI.

Risk Factors Associated With Postoperative Pulmonary Infection in Elderly Patients With Hip Fracture: A Longitudinal Study

This study aimed to conduct a longitudinal study to explore the influencing factors of pulmonary infection in elderly patients with hip fracture after surgery, to provide evidence and reference for the early identification and nursing care of patients at high risk of postoperative pulmonary infection.A secondary analysis was conducted of electronic medical record data from elderly patients with hip fractures treated in a tertiary hospital from January 1, 2020 to June 30, 2021.A total of 526 patients were included. Age ≥70 years (odd ratio [OR] 2.042, 95% confidence interval [CI] [1.516-4.022]), history of smoking (OR 2.755, 95% CI [2.009-3.175]), time from fracture to operation ≥5 days (OR 3.117, 95% CI [1.925-3.911]), American Society of Anesthesiologists grade ≥II (OR 1.254, 95% CI [1.053-1.921]), chronic obstructive pulmonary disease (OR 2.832, 95% CI [1.775-3.808]), hypoproteinemia (OR 1.395, 95% CI [1.022-1.841]), red blood cell distribution width >15% (OR 3.142, 95% CI [2.104-4.172]), intensive care unit stay (OR 2.174, 95% CI [1.083-3.718]) and duration of mechanical ventilation ≥180 minutes (OR 3.117, 95% CI [2.199-4.807]) were the independent risk factors (all p < .05).Early nursing care should be taken for patients with risk factors to reduce the pulmonary infection.

The impact of body mass index on mortality rates of hip fracture patients: a systematic review and meta-analysis

Obesity has been recognized as a global epidemic as approximately one-third of the world's population. Findings on early and late mortality rates between obese, overweight, and underweight vs normal body mass index (BMI) patients confirm that the obese and overweight patients were found to have lower risk and underweight patients were found to have increased risk of mortality as compared to normal weighted patients. It is unclear if the "obesity paradox" exists with survival outcomes of hip fracture patients. We hereby reviewed early (in-hospital and 30-day mortality) and late mortality (≥ 1-year) rates between obese, overweight, and underweight vs normal body mass index (BMI) patients with hip fractures. PubMed, Embase, ScienceDirect, CENTRAL, and Google Scholar were searched for studies reporting mortality rates of hip fracture patients based on BMI. We pooled crude and adjusted mortality rates in a random-effects model. Eleven studies were included. Meta-analysis indicated significantly reduced risk of early (RR: 0.64 95% CI: 0.59, 0.69 I² = 0% p < 0.00001) and late mortality rates (RR: 0.78 95% CI: 0.67, 0.91 I² = 93% p = 0.002) in obese vs normal BMI patients. Meta-analysis failed to demonstrate any statistically significant difference in early mortality (RR: 0.90 95% CI: 0.54, 1.53 I² = 44% p = 0.71) but significantly reduced risk of late mortality in overweight vs normal BMI patients (RR: 0.85 95% CI: 0.73, 0.93 I² = 84% p = 0.003). Scarce data suggested increased risk of early (RR: 1.44 95% CI: 1.08, 1.93 I² = 26% p = 0.01) and late mortality (RR: 1.23 95% CI: 1.08, 1.41 I² = 7% p = 0.002) in underweight vs normal BMI patients. Adjusted data corroborated the reduced risk of mortality in overweight (HR: 0.78 95% CI: 0.74, 0.83 I² = 0% p < 0.0001) and obese patients (HR: 0.66 95% CI: 0.60, 0.73 I² = 0% p < 0.0001). Our results indicate that the "obesity paradox" exists with survival outcomes of hip fracture patients. Obese and overweight patients were found to have lower risk and underweight patients were found to have increased risk of mortality as compared to normal weighted patients.

The Role of Smoking and Body Mass Index in Mortality Risk Assessment for Geriatric Hip Fracture Patients

Background

Smoking, obesity, and being below a healthy body weight are known to increase all-cause mortality rates and are considered modifiable risk factors. The purpose of this study is to assess whether adding these risk factors to a validated geriatric inpatient mortality risk tool will improve the predictive capacity for hip fracture patients. We hypothesize that the predictive capacity of the Score for Trauma Triage in the Geriatric and Middle-Aged (STTGMA) tool will improve.

Methodology

Between October 2014 and August 2021, 2,421 patients >55-years-old treated for hip fractures caused by low-energy mechanisms were analyzed for demographics, injury details, hospital quality measures, and mortality. Smoking status was recorded as a current every-day smoker, former smoker, or never smoker. Smokers (current and former) were compared to non-smokers (never smokers). Body mass index (BMI) was defined as underweight (<18.5 kg/m²), healthy weight (18.5-24.9 kg/m²), overweight (25.0-24.9 kg/m²), or obese (>30 kg/m²). The baseline STTGMA tool for hip fractures (STTGMAHIP_FX_SCORE) was modified to include patients’ BMI and smoking status (STTGMA_MODIFIABLE), and new mortality risk scores were calculated. Each model’s predictive ability was compared using DeLong’s test by analyzing the area under the receiver operating curves (AUROCs). Comparative analyses were conducted on each risk quartile.

Results

A comparison of smokers versus non-smokers demonstrated that smokers experienced higher rates of inpatient (p = 0.025) and 30-day (p = 0.048) mortality, myocardial infarction (p < 0.01), acute respiratory failure (p < 0.01), and a longer length of stay (p = 0.014). Comparison among BMI cohorts demonstrated that underweight patients experienced higher rates of pneumonia (p = 0.033), decubitus ulcers (p = 0.046), and the need for an intensive care unit (ICU) (p < 0.01). AUROC comparison demonstrated that STTGMA_MODIFIABLE significantly improved the predictive capacity for inpatient mortality compared to STTGMAHIP_FX_SCORE (0.792 vs. 0.672, p = 0.0445). Quartile stratification demonstrated the highest risk cohort had a longer length of stay (p < 0.01), higher rates of inpatient (p < 0.01) and 30-day mortality (p < 0.01), and need for an ICU (p < 0.01) compared to the minimal risk cohort. Patients in the lowest risk quartile were most likely to be discharged home (p < 0.01).

Conclusions

Smoking, obesity, and being below a healthy body weight increase the risk of perioperative complications and poor outcomes. Including smoking and BMI improves the STTGMAHIP_FX_SCORE tool to predict mortality and risk stratify patient outcomes. Because smoking, obesity, and being below a healthy body weight are modifiable patient factors, providers can counsel patients and implement lifestyle changes to potentially decrease their risk of longer-term poor outcomes, especially in the setting of another fracture. For patients who are former smokers, providers can use this information to encourage continued restraint and healthy choices.

Inverse relation of body weight with short-term and long-term mortality following hip fracture surgery: a meta-analysis

Background

The obesity paradox, which suggests that high body weight is positively associated with survival in some diseases, has not been proven in patients with hip fracture. In this study, meta-analysis of previous studies on the impacts of body weight on postoperative mortality following hip fracture surgery in older adults was conducted.

Methods

PubMed, Embase, and Cochrane library were searched for studies investigating the correlation between mortality after hip fracture surgery and body weight. The search main items included: (“Body mass index” OR “BMI” or “body weight”) and (“hip fracture” or “hip fractures”). Studies contained data on short-term (≤ 30-day) and long-term (≥ 1 year) mortality after hip fracture and its association with distinct body weight or BMI groups were reported as full-text articles were included in this meta-analysis.

Results

Eleven separate studies were included. The definitions of underweight and obesity differed among the included studies, but the majority of the enrolled studies used the average body weight definition of a BMI of 18.5 to 24.9 kg/m²; underweight referred to a BMI of < 18.5 kg/m²; and obesity pertained to a BMI of > 30 kg/m². Based on the generalized definitions of body-weight groups from the enrolled studies, the group with obesity had lower long-term (odds ratio [OR]: 0.63, 95% CI: 0.50–0.79, P < 0.00001) and short-term (OR: 0.63, 95% CI: 0.58–0.68, P ≤ 0.00001) mortality rates after hip fracture surgery when compared with patients with average-weight group. However, compared with the average-weight group, the underweight group had higher long-term (OR: 1.51, 95% CI: 1.15-1.98, P=0.003) and short-term (OR: 1.49, 95% CI: 1.29-1.72, P<0.00001) mortality rates after hip fracture surgery.

Conclusions

Current evidence demonstrates an inverse relation of body weight with long-term and short-term mortality after hip fracture surgery in older adults.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-022-03131-3.