Acute Kidney Injury, Renal Function, and the Elderly Obese Surgical Patient

Abstract

Objective To investigate the association between obesity and perioperative acute kidney injury (AKI), controlling for preoperative kidney dysfunction. Summary Background Data More than 30% of patients over the age of 60 are obese, and therefore at risk for kidney disease. Post-operative AKI is a significant problem. Methods We performed a matched case control study of patients enrolled in the Obesity and Surgical Outcomes Study (OBSOS), using Medicare claims data enriched with detailed chart review. Each AKI patient was matched to a non-AKI control similar in procedure type, age, sex, race, emergency status, transfer status, baseline eGFR, admission APACHE score, and the risk of death score with fine balance on hospitals. Results We identified 514 AKI cases and 694 control patients. Of the cases, 180 (35%) followed orthopedic procedures and 334 (65%) followed colon or thoracic surgery. After matching, obese patients undergoing a surgical procedure demonstrated a 65% increase in odds of AKI within 30 days from admission (OR=1.65, p<0.005) when compared to the non-obese patients. After adjustment for potential confounders, the odds of post-operative AKI remained elevated in the elderly obese (OR=1.68, p=0.01.) Conclusions Obesity is an independent risk factor for post-operative AKI in patients over 65 years of age. Efforts to optimize kidney function pre-operatively should be employed in this at risk population along with keen monitoring and maintenance of intra-operative hemodynamics. When subtle reductions in urine output or a rising creatinine are observed post-operatively, timely clinical investigation is warranted to maximize renal recovery.

Surgical Risks and Costs of Care are Greater in Patients Who Are Super Obese and Undergoing THA

“…These subjective conclusions were offered despite the documented 4.42 times greater dislocation rate in the group with a BMI of 35 kg/m 2 or greater. Our data do not support a continuous increase in renal failure as previously reported [11][12][13]. Our data do correspond to that of Hanly et al [10] who reported a 12.8%, 30-day readmission rate.…”

The impact of hyperglycemia and obesity on hospitalization costs and clinical outcome in general surgery patients

“…This finding corroborates those of several other studies showing that higher BMI is associated with increased risk for AKI in the postoperative setting (Kelz et al, 2013;Schmid et al, 2014). A possible explanation may be that obesity may predispose patients to AKI postoperatively because volume assessment and resuscitation is more difficult in the obese patient, which places patients at risk for pre-renal AKI (Kelz et al, 2013).…”

Acute Kidney Injury After Abdominal Surgery: Incidence, Risk Factors, and Outcome

“…Several pre-and perioperative risk factors for developing AKI after abdominal surgery have been reported, including age, obesity, hypertension, COPD, elevated preoperative SCr level, and more Revised Cardiac Risk Index risk factors, although studies have yielded somewhat discordant results. 13,15,16,30 After multivariate adjustment, female sex, hypertension, preoperative CKD, ASA physical status classification of IV or V, and reoperation were identified as independent risk factors for AKI. The strong association of the commonly used perioperative mortality and cardiac morbidity risk indices with AKI is of special interest and further demonstrates their usefulness in the overall perioperative risk assessment.…”