Dialysis Patients Have High Rate of Post-Op Complications

Elizabeth DeVita-Raeburn

October 15, 2012

October 15, 2012 — Patients receiving long-term dialysis who undergo major, nonemergent general surgery have an increased risk for postoperative complications and death, according to a large retrospective cohort study published online October 15 in the Archives of Surgery. The risk is highest in patients aged 65 years and older, the authors note.

The study, one of the largest to date on this issue, cites a postoperative death and complication rate of 12.7%. That number is considerably larger than figures cited in some earlier studies, which report a postoperative death and complication rate ranging from 1% to 6%.

Most of the earlier studies were based on small retrospective reviews from single institutions, which mixed minor procedures with major interventions, explain lead author Csaba Gajdos, MD, assistant professor, Division of Gastroenterology, Tumor, and Endocrine Surgery, University of Colorado School of Medicine in Aurora, and colleagues.

"[T]here is a relative paucity of data on the complication and mortality rates of dialysis patients undergoing general surgery," Dr. Gajdos and colleagues write.

The researchers analyzed 30-day postoperative data on 165,600 patients enrolled in the American College of Surgeons National Surgical Quality Improvement Program database. All patients enrolled in the study had undergone nonemergent major surgery between 2005 and 2008, and 1506 of the patients were receiving long-term dialysis.

Compared with patients not receiving dialysis, patients receiving dialysis had a notably greater rate of 30-day overall complications (composite outcome, 28.6% vs 10.7%, respectively; P < .001), death (12.7% vs 1.5%, respectively; P < .001), and return to the operating room (18.5% vs 4.9%, respectively; P < .001). The average length of postoperative surgical stay was also more than twice as long for patients receiving dialysis compared with patients not receiving dialysis (13.4 vs 5.8 days, respectively; P < .001).

Patients receiving dialysis who were also undergoing elective surgery were significantly more likely than patients not receiving dialysis to develop pneumonia (adjusted odds ratio [OR], 1.28; 95% confidence interval [CI], 1.04 - 1.57), require unplanned intubation (adjusted OR, 1.82; 95% CI, 1.48 - 2.23), acquire ventilator dependence (adjusted OR, 1.94; 95% CI, 1.65 - 2.29), and return to the operating room within 30 days (adjusted OR, 1.94; 95% CI, 1.68 - 2.25). In addition, patients receiving dialysis were more likely to develop a pulmonary outcome (adjusted OR, 1.89; 95% CI, 1.64 - 2.18), vascular outcome (adjusted OR, 1.69; 95% CI, 1.04 - 2.75), composite outcome (adjusted OR, 1.55; 95% CI, 1.37 - 1.75), and death (adjusted OR, 2.57; 95% CI, 2.15 - 3.08) within 30 days of surgery. Adjustments in these analyses were made for race, sex, age, work relative value units, American Society of Anesthesiologists classification, and whether the patient had undergone an operation within the previous 30 days; also, surgical site infection was additionally adjusted for wound classification.

Stroke, myocardial infarction, and unplanned intubation were the most lethal complications among patients receiving dialysis. Of all patients receiving dialysis, older patients (those aged 65 years or older) undergoing elective general surgery were significantly more likely to die postoperatively compared with younger patients (OR, 2.65; 95% CI, 1.88 - 3.74).

The results are not entirely surprising, according to the authors. "The combined systemic effects of chronic renal disease create an altered physiological state for dialysis patients in the perioperative period," they note. "This...influences the way complications are handled by the body and decreases our ability to rescue the patient once a complication happens."

"These findings highlight the importance of dialysis dependence as a risk factor for poor surgical outcomes. It should be considered along with old age and functional dependence as a characteristic that identifies patients at extremely high risk," Lawrence B. Oresanya, MD, a surgical resident, and Emily Finlayson, MD, an assistant professor in residence, both at the University of California, San Francisco, write in an accompanying editorial.

"[W]henever possible," they add, "strong consideration should be given to less invasive and nonoperative alternatives for the management of conditions for which surgery is generally recommended in healthier patients."

One limitation of the study was the fact that although the database contained a large variety of general surgical operations, the sample size was not large enough to perform analyses for each type of operation. The dialysis subgroup was also relatively small, the authors note. Although an effort was made to exclude patients with acute renal failure from the study group, it might not have been entirely successful.

In addition, although the study's authors attempted to exclude the creation or revision of hemodialysis access as a primary procedure, they note that it was possible that the higher rate of 30-day reoperations in patients receiving dialysis could have been caused by vascular access–related complications.

Statistical analysis for this study was supported by the University of Colorado Department of Surgery and School of Medicine. The authors and editorialists have disclosed no relevant financial relationships.

Arch Surg. Published online October 15, 2012. Article extract, Critique extract

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