By George Ochoa

Obese patients who underwent laparoscopic appendectomy had superior clinical outcomes, including lower overall morbidity, than those who underwent an open approach, according to a recent study (J Am Coll Surg 2012;215:88-100).

Using data from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database (2005-2009), the researchers included 13,330 obese patients (body mass index [BMI] >30 kg/m2) who underwent open (22%) or laparoscopic (78%) appendectomy as the primary surgical procedure and who had a postoperative diagnosis of acute appendicitis. To minimize the effects of treatment-selection bias in the aggregate cohort, the investigators created a 1:1 matched cohort (N=2,228) using 41 baseline risk-adjustment factors.

In the aggregate cohort, laparoscopic appendectomy was associated with a 57% reduction in 30-day overall morbidity after multivariable risk-adjusted analysis (odds ratio [OR], 0.43; 95% confidence interval [CI], 0.36-0.52; P<0.0001). In the matched cohort, the reduction in overall morbidity associated with laparoscopic appendectomy was 53% (OR, 0.47; 95% CI, 0.32-0.65; P<0.0001). Laparoscopic appendectomy was associated with reduced serious morbidity/mortality in both the adjusted aggregate cohort (OR, 0.54; 95% CI, 0.43-0.68; P<0.0001) and matched cohort (OR, 0.57; 95% CI, 0.35-0.93; P=0.021). Mortality by itself was not associated with either surgical approach.

Morbidity increased substantially with greater BMI in patients receiving open appendectomy, but not in patients receiving laparoscopic appendectomy. In the matched cohort, mean hospital length of stay (1.2 days less) and operative time (11 minutes less) were shorter in the laparoscopic than the open group.

The study had several limitations, namely that it only included patients from NSQIP-affiliated hospitals, and it was a retrospective data analysis.

“For obese patients with appendicitis, laparoscopic appendectomy is the preferred surgical approach as it is the safest, least morbid and quickest, which also has the shortest length of hospital stay,” said lead author of the current study, Rodney Mason, MD, PhD, associate professor of clinical surgery, Keck School of Medicine, University of Southern California, Los Angeles.

Dr. Mason noted that there are approximately 70 published randomized trials comparing open with laparoscopic appendectomy, but none specifically look at obese patients; such a trial examining obese patients would take time and likely involve one or just a few hospitals. The alternative, “using this matching technique [on] the large NSQIP database, provides … evidence which is as good as or, in some aspects, even superior to a randomized controlled trial.”

Commenting by email, Esteban Varela, MD, MPH, FACS, associate professor of surgery, Minimally Invasive and Bariatric Surgery, Washington University School of Medicine, St. Louis, who was not associated with the study, said, “Although the study is not novel, it confirms the findings of other similar studies using large numbers of patients from administrative and clinical databases. See our study from 2008 referenced in the paper (Am J Surg 2008;196:218-222), which used an administrative database to compare outcomes of morbidly obese patients undergoing laparoscopic versus open appendectomy.”

Dr. Varela added, “I don’t anticipate any clinical changes at this time, as most surgeons now understand the benefits of laparoscopy in this population.”