Causes of short-term mortality after appendectomy: a population-based case-controlled study

Abstract

Objective: This case control study is a detailed analysis of the causes of death and the risk factors of short-term mortality after appendectomy.

Summary background data: Although death is a rare event after appendectomy, we found a 7-fold excess mortality after appendectomy overall and a 9-fold excess mortality after negative appendectomy, compared to the background population in a previous study from Sweden, in accordance with others.

Materials and methods: All patients who died within 30 days after appendectomy, and controls matched to age, sex and period, were identified of 119,060 patients who were operated with appendectomy in 1987 to 1996 from the Swedish National Inpatient Registry. Causes of death and differences between the cases and controls in comorbidity and appendectomy diagnoses were analyzed on the basis of a review of hospital records. Only patients and controls with appendectomy as the only surgical intervention and without prevalent malignant diagnosis were included in the analysis to avoid bias.

Results: A total of 179 patients who died within 30 days and 400 matched controls remained for the analyses. Nonproductive and negative exploration was strongly associated with mortality [odds ratio (OR), 5.11; confidence interval (CI), 2.09-12.48; P < 0.001 and OR, 2.38; CI, 1.24-4.57; P = 0.009, respectively] in contrast to perforated appendicitis (OR, 1.60; CI, 0.95-2.70; P = 0.078) after adjustment for age, sex, and comorbidity. Chronic obstructive pulmonary disease (OR, 3.31; CI, 1.05-10.45, P = 0.041), renal insufficiency (OR, 2.32; CI, 1.26-4.27; P = 0.007), and diabetes mellitus were also independent risk factors (OR, 2.39; CI, 1.12-5.12; P = 0.025). Cardiovascular or thromboembolic disease was responsible for the death in more than 50% of the cases, whereas appendicitis was responsible in only 17.9%.

Conclusions: Appendicitis is only responsible for a small portion of the deaths after appendectomy. Comorbidity and negative appendectomy are strongly associated with mortality, suggesting that comorbidity, diagnostic failure, and the anesthesiosurgical trauma may play an important role.