Daytime versus Nighttime in Acute Appendicitis

Little is known about patients with appendicitis presenting at nighttime. It is hypothesized that patients presented at night more frequently have a complicated (gangrenous or perforated) appendicitis and therefore develop more postoperative complications.

In this study data were used from the nationwide, prospective SNAPSHOT study appendicitis, including 1975 patients undergoing surgery for suspected appendicitis. This study included only adults. Two primary outcomes were defined: (A) The proportion of patients with complicated appendicitis and (B) the proportion of patients with a complication postoperatively presenting during daytime versus nighttime period. Analysis for both complicated and uncomplicated appendicitis was performed, and a multivariate model was used to correct for baseline characteristics and time to surgery.

In total, 1361 adult patients with appendicitis were analyzed. Both at nighttime and at daytime, 34% had complicated appendicitis. In patients presenting in the daytime, 12.1% developed a postoperative complication versus 18.6% for presentation at night (p = 0.008). In a multivariate analysis, the risk for a postoperative complication when presenting at night was significantly increased (adjusted OR 1.74; 95% CI 1.14-2.66, p = 0.01). Surgery within eight hours after presentation does not lower this risk (adjusted OR 1.37; 95% CI 0.97-1.95, p = 0.078).

Complicated appendicitis is seen as frequently during the day as at nighttime. For patients who present at nighttime with acute appendicitis, the risk of a postoperative complication is higher compared with a presentation at daytime. In multivariate analysis, nighttime presentation but not surgery within 8 h after presentation is independently associated with postoperative complication risk.