Safety and impact on diagnostic accuracy of early analgesia in suspected acute appendicitis: a meta-analysis

Abstract

Background: The safety of early analgesia in patients suspected to have acute appendicitis (AA) is still controversial.

Methods: Double blind randomized clinical trials comparing patients receiving or not receiving opiates for early analgesia in suspected AA were selected for meta-analysis according to PRISMA guidelines. Primary outcomes were the number of patients with AA confirmed by histology and the number of patients undergoing surgical intervention. Secondary outcomes were missed diagnoses, false positive AA and complication rate. Effect sizes were calculated using a Mantel-Haenszel fixed effects model.

Results: Previously published papers mostly analyzed surrogate end-points such as physician's confidence about the diagnosis or the alteration of clinical signs, subjective parameters dependent on personal perception. Our article focused on clinical outcome and specifically investigated those potentially related to AA instead of unspecified abdominal pain. Opiate administration did not have an impact on the number of histologically proven AA (OR = 1.196 [0.875-1.635]; P = 0.261). Differences in appendectomy rates were only slightly above the threshold for statistical significance (OR = 1.350 [0.966-1.887]; P = 0.079), suggesting that analgesia might influence the treatment approach. On the other hand missed diagnoses (OR = 0.509 [0.087-2.990]; P = 0.455) and false positive AA (OR = 1.071 [0.596-1.923]; P = 0.818) ascertained by histologic examination were unaffected, so diagnostic accuracy was retained. Safety was not compromised by opiates, as the difference in complication rates did not reach statistical significance (OR = 0.615 [0.217-1.748]; P = 0.372).

Conclusion: Early analgesia with opiates in suspected AA might influence the approach to treatment, but does not appear to alter diagnostic accuracy or surgical outcome. To support our findings, further trials on larger sample sizes from different age groups and both genders are needed.

Keywords: Abdominal pain; Acute appendicitis; Analgesia.