Poor Reporting of Analgesia in Laboratory Animals: A Systemic Problem

Proper use of pain relief (analgesics) in laboratory animals is a scientific and ethical imperative. Both the Animal Welfare Act and US Public Health Service policy require appropriate use of analgesics for painful procedures, with clear justification and approval required for withholding them. When results are published, clear and precise descriptions of the analgesic regimens allow other scientists to critically analyze the research outcomes (which can be affected by use or withholding of analgesics) and increase the reproducibility of the experiments. It also allows reviewers to be better assured that animal welfare was rigorously considered in the study design.

Multiple articles have reviewed how research procedures are described (Buck, 2007, Nature; Stokes et al., 2009, Laboratory Animals; Taylor, 2010, Alternatives to Laboratory Animals; Coulter et al., 2011, BMC Veterinary Research). In each case, these reviews have detailed missing descriptions of anesthesia and analgesia, and have called on scientists to improve their reporting. Guidelines for reporting animal research have been published by national and international research organizations (ARRIVE: 2010, CAMARADES: 2015, NAS: 2011) and adopted by major journals as standards for publication.

Yet, a recent article in PLoS ONE (Carbone and Austin, 2016, available at http://bit.ly/2aGLl6o) found published descriptions are still lacking. In a thorough review of 10 major surgical procedures, the authors examined 400 manuscripts, looking to see whether anesthesia or analgesia is mentioned at all, whether there is any mention of post-surgical analgesia, and how completely the analgesics are described. They found that 62 contained no mention of any anesthetic or analgesic. Less than 25 percent included a description of post-surgical analgesia or named the specific analgesic used. Further, even after specific guidance regarding neurological studies (CAMARADES, 2015) was published, many manuscripts described use of anesthetics and analgesics that were not even recommended for use in those types of studies.

The dearth of analgesic descriptions in the published studies does not mean that analgesics were withheld, as the authors point out. However, it does mean that it is impossible for other scientists to determine the potential effects of using or withholding pain relief on the study outcomes. It also makes it difficult to reproduce the study or even determine the validity of the conclusions from the studies. Journals are complicit in this poor reporting. Even as they endorse guidelines, they are clearly not enforcing them.

Poor reporting of pain management is both an animal welfare and a scientific concern. The authors make a case that publication standards should be part of the federal regulations, as part of the research process. They suggest that researchers who must withhold analgesics should specifically state that they were withheld and provide justification for their decision in the published research. When over 75 percent of publications provide no description of analgesia, it perpetuates the notion that use of pain-relieving drugs is optional and has a deleterious effect on the study outcome. As concluded by the authors, when this happens, the animals suffer and the data suffer.