Relationships between sites of abdominal pain and the organs involved: a prospective observational study

OBJECTIVES: Abdominal pain is one of the most frequent chief complaints in primary care settings. The aim of the present study was to determine the positive likelihood ratios (PLRs) and negative likelihood ratios (NLRs) of the relationships between the sites of abdominal pain and the organs involved. DESIGN: Prospective observational study. SETTING: A single tertiary centre, a university hospital in Japan. PARTICIPANTS: A total of 2591 new outpatients visited the Department of General Medicine at a university hospital from April 2017 to March 2018. Of these, 326 patients aged ≥20 years with abdominal pain were enrolled. RESULTS: Sites of abdominal pain were classified into 11 categories including nine different abdominal sections, ‘generalised abdomen’ and ‘site-indeterminate’. The PLRs between ‘right subcostal’ and ‘liver and biliary tract’; between ‘right subcostal’ and ‘musculoskeletal’; between ‘epigastric’ and ‘oesophagus, stomach and duodenum’; between ‘right or left flank’ and ‘urinary tract’; between ‘left flank’ and ‘dermatological’; and between ‘mid-lower’ and ‘intestinal’ ranged from 2.17 to 4.14. The PLRs between ‘epigastric’ and ‘urinary tract’; between ‘mid-lower’ and ‘liver and biliary tract’; between ‘periumbilical’ and ‘urinary tract’; and between ‘generalised abdomen’ and ‘oesophagus, stomach and duodenum’ were low, ranging from 0.17 to 0.25. The NLR ranged from 0.5 to 1.5, excluding the relationship between ‘left flank’ and ‘dermatological’. CONCLUSION: The presence of pain at right subcostal, epigastric, right or left flank and mid-lower sites might be useful for identifying the organs involved. Additionally, the presence of pain at mid-lower, epigastric, periumbilical and generalised abdominal sites might be helpful for denying the involvement of some organs. Some sites of abdominal pain can be indicative of the organs involved. Trial registration number UMIN000037686