Likelihood Ratio Extravaganza

We had a likelihood ratio EXTRAVAGANZA during our noon report last week with Dr. Lewis. Dr. Lewis presented a case of a patient who presented with subacute progressive fatigue, dyspnea on exertion and melena who was found to have a hgb in the 4’s (!) and MCV of 65 on presentation.

We reviewed the JAMA rational clinical exam article on severe upper GI bleed: https://jamanetwork.com/journals/jama/article-abstract/1105075

Likelihood ratio for symptoms of UGIB:

  • Reported history of Melena : +LR 5.1-5.9
  • Melenic stool on exam: +LR 25
  • Serum BUN:Cr ratio >30: +LR 7.5
  • Blood clots in stool: LR 0.05
JL7.17.19.JPG

Dr. Lewis shared another systematic review on diagnostic value of symptoms for colorectal cancer in primary care: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3080228/

  • Positive predictive value for symptoms:

    • Rectal bleeding: 8.1%

    • Abdominal pain: 3.3%

    • Anemia: 9.7%

  • Rectal bleeding + weight loss: +LR 1.9

  • Rectal bleeding + change in bowel habits: +LR 1.8

References:

  1. Srygley FD, Gerardo CJ, Tran T, Fisher DA. Does this patient have a severe upper gastrointestinal bleed?. JAMA. 2012;307(10):1072-9.

  2. Astin M, Griffin T, Neal RD, Rose P, Hamilton W. The diagnostic value of symptoms for colorectal cancer in primary care: a systematic review. Br J Gen Pract. 2011;61(586):e231–e243. doi:10.3399/bjgp11X572427