Author Interviews, Surgical Research, University Texas, Weight Research / 27.12.2014
PREOP-gallstones: Surgeon Develops Prediction Model For Elective Gallbladder Removal
MedicalResearch.com Interview with:
Taylor S. Riall, MD, PhD
Professor, John Sealy Distinguished Chair in Clinical Research
Department of Surgery, University of Texas Medical Branch,
Galveston, TX
Medical Research: What is the background for this study? What are the main findings?
Dr. Riall: In patients who have symptoms related their gallstones – most commonly sharp right upper quadrant abdominal pain (often associated with fatty meals), nausea, and vomiting - the current recommendation is to remove the gallbladder (perform cholecystectomy). However, in older patients there are multiple factors that make this decision difficult. Older patients have more associated medical problems (like diabetes, heart disease, etc.) making elective surgery higher risk. On the flip side, older patients are at higher risk of developing complications from their gallstones, and once they do, their mortality (death from gallbladder disease) and complications increase substantially.
In recent study of Medicare beneficiaries with symptomatic gallstones, we found that fewer than 25% underwent elective removal of the gallbladder after an initial episode of pain or symptoms related to their gallbladder. We then developed a model that predicted the likelihood of these same patients requiring emergent gallstone-related complications if they did not have their gallbladder removed electively.
This information prompted the current study. We sought to determine if the patients getting their gallbladders removed were the ones at highest risk for complications. Similar to the previous study, we found that only 22% of Medicare beneficiaries in this study (a different population) underwent elective gallbladder removal. We divided patients into three groups based on our risk prediction model – those with <30% risk, 30-60% risk, and >60% risk of requiring acute gallstone-related hospitalization. Please note that while we call the <30% risk group “low” risk, a 17% chance of hospitalization is actually a significant risk – much higher than seen in other medical conditions for which surgery or other interventions may be considered.
- First, our model worked well – the ACTUAL hospitalization rate was 17%, 45%, and 69% in the two years after the first symptoms.
- Second, whether patients had their gallbladder removed seemed unrelated to risk. 22% of patients in the lowest risk group, 21% in the middle risk group, and 23% in highest risk group had their gallbladder removed. Even more striking, in the healthiest patients – those with no medical problems and no reason not to perform elective surgery - cholecystectomy rates actually decreased with increasing risk of emergent admission. Cholecystectomy was performed in 34% of patients in the low risk group, 25% of patients in the moderate risk group, and 26% of patients in the highest risk group.
- In addition, fewer than 10% of patients who didn’t have their gallbladder removed were ever seen by a surgeon, suggesting that this decision is being made at the level of the primary care or emergency physician and not necessarily patient choice.


















alResearch.com Interview with:
David C. Johnson, MD, MPH
Department of Urology
University of North Carolina School of Medicine
Medical Research: What are the main findings of the study?
Dr. Johnson: The first main finding from this study is that the likelihood of benign pathology after surgical removal of a renal mass suspected to be malignant based on pre-operative is inversely proportionate to size. This concept is well-established, however we systematically reviewed the literature for surgical series that published rates of benign pathology stratified by size and combined these rates to determine a single pooled estimate of benign pathology of pre-operatively suspicious renal masses for each size strata. Using benign pathology rates from US studies only, we found that 40.4% of masses < 1 cm, 20.9% of masses 1-2 cm, 19.6% of masses 2-3 cm, 17.2% of masses 3-4 cm, 9.2% of masses 4-7 cm, and 6.4% of masses >7 cm are benign.
The more novel finding from this study was the quantification of a previously unmeasured burden of over treatment in kidney cancer. By combining the above mentioned rates of benign pathology with epidemiological data, we estimated that the overall burden of benign renal masses surgically removed in the US to approach 6,000 per year in 2009. This represented an 82% increase over the course of a decade. Most importantly, we found an overwhelmingly disproportionate rise in the surgical treatment of renal masses in the smallest size categories – those which were most likely to be benign. We found a 233%, 189% and 128% increase in surgically removed benign renal lesions < 1 cm, 1-2 cm, and 2-3 cm, respectively from 2000 – 2009 in the US.




