Weight loss rate is a critical and statistically significant predictor of post-LSG gallstone formation

Symptomatic gallstone disease after laparoscopic sleeve gastrectomy has an incidence rate of 16.3%, according to a study by researchers from Hamad Medical Corporation, Doha, Qatar. The most compelling finding from this study is that the weight loss rate, rather than total weight, is a critical and statistically significant predictor of gallstone formation, especially for early onset, even though female sex remains a strong predisposing factor. Therefore, they said a selective approach, based on individual risk factors for each patient, is warranted, with close follow-up of such patients.

The authors noted that several factors identified in the medical literature may increase the chance of developing symptomatic gallstones after LSG. Some studies suggest that having a higher BMI before surgery might be linked to an increased risk of symptomatic gallstones following bariatric surgery.

Additional research has indicated that losing more than 1.5 kg per week or achieving a total weight loss of 25-30% is linked to a significantly higher risk of gallstone formation. Notably, patients who develop gallstones after LSG tend to lose more weight in the initial months following the surgery compared to those who do not experience this complication. The amount and speed of weight loss appear to be directly correlated with the likelihood of gallstone formation in this patient group.

Therefore, this study sought to identify the prevalence of symptomatic gallstone disease in patients after LSG, the incidence of those who underwent cholecystectomy post-sleeve gastrectomy, as well as to evaluate the potential benefits of prophylactic cholecystectomy in this population.

Outcomes

A total of 105 patients underwent LSG were included in the study (64 female (61.0%) and 41 male (39.1%) patients), mean age of 29.1 ± 12.7 years, with a median of 26 years and a range of 14-61 years. After excluding the patients who had already undergone laparoscopic cholecystectomy (LC) prior to LSG and asymptomatic patients, a total of 98 patients remained in the analysis.

Among these, 16 patients developed symptomatic gallstone disease following LSG. Patients who developed gallstones were younger (median age 21.5 years) compared to those who did not develop gallstones (median age 26 years).

A notable gender disparity was observed, with female patients comprising 81.2% of gallstone cases compared to only 18.8% of males. In contrast, the non-gallstone group had a more balanced gender distribution, with 56.1% female and 43.9% male. Nevertheless, this was not statistical significant to conclude that there is a significant association between gender and the presence or absence of gallstones.

Patients with gallstones experienced a mean weight loss of 37.62 ± 12.61 kg, representing a 30.80 ± 9.57% reduction from their initial weight. Similarly, BMI decreased by a mean of 13.75 ± 5.14 kg/m2. These substantial changes in weight and BMI highlight the rapid weight loss that typically precedes gallstone formation in this population.

The median time to diagnosis was 11.3 months, suggesting that the highest risk period may be around the one-year mark post surgery, which coincides with the period when weight loss typically begins to plateau after bariatric procedures.

“This timing may reflect a critical intersection of factors, including stabilising weight, changing dietary patterns, and adaptation of gallbladder function,” the authors noted.

The analysis revealed that patients who developed gallstones experienced a mean absolute weight reduction of 37.62 ± 12.61 kg (median 35.50 kg, range 12.0-59.0 kg), corresponding to a percentage weight reduction of 30.80 ± 9.57% (median 31.51%, range 9.1-44.2%) from their pre-surgical weight.

However, the most compelling finding of this study was the relationship between the rate of weight loss and the timing of gallstone diagnosis. The mean rate of weight loss in patients who developed gallstones was 4.86 ± 5.11 kg/month (median 2.78 kg/month, range 1.1 - 22.1 kg/month).

Figure 1: Pearson correlation analysis plot

Figure 1 shows that the data points illustrate a clear downward trend from left to right, which is summarised by the descending regression line. This indicates a negative correlation, indicating that as the rate of weight loss increases, the time to gallstone diagnosis tends to decrease (p=0.0262). Thus, patients with a faster rate of weight loss are strongly associated with a shorter time to the development of gallstone disease in this group of patients.

“Given our findings, patients experiencing very rapid weight loss, particularly females, may warrant closer monitoring or consideration for prophylactic interventions. However, more extensive research is needed to establish definitive criteria for such interventions,” the researchers concluded. “Future research directions should include larger prospective studies with standardized follow-up protocols, the inclusion of both symptomatic and asymptomatic gallstone cases, and consideration of additional variables, such as the rate of weight loss, dietary factors, and genetic markers. Such comprehensive approaches would further elucidate the complex pathophysiology of post-bariatric surgery gallstone disease, inform evidence-based preventive strategies, and optimize patient management strategies.”

The findings were reported in the paper, 'Incidence of Symptomatic Gallstone Disease in Bariatric Patients Undergoing Sleeve Gastrectomy, and the Dilemma of Prophylactic Cholecystectomy: A Single-Center Retrospective Study', published in Cureus. To access this paper, please click here