Association of Serum Bilirubin, Cholesterol, Calcium and Phosphate Levels with Gallstone Type in Patients Undergoing Cholecystectomy: A Cross-Sectional Study

Background: Gallstone disease is a frequent hepatobiliary disorder that is caused by the interplay of metabolic, biochemical and environmental factors. The known roles of cholesterol, bilirubin, calcium and phosphate in gallstone formation are very important. The present study aimed to assess the correlation between the serum biochemical parameters and gallstone characteristics in cholelithiasis patients. Material and Methods: It is a cross sectional study (observational) which was carried out for a period of 18 months in the Department of General Surgery, Gandhi Medical College and Hamidia Hospital, Bhopal. The total number of patients included were 90 who were diagnosed with ultrasonography as having cholelithiasis and were operated for cholecystectomy. Serum total bilirubin, total cholesterol, calcium and inorganic phosphate levels were measured preoperatively. Gallstones were grouped into three categories: cholesterol stones, pigment stones or mixed stones according to their morphology. One-way analysis of variance (ANOVA), Pearson's correlation coefficient and the Chi-square test were used to analyze the statistical data, where p value <0.05 was statistically significant. Results: The mean age of the study population was 46.48 ± 14.15 years, and females constituted 73.3% of patients. Pigment stones were the most common type (41.1%), followed by mixed stones (34.4%) and cholesterol stones (24.4%). Multiple gallstones were present in 67.8% of patients, while choledocholithiasis was observed in 7.8%. Mean serum bilirubin, calcium, phosphorus, and cholesterol levels were 1.11 ± 0.53 mg/dL, 8.69 ± 1.01 mg/dL, 3.81 ± 1.24 mg/dL, and 158.95 ± 39.01 mg/dL, respectively. Serum bilirubin levels differed significantly among gallstone types and were highest in patients with pigment stones (p <0.001). No significant differences were observed for serum calcium (p = 0.424), phosphorus (p = 0.638), or cholesterol (p = 0.944). No significant correlations were identified among the studied biochemical parameters. Conclusion: Gallstone disease was more common in middle-aged females, with pigment stones being the predominant stone type. Serum bilirubin demonstrated a significant association with gallstone type, particularly pigment stones, whereas serum calcium, phosphorus, and cholesterol showed no significant association. These findings suggest a potential role of bilirubin metabolism in pigment stone formation and highlight the multifactorial nature of gallstone pathogenesis.

Keywords: Cholelithiasis; Gallstones; Bilirubin; Cholesterol; Calcium; Phosphate.