Biochemical composition and demographic distribution of kidney stones: a hospital-based cross-sectional study in Eastern Nepal

BACKGROUND: Nephrolithiasis is a major urological condition globally, with an increasing prevalence linked to shifting dietary patterns and climatic changes. In Nepal, the growing number of kidney stone cases presents a substantial challenge to the healthcare system. Understanding the chemical nature of these stones and their relationship with demographic factors and systemic biochemical markers is essential for developing effective localized clinical management and prevention strategies. OBJECTIVE: This study aims to analyze the biochemical composition of kidney stones and evaluate their demographic distribution among patients at a tertiary care center in Eastern Nepal. METHODS: A descriptive hospital-based cross-sectional study was conducted at the B.P. Koirala Institute of Health Sciences (BPKIHS), Dharan. The study included final 111 patients who underwent surgical intervention for urolithiasis. The stone composition was determined using standard qualitative inorganic chemical analysis techniques. Statistical analysis was performed using SPSS version 11.5, employing Chi-square tests to assess associations. RESULTS: The study population showed a male predominance, with males comprising 57.7% and females 42.3%, resulting in a male-to-female ratio of 1.36:1. The mean age of participants was 43.51 ± 13.72 years, with the highest prevalence in the 31-45 age group (48.6%). Chemical analysis revealed that calcium oxalate was the most prevalent stone type (59.5%), followed by calcium phosphate (12.6%), struvite (11.7%), and mixed stones (10.8%). Uric acid and cystine stones were least common (2.7% each). Urinary pH was significantly associated with stone composition (p = 0.01), with acidic pH favoring Calcium Oxalate and alkaline pH favoring Calcium Phosphate. Struvite stones exhibited the largest dimensions (median 20 mm). CONCLUSION: Calcium oxalate is the main constituent of kidney stones in Eastern Nepal, with a higher occurrence in males and individuals aged 31-45 years, particularly from the Terai region. Urinary pH showed a significant association with stone composition. Struvite stones were associated with larger stone size. These findings highlight the importance of routine stone analysis and urinary pH evaluation for targeted prevention and personalized management of nephrolithiasis.