Pancreatic exocrine insufficiency is a risk factor for kidney stones in patients with chronic pancreatitis.

Introduction: Most patients with chronic pancreatitis (CP) develop pancreatic exocrine insufficiency (PEI) over the course of the disease. PEI may lead to hyperoxaluria and development of urinary oxalate stones. It has been postulated that the patients with CP may be at increased risk of kidney stone formation, but the data is scarce. We aimed to estimate incidence and risk factors for nephrolithiasis in a Swedish cohort of patients with CP.

Patients And Methods: We performed retrospective analysis of an electronical medical database of patients diagnosed with definite CP during 2003-2020. We excluded patients <18 years of age, those with missing relevant data in medical charts, patients with probable CP (according to the M-ANNHEIM classification system) and those in whom kidney stones were diagnosed before CP diagnosis.

Results: Some 632 patients with definite CP were followed over a median of 5.3 (IQR 2.4-6.9) years. There were 41 (6.5%) patients diagnosed with kidney stones, of whom 33 (80.5%) were symptomatic. Comparing to patients without kidney stones, patients with nephrolithiasis were older, with median age of 65 (IQR 51-72) years, and a male predominance (80% vs 63%). Cumulative incidence of kidney stones was 2.1%, 5.7%, 12.4% and 16.1% at 5, 10, 15, and 20 years after CP diagnosis, respectively. Multivariable cause-specific Cox regression analysis revealed PEI as independent risk factor for nephrolithiasis (adjusted HR 4.95, 95%CI 1.65-14.84; p = 0.004). Another risk factors were increase in BMI (aHR 1.16 95% CI 1.04-1.30; p = 0.001 per unit increment), and a male sex (4.51, 95% CI 1.01-20.3, p = 0.049).

Conclusion: PEI and increase in BMI are risk factors for kidney stone development in patients with CP. Male CP patents are particularly at increased risk of nephrolithiasis. This should be taken into consideration in general clinical approach to raise awareness among patients and medical workers.