Association of Constipation with risk of end-stage renal disease in patients with chronic kidney disease.

Background: Chronic Kidney Disease (CKD) is a growing public health problem. Many risk factors were identified and interventions were applied accordingly, but the incidence of end-stage renal disease continued increasing. Some other risk factors may be ignored. Gut microbiota has been recognized as an important endogenous organ. The kidney-gut axis would contribute to gut dysbiosis, which might worsen CKD. Constipation, commonly seen in CKD, was one of the clinical presentation of gut dysbiosis. The clinical impact of constipation to CKD remains unknown. Our study aimed at assessing the risk of ESRD between CKD patients with and without constipation in a nationwide database.
Methods: We identified newly diagnosed cases of CKD without constipation history before in 2000-2011 from the Taiwan National Health Insurance database. Subjects who developed constipation later formed constipation group. The others without constipation matched by propensity score formed non-constipation group. The incidence rates and hazards of ESRD in patients with and without constipation by the end of 2013 were compared by using Cox proportional hazard models with a time-dependent variable.
Results: The incidences of ESRD per 1000 person-years were 22.9 for constipation group and 12.2 for non-constipation group, respectively. Cox proportional hazard models with a time-dependent variable revealed an adjusted hazard ratio of 1.90 (95% CI, 1.60-2.27). Compared to the CKD patients without constipation, adjusted hazard ratio for the CKD patients with laxatives < 33, 33-197 and ≥ 198 days per year were 0.45 (0.31-0.63), 1.85 (1.47-2.31) and 4.41 (3.61-5.39) respectively.
Conclusion: In a population of newly-diagnosed CKD patients, we observed that subjects with de novo constipation, as compared with non-constipation, have increased risk of developing ESRD. More severe constipation would increase the risk further.