On the comparison of survival curves of two groups of chronic kidney disease patients based on progressively censored data

Abstract

Introduction: Chronic kidney disease (CKD) is the progressive loss of kidney function. Prevalence of every stage of CKD is rising over the period with increasing number of diabetic, hypertensive and elderly population. It is becoming a problem of epidemic proportions in India. Objectives: Comparison of the survival function of CKD patients with different disease stages criticality grouped on the basis of gender, diabetes and hypertension. Patients and Methods: The retrospective data of 117 patients suffering from CKD during the period March 2006 to October 2016 is used. In the present study, log-rank, Gehan-Wilcoxon, Tarone-Ware, Peto-Peto, modified Peto-Peto and tests belonging to Fleming-Harrington test family with different (p, q) values are applied to test the statistical significance of the difference between two survival functions under different conditions. The parametric test has also been applied to compare the survival time distribution of two groups. Results: Kaplan-Meier method and survival comparison tests suggest no difference between survival experiences of the two groups namely female and male on the basis of grouping variable gender. However, in simulation study as we increase the sample size it is observed that it affects more women than men especially in stage 3 of CKD patients. The survival functions of two groups of CKD patients based on diabetes and hypertension differ significantly. Conclusion: The survival experiences of two groups of CKD patients based on the grouping variables diabetes and hypertension differ significantly on the basis of real data and simulation study. The grouping variable gender as a significant factor becomes evident only when large samples are generated under simulation study