Medical Sociology of Dialysis Unit Queue Prioritization and Transplant List Attrition Among End-Stage Renal Patients in Nigerian Teaching Hospitals: A Discrete-Time Survival Analysis of Bed-Scarcity Exposure

Dialysis units in Nigerian teaching hospitals ration scarce chairs through informal queue prioritisation, and the transplant-list consequences of that rationing are difficult to estimate because randomisation is infeasible and secular trends confound simple before–after comparisons. No observational data are used or claimed; the analysis characterises the operating characteristics of the design under a declared variance structure with between-cluster standard deviation 6.0, residual standard deviation 4.5 and intraclass correlation 0.64. Power was estimated across 2000 replications per design cell for cluster counts of 8, 16, 24 and 32 and effects of 3, 5 and 8 percentage points. The design required 54 clusters to detect a 5-percentage-point effect at 80% power. The results indicate that the intraclass correlation of 0.64 dominates the power profile, that minimum detectable effects fall steeply as clusters increase from 8 to 32, and that the BACI interaction is estimable but fragile at the cluster counts typical of single-state hospital samples. Medical sociology studies of dialysis rationing should treat cluster count, not patient count, as the binding design constraint, and it specifies the conditions under which BACI estimation can support credible claims about queue exposure and transplant attrition.