Maternity hospitals ranking on prophylactic caesarean section rates: uncertainty associated with ranks

Objective: Ranking maternity hospitals on prophylactic caesarean section ra tes. Study design: The study population was a sample of 8470 women having d elivered in the 86 maternity hospitals of the Rhone-Alpes region (France) i n 1990. A two-level logistic model and the Gibbs sampling method were used to estimate the adjusted rate and rank of each maternity hospital with thei r 95% credible interval. Results: Ranking of maternity hospitals was substa ntially modified after adjusting for differences in case-mix. The 95% credi ble intervals of the ranks were generally wide and overlapping. No maternit y hospital could be confidently placed in the upper quarter nor in the lowe r quarter of the league table. Conclusion: The use of ranks based on rates to compare hospitals may be seriously misleading; thus, league tables need an accompanying reading guide. Furthermore, some rules should be respected, including the need to make accurate case-mix adjustments, to reduce the ra te instability in smaller hospitals, and to highlight the uncertainty assoc iated with ranks. (C) 2001 Elsevier Science Ireland Ltd. All rights reserve d.