The relationship between provider volume and mortality rate: volume data of German centres of excellence

The purpose of this study was to determine the percentage of centres of exc ellence (COEs) in Germany that achieved, for selected diagnoses and interve ntions, annual hospital or surgeon threshold volumes associated with a lowe r mortality rate. A systematic review and evaluation of the literature identified the most re levant study for each diagnosis and intervention selected. Each diagnosis a nd intervention was only considered if the most relevant source yielded a t hreshold volume associated with a reduced mortality rate. COEs received que stionnaires on the annual volume of such diagnoses and interventions for ea ch department, providing physician (median), and senior consultant in 1999. For most of the diagnoses and interventions considered, the percentage of C OEs meeting their respective threshold volumes exceeded 50%. Exceptions wer e carotid endarterectomy (performed in departments of general cardiac surge ry) and liver transplantation. The percentage of providing physicians and s enior consultants performing to the desired standard remained above 75% for most of the diagnoses and interventions. Exceptions were surgeons dealing with carotid endarterectomy, correcting congenital heart disease (both perf ormed in departments of general cardiac surgery), and correcting primary hy perparathyroidism. That a smaller percentage of centres for general cardiac surgery, liver tra nsplantation, and primary hyperparathyroidism operates at their threshold v olumes may be due to a relative oversupply of centres specialising in these treatments as well as a the lack of regional centres with a high referral rate. Due to the country-specificity of studies performed on the relationsh ip between volume and mortality rate, it is highly recommended that Germany -specific volume-outcome studies be performed particularly in specialties w ith relatively low case volumes.