[Substitution indexes in ambulatory surgery: measure, count and compare]

Compare the substitution indexes of the ambulatory surgery activity done in the Vall d'Hebron Hospital with those indexes obtained from the all public hospitals of Catalonia which constitute the Public Hospital Net.

There have been calculated the substitution indexes of the 65% of DRGs which are treated with ambulatory surgery at the Vall d'Hebron Hospital and in the global of public hospital net in Catalonia. For this purpose, it has been used the MBDS of the years 1998 and 1999. The means of the substitution indexes have been compared with a Z test.

The means of the substitution indexes are of a 48.88% for the Vall d'Hebron Hospital and of a 35.14% for the whole public hospitals. The difference is statically significant (p < 0.0001). Moreover, the highest substitution indexes are the same for both groups and are the follow: 039, 229,364, 262, 062, 362 y 342.

Taking into account the present techniques of benchmarking in the health care field, this work shows that the substitution indexes are a valid tool that can be used to compare hospitals, specially in the case that it could be possible to work with robust data bases.