Differences in the utilization rate of diagnostic methods after acute
myocardial infarction between hospitals with differing degree of
development in cardiology: RIGA study.

*Muñiz Javier; **Freire Evaristo; ***Pérez Martínez Fernando; "Juane Sánchez Rafael; *Castro Beiras Alfonso on behalf of Grupo RIGA.

*Hospital Juan Canalejo - Instituto Universitario de Ciencias da Saúde
Asociación de Estudios Biomédicos de Galicia, La Coruña, Spain
**Complejo Hospitalario Cristal Piñor, Ourense
***Sanatorio Modelo. La Coruña, Spain
"Sanatorio Modelo. La Coruña, Spain
Galicia, Spain.

Conclusions: There is a wide variation in the utilization rate of procedures in the management of AMI even between hospitals close geographically and, in theory, without differences in the provision of services to their patients. Availability is the key factor to the use of catheterization. In the centers without cath-lab, the less frequent use of catheterization is counterbalanced by the odd use of some other procedures, like Holter.

Introduction:

The use of diagnostic and therapeutical procedures varies widely between countries due to different criteria and organization of health services. When these differences appear among hospitals from small geographical areas within a country that, in addition to be close, share a common health system and the main organizational characteristics, the reasons for the observed variability are other than the above mentioned. Studying these differences and exploring their determinants is relevant in order to correct them, if needed, to be able to improve the quality of the helth services provided

This study has been done to assess whether the degree of development of cardiology in a hospital determines the utilization rate of diagnostic and therapeutical procedures soon after an acute myocardial infarction (AMI) in Galicia, N-W Spain.

Methods: 

This study is based in the RIGA study (Registry of Infarctions in Galicia),, already reported¹, a hospital-based registry of AMI hospitalizations in Galicia, established to specifically monitor in-hospital treatment and procedures undergone by AMI patients, as well as their short term prognosis.
Of interest to this study, 727 AMI patients admitted to hospitals in Galicia between February-July 1995 were included. Hospitals are clasified in two groups: with (group A, 3 centers) and without (B, 13 centers) cath-lab as an indirect measurement of the type of cardiology offered. Only urban centers have been included in this analysis, which led to the exclusion of 3 centers (51 patients) that participated in the RIGA study. A relation of investigators and participatong hospitals is presented in figure 1. Data on their demographic characteristics (age, sex, marital and working status), family and personal history of cardiovascular disease and risk factors, clinical characteristics of the AMIs, treatment received during the hospital stay and after being discharged, were collected.
Data analysis
Proportions and means ± standard deviation are computed and compared by means of chi-square or student t-test where necessary. Odds ratio (and their 95% confidence interval) of using the diagnostic procedure depending the type of hospital are computed, being type B hospitals the reference group.

Fig. 1: Centers and investigators

Patients in both groups did not differed in any of a number important characteristics (table 1) except, marginally, in location of the infarction. There were important differences in the utilization rate of several diagnostic and therapeutical procedures and no differences in the otucome measured (in-hospital length of stay and mortality) (table 2).

Table 2

Although the profile of patients is similar between both types of hospitals, the use of diagnostic procedures varies very much.
In Galicia, when a person suffers an AMI and is admitted to a hospital, the type of hospital he/she is admitted seems to determine his/her chances of receiving procedures and treatments that are recomended, including thrombolysis. It appears that, among attending physicians, there is the need of doing "something" to these patients and if a diagnostic catheterization cannot be offered (or it is complicated to do so) the rate of utilization of other procedures rises. This is the case for Holter monitoring.
Efforts to correct these differences have to be established because although they do not affect the length of stay and the in-hospital mortality, its nature should affect the long term mortality, in particular the smaller proportion of patients who undergo thrombolysis in type B hospitals.

Top

There is a wide variation in the utilization rate of procedures in the management of AMI even between hospitals close geographically and, in theory, without differences in the provision of services to their patients. This differences are not explained by differences in the characteristics of the patients admitted. Availabity is the key factor to the use of catheterization. In the centers withouts cath-lab, the less frequent use of catheterization is conterbalanced by the odd use of some other procedures, like Holter.

This study has been possible through an investigation contract with MSD España.
It has been presented at the European Congress of Cardiology, 1998

This company contributed to the Congress: