[Significance of comorbidity in the control of the quality of treatment of dialysis patients].
The Uruguayan Dialysis Registry (UDR) is an obligatory registry and includes all the patients on dialysis treatment in the country. The dialysis prevalence rate at 12-31-1997 was 604 pmp and the mortality rate in 1997 was 132 deaths per 1,000 patient years at risk. Adjusted mortality of each dialysis center in the country (n = 35) is calculated every year. In this paper, mortality in the different centers was compared applying the usual methodology in order to identify centers with higher mortality and the importance of comorbidity m the mortality comparison among centers was analyzed. 1. The prevalent and incident population of the 1992-1996 period was considered (n 2989). The mortality rate of each dialysis center, adjusted for age and nephropathy by indirect standardization, was calculated. The prevalent and incident population (1985-1991) of the UDR was used as standard. Standardized mortality rate (SMR) for each center and for the total population was obtained dividing observed deaths by expected deaths. 2. The prevalent population at january 1, 1994 was considered (n 1131) and the observation period was extended from january 1, 1994 to december 31, 1997. Demographic and co-morbidity data were collected at the start of the observation period. Multivariate analysis of survival was applied to identify significant risk factors (Cox hazard regression model). The mortality rate of each dialysis center was adjusted for the significant risk factors. Seven centers had significant higher mortality rate adjusted for age and nephropathy than the average of the standard population. Four year survival in the 7 centers (51.6%) was lower than in the other 28 centers (63.6%) (p = 0.0001). In the multivariate analysis, 5 variables (age, diabetes, arteriosclerotic heart disease, cerebrovascular disease and peripheral vascular disease) were significantly related with mortality. The relative risk of death, adjusted for the five significant risk factors showed higher significant mortality only in four centers. Three centers did not show mortality differences with the other centers when mortality was analyzed in the multivariate analysis with the significant risk factors. We concluded that adjusting the mortality rate to the significant risk factors allow to discriminate if the differences observed among centers are related or not to an unequal distribution of the risk factors.
Mazzuchi
N
N
Instituto de Nefrología y Urología Ramón y Cajal 2550 Montevideo 11600 C.C. 16217 Uruguay. regslanh@chasque.apc.org
González
C
C
González-Martínez
F
F
Schwedt
E
E
Correa
A
A
Correa
F
F
Fernández-Cean
J
J
D006801:Humans; D007676:Kidney Failure, Chronic / Q000150:complications* / Q000401:mortality*; D011786:Quality Control; D006435:Renal Dialysis / Q000592:standards*; D015996:Survival Rate