Risk factors associated with mortality in systemic lupus erythematosus. A case-control study in a tertiary care center in Mexico City.

OBJECTIVE: To identify the mortality risk factors in a group of Mexican patients with SLE. METHODS: A case-control autopsy study in a tertiary care center in Mexico, City. Patients with SLE who died during 1958 to 1994 with an autopsy study were selected as cases, and alive patients matched by age (+/- 3 years), decade of SLE onset, and disease duration (+/- 5 years) were defined as controls. Clinical charts were reviewed looking at clinical variables. SLE disease activity was evaluated with the MexSledai index, and SLE disease severity with the Severity Index. Variables were classified as present at any moment during the follow-up and 3 months before death in cases or cut-off date in controls. STATISTICAL ANALYSIS: matched univariate and multivariate analysis by multiple logistic regression were performed, and the results were presented as odds ratio and 95% confidence intervals (OR, 95%CI). RESULTS: 76 matched pairs of patients were studied. Age, gender, and years offormal education were similar in the cases and controls. Variables associated with mortality three months before death were: lung involvement OR= 15.6, 95%CI (4.8-50.3), p<0.001; severe thrombocytopenia 9.6 (2.9-31.7), p<0.001; heart involvement 5.8 (2.6-13.0), p<0.001; and the severity index (cases 8.8 mu, 2.4 sigma vs controls 3.5, 2.0, respectively) 2.2 (1.5-3.4), p<0.001. Variables associated with mortality detected at any moment before death were kidney involvement 2.16 (1.09-4.29), p<0.02; the steroid therapeutic index 2.3 (1.2-4.5), p<0.001; number of previous admissions 2.4 (1.4-4.3), p<0.001; the MEX-SLEDAI index (cases 21.6 mu 6.3 sigma vs controls 12.6, 5.8), 1.2 (1.1-1.3), p<0.001; and the number of severe infections 14.4 (4.4-46.2), p<0.001. Protective variables were skin involvement 0.1 (0.3-0.6), p<0.001; daily dose of chloroquine (cases 3.9 mu, 24.1 sigma vs controls 39.4, 60.0 mg), p <0.0001 and the time from thefirst SLE symptom to the patient's demise or the cut-off date 0.7(0.6-0.9), p<0.001. Multiple logistic regression showed that the model which best explained mortality consisted of a severity index 2.6 (1.7-3.8), p<0.001; heart disease 6.5 (1.5-28.2), p=0.01, and steroid therapeutic index 3.3 (1.6-6.6), p=0.001. CONCLUSIONS: An active SLE with multi-organic involvement, steroids and infections were associated with mortality in Mexican patients with lupus attended in a tertiary care center A protective effect of cutaneous disease and chloroquine use was observed.

[Ionizing radiation at low doses and cancer: epidemiological controversy]. / Radiación ionizante a dosis bajas y cáncer: controversia epidemiológica.

The carcinogenic effects of ionizing radiation at high doses are un questionable. On the other hand, the deleterious exposure effects to low doses have not been totally proven, mainly due to methodological problems and difficulty in measuring reliable dose exposure. In this paper, some recent studies examining the effects of ionizing radiation in some occupational groups are reviewed and discussed. Also, the main areas of epidemiologic controversy are stressed. For future experiences, prospective, longitudinal studies with occupational cohorts, measuring radiation exposure with adequate registry and follow-up, are suggested.

[Therapeutic effectiveness of anticoagulation in acute myocardial infarction: a case-control study]. / Efectividad terapéutica de la anticoagulación en el infarto agudo del miocardio: un estudio de casos y controles.

The main aim was to assess the role of anticoagulant therapy (AT) in reducing the mortality for patients with acute myocardial infarction (AMI). A pair-matched case-control study was designed according to three confounding factors: gender, age (+/- 5 years), and hospitalization date (+/- 13 months). Cases were defined as patients with AMI who died during hospitalization and controls were those patients with AMI who survived. Excluded from the study were patients with strong indications or contraindications for use of AT, and also those with early death (less than 12 hr). The study undertaken at the National Institute of Cardiology "Ignacio Chávez" of Mexico City and all necessary information was obtained from clinical charts of patients discharged between the period from January 1, 1975 to December 31, 1985. Complete information was accomplished for 212 pairs of cases and controls. A protective odds ratio (favoring use of AT) = 12.1 (p less than 0.0001, 95% CI 4.2-34.9) was obtained by means of a multiple logistic regression analysis by conditional method. Other variables that entered into the logistic model were: antithrombotic therapy, severity measured by Killip scale and by Norris index. Such findings support the favorable therapeutic role of AT in patients with AMI.

[Evaluation of epidemiological articles published in 2 journals in the area of public health]. / Una evaluación de los artículos epidemiológicos publicados en dos revistas del área de la salud pública.

The main aim of this study was to assess the quality and quantity of the Mexican epidemiologic production published in two journals: Salud Pública de México (SPM) and Boletín de la Oficina Sanitaria Panamericana (BOSP). A previously accepted criterion was used to qualify a paper as an epidemiologic work. The period of study was eleven years (1975-1985) with 89 classified paper as "epidemiologic reports" (36 of BOSP and 53 of SPM). The variables included: original or revision's report; epidemiologic design; measures employed (frequency, association or potential impact); condition (contagious diseases, chronic-degenerative diseases or physiologic status); use of prevalent cases, incident cases or deaths; internal and external validity; bias' recognition; and number of references. Among the results that stand out are the proportion of cross-sectional designs (51.75), the weight for communicable diseases (36%), the detection of potential bias (65.7%) and the reports without references (30%). The discussion is centered in the main implications of these results when they are used to make decisions in the planning, operation and assessment of health services and in the generation of new epidemiologic knowledge.

[Differential mortality by sex. Causes and behavior of respiratory and gastroenteric infections in Mexico]. / Mortalidad diferencial por sexo. Causas y comportamiento de las infecciones respiratorias y gastroenterales en México.

The differential in mortality by sex has not been broadly studied in Mexico. In this work mortality by sex in under one year old children and infants by federal entity for the main infectious diseases during 1980-1982 was analyzed. The results showed that the rate of mortality by sex (RMS) for under one year old children was higher than one, which means that there is a male over-mortality for that group of age. In the one to four year old children group, there were three entities that showed over-mortality among women. The analysis of the proportional mortality revealed that 40 to 50 percent of deaths in under one year old children were due to gastroenteral and respiratory infections. The probable causes of the male over-mortality observed and the need to determine the regional patterns of mortality are also discussed.

[Analysis of multiple-cause mortality: a new approach]. / El análisis de la mortalidad por causa múltiple: un nuevo enfoque.

Due to changes in mortality patterns, cronic and degenerative diseases have become a major problem in Mexico. Description and explanation of this kind of deaths is difficult by means of a single cause of death. In order to have a better understanding of this fenomenum an analysis of 4021 deaths occurred in Mexico city during april and may in 1985 using multiple cause of death was performed, this analysis take count of all causes reported in death certificates. With the method of multiple cause we found that the number of associated deaths, for example with hypertension and nutritional deficiencies, was considerably greater that when reported as underlying cause.

[Malnutrition as a multiple cause of death]. / El análisis de la desnutrición como causa múltiple de muerte.

With the purpose of describing the role of malnutrition at death time, an analysis of multiple causes of death in children under five years-old was performed on deaths which occurred during April and May 1985 in Mexico City. A proportional mortality analysis was done taking in consideration all the causes listed on the death certificate, not only the underlying causes. The number of deaths associated to malnutrition was greater by multiple cause than by underlying cause (OR = 7.9, 95% CI 5.0-12.7, p = 0.00000). The importance of considering multiple causes of death, mainly when there are frequent diseases which are some times recorded as underlying cause of death, is also discussed.