Ramón Gálvez-Vargas

Influence of nosocomial infection on mortality rate in an intensive care unit

Objective: To assess the impact of nosocomial infection on the mortality rate in an intensive care unit (ICU). Design: Prospective cohort study. Setting: The ICU of the University of Granada Hospital in Spain. Patients: All patients (n=279) admitted for ≥48 hrs at the ICU between December 1986 and April 1988. Measurements: Nosocomial infections were diagnosed according to Study on the Efficacy of Nosocomial Infection Control (SENIC) and Centers for Disease Control criteria. Patient severity on admission (using Acute Physiology and Chronic Health Evaluation (APACHE II) and Therapeutic Intensity Scoring Systems were also used. Results: Mortality risk was 2.48 times higher in patients with a nosocomial infection than in noninfected patients. Relative risk of mortality in nosocomially infected patients was higher in young and less severely ill patients, in those patients with respiratory diseases, and in those patients with longer ICU stays. Logistic stepwise regression analysis, adjusting for several confounding factors (affected organ system, APACHE II score, and therapeutic intensity), showed that the risk of death in nosocomially infected patients was 2.1 times greater (95% confidence interval = 1.0 to 4.41) than in patients without such infection. Conclusions: Nosocomial infection increases the risk of death. The effect is stronger in younger and less severely ill patients. (Crit Care Med 1994; 22:55‐60)

Risk factors in falls among the elderly according to extrinsic and intrinsic precipitating causes.

The aim of this prospective cohort study was to identify the risk factors involved in falls in 190 elderly residents of two geriatric centres in Granada (Andalusia, Spain). Because different types of falls may be associated with different factors, falls were classified according to the precipitating cause, either extrinsic or intrinsic. The incidence density and the ratios for crude and adjusted density were calculated. Cox proportional risk analysis was used to calculate adjusted incidence density ratios. Of the 121 falls identified, 63 (52.1%) had a extrinsic precipitating cause, 43 (35.5%) had an intrinsic precipitating cause, and no precipitating cause was determined in 15 falls. The rate of falls with an extrinsic precipitating cause was 0.39 per person per year, while falls with an intrinsic precipitating cause showed a frequency of 0.27 per person per year. For falls with an extrinsic precipitating cause, the most significant risk factors were: age, diabetes mellitus, a history of falling, and treatment with neuroleptics or oral bronchodilators. The number of illnesses acted as a protective factor. For falls with an intrinsic precipitating cause, the independent risk factors were: age, diabetes, dementia, alterations of gait and balance, previous falls, and treatment with digitalins, neuroleptics or antidepressants. These results suggest that the susceptibility to a fall with an intrinsic precipitating cause is easier to identify and has a greater potential for being controlled.

Driver dependent factors and the risk of causing a collision for two wheeled motor vehicles

Objective: To assess the effect of driver dependent factors on the risk of causing a collision for two wheeled motor vehicles (TWMVs). Design: Case control study. Setting: Spain, from 1993 to 2002. Subjects: All drivers of TWMVs involved in the 181 551 collisions between two vehicles recorded in the Spanish registry which did not involve pedestrians, and in which at least one of the vehicles was a TWMV and only one driver had committed a driving infraction. The infractor and non-infractor drivers constituted the case and control groups, respectively. Main outcome measures: Logistic regression analyses were used to obtain crude and adjusted odds ratio estimates for each of the driver related factors recorded in the registry (age, sex, nationality, psychophysical factors, and speeding infractions, among others). Results: Inappropriate speed was the variable with the greatest influence on the risk of causing a collision, followed by excessive speed and driving under the influence of alcohol. Younger and older drivers, foreign drivers, and driving without a valid license were also associated with a higher risk of causing a collision. In contrast, helmet use, female sex, and longer time in possession of a driving license were associated with a lower risk. Conclusions: Although the main driver dependent factors related to the risk of causing a collision for a TWMV were similar to those documented for four wheeled vehicles, several differences in the pattern of associations support the need to study moped and motorcycle crashes separately from crashes involving other types of vehicles.

Proportion of Hospital Deaths Associated with Adverse Events

OBJECTIVES To determine the fraction of hospital deaths potentially associated with the occurrence of adverse events (AE). DESIGN A paired (1:1) case-control study. SETTING An 800-bed, teaching tertiary care hospital. PATIENTS All patients older than 14 years admitted to the hospital between January 1, 1990, and January 1, 1991, were eligible. All 524 consecutive deaths (death rate of 3.74%) that occurred in the hospital comprised the case group. For each case, a control patient was matched for both primary diagnosis on admission and admission date. MEASUREMENTS The proportion of hospital deaths associated with adverse events (defined as problems of any nature and seriousness faced by the patient during hospitalization, and potentially traceable to clinical or administrative management) was estimated from attributable risks adjusted for age, sex, service, severity of illness, length of stay, and quality of the medical record. RESULTS For stays longer than 48 hours, the adjusted attributable risk for all adverse events was estimated to be 0.51 (0.40-0.61). When the data were stratified according to the category of adverse event, the attributable risks remained significant except for administrative problems. The greatest proportion of deaths associated with adverse events was observed for surgical adverse events [0.56 (0.38-0.71)] and nosocomial infection [0.22 (0.14-0.28)]. CONCLUSIONS A significant proportion of intrahospital deaths were associated with AE. These results suggest the need to consider programs focused on the prevention of mortality from AE.

Recall bias in a case-control study of low birth weight

The role of report/recall bias in case-control studies of low birth weight (LBW) was investigated in women who gave birth at a tertiary hospital. Prenatal exposure information reported at the postpartum interview was compared with that documented during pregnancy in obstetric records. 169 cases of LBW and 198 controls were selected. The two sets of information on case mothers and control mothers were compared, using the medical record as a reference. Kappa values were estimated. No trend was observed to increase/decrease the sensitivity and specificity of recall. Agreement on alcohol use was very low (kappa = 0.11 for case mothers and 0.03 for control mothers): on obstetrical records, only 12 mothers of cases reported habitual alcohol intake at the first prenatal care visit, whereas in the interview 69 said yes to the same question; in control mothers, the figures were 4 and 89 respectively. Odds ratios (ORs) of exposure estimated from the two sets of data did not differ importantly in 8 variables. Interview data yielded ORs for hypertension (8.39 versus 4.63), anemia (0.44 versus 0.99) that were farther from the null, and ORs in the opposite direction for alcohol (0.83 versus 1.61) and any drug (0.64 versus 1.42). In conclusion, given that OR figures are similar for most variables and no trend is observed in sensitivity/specificity, mothers of normal births can be an adequate reference group, using personal interviews to obtain information on lifestyle, and medical records for conditions.

Proportion of hospital deaths potentially attributable to nosocomial infection.

OBJECTIVE To determine the fraction of hospital deaths potentially associated with nosocomial infection (NI). DESIGN A matched (1:1) case-control study. SETTING An 800-bed, tertiary-care, teaching hospital. PATIENTS All patients older than 14 years who were admitted to the hospital between January 1, 1990, and January 1, 1991, were eligible. All 524 consecutive deaths that occurred in the hospital comprised the case group. For each case, a control patient was matched for primary admission diagnosis and admission date. OUTCOME MEASURES The proportion of hospital deaths potentially associated with NI was estimated from the population attributable risk (PAR) adjusted for age, gender, service, severity of illness, length of stay, and quality of the medical record. RESULTS For stays longer than 48 hours, the PAR for all NIs was estimated to be 21.3% (95% confidence interval [CI95], 16.8%-30.5%). The greatest proportion of deaths potentially associated with NIs was observed in patients with only one infection (PAR, 15.0%; CI95, 10.9%-22.6%) and bacteremia or sepsis (PAR, 7.7%; CI95, 4.6%-11.6%). CONCLUSIONS NIs are associated with a large proportion of intrahospital deaths. This information may help clinicians and healthcare managers to assess the impact of programs for the prevention and control of NIs on intrahospital death.

Risk compensation theory and voluntary helmet use by cyclists in Spain

Objective: To obtain empirical data that might support or refute the existence of a risk compensation mechanism in connection with voluntary helmet use by Spanish cyclists. Design: A retrospective case series. Setting: Spain, from 1990 to 1999. Subjects: All 22 814 cyclists involved in traffic crashes with victims, recorded in the Spanish Register of Traffic Crashes with Victims, for whom information regarding helmet use was available. Main outcome measures: Crude and adjusted odds ratios for the relation between committing a traffic violation and using a helmet. Results: Fifty four percent of the cyclists committed a traffic violation other than a speeding infraction. Committing a traffic violation was associated with a lower frequency of helmet use (adjusted odds ratio (aOR) 0.63, 95% confidence interval (CI) 0.58 to 0.69). Cycling at excessive or dangerous speed, a violation observed in 4.5% of the sample, was not significantly associated with helmet use either alone (aOR 0.95, 95% CI 0.56 to 1.61) or in combination with any other violation (aOR 0.97, 95% CI 0.79 to 1.20). Conclusions: The results suggest that the subgroup of cyclists with a higher risk of suffering a traffic crash are also those in which the health consequences of the crash will probably be higher. Although the findings do not support the existence of a strong risk compensation mechanism among helmeted cyclists, this possibility cannot be ruled out.

Impact of different levels of carbohydrate intolerance on neonatal outcomes classically associated with gestational diabetes mellitus

OBJECTIVE To compare the influence of different levels of carbohydrate intolerance on neonatal outcomes. STUDY DESIGN The cohort constituted by the 1962 pregnant women screened for gestational diabetes who gave birth at the University Hospital of Granada (Spain) in the year 1995 was followed retrospectively. Women were classified into three groups: diagnosis of gestational diabetes, positive screen but non-gestational diabetes, and negative screen. Frequency of adverse newborn outcomes were quantified for each group and compared for statistical significance. RESULTS Gestational diabetes was associated with a greater incidence of high birth weight, hypoglycemia and hypocalcemia. Adequate metabolic control of the illness reduced the risk of adverse outcomes. Birth weight traced a positive slope with respect to the degree of carbohydrate intolerance. Regardless of carbohydrate intolerance, macrosomia was always higher among gravidae with gestational diabetes risk factors than among women without them. CONCLUSION Both maternal gestational diabetes risk factors and greater carbohydrate intolerance in gravidae are associated with an increase in adverse newborn outcomes.

Oral contraceptives and cancer of the cervix uteri: A meta-analysis

Aim and objective: Because the findings of epidemiologic studies of the relationship between oral contraceptive use and cervical cancer have not been consistent, we reanalyzed the relationship.

Predictive value of a screen for gestational diabetes mellitus : influence of associated risk factors

Background. There is a need for solid evidence of the relative advantages of universal vs. selective screening for gestational diabetes mellitus. Our study of a broad obstetric population determines the positive predictive value of the 50‐g oral glucose challenge test for screening in the presence and absence of classical gestational diabetes risk factors.