Relative Risk Of Hospital Admission Research Articles

Respiratory syncytial virus infection in high risk infants and the potential impact of prophylaxis in a United Kingdom cohort

BACKGROUNDBronchiolitis caused by respiratory syncytial virus (RSV) is an important cause of morbidity in ex-premature infants. In a randomised placebo controlled trial monoclonal antibody prophylaxis showed a 55% reduction in...

Rates and relative risk of hospital admission among women in violent intimate partner relationships.

This study assessed the history of hospitalization among women involved in violent intimate relationships. In this 1-year retrospective cohort study, female residents of King County, Washington, who were aged 18 to 44 years and who had filed for a protection order were compared with nonabused women in the same age group. Outcome measures included overall and diagnosis-specific hospital admission rates and relative risk of hospitalization associated with abuse. Women known to be exposed to a violent intimate relationship were significantly more likely to be hospitalized with any diagnosis (age-specific relative risks [RRs] ranging from 1.2 to 2.1), psychiatric diagnoses (RR = 3.6, 95% confidence interval [CI] = 2.8, 4.6), injury and poisoning diagnoses (RR = 1.8, 95% CI = 1.2, 2.8), digestive system diseases (RR = 1.9, 95% CI = 1.3, 2.9), and diagnoses of assault (RR = 4.9, 95% CI = 1.1, 22.1) or attempted suicide (RR = 3.7, 95% CI = 1.6, 9.2) in the year before filing a protection order. This study showed an increased relative risk of both overall and diagnosis-specific hospitalizations among abused women. Intimate partner violence has a significant impact on women's health and use of health care.

Myocardial infarction and acute cholecystitis: an application of sequence symmetry analysis.

Using a statewide hospital discharge database and a novel epidemiology method, sequence symmetry analysis (Epidemiology. 1996;7:478-84), I examined the relative risk for hospital admission for acute cholecystitis after admission for myocardial infarction. In sequence symmetry analysis, the ratio of the number of subjects in a fixed population who experienced two events in a "causal" vs "noncausal" temporal sequence estimates the incidence rate ratio (IRR). Of 514 patients admitted for both myocardial infarction and acute cholecystitis during a 3-year window period, 295 were admitted for myocardial infarction first and 219 for acute cholecystitis first, yielding a null sequence-adjusted IRR of 1.45 [95% confidence interval (CI) = 1.28-1.64]. A similar analysis for a known relation (myocardial infarction-->congestive heart failure, N = 27,850) showed the expected association [adjusted IRR = 1.92 (95% CI = 1.88-1.95)], whereas an analysis for a relation hypothesized not to be strong (congestive heart failure-->acute cholecystitis, N = 775) showed only a small association [adjusted IRR = 1.16 (95% CI = 1.05-1.28)]. Subgroup analysis revealed time courses that supported each relation as causal. Hospitalization for myocardial infarction may increase the risk for subsequent hospitalization for acute cholecystitis.

Monitoring Nitrogen Dioxide and its Effects on Asthmatic Patients: Two Different Strategies Compared

Objectives: To develop a `methodologyassessment' to evaluate the strengths and theweaknesses of two different epidemiological approachesand to identify the best suited monitoring strategy tomeasure the effects of `normal levels' of nitrogendioxide exposure on the health of an urban population.Methodology: all exposures to nitrogen dioxidewere determined with passive samplers, each samplerconsisting of 3 measuring Palmes tubes. In the firststudy the nitrogen dioxide exposure was assessed in 23school children (11 asthmatic and 12 non asthmatic).Children wore samplers for a week and parallelmeasurements were made in their kitchens, in bedroomsand outside their homes. The second study consisted ina case-control study where the relative risk ofhospital admission was calculated considering nitrogendioxide levels in a city of northern Italy. 110asthmatic patients were compared to a control group of 5322 people.Results: Personal sampler measurementshighlighted significant differences in exposure when nitrogen dioxide atmospheric levels were compared inasthmatic and healthy children (p<0.05). No otherparameters were significant in the two groups. Asignificant action of atmospheric nitrogen dioxide onhospital admission was demonstrated (p<0.01).Conclusions: Although a cause-effect relation assuch cannot be identified, the studies show a relationbetween the exposure to nitrogen dioxide and thepresence of adverse effects on people's health.However the `disadvantage' is for subjects withasthmatic pathologies, compared to the others. Tomanage this problem most effectively, a combinedapproach with the activation of specific personalmonitoring campaigns of the subjects with verifiedrisk seems necessary. This requires `reading' the dataresulting from most extensive and up to dateinformation systems, capable of a thorough controlboth of the living environment and of the clinicaloutcome of the whole population.

Carbon Monoxide and Hospital Admissions for Congestive Heart Failure: Evidence of an Increased Effect at Low Temperatures

The combined effects of carbon monoxide and low temperature on daily variation in hospital admissions for congestive heart failure (CHF) were examined for a 4-year period in Chicago, Illinois. Medicare hospital admissions for CHF were analyzed as a function of the maximum hourly temperature, maximum hourly levels of carbon monoxide (CO), and other criteria pollutants in Chicago for each day of the 4-year period (1986-1989). The regression analyses for the time series were conducted using single and multipollutant models with interaction terms and adjustments for weather, weekly cycles, seasonal effects, and secular trend. The data were also grouped into three temperature ranges, &lt;40 degrees, 40 degrees-75 degrees, and &gt;75 degrees F, and the relationship between CO and CHF admissions was evaluated for each range. For the 4-year time series, the CO level was positively associated with hospital admissions for CHF in the single pollutant and multipollutant models after adjustment for seasonal effects and weather pattern. The relative risks of hospital admissions for CHF in Chicago associated with the 75th percentile of exposure to CO in the high, medium, and low temperature ranges were 1.02 [95% confidence interval (CI), 0.95-1.10], 1.09 (CI, 1.04-1.14), and 1.15 (CI, 1.09-1.22), respectively. In these data, the effect of CO on hospital admissions for CHF was temperature dependent, with the magnitude of the effect increasing with decreasing temperature. This synergy may help to explain the association between ambient CO and CHF admissions demonstrated in other studies.

Aspirin, Nonsteroidal Anti-Inflammatory Drugs, and Epistaxis

To assess the relationship between nonsteroidal anti-inflammatory drugs (NSAIDs) and spontaneous epistaxis in adults over 50 years old, a case control study was carried out by using a record linkage database for the population of Tayside, Scotland, which included 319,465 people. The study group consisted of 326 patients who were hospitalized with epistaxis between May 1989 and December 1992, but who had not previously been hospitalized with this diagnosis. Six community controls and 4 hospital controls, matched for age and sex to each case, were used. Previous exposure to prescribed aspirin and other NSAIDs was investigated. There was a significant association between aspirin exposure and epistaxis when either community or hospital controls were used (p < .001). Patients who had aspirin prescriptions had a relative risk of hospital admission for epistaxis of between 2.17 and 2.75, depending on the control group used. No association between non-aspirin NSAIDs and epistaxis was evident with either control group.

Health effects of an air pollution episode in London, December 1991.

In December 1991 London experienced a unique air pollution episode during which concentrations of nitrogen dioxide rose to record levels, associated with moderate increases in black smoke. The aim of this study was to investigate whether this episode was associated with adverse health effects and whether any such effects could be attributed to air pollution. The numbers of deaths and hospital admissions occurring in Greater London during the week of the episode were compared with those predicted using data from the week before the episode and from equivalent periods from the previous four years. Relative risks (RR) (episode week versus predicted) for adverse health events were estimated using log linear modelling and these were compared with estimates from control areas which had similar cold weather but without increased air pollution. In all age groups mortality was increased for all causes (excluding accidents) (relative risk = 1.10) and cardiovascular diseases (1.14); non-significant increases were observed for all respiratory diseases (1.22), obstructive lung diseases (1.23), and respiratory infections (1.23). In the elderly (65 + years) the relative risk of hospital admission was increased for all respiratory diseases (1.19) and for obstructive lung diseases (1.43), and a non-significant increase was observed for ischaemic heart disease (1.04). In children (0-14 years) there was no increase in admissions for all respiratory diseases and only a small non-significant increase for asthma. When compared with control areas the relative risks became non-significant but remained increased. The air pollution episode was associated with an increase in mortality and morbidity which was unlikely to be explained by the prevailing weather, a coincidental respiratory epidemic, or psychological factors due to publicity. Air pollution is a plausible explanation but the relative roles of nitrogen dioxide and particulates cannot be distinguished.

Ambient air pollution and hospitalization for congestive heart failure among elderly people in seven large US cities.

Preexisting data sets were used to investigate the association between hospital admissions for congestive heart failure and air pollutants. Medicare hospital admissions data, ambient air pollution monitoring data, and meteorological data were used to create daily values of hospital admissions for congestive heart failure, maximum hourly temperature, and maximum hourly levels of carbon monoxide, nitrogen dioxide, sulfur dioxide, and ozone. Data were compiled for each of seven cities (Chicago, Detroit, Houston, Los Angeles, Milwaukee, New York, and Philadelphia) for 1986 through 1989. Single-pollutant and multipollutant models with adjustments for temperature, seasonal effects, and weekly cycles were used in conducting negative binomial regression analyses. Ambient carbon monoxide levels were positively associated with hospital admissions for congestive heart failure in the single-pollutant and multipollutant models for each of the seven cities. The relative risk of hospital admission for congestive heart failure associated with an increase of 10 ppm in carbon monoxide ranged from 1.10 in New York to 1.37 in Los Angeles. Hospital admissions for congestive heart failure exhibited a consistent association with daily variations in ambient carbon monoxide. This association was independent of season, temperature, and other major gaseous pollutants.

Oral contraceptives and thromboembolism.

Among patients of general practitioners married women aged 15-49 who were neither pregnant during the previous 12-month period nor using oral contraceptives the incidence of venous thromboembolism increased with parity: .7 per 1000 for nulliparous women (5 cases observed) 1.5 per 1000 for women of parity 1 (15 cases) 1.9 per 1000 for women of parity 2 (21 cases) 2.9 per 1000 for women of parity 3 (15 cases) 5.0 per 1000 for women of parity 4 and over (18 cases). The incidences of venous thromboembolism in pregnant or puerperal women aged 40-49 32.5 per 1000 (4 cases) and in women aged 30-39 8.8 per 1000 (11 cases) exceeded that of women aged 15-29 3.9 per 1000 (14 cases). Among oral contraceptive users the incidence rose from 2.1 per 1000 (2 cases: women aged 15-29) to 5.9 per 1000 (7 cases; ages 30-39) to 14.7 per 1000 (7 cases; ages 40-49). Among other women incidences were .6 per 1000 for ages 15-29 (5 cases) 1.1 per 1000 for ages 30-39 (15 cases) and 3.4 per 1000 for ages 40-49 (52 cases). A report showing the incidence of thromboembolism in hospital patients to vary little with age or parity estimated the relative risk of hospital admission for thromboembolism as 6.3 to 1 for oral contraceptive users. Another study estimates a bias of 2.5 to 1 in favor of a woman with thromboembolism and taking oral contraceptives being admitted to hospital compared with women who are not using oral contraceptives. Increased admission rates rather than increased severity of thromboembolic disorders in oral contraceptive users are responsible.