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Biomedical subjects

D W Bentley

Publications and source records attributed to D W Bentley.

At least 19 recordsLinked to original sources
PubMed1998

The risk of hospitalization for ischemic stroke among older adults.

OBJECTIVES: The purpose of this study was to identify risk factors for stroke and to estimate their relative importance in a large, nationally representative sample of very old men and women. METHODS: The study was designed as a secondary analysis of the Longitudinal Study on Aging. Baseline (1984) in-person interview data were linked to Medicare hospitalization records for 1984 to 1991. Participants were 6,071 noninstitutionalized adults 70 years old or older at baseline. Hospitalization for ischemic stroke was defined as having one or more episodes with a primary discharge diagnosis containing ICD-9-CM codes of 433.0-434.9, 436, and 437.0-437.1. Multivariable proportional hazards regression was used to estimate the risks associated with previously identified epidemiologic factors. RESULTS: Five hundred and three persons (8.3%) had at least one primary discharge diagnosis of ischemic stroke. In descending order of importance-based on the partial r statistics associated with their adjusted hazards ratios (AHRs), the salient risk factors were having a previous history of stroke (AHR = 2.86), age (AHR = 1.04 per year), diabetes (AHR = 1.78), male gender (AHR = 1.42), lower body limitations (AHR = 1.09 per limitation), arthritis (AHR = 0.74), hypertension (AHR = 1.29), and poverty (AHR = 1.33). CONCLUSION: Patients presenting with the high risk factors identified in this study should be considered for further evaluation and monitoring. Current protocols for the therapeutic management of these higher risk patients should be considered, and compliance should be encouraged.

Aged↗
PubMed1998

The sequelae of hospitalization for ischemic stroke among older adults.

OBJECTIVES: To estimate the independent effect of hospitalization for ischemic stroke on change in functional status, subsequent hospitalization, and mortality. DESIGN: Secondary analysis of the nationally representative Longitudinal Study on Aging. Baseline (1984) interview data were linked to Medicare hospitalization and death records for 1984-1991 and to functional status reports at three biennial follow-ups. SETTING: In-person and telephone interviews were conducted. PARTICIPANTS: A total of 6071 noninstitutionalized respondents 70 years old or older at baseline. MEASUREMENTS: Hospitalization for ischemic stroke was defined as having one or more episodes with primary discharge ICD9-CM codes of 433.0-434.9, 436, and 437.0-437.1. Two reference groups were used: those who were hospitalized for something other than stroke, and those who were not hospitalized at all. The statistical methods employed were multivariable proportional hazards, logistic, and linear regression. RESULTS: The adjusted hazards ratio for having a primary hospital discharge diagnosis of ischemic stroke on mortality was 7.57 (CI95% = 6.47 to 8.85) versus 3.67 (CI95% = 3.28 to 4.10) for having been hospitalized for something other than stroke (both compared with the reference category of those not hospitalized at all). The adjusted odds ratio for having any subsequent hospitalization associated with having a primary hospital discharge diagnosis of ischemic stroke (compared with having been hospitalized for something other than stroke) was not significantly elevated (AOR = 1.16; CI95% = .94 to 1.42). However, the percent increases in the subsequent number of hospital episodes, total charges, and total length of stay for those who were hospitalized for ischemic stroke relative to those hospitalized for something other than stroke were significant (P < .001), and ranged from 16.3 to 39.0%. Hospitalization for ischemic stroke was also related significantly to greater increases in the regression-adjusted mean number of instrumental activities of daily living and lower body function limitations at follow-up. CONCLUSION: Hospitalization for ischemic stroke among older adults substantially increases the risk of subsequent mortality, the volume of hospital resource consumption, and greater functional decline, even when compared with hospitalization for something other than stroke. Therefore, greater attention to the prevention and management of ischemic stroke is needed.

Activities of Daily Living↗
PubMed1997

Humoral and cellular immune responses following vaccination with purified recombinant hemagglutinin from influenza A (H3N2) virus.

Adults were immunized with either baculovirus-expressed, purified recombinant hemagglutinin (rHA) from influenza A/Beijing/32/92 (H3N2) virus or saline placebo and evaluated for humoral and in vitro cellular immune responses. Compared with responses in placebo recipients, vaccinees had greater postvaccination H3(Beijing/32) HA (H3)-specific lymphoproliferation and interleukin (IL)-2, IL-10, and interferon-gamma (IFN-gamma) production. Mean increases in the production of IL-10 (> or = 20-fold) and IL-2 (10-fold) were relatively greater than that of IFN-gamma (4-fold) or IL-4 (no change). Serum H3 antibodies were induced in 80% of rHA recipients, and the rise in antibody titer was significantly correlated with changes in IL-2, IL-10, and IFN-gamma concentrations. Vaccination with rHA only minimally enhanced anti-influenza virus cytotoxic T lymphocyte activity. These data demonstrate that rHA immunization of adults elicits a significant recall response by memory B and T lymphocytes and suggest that the cytokine response to vaccination has a T helper cell type 0-like profile.

Adolescent↗
PubMed1994

Rational approach to the antibiotic treatment of pneumonia in the elderly.

The incidence of pneumonia is highest among the aged compared with other adult populations, and causes significant morbidity and mortality among this group. Most episodes of pneumonia are caused by aspiration of oropharyngeal flora into the lungs and failure of lung defence mechanisms to eliminate the aspirated bacteria. Studies in elderly patients have shown a high rate of oropharyngeal carriage of Gram-negative bacilli and polymicrobial/mixed flora pneumonias, especially in debilitated elderly patients in nursing homes or hospitals. This information is helpful to practitioners in prescribing empirical antibiotic therapy for elderly patients with pneumonia. Because of the many additional concerns which must be considered in the rational selection of an antibiotic regimen, e.g. route of administration, compliance, drug pharmacokinetics and pharmacodynamics, drug toxicity, and drug-disease interactions, it is also helpful for practitioners to become familiar with a small number of the large group of available antibiotics. Based on these considerations and the presumed bacteriology of pneumonia in the elderly in the 3 clinical settings (community, nursing home and hospital), a limited number of antibiotics are recommended for empirical antibiotic regimens for elderly patients with pneumonia. In particular, beta-lactamase inhibitors and cotrimoxazole (trimethoprim-sulfamethoxazole) are recommended, with ciprofloxacin as an alternative agent. There is a limited role for third-generation cephalosporins and extended-spectrum penicillins. Aminoglycosides are only recommended for patients with pneumonia in the intensive care unit on mechanical ventilation. Monotherapy (single agent) should be used whenever possible.

Aged↗
PubMed1993

Disposition of intramuscular cefonicid in elderly patients.

OBJECTIVE: To examine the disposition of intramuscular (IM) cefonicid in elderly patients with bacterial pneumonia. DESIGN: Pharmacokinetic study. SETTING: A 620-bed university-affiliated long-term care institution with its own 39-bed acute care unit. PATIENTS: Nine consecutive elderly patients with bacterial pneumonia treated with IM cefonicid. MEASUREMENTS: Blood samples were collected on the seventh day of therapy over a 24-hour period and analyzed by high performance liquid chromatography. Pharmacokinetics parameters (volume of distribution, half-life, and clearance) and protein binding were calculated. Clinical outcome of IM cefonicid therapy was also noted. RESULTS: The estimated creatinine clearance (CIcr) ranged from 32 to 145 mL/min. Peak cefonicid serum concentrations occurred at 0.5-1.5 hours, with a mean value of 118 +/- 41 micrograms/mL. Cefonicid concentrations declined monoexponentially to 57 +/- 16 micrograms/mL at 12 hours and 28 +/- 14 micrograms/mL at 24 hours. The mean apparent distribution volume was 0.2 +/- 0.07 L/kg, and the mean apparent total clearance was 15 +/- 12 mL/min. The half-life ranged from 3.1 to 38 hours. A linear correlation was noted between Clcr and cefonicid clearance (r = 0.99). CONCLUSIONS: Cefonicid absorption was variable among these patients, and the serum half-life was longer than previous values noted in younger patients with similar degree of renal dysfunction. Pharmacokinetic and clinical outcome data from our study group indicate the potential role of IM cefonicid in treating elderly patients with bacterial pneumonia.

Absorption↗
PubMed1992

Streptococcus pyogenes outbreak in a long-term care facility.

BACKGROUND: Although outbreaks involving Streptococcus pyogenes have been uncommon among the elderly population, recent reports suggest that this organism is an important nosocomial pathogen among institutionalized older patients and carries significant morbidity and mortality. An outbreak of S. pyogenes, type M12, T12, occurred in a large long-term care institution serving the ill and chronically disabled. The outbreak involved 14 residents of the intermediate care facility and lasted for 4 months. METHODS: A prospective epidemiologic investigation was initiated at the onset of the outbreak. Pertinent clinical and demographic information regarding both residents and personnel was obtained by interview, review of medical and surveillance records, and examination of patients for lesions. Cultures were obtained within 24 hours of symptom onset from those with characteristic clinical symptoms. Unpaired convalescent sera were tested for group A streptococcal extracellular antigens by a rapid hemagglutination slide test. Control measures included active surveillance of residents and staff for suspicious clinical syndromes, transfer of high-risk patients, elimination of a common seating area, and improved handwashing and hygiene measures. RESULTS: The attack rate was 7.5%, with 64.3% of these patients residing on one unit. S. pyogenes was isolated from eight residents, 5 residents had a characteristic syndrome and an elevated streptozyme hemagglutination titer of 400, and 1 resident died within hours of having cellulitis of the groin. Clinical syndromes included cellulitis, pharyngitis, bronchitis, pneumonia, and septicemia. Seven residents required acute care; two residents died within 3 weeks of the onset, yielding a case fatality rate of 14.3%. CONCLUSIONS: The major means of transmission appeared to be direct contact between residents, although transmission from an infected staff member may have accounted for some cases. The hypothesis of long-term colonization was supported by the extended times between infections. The severity of illness and the apparent transmission through direct contact between residents warrants (1) early detection of infected lesions, (2) recognition of invasive illness, (3) prompt effective treatment, and (4) surveillance for S. pyogenes infections among residents and personnel.

Aged↗
PubMed1992

Methicillin-resistant Staphylococcus aureus: a questionnaire survey of 75 long-term care facilities in western New York.

OBJECTIVES: To determine the frequency of recognition of methicillin-resistant Staphylococcus aureus (MRSA) as an infection control problem and its prevalence among long-term care facilities, and to evaluate whether certain long-term care facility characteristics such as bed size, ownership, level of infection control activity, and frequency of resident transfers to acute care hospitals are related to the recognition or prevalence of MRSA in this setting. DESIGN: Questionnaire survey. SETTING: Seventy-five long-term care facilities in the 8 counties of western New York. RESULTS: Seventy-five of 81 (92.6%) long-term care facilities returned a completed questionnaire. Seventy-nine percent were considered to have a "limited" level of infection control activity (part-time infection control practitioner who spent less than 10 hours a week on infection control activities). The larger the long-term care facility, the more time was spent on infection control activities (p = .01). Seventy-two percent of the long-term care facilities screened new admissions for MRSA by reviewing culture reports; 69% of the long-term care facilities had a specific infection control policy for MRSA. Sixteen of the 75 (21%) facilities felt they had an infection control problem with MRSA. By univariate analysis, the only characteristic significantly associated with this recognition was use of nurse practitioners or physician assistants by a facility (p < .05). Eighty-one percent of the 75 long-term care facilities had identified one or more patients with MRSA in the year prior to the survey. By univariate analysis, the only characteristics that were significantly associated with the number of residents with MRSA were the monthly average number of residents transferred to acute care facilities (p = .034) and facility bed size (p = .022); there was also a trend toward increasing intensity of infection control activities (p = .085). However, facility bed size and the average number of resident transfers per month to acute care facilities were strongly associated (p = .0002). By stepwise logistic regression analysis, only bed size was an independent predictor of the number of residents with MRSA. Many long-term care facilities had tried to eradicate MRSA; ciprofloxacin was most commonly used to eradicate MRSA. CONCLUSIONS: The vast majority of the 75 long-term care facilities in the 8 counties of western New York have identified patients with MRSA, although only a minority (21%) of them actually believed that an infection control problem existed. Facility size (a surrogate for the monthly average number of resident transfers to acute care facilities) seems to be an important factor in determining the number of residents with MRSA in long-term care facilities in our geographic region. The major longitudinal studies of MRSA in such facilities have so far been done only in Veterans Affairs facilities. Further studies are needed in freestanding long-term care facilities, the largest group of long-term care facilities in the United States, to determine the epidemiology of MRSA in this setting and to develop practical and valid infection control methods for residents with MRSA.

Health Facility Size↗
PubMed1992

Vaccinations.

Tetanus-diphtheria toxoid, influenza virus vaccines, and pneumococcal vaccine are recommended for older persons in the United States by the Centers for Disease Control. But most high-risk older persons remain unvaccinated, despite experiencing relatively high rates of tetanus, influenza-related complications, and pneumococcal disease, and having available effective, safe, and low-cost vaccines. Strategies for improving these vaccination rates require an intensive approach focused on (1) identifying older persons with high-risk conditions, (2) improving the delivery of vaccines, (3) improving the acceptance of vaccines by older persons, and (4) establishing mandatory immunization programs.

Aged↗
PubMed1990

Risk factors for nosocomial pneumonia in the elderly.

PURPOSE: Pneumonia is now the second most frequent hospital-acquired infection in acute-care facilities, and recent studies indicate that the incidence rate for nosocomial pneumonia in long-term-care facilities is of similar magnitude. The mortality rate is high, especially in the elderly. With prevention of this complication as an overall priority, this study was designed to determine the risk factors associated with nosocomial pneumonia in the elderly in both acute-care and long-term-care settings. PATIENTS AND METHODS: An epidemiologic case-control study was undertaken to compare patients or residents who developed radiographically confirmed pneumonia with control subjects who did not have and did not develop respiratory infection. Thirty-three cases were identified in the acute-care setting during the 18-week period, and 27 cases were identified in the long-term-care setting. Two matched controls were chosen for each case. Data collection involved review of the medical record and verification by medical personnel while the cases or controls were still institutionalized. Risk factor variables were analyzed using an odds ratio and 95% confidence interval calculation for matched triplets, and chi-square analysis. Selected risk factors were entered into a backward stepwise logistic regression to determine the best combination of risk factors for each setting. RESULTS: In the acute-care setting, current neurologic disease, current renal disease, deteriorating health, altered level of consciousness, disorientation, dependent bathing, dependent bowel function, dependent feeding, aspiration, difficulty with oropharyngeal secretions, and presence of a nasogastric tube were significant risk factors. In the long-term-care setting, deteriorating health, malnourishment, recent weight change, altered level of consciousness, disorientation, aspiration, difficulty with oropharyngeal secretions, suctioning, presence of a nasogastric or gastric tube, upper respiratory infection, inhalation therapy, increased confusion, and increased agitation were determined to be significant. Current pulmonary disease, previous infection, and antibiotic therapy were found not to be associated with the onset of nosocomial pneumonia. Through logistic regression, the best models for prediction of nosocomial pneumonia in the elderly were identified. In the acute-care setting, difficulty with oropharyngeal secretions and presence of a nasogastric tube were the best predictors. In the long-term-care setting, difficulty with oropharyngeal secretions, deteriorating health, and occurrence of an unusual event were the best combination of predictors. CONCLUSION: These data confirm prior findi

Aged↗
PubMed1990

Seizure with ciprofloxacin and theophylline combined therapy.

Ciprofloxacin has been reported to cause theophylline toxicity by inhibiting theophylline metabolism. A 93-year-old woman without a known seizure history, while on ciprofloxacin and theophylline combined therapy, experienced a grand mal seizure. Her serum theophylline concentration at the time was 20 micrograms/mL. On previous occasion of theophylline toxicity, she had a serum theophylline concentration of 27 micrograms/ml but the patient did not experience any seizure. Several reports suggest that the combination of theophylline and ciprofloxacin has an additive inhibitory effect on gamma-aminobutyric acid (GABA) sites. Inhibition of the binding of GABA to its receptor sites has been related to the convulsant effects of other drugs. The seizure in our patient may have been caused by altered pharmacokinetics and pharmacodynamics brought about by combined therapy of theophylline and ciprofloxacin.

Aged↗
PubMed1990

Infection control in the nursing home: the physician's role.

Infection control in the nursing home or long-term care facility is an increasingly complex activity. The high rates (approximately 15%) and special risks (group activities, crowding) for nosocomial infection demand special attention by attending physicians. Some specific responsibilities include: recognition of infection; knowledge and use of basic infection control principles; appropriate antibiotic use; review of immunizations; facilitation of communications among office, hospital, and long-term care facility; and involvement with infection control program(s).

Allied Health Personnel↗
PubMed1987

Immune response of elderly adults to pneumococcus: variation by age, sex, and functional impairment.

The immune response of 271 elderly persons to the new 23-valent pneumococcal vaccine was studied prospectively. Sera were obtained prevaccination, at 1 month post- and 12 months postvaccination. They were analyzed by radioimmunoassay for the presence of antibody Types 1, 3, 6A, 7F, 8, and 9N. The results showed differences in antibody levels by sex of the individual (p less than .01 pre and p = .04 at 1 month post), with women having lower antibody levels than men. Women responded better to vaccination than men (p = .05), but they also lost their acquired antibodies faster (p less than .01). No age effect and no effect of level of functioning were observed within this group of elderly individuals. Participants who died had high initial levels and responded well. Major differences between the six types were noticed. Type 6A exhibited the described pattern most clearly, whereas Type 3 often behaved in an opposite pattern from the other five types. We conclude that sex differences persist even among elderly adults, that high levels of antibodies are not necessarily an indicator of good health, and that much unexplained variation between antibody types exist.

Aged↗