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Results for “multiple linear regression”

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PubMed1997

Cytomegalovirus disease is associated with increased cost and hospital length of stay among orthotopic liver transplant recipients.

Cytomegalovirus (CMV) is a cause of considerable morbidity and mortality among orthotopic liver transplant (OLT) recipients. To study the impact of CMV on cost and hospital length of stay in this population, we undertook an analysis of a cohort of OLT recipients from four transplant centers in Boston who participated in a CMV prophylaxis trial. First posttransplant year hospital length of stay (including the hospital stay after transplantation and readmissions within 1 year after transplantation) was available for all 141 patients included in the study. In a multiple linear regression model bacteremia (P=0.0001), CMV disease (P=0.0007), abdominal reexploration (excluding retransplantation) (P=0.0070), recipient age < or = 16 years (P=0.0352), and the number of units of blood products (red blood cells, platelets, or fresh frozen plasma) administered during transplantation (P=0.0523) were shown to be independently associated with longer first posttransplant year hospital length of stay. Cost data for in-hospital care for the year beginning with admission for liver transplantation were available for 66 OLT recipients. Using a multiple linear regression model, development of CMV disease (P=0.0001), the number of units of blood products administered during transplantation (P=0.0001), bacteremia (P=0.0002), decreased pretransplant renal function (estimated by creatinine clearance) (P=0.0109), and need for retransplantation (P=0.0619) were shown to be independently associated with higher cost. These data strongly suggest that CMV disease has a direct impact on cost and hospital length of stay in liver transplantation.

Adolescent↗

PubMed1995

Comparison of the effects of hydrophobicity, amphiphilicity, and alpha-helicity on the activities of antimicrobial peptides.

Multiple linear regression was used to quantify the dependence of the antimicrobial activity of 13 peptides upon three calculated or experimentally determined parameters: mean hydrophobicity, mean hydrophobic moment, and alpha-helix content. Mean hydrophobic moment is a measure of the amphiphilicity of peptides in an alpha-helical conformation. Antimicrobial activity was quantified as the reciprocal of the measured minimal inhibitory concentration (MIC) against Escherichia coli. One of the peptides was magainin 2, and the remainder were novel peptides designed for this study. The multiple linear regression results revealed that the amphiphilicity of the peptides was the most important factor governing antimicrobial activity compared to mean hydrophobicity or alpha-helix content. A better regression of the data was obtained using ln(1/MIC+constant) as the dependent variable than with either 1/MIC or ln(1/MIC). These results should be useful in designing peptides with higher antimicrobial activity.

Amino Acid Sequence↗

PubMed1998

Reproducibility and validity of the assessment of clinical furcation parameters as related to different probes.

The aim of this study was to investigate the reliability of the assessment of clinical furcation parameters (horizontal attachment levels [CAL-H], class of furcation invasion). Replicate measurements of CAL-H and furcation class were performed within 14 days in 420 molars of 105 patients with advanced periodontitis using a Nabers- (n=50), a TPS- (n=30) and a PCPUNC15-probe (n=25). Validity of clinical assessments was assessed by intrasurgical measurements. The standard deviation of single measurements (s) was calculated as a measure of the reproducibility of CAL-H measurements and weighted kappa-coefficients (Kw) to estimate the agreement of furcation class assessments. The s ranged from 0.55 to 1.13 mm (Nabers), 0.55 to 1.02 mm (TPS), and 0.58 to 1.11 mm (PCPUNC15). For all probes, a statistically significantly smaller measurement error was observed in buccal and lingual sites than in mesiolingual and distolingual furcations (P < 0.005). The Kw ranged from 0.59 to 0.89 (Nabers), 0.50 to 0.80 (TPS), and 0.53 to 0.72 (PCPUNC 15). Multiple linear regression analysis identified distolingual location, probing depth (PD) and CAL-H as factors influencing the variability of CAL-H measurements. Whereas there was no statistically significant difference between pre- and intrasurgical CAL-H measurements using the Nabers probe, the TPS and PCPUNC15 probe underestimated CAL-H for distolingual furcations (P < 0.025). Using the Nabers probe, no asymmetries between pre- and intrasurgically obtained class of furcation involvement were revealed, while the TPS and PCPUNC15 probe underestimated furcation degrees (P < 0.1). Multiple linear regression analysis identified distolingual location and height of furcation, as well as PD, vertical attachment level (CAL-V) and type of probe, as factors influencing the validity of CAL-H measurements. Clinical diagnosis of furcation lesions using the 3 mm incrementally marked Nabers probe provides reproducible and valid information about furcation invasion.

Adult↗

PubMed1994

[Epidemiology of emphysema: analysis by autopsy in a series of elderly patients].

Epidemiologic studies indicate that various factors are involved in causing emphysema, although it is uncertain exactly how these factors contribute. Thus the correlation between pathological changes and clinical manifestations was studied. Results of autopsies done on 1940 men and 1791 women from 1978 to 1992 were analyzed retrospectively. Emphysema was graded, from macroscopic findings as follows: none (E 0), slight (E 1), moderate (E 2), and severe (E 3). The severity of anthracocsis was graded as well. Information regarding clinical diagnosis, smoking habits, and available spirometric data were obtained by reviewing the medical records. Prevalence of each grade of emphysema was: in men, E 0-48.6%, E 1-31.6%, E 2-15.8%, and E 3-4.0%; in women, E 0-81.6%, E 1-13.7%, E 2-3.7%, and E 3-0.8%. Pneumonia, lung cancer, and gastric ulcer were significant complications of emphysema, and may have contributed to the cause of death. The effects of various risk factors on the severity of emphysema were evaluated by multiple linear regression analysis. Male sex, age, smoking habit, and grade of the anthracosis were independent factors affecting the development of emphysema. Among them, anthracosis grade and smoking habit were found to be strongly contributing factors. Emphysema grade and FEV1% were significantly correlated, but several patients with moderate or severe emphysema did not show airflow obstruction. Therefore, receiver operating characteristic (ROC) curves were constructed to evaluate the value of the FEV1% in the diagnosis of emphysema. The diagnostic value of the FEV1% alone was low, so a multiple linear regression equation with three factors (sex, smoking habit, and FEV1%) was constructed.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

PubMed1988

Evaluation of a proposed standard reporting system for preoperative angiograms in infrainguinal bypass procedures: angiographic correlates of measured runoff resistance.

Preoperative angiography is widely used to estimate runoff before peripheral vascular bypass surgery. The Ad Hoc Committee on Reporting Standards for the Society for Vascular Surgery and the International Society for Cardiovascular Surgery recently proposed an angiographic scoring system that grades the quality of vessels distal to the proposed bypass site and calculates an overall runoff score after adjusting each vessel score by an arbitrary weighting factor. We compared this score with intraoperatively measured runoff resistance in 67 patients undergoing infrainguinal bypass. Correlation between overall runoff score and measured resistance varied with the distal bypass site and was reasonably predictive for femoropopliteal above-knee bypasses (r = 0.67, p = 0.004, N = 17) and femoroposterior tibial bypasses (r = 0.73, p = 0.03, N = 9), but not for femoropopliteal below-knee (r = 0.05, p = 0.76, N = 34) or femoroperoneal (r = 0.57, p = 0.18, N = 7) bypasses. When multiple linear regression was used to calculate the weighting factors (rather than using arbitrarily assigned factors), the correlation between overall angiogram score and measured resistance improved substantially for femoropopliteal above-knee (r = 0.85, p = 0.00006), femoropopliteal below-knee (r = 0.50, p = 0.03) and femoroperoneal (r = 0.83, p = 0.02) bypasses. Correlation for the entire group of 67 patients improved from r = 0.30 (p = 0.02) to r = 0.64 (p = 0.0001). We conclude that the committee's scoring system correlates with measured runoff resistance but can be improved by the use of multiple linear regression to calculate weighting factors for each vessel in the outflow tract.

Anastomosis, Surgical↗

PubMed1997

Increased risk of breast cancer in splenectomized patients undergoing radiation therapy for Hodgkin's disease.

PURPOSE: Second malignancies have been reported among patients who were treated by radiation therapy or chemotherapy alone or in combination. Studies have implied an increased risk of breast cancer in women who received radiotherapy as part of their treatment for Hodgkin's disease. This review was performed to determine if there is an association between splenectomy and subsequent breast cancer. METHODS AND MATERIALS: One hundred and thirty-six female patients with histologically proven Hodgkin's disease were seen in the Division of Radiation Oncology between 1962 and 1985. All patients received mantle or mediastinal irradiation as part of their therapy. The risk of breast cancer was assessed and multiple linear regression analysis was performed on the following variables: patient age, stage, dose and extent of radiation field, time after completing radiation therapy, splenectomy, and chemotherapy. RESULTS: Breast cancer was observed in 11 of 74 splenectomized patients and in none of 62 patients not splenectomized. The mean follow-up was 13 years in splenectomized patients and 16 years, 7 months in nonsplenectomized patients. Nine patients developed invasive breast cancer and two developed ductal carcinoma in situ. Splenectomy was the only variable independently associated with an increased risk of breast cancer (p < 0.005) in multiple linear regression analysis; age, latency, and splenectomy considered together were also associated with an increased risk of breast cancer (p < 0.01). CONCLUSION: Our data show an increased risk of breast cancer in splenectomized patients who had treatment for Hodgkin's disease. A multiinstitutional survey may better define the influence of splenectomy relative to developing breast cancer in patients treated for Hodgkin's disease. The risk of breast cancer should be considered when recommending staging laparotomy, and we recommend close follow-up examination including routine mammograms for female patients successfully treated for Hodgkin's disease.

Adolescent↗

PubMed1998

Functional indices for sciatic, peroneal, and posterior tibial nerve lesions in the mouse.

The sciatic functional index previously described in rats has proven to be a reliable index of functional recovery following sciatic nerve injury and repair. A similar functional assay of sciatic, peroneal, and posterior tibial nerve lesions was developed in a mouse model. Forty-eight C57/BL6 mice were randomly divided into 4 groups: sham surgery, sciatic nerve transection, peroneal nerve transection, and posterior tibial nerve transection. Preoperative and postoperative (48 hours) walking tracks were obtained. The pawprints were analyzed in a blinded fashion for measurements of print length (PL), toe spread (TS), intermediate toe spread (IT), and the orthogonal distance from the toe of one paw to the hind pad of the opposite paw (TOF). Multiple linear regression analysis was performed using these measurements to determine their significance and appropriate weighted contribution to the index formula for each nerve lesion. For the sciatic functional index, changes in the PL (P = 0.0092) and TS (P = 0.0008) were significant, resulting in an R2 value of 0.88. For the peroneal functional index, only TS (P < 0.0001) was significant with R2 = 0.83. For the posterior tibial index, only PL (P < 0.0001) was significant with R2 = 0.89. Formulas for a sciatic, peroneal, and posterior tibial functional index were created based on the coefficients derived from the multiple linear regression analysis. The indices that were developed will allow investigators to assess functional recovery following specific nerve lesions in mice.

Animals↗

PubMed1998

Impaired ventilatory function and elevated insulin levels in nondiabetic males: the Normative Aging Study.

Lower levels of baseline ventilatory function have consistently been associated with increased risk of cardiovascular mortality in prospective studies, but the underlying mechanisms are not known. Increased risk of coronary heart disease is associated with higher serum insulin levels. This report examines the relationship between ventilatory function and indirect measures of insulin resistance. Cross-sectional data from 922 nondiabetic participants in the Normative Aging Study were analysed using multiple linear regression models with adjustment for potential confounders. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were examined in relation to indicators of insulin resistance, i.e. fasting insulin and the fasting insulin resistance index (FIRI). Diabetics were excluded because impaired insulin secretion interferes with the validity of these as measures of insulin resistance. Fasting insulin and FIRI were negatively correlated with FVC and FEV1 (all p< 0.001). These associations persisted after adjusting for potential confounders including age, height, body mass index, waist to hip circumference ratio, physical activity, alcohol intake and smoking in separate multiple linear regression models, for both insulin (all p< or =0.0008) and FIRI (all p< or =0.0001). Negative cross-sectional associations between ventilatory function and indirect measures of insulin resistance were found in nondiabetic males. Insulin resistance may contribute to the previously unexplained association between ventilatory function impairment and cardiovascular mortality. Mechanisms underlying the relationship between insulin resistance and decreased ventilatory function remain to be elucidated.

Adult↗

PubMed1997

Determinants of parental authorization for involvement of newborn infants in clinical trials.

OBJECTIVE: Parents have the right to decide on behalf of their infants whether to enroll them in controlled clinical trials. We determined the degree to which such parental decisions are influenced by risk and benefit considerations compared with other factors. DESIGN: Cross-sectional survey. PARTICIPANTS: Parents who had recently given or declined consent to one of three controlled trials in the neonatal intensive care unit. INTERVENTION: Parents were asked to complete a questionnaire that consisted of 15 sociodemographic items and 13 scaled responses to statements assessing the probability and magnitude of risk and benefit as well as perceived illness severity, attitudes toward research, and the consent process. ANALYSIS: Responses were subjected to factor analysis to identify underlying constructs. The sample was then randomly split, and multiple regression was performed on each half. RESULTS: The response rate was 83% (103 of 124) for those who had consented and 86% (37 of 43) for those who had declined. Factor analysis yielded three factors: (1) illness severity, (2) perceptions of risk or benefit and attitudes to research, and (3) sociodemographic characteristics. Multiple linear regression showed a significant multiple correlation of consent decision (r = .502), but only the second factor contributed. The analyses on split halves of the sample were comparable. Thirty-two percent of all parents agreed with the statement, "I would prefer to have the doctors advise me whether my baby should be in the study, rather than asking me to decide." CONCLUSIONS: In making consent decisions on behalf of their newborn infants, parents are influenced by risk and benefit assessments, attitudes toward research, and the integrity of the consent process. Illness severity or sociodemographic characteristics do not seem to be of similar importance. Rather than making the decision alone, a significant minority of parents would prefer to have the physicians advise them whether to volunteer their infants for a clinical trial.

Attitude to Health↗

PubMed1993

Black clouds. Work load, sleep, and resident reputation.

OBJECTIVE: Although it is assumed that residents in a specific training program will have comparable experiences, residents commonly perceive that some have consistently more difficult times on call. Such residents in our program are said to have "black clouds." We sought to determine if these perceptions were related to differences in real work load. METHODS: We collected data about the on-call experiences of our first-year pediatric residents (PL-1s) for 358 days (1355 on-call experiences) during the 1984-1985 academic year. Every PL-1 (n = 19) reported the following data the morning after each night on call: hours of sleep, number of admissions, total number of patients, number of deaths, number of transfers to the pediatric intensive care unit, number of delivery room trips, and a subjective assessment of work load, using a three-point scale. The reputation of each house officer was determined by asking all residents in the program (PL-1s, PL-2s, and PL-3s) to rate each other three times during the year regarding how hard they worked on call. RESULTS: There were significant differences among PL-1s in how difficult they perceived their work load to be and in how much they slept (P < .001 using analysis of variance). However, actual work load (as measured by the number of either admissions or patients) did not vary significantly among the residents. There was a strong negative association between self-perception of work load and hours of sleep (r = -.75; 95% confidence interval, -0.73 to -0.76). Sleep was the major predictor of perceived work load (multiple R2 = .563 using multiple linear regression analysis). The absence of an association between perceived and actual work load is attributed to large differences in the residents' working styles. This is evidenced by a wide range of correlations among PL-1s between the number of admissions and hours of sleep (range of r values, -.66 to -.16). A reputation for difficult on-call experiences was strongly associated with few hours of sleep (r = -.77; 95% confidence interval, -0.49 to -0.91), but not with actual work load measured by the number of admissions, patients, deaths, or other variables. Sleep was the major predictor of reputation (multiple R2 = .567 using multiple linear regression analysis). CONCLUSIONS: Some residents did have a black cloud; they slept less, perceived that they worked harder than average, and had a reputation for having difficult on-call experiences. Residents with a black cloud function differently from their colleagues; for example, some may be inefficient, while others may create extra work for themselves. Residency program directors must recognize these functional differences to effectively evaluate and counsel house officers.

Analysis of Variance↗

PubMed1996

Insulin-like growth factor I as a predictor of cortical bone mass in a long-term study of ovariectomized and estrogen-treated rats.

The relationship between serum insulin-like growth factor I (IGF-I) and cortical bone mass, formation and resorption and length of bone in a long-term experiment on intact, ovariectomized and estrogen-treated/substituted rats was studied by using multiple linear regression analysis. The study comprised intact rats killed at 2, 6, 9, 12, 15, and 24 months of age, rats ovariectomized 6 months old and killed at 9, 12, 15, and 24 months of age, and intact and ovariectomized rats treated with a low dose of estrogen for 8 months before they were killed at 24 months of age. Serum IGF-I, bone length and total, subperiosteal and subendocortical bone mass in mid-diaphyseal cross sections of the femur were determined. Changes in the latter two variables, respectively, represent the net result of subperiosteal bone formation and subendocortical bone resorption. Multiple linear regression analysis showed that IGF-I was a positive determinant of cortical bone mass and subperiosteal bone formation. In aged rats, IGF-I was also a positive determinant of bone length, whereas IGF-I was not found to be a determinant of subendocortical bone resorption. The analyses showed that long-term treatment of aged rats with a low dose of estrogen had a dual effect on cortical bone by inhibiting subperiosteal formation and subendocortical resorption. The results revealed a relationship between endogenous circulating IGF-I and local anabolic actions of the growth factor in bones. Thus, IGF-I may be a valuable serum marker of cortical bone formation and length of long bones when considering estrogen-depleted and estrogen-treated rats.

Animals↗

PubMed1976

Specificity of release of biogenic amines from isolated rat brain tissue as a function of the meta substituent of N-ethylamphetamine derivatives.

The actions of several meta-substituted N-ethylamphetamines on the release, uptake and catabolism of biogenic amines were investigated in vitro in two regions of rat brain. Each of the compounds released 3H-norepinephrine from chopped cerebral cortex, and 3H-dopamine and 3H-5-hydroxytryptamine from chopped corpus striatum. Stepwise multiple linear regression analyses indicated that the potencies (EC50 values) with which the compounds released 3H-norepinephrine were inversely related (r = 0.94) to the size of the meta substituent. Addition of substituent lipophilic or electronic effects to the regression equation did not greatly improve the correlation. However, the maximal release of 3H-norepinephrine produced by these compounds was directly related only to substituent lipophilic effects (r = 0.95). The potencies and maxima with which the compounds released 3H-dopamine or 3H-5-hydroxytryptamine and the potencies with which the compounds inhibited the uptake of the 3H-amines were not correlated with substituent size, lipophilicity or electronegativity. Variations in meta substituent also altered the degree to which the release 3H-amines were metabolized by monoamine oxidase. Multiple linear regression analyses indicated that for each of the 3H-amines, the maximal percent increase in 3H-deaminated metabolites produced by the drugs was directly correlated only with substituent size (r = 0.85, 0.89 and 0.95 for 3H-norepinephrine, 3H-dopamine and 3H-5-hydroxytryptamine, respectively). Comparisons among the potencies with which compounds released the various 3H-amines indicated that, in general, as substituent size increased, the compounds became relatively less potent in releasing 3H-catecholamines and relatively more potent in releasing 3H-5-hydroxytryptamine. Thus, these studies indicate that variations in the meta substituent group of N-ethylamphetamine derivatives determine the affinity of the derivatives for norepinephrine nerve endings and the relative affinities of the derivatives for norepinephrine, dopamine and 5-hydroxytryptamine nerve endings.

Amphetamines↗

PubMed1991

All cause mortality and its determinants in middle aged men in Finland, The Netherlands, and Italy in a 25 year follow up.

STUDY OBJECTIVE: The aims were (1) to compare all cause mortality in population samples of different cultures; and (2) to cross predict fatal event by risk functions involving risk factors usually measured in cardiovascular epidemiology. DESIGN: The study was a 25 year prospective cohort study. The prediction of all cause mortality was made using the multiple logistic equation as a function of 12 risk factors; the prediction of months lived after entry examination was made by the multiple linear regression using the same factors. POPULATION SAMPLES: There were five cohorts of men aged 40-59 years, from Finland (two cohorts, 1677 men), from The Netherlands (one cohort, 878 men), and from Italy (two cohorts, 1712 men). SETTING: The Finnish cohorts came from geographically defined rural areas, the Dutch cohort from a small town in central Holland, and the Italian cohorts from rural villages in northern and central Italy. MEASUREMENTS AND MAIN RESULTS: All cause mortality was highest in Finland (557 per 1000), and lower in The Netherlands (477) and in Italy (475). The solutions of the multiple logistic function showed the significant and almost universal predictive role of certain factors, with rare exceptions. These were age, blood pressure, cigarette smoking, and arm circumference (the latter with a negative relationship). Similar results were obtained when solving a multiple linear regression equation predicting the number of months lived after entry examination as a function of the same factors. The prediction of fatal events in each country, using the risk functions of the others, produced limited errors, the smallest one being -2% and the largest +11%. When solving the logistic model in the pool of all the cohorts with the addition of dummy variables for the identification of nationality, it also appeared that only a small part of the mortality differences between countries is not explained by 12 available risk factors. CONCLUSIONS: A small set of risk factors seems to explain the intercohort differences of 25 year all cause mortality in population samples of three rather different cultures.

Adult↗

PubMed1994

The use of epidemiological concepts and techniques to discern factors associated with the nitrate concentration of well water on swine farms in the USA.

This epidemiological study investigates the relationship between various factors associated with swine farms and the nitrate concentration of well water in the USA. Through a random sampling procedure, 605 swine farms located in 18 states were selected for inclusion in this study. A total of 631 well water samples were collected from these farms and tested for a variety of elements and compounds. The concentrations of nitrate, nitrite, sulfate, chloride, sodium, potassium, ammonia, fluoride, bromide and lithium were determined by an ion chromatograph while an inductively coupled argon plasma emission spectrophotometer was used to determine the concentrations of calcium, magnesium, barium, zinc, iron and phosphate. Data concerning various farm factors were gathered via a personally administered questionnaire. The data were examined using both multiple linear regression and logistic regression. Results indicate that 53.6% (338/631) of the wells contained detectable levels of nitrate, 11.7% (74/631) had nitrate levels exceeding 45 ppm and 4.3% (27/631) exceeded 100 ppm. Logistic models demonstrated an association between nitrate concentrations > 45 ppm, increasing water potassium levels and wells < 100 ft deep. Nitrate levels > 100 ppm were related to increasing water concentrations of potassium, magnesium, barium and zinc, wells 6-10 years old, increasing distance from the study farm to the nearest cattle farm and a greater distance to the nearest waterway located off the study farm. A negative association was seen between nitrate concentrations > 100 ppm, the water level of sulfate, and the use of the same well to supply both the household and livestock. Multiple linear regression models revealed a positive association between increasing nitrate concentration and the water levels of chloride, calcium, zinc and the greater number of miles from the study farm to the nearest farm with cattle or sheep. A negative association was noted between the concentration of well water nitrate and the water levels of sulfate and ammonia, the use of water treatment, the number of miles to the nearest farm with poultry, the employment of water treatment and the use of the same well to supply water to both livestock and the household.

Agriculture↗

PubMed1993

Menadione nicotinamide bisulfite is a bioactive source of vitamin K and niacin activity for chicks.

Young chicks were fed a vitamin K-deficient soybean concentrate basal diet containing graded levels of menadione from menadione nicotinamide bisulfite (MNB) or menadione dimethyl-pyrimidinol bisulfite (MPB) to assess prothrombin time as a function of menadione intake. Prothrombin time decreased linearly as menadione dose increased from 0 to 400 micrograms/kg. Multiple linear regression slope-ratio calculations indicated that both sources of menadione were of equal potency. To assess niacin bioactivity of MNB, graded doses of nicotinamide (0 to 5 mg/kg) from MNB or nicotinamide were added to a niacin-deficient diet based upon corn, corn gluten meal and vitamin-free casein. Weight gain increased linearly as a function of nicotinamide dose, and multiple linear regression analysis of weight gain as a function of supplemental nicotinamide intake revealed no significant differences in slope between the two sources of nicotinamide. Using excess doses, MNB was compared with MPB in acute (single crop intubation) or chronic (fed in the diet for 14 d) toxicity trials. With a single menadione dose of 1600 mg/kg body wt, weight gain in the subsequent 14-d period was reduced by MNB but not by MPB. Mortality rates of 25 and 17% occurred for MPB and MNB, respectively, at this dose level. Doses lower than 1600 mg/kg body wt caused neither morbidity nor mortality. When provided in the diet for a 14-d feeding period, menadione doses of 3000 mg/kg diet from MNB reduced gain, feed intake, gain:feed ratio and blood hemoglobin concentration. Menadione doses of 6000 mg/kg diet were required to produce morbidity of this type when MPB was fed.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

PubMed1999

Potential risk factors associated with thrombocytopenia in a surgical intensive care unit.

We conducted a retrospective chart review of 193 patients admitted during a 3-month period to determine the frequency of and potential risk factors associated with thrombocytopenia, and the association of acquired thrombocytopenia with length of stay in a surgical-trauma intensive care unit (SICU) and mortality. All records were reviewed beginning 24 hours after admission. Patients were followed for the duration of SICU stay or until death. Data collected and analyzed as potential risk factors for thrombocytopenia were age, gender, admitting diagnosis, classification (trauma, surgical, medical), APACHE II score, medical history, all scheduled drugs with start and stop dates, select laboratory values, arterial or central line placement, and complications. Thrombocytopenia occurred in 25 (13%) patients. These patients were more likely (p<0.05) than those without thrombocytopenia to have the following potential risk factors: presence of a central or arterial line (76% vs 46%, p<0.025), nonsurgical diagnosis (60% vs 37%, p<0.05), diagnosis of sepsis (p<0.001), and administration of phenytoin (p<0.01), piperacillin (p<0.005), imipenem-cilastatin (p<0.001), and vancomycin (p<0.005). A longer SICU stay (mean 21 vs 4.5 days, p<0.05) and increased mortality (16% vs 4%, p<0.05) were significantly associated with thrombocytopenia. Cefazolin administration was significantly associated with nonthrombocytopenia (p<0.05). Factors not associated with thrombocytopenia were age, gender, and administration of histamine2-receptor antagonists, heparin, enoxaparin, penicillins, ceftazidime, ceftriaxone, chloramphenicol, and amphotericin B. A central or arterial line was the only factor associated with the development of thrombocytopenia in a multiple linear regression analysis (p=0.0003, multiple r=0.2580). Thrombocytopenia is not a common occurrence in the SICU, but is associated with a longer SICU stay and increased mortality.

Adolescent↗

PubMed1991

Predictors and prevalence of obstructive sleep apnoea and snoring in 1001 middle aged men.

One thousand and one men, aged 35-65 years, were identified from the age-sex register of one group general practice. Over four years 900 men were visited at home and asked questions about symptoms potentially related to sleep apnoea and snoring. Height, weight, neck circumference, resting arterial oxygen saturation (SaO2), and spirometric values were also determined. All night oximetry was then performed at home and the tracing analysed for the number of dips in SaO2 of more than 4%. Subjects with more than five dips of 4% SaO2 or more per hour were invited for sleep laboratory polysomnography. Seventeen per cent of the men admitted to snoring "often." Multiple linear regression techniques identified and ranked neck circumference (r2 = 7.2%), cigarette consumption (r2 = 3.4%), and nasal stuffiness (r2 = 2%) as the only significant independent predictors of snoring. Together these account for at least a sixfold variation in the likelihood of being an "often" snorer. Forty six subjects (5%) had greater than 4% SaO2 dip rates of over five an hour and 31 of these had full sleep studies. Three subjects had clinically obvious and severe symptomatic obstructive sleep apnoea, giving a prevalence of three per 1001 men (0.3%; 95% confidence interval 0.07-0.9%). Eighteen men had obstructive sleep apnoea only when supine and in 10 the cause of the SaO2 dipping on the original home tracing was not elucidated. The greater than 4% SaO2 dip rates correlated with the history of snoring. Multiple linear regression techniques identified and ranked neck circumference (r2 = 7.9%), alcohol consumption (r2 = 3.7%), age (r2 = 1%) and obesity (r2 = 1%) as the only significant independent predictors of the rate of overnight hypoxic dipping. This study shows that snoring in this randomly selected population correlates best with neck size, smoking, and nasal stuffiness. Obstructive sleep apnoea, defined by nocturnal hypoxaemia, correlates best with neck size and alcohol, and less so with age and general obesity.

Adult↗

PubMed1996

Interleukin-2 receptor levels in sera of patients with rheumatoid arthritis treated with sulfasalazine, parenteral gold, or placebo.

OBJECTIVE: To evaluate the associations of soluble serum interleukin-2 receptor (sIL-2R) levels in patients with rheumatoid arthritis (RA) with clinical and laboratory measures of disease activity and the predicted response to therapy. METHODS: sIL-2R levels were determined by ELISA in 137 patients with RA, not previously treated with 2nd line therapy. Patients were enrolled in a prospective, randomized, placebo controlled trial of sulfasalazine (SSZ) versus gold sodium thiomalate (GSTM), sponsored by the Cooperative Systematic Studies of Rheumatic Diseases. Using correlation analysis and regression modeling, the clinical utility of sIL-2R as a measure of disease activity and predictor of outcome was assessed. RESULTS: 91 women and 46 men with a mean age of 51 +/- 13 years and mean duration of disease of 64 +/- 78 months participated in this study. The mean sIL-2R level in all patients with RA was markedly elevated (980 +/- 589 U/ml) compared with that in healthy control subjects (446 +/- 196 U/ml; p = < 0.0001). There was no correlation between the sIL-2R levels and the joint pain/tenderness count, either at study entry or completion. There were significant positive correlations between the baseline sIL-2R and baseline erythrocyte sedimentation rate (ESR) and between the change in sIL-2R and the change in ESR. Both a multiple linear regression model and a multiple logistic regression model showed that baseline sIL-2R levels were not predictive of clinical outcome. CONCLUSION: sIL-2R levels are significantly elevated in patients with active RA and correlate positively with ESR. However, these results indicate that in patients with early RA, sIL-2R levels are neither associated with standard disease activity criteria nor predictive of the response to therapy with SSZ or GSTM, even after controlling for the simultaneous effects of other important clinical variables.

Adult↗