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PubMed1982

Intrauterine weight retardation and the concomitant length retardation: a statistical analysis of anthropometric data.

In 237 low birth weight for gestational age term infants (birth weight less than or equal to 10th percentile; gestational age less than or equal to 37 wk) percentage deviations of birth weight and crown-heel length for gestational age were correlated (a) in a series of linear regressions of three subsequent groups formed according to the magnitude of weight retardation (b) in the pooled material by non-liner regression. Linear regressions yielded equivocal results as to the existence of concomitant length retardation (no correlation in group 1, significant correlation in group 2 and 3). The significant non-linear correlation (i = 0.66 ; p less than 0.001) and the exponential type regression curve (Y) % length deficit = 2.45 1.04 X' % weight deficit) gave an explanation of the controversial findings. If mild to moderate weight retardation is included in studies comparing weight and length, a greater variability and, possibly, a conclusion of non-existence of concomitant retardation will result while, if severe or extreme weight retardation are screened out using stricter criteria, (e.g. 5th, 3rd percentiles, -2 SD) one would find more infants with significant length retardation, and the conclusions would be the opposite, i.e. an obligatory length retardation following malnutrition. In anthropometric-statistical studies the results should never be generalized and extrapolated below, or beyond the cut-off points chosen.

Birth Weight↗
PubMed2002

Liposomal doxorubicin in conjunction with reirradiation and local hyperthermia treatment in recurrent breast cancer: a phase I/II trial.

PURPOSE: This is the first study to evaluate the tolerability and activity of liposomal doxorubicin (Caelyx; Schering-Plough Pharmaceuticals) < or =60 mg/km(2) in patients with locally recurrent breast cancer, when administered in conjunction with reirradiation and local hyperthermia treatment. EXPERIMENTAL DESIGN: Fifteen female patients, who had undergone a radical mastectomy and conventional radiotherapy (60 Gy) in the front chest wall, were entered on a multimodal protocol consisting of initial treatment with radiotherapy and a monthly infusion of liposomal doxorubicin < or =60 mg/m(2) in conjunction with local hyperthermia treatment. All patients received reirradiation up to a total dose of 30.6 Gy (1.8 Gy/fraction, 5 days a week). To evaluate the drug's safety, the first 5 patients initially received a dose of 40 mg/m(2) liposomal doxorubicin, which was then escalated to 60 mg/m(2). The other 10 patients received 60 mg/m(2) for all six cycles of chemotherapy. Hyperthermia (HT) was produced in the region of interest (ROI) using waveguides at a frequency of 433 MHz. The RSS was obtained from the curves representing the change in the ROI's surface with time for each patient, as fitted by linear regression. Linear regression analysis was used to study the relationship between the time interval from liposomal doxorubicin infusion to HT and the RSS. RESULTS: At doses of < or =60 mg/m(2), liposomal doxorubicin was well tolerated, with only mild hematological and nonhematological toxicity. All patients showed an objective measurable response, with 3 patients (20%) demonstrating a clinically complete response. There was a significant correlation between the duration of response and Avg Min T(90) > 44 degrees C (r(s) = 0.917, P < 0.0001) and the Mean[Tmin] (r(s) = 0.909, P < 0.0001). The RSS was significantly correlated with the interval between liposomal doxorubicin infusion and HT, as the smaller the time interval, the greater the clinical benefit (r = 0.76, P = 0.001). CONCLUSIONS: The multimodal treatment was effective and well tolerated, producing an objective measurable response in all patients. Local HT had a significant effect on patients' response to the drug. The relationship between thermal dose and liposomal action requires further investigation.

Antineoplastic Agents↗
PubMed1999

Variations in 'avoidable' mortality: a reflection of variations in incidence?

BACKGROUND: Variations in 'avoidable' mortality may reflect variations in the quality of care, but they may also be due to variations in incidence or severity of diseases. We studied the association between regional variations in 'avoidable' mortality and variations in disease incidence. For a selection of conditions we also analysed whether the proportion of in-hospital deaths can explain the regional variations in incidence-adjusted mortality. METHODS: Relative risks for mortality, incidence, incidence-adjusted mortality and in-hospital mortality (1984-1994) were calculated by log-linear regression. Linear regression was used to examine the relationship between mortality and incidence on the one hand, and between incidence-adjusted mortality and in-hospital mortality on the other. RESULTS: Significant regional mortality variations were found for cervical cancer, cancer of the testis, hypertensive and cerebrovascular disease, influenza/pneumonia, cholecystitis/lithiasis, perinatal causes and congenital cardiovascular anomalies. Regional mortality differences in general were only partly accounted for by incidence variations. The only exception was cervical cancer, which no longer showed significant variations after adjustment for incidence. The contribution of inhospital mortality variations to total cause-specific mortality variations varied between conditions: the highest percentage of explained variance was found for mortality from CVA (60.1%) and appendicitis (29.2%). CONCLUSIONS: Incidence data are a worthy addition to studies on 'avoidable' mortality. It is to be expected that the incidence-adjusted mortality rates are more sensitive for quality-of-care variations than the 'crude' mortality variations. Nevertheless, further research at the individual level is needed to identify possible deficiencies in health care delivery.

Adolescent↗
PubMed2000

Regional trend variations in infant mortality due to perinatal conditions in the Netherlands.

CONDENSATION: In the Netherlands, regional variations in trends in infant mortality due to perinatal conditions (1984-1994) exist, which could not be explained by health care characteristics (i.e., place or supervision of delivery and the presence of specialised neonatal care). The only sociodemographic factor that showed a consistent correlation with mortality was the percentage of Roman Catholic inhabitants of a region. OBJECTIVE: To describe and explain regional variations in trends in infant mortality due to perinatal conditions. STUDY DESIGN: A mixed (geographical and temporal) ecological design has been used. Infant mortality due to perinatal conditions was defined as mortality in the first year of life caused by diseases of the newborn period (chapter XV of the ICD-9). Trends in sex-adjusted mortality for the period 1984-1994 as well as mortality levels at the start of this period were calculated using log linear regression. Linear regression was used to examine the association between mortality trends and starting levels on the one hand and both health care and sociodemographic factors on the other. RESULTS: Statistically significant variations in mortality trends were found between regions. The trends in the two Southern regions were found to deviate significantly from the national trend. No strong association was found between mortality and each of the health care factors (i.e. place and/or supervision of delivery and the presence of specialised neonatal care). The only sociodemographic factor that showed consistent results was the percentage of Roman Catholic inhabitants of a region: A higher percentage in 1985 was associated with a higher mortality in 1985 and a stronger mortality decline during the period 1984-1994. This association could not be explained by parity or the age of the mother. CONCLUSIONS: Regional differences in trends in infant mortality due to perinatal conditions in the Netherlands could not be explained by variations in health care factors. This is an important finding as the Dutch system of obstetric care, that includes a considerable number of home deliveries, has been subject to much debate. Further research that includes other causes of death and determinants is needed to unravel the causes of the trend variations.

Adult↗
PubMed2002

Cost-effectiveness of targeting patients undergoing cardiac surgery for therapy with intravenous amiodarone to prevent atrial fibrillation.

OBJECTIVES: This study evaluated the cost-effectiveness of administering prophylactic intravenous (IV) amiodarone therapy to patients undergoing cardiac surgery according to their predicted risk of postoperative atrial fibrillation. BACKGROUND: Atrial fibrillation (AF) is a common complication of cardiovascular surgery that is associated with a significant increase in hospitalization costs. Intravenous amiodarone has been shown to decrease the incidence of postoperative AF. METHODS: All 8,709 patients who underwent coronary artery bypass grafting (CABG), 1,217 patients who underwent valve replacement and 624 patients who underwent CABG and valve replacement procedures (CABG + valve) from January 1, 1994, to June 30, 1999, at Emory University Hospitals were studied. Models predicting the risk of AF were developed using logistic regression; linear regression was used to estimate the influence of AF on hospitalization costs. Cost-effectiveness was evaluated for patient subsets identified according to their predicted risk of AF. RESULTS: Postoperative AF rates were 17.7% for CABG, 24.6% for valve and 33.8% for CABG + valve. Using 5,000 dollars as an acceptable cost per episode of atrial fibrillation averted, prophylactic IV amiodarone in CABG patients was not found to be cost-effective. Therapy would be recommended for roughly 5% of valve patients with a predicted risk of atrial fibrillation >45%, and roughly two thirds of CABG + valve patients who have a predicted risk of >30%. CONCLUSIONS: Cost-effectiveness of prophylactic IV amiodarone varies according to type of surgery and the predicted risk of atrial fibrillation. Older patients undergoing valve replacement, particularly those with a history of chronic obstructive pulmonary disease, and those undergoing concomitant CABG are likely to be the most appropriate candidates for IV amiodarone therapy in the perioperative period.

Aged↗
PubMed2004

Non-linear cardiac output dynamics during ramp-incremental cycle ergometry.

Published literature asserts that cardiac output (Q(.) = V(.) >O(2)x1/C((a-v))O(2)) increases as a linear function of oxygen uptake with a slope of approximately 5-6 during constant work rate exercise. However, we have previously demonstrated that C((a-v))O(2) has a linear relationship as a function of V(.)O(2) during progressively increasing work rate incremental exercise. Therefore, we hypothesized that Q(.) may indeed have a non-linear relationship with respect to V(.)O(2) during incremental, non-steady state exercise. To investigate this hypothesis, we performed five maximal progressive work rate exercise studies in healthy human subjects. Q(.) was determined every minute during exercise using measured breath-by-breath V(.) >O(2), and arterial and pulmonary artery measurements of PO(2), hemoglobin saturation, and content. Q(.) was plotted as a function of V(.) >O(2) and the linear and non-linear (first order exponential and hyperbolic) fits determined for each subject. Tests for linearity were performed by assessing the significance of the quadratic terms added to the linear relation using least squares estimation in linear regression. Linearity was inadequate in all cases (group P<0.0001). We conclude that cardiac output is a non-linear function of V(.)O(2 )during ramp-incremental exercise; the pattern of non-linearity suggests that while the kinetics of Q(.) > are faster than those of V(.) >O(2) they progressively slow as work rate (and V(.) >O(2)) increases.

Adult↗
PubMed2004

Incidence of retinoblastoma from 1958 to 1998 in Northern Europe: advantages of birth cohort analysis.

PURPOSE: To assess change in incidence of retinoblastoma in Northern Europe and to compare commonly used methods for calculating its incidence against birth cohort analysis. DESIGN: Retrospective cohort study. PARTICIPANTS: Individual and pooled data of 291 Swedish and 174 Finnish children diagnosed with retinoblastoma between 1958 and 1998. MAIN OUTCOME MEASURES: Incidence per 1 million children younger than 5 years of age (37 812 035 person- years at risk) and per 100 000 live births (7 152 265 live-born children at risk). METHODS: Data were from Swedish and Finnish Cancer Registries and corresponding national referral centers for retinoblastoma. Incidence was calculated both by standard analysis per children younger than 5 years of age and per live births, and by birth cohort analysis. Curves were smoothed with robust, locally weighted regression. Linear regression was used to fit pooled data. RESULTS: The number of new retinoblastoma cases per year ranged from 0 to 13 (1-13 per birth cohort) in Sweden and from 0 to 10 in Finland (1-9 per birth cohort). The mean incidence was 11.8 (95% confidence interval [CI], 10.5-13.1) and 11.2 (95% CI, 9.4-13.0) per 1 million children younger than 5 years of age in Sweden and Finland, respectively, and 6.7 (95% CI, 5.9-7.5) and 6.2 (95% CI, 5.3-7.2) per 100 000 live births, respectively. Analysis based on year of diagnosis suggested moderate increase in incidence since 1990, but by birth cohort analysis, incidence rates were stable for both countries. The pooled incidence by birth cohort was 6.0 (95% CI, 5.4-6.6) per 100 000 live births, corresponding to 1 in 16 642 (95% CI, 15 105-18 528) live births. CONCLUSIONS: The data suggest that the incidence of retinoblastoma is stable in Northern Europe. Analysis based on birth cohort is recommended for future epidemiologic studies, because it minimizes the effect of variable age at diagnosis of this developmental cancer and results in less variable incidence rates than standard analysis based on year of diagnosis.

Adolescent↗